Vintage Synth Repair

> Carefully take off and reset all your connectors carefully (oxidation issue?
> Unless it's a Hurricaine Katrina dx-7 or deep humid south, then it's a true
> disaster) and check the battery level on the settings.  Google as it is not
> a well documented button press, but is on the dx-7 sites.
> I think you need to copy memory from the cardridge to RAM or in by sysex.
> It Sounds like its just been off for a very long time.  The build quality is very high.  
> You just need to write in fresh to the memory is my guess.  Oh and do change the battery, simple and off ebay for that.  
> 
> Lorne in Canada (dx-7 w/new battety/lcd/and supermax board)
> 
> From: vintagesynthrepair@yahoogroups.com
> [mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of alesisfusion8hd
> Sent: Monday, March 05, 2012 9:20 PM
> To: vintagesynthrepair@yahoogroups.com
> Subject: [vintagesynthrepair] Looking for DX7 service manual
> 
> Hi group,
> 
> I recently bought a first generation DX7 for $ 50. Problem on startup:
> sometimes starts up OK, sometimes keeps looping, sometimes seems OK but
> actually frozen. 
> When it starts up OK, I found only garbage in the internal memory, but it
> works with the cartridge. It does not memorize my settings, and main output
> seems dead (headphone OK). I've suspected and replaced the battery cell.
> I was able to run the self tests up to test #5 (analog inputs), but I have
> no foot controller to complete this stage.
> I checked the PSU and the voltage source on the main board (+2.5V, +7.5V and
> +5AV) and everything is OK. 
> I suspect a signal is missing on the sub-CPU (6805), or a defective RAM.
> I picked up the schematic and the service manual on Dave Benson's site, but
> it seems to be altered after page 20. All other services manual I found on
> the web has the same issue. Does anyone have a full copy of it?
> 
> Thanks,
> François
>

>
> Hi my friend.
> 
> Unfortunately there is no complete Service manual for DX7 (first edition)
> on the internet.
> 
> Try these :
> 
> 1- Replace all the electrolytic capacitors in the power supply board.
> 2- Send a fresh sound bank from the PC to the keyboard using a midi
> interface.
> 
> I hope it will make your dx7 work properly.
> 
> Good luck.
> Ciro
> 
> On Tue, Mar 6, 2012 at 8:49 AM, alesisfusion8hd <babouche369@...>wrote:
> 
> > **
> >
> >
> > Hi group,
> >
> > I recently bought a first generation DX7 for $ 50. Problem on startup:
> > sometimes starts up OK, sometimes keeps looping, sometimes seems OK but
> > actually frozen.
> > When it starts up OK, I found only garbage in the internal memory, but it
> > works with the cartridge. It does not memorize my settings, and main output
> > seems dead (headphone OK). I've suspected and replaced the battery cell.
> > I was able to run the self tests up to test #5 (analog inputs), but I have
> > no foot controller to complete this stage.
> > I checked the PSU and the voltage source on the main board (+2.5V, +7.5V
> > and +5AV) and everything is OK.
> > I suspect a signal is missing on the sub-CPU (6805), or a defective RAM.
> > I picked up the schematic and the service manual on Dave Benson's site,
> > but it seems to be altered after page 20. All other services manual I found
> > on the web has the same issue. Does anyone have a full copy of it?
> >
> > Thanks,
> > François
> >
> >  
> >
>

hi
there was no complete Service manual for DX7 (first edition)
on the internet.but now it is
i just upload the complete DX-7 first service manual in Files
hope it will help......

--- In vintagesynthrepair@yahoogroups.com, Kashayar Dashtdar wrote:
>
> Hi my friend.
>
> Unfortunately there is no complete Service manual for DX7 (first edition)
> on the internet.
>
> Try these :
>
> 1- Replace all the electrolytic capacitors in the power supply board.
> 2- Send a fresh sound bank from the PC to the keyboard using a midi
> interface.
>
> I hope it will make your dx7 work properly.
>
> Good luck.
> Ciro
>
> On Tue, Mar 6, 2012 at 8:49 AM, alesisfusion8hd wrote:
>
> > **
> >
> >
> > Hi group,
> >
> > I recently bought a first generation DX7 for $ 50. Problem on startup:
> > sometimes starts up OK, sometimes keeps looping, sometimes seems OK but
> > actually frozen.
> > When it starts up OK, I found only garbage in the internal memory, but it
> > works with the cartridge. It does not memorize my settings, and main output
> > seems dead (headphone OK). I've suspected and replaced the battery cell.
> > I was able to run the self tests up to test #5 (analog inputs), but I have
> > no foot controller to complete this stage.
> > I checked the PSU and the voltage source on the main board (+2.5V, +7.5V
> > and +5AV) and everything is OK.
> > I suspect a signal is missing on the sub-CPU (6805), or a defective RAM.
> > I picked up the schematic and the service manual on Dave Benson's site,
> > but it seems to be altered after page 20. All other services manual I found
> > on the web has the same issue. Does anyone have a full copy of it?
> >
> > Thanks,
> > François
> >
> >
> >
>

No virus found in this message.
Checked by AVG - www.avg.com
Version: 2012.0.1913 / Virus Database: 2114/4858 - Release Date: 03/08/12

>
> 
> hi 
> there was no complete Service manual for DX7 (first edition)
> on the internet.but now it is 
> i just upload the complete  DX-7 first service manual in Files
> hope it will help......
> 
> --- In vintagesynthrepair@yahoogroups.com, Kashayar Dashtdar <vdashtdar@> wrote:
> >
> > Hi my friend.
> > 
> > Unfortunately there is no complete Service manual for DX7 (first edition)
> > on the internet.
> > 
> > Try these :
> > 
> > 1- Replace all the electrolytic capacitors in the power supply board.
> > 2- Send a fresh sound bank from the PC to the keyboard using a midi
> > interface.
> > 
> > I hope it will make your dx7 work properly.
> > 
> > Good luck.
> > Ciro
> > 
> > On Tue, Mar 6, 2012 at 8:49 AM, alesisfusion8hd <babouche369@>wrote:
> > 
> > > **
> > >
> > >
> > > Hi group,
> > >
> > > I recently bought a first generation DX7 for $ 50. Problem on startup:
> > > sometimes starts up OK, sometimes keeps looping, sometimes seems OK but
> > > actually frozen.
> > > When it starts up OK, I found only garbage in the internal memory, but it
> > > works with the cartridge. It does not memorize my settings, and main output
> > > seems dead (headphone OK). I've suspected and replaced the battery cell.
> > > I was able to run the self tests up to test #5 (analog inputs), but I have
> > > no foot controller to complete this stage.
> > > I checked the PSU and the voltage source on the main board (+2.5V, +7.5V
> > > and +5AV) and everything is OK.
> > > I suspect a signal is missing on the sub-CPU (6805), or a defective RAM.
> > > I picked up the schematic and the service manual on Dave Benson's site,
> > > but it seems to be altered after page 20. All other services manual I found
> > > on the web has the same issue. Does anyone have a full copy of it?
> > >
> > > Thanks,
> > > François
> > >
> > >  
> > >
> >
>

>
> Thanks man, the tuning procedure is exactly what I was missing. 
> 
> I've cleaned up all the connectors (on main board and sub boards); it didn't solve my issue, but it's a good start. I've also tipped on all chips & components to track any dry joint (I'd this issue on a Kurzweil 1000).
> The issue really resides in the digital part during the init phase. Happily, I've got another DX7, in working condition; I can make some comparisons.
> 
> 
> --- In vintagesynthrepair@yahoogroups.com, "z3sound" <z3sound@> wrote:
> >
> > 
> > hi 
> > there was no complete Service manual for DX7 (first edition)
> > on the internet.but now it is 
> > i just upload the complete  DX-7 first service manual in Files
> > hope it will help......
> > 
> > --- In vintagesynthrepair@yahoogroups.com, Kashayar Dashtdar <vdashtdar@> wrote:
> > >
> > > Hi my friend.
> > > 
> > > Unfortunately there is no complete Service manual for DX7 (first edition)
> > > on the internet.
> > > 
> > > Try these :
> > > 
> > > 1- Replace all the electrolytic capacitors in the power supply board.
> > > 2- Send a fresh sound bank from the PC to the keyboard using a midi
> > > interface.
> > > 
> > > I hope it will make your dx7 work properly.
> > > 
> > > Good luck.
> > > Ciro
> > > 
> > > On Tue, Mar 6, 2012 at 8:49 AM, alesisfusion8hd <babouche369@>wrote:
> > > 
> > > > **
> > > >
> > > >
> > > > Hi group,
> > > >
> > > > I recently bought a first generation DX7 for $ 50. Problem on startup:
> > > > sometimes starts up OK, sometimes keeps looping, sometimes seems OK but
> > > > actually frozen.
> > > > When it starts up OK, I found only garbage in the internal memory, but it
> > > > works with the cartridge. It does not memorize my settings, and main output
> > > > seems dead (headphone OK). I've suspected and replaced the battery cell.
> > > > I was able to run the self tests up to test #5 (analog inputs), but I have
> > > > no foot controller to complete this stage.
> > > > I checked the PSU and the voltage source on the main board (+2.5V, +7.5V
> > > > and +5AV) and everything is OK.
> > > > I suspect a signal is missing on the sub-CPU (6805), or a defective RAM.
> > > > I picked up the schematic and the service manual on Dave Benson's site,
> > > > but it seems to be altered after page 20. All other services manual I found
> > > > on the web has the same issue. Does anyone have a full copy of it?
> > > >
> > > > Thanks,
> > > > François
> > > >
> > > >  
> > > >
> > >
> >
>

>
> Just a follow up. I nailed down my issue to the Sub-CPU 6805 (IC 13) which sometimes does not boot up the right way. When I reset it by grounding pin 28, everything runs smoothly.
> My guess is the condition on power up does not reset the sub-CPU long enough (the 63B03 boots every time; less sensitive? ). That's the best case. The worst case is a defective 6805.
> I changed the 10 uF cap of the Initial Clear, but no success. I'll take a chance and change the 4700 uF on the PSU, or simply switch it with my other DX7.
> 
> --- In vintagesynthrepair@yahoogroups.com, "alesisfusion8hd" <babouche369@> wrote:
> >
> > Thanks man, the tuning procedure is exactly what I was missing. 
> > 
> > I've cleaned up all the connectors (on main board and sub boards); it didn't solve my issue, but it's a good start. I've also tipped on all chips & components to track any dry joint (I'd this issue on a Kurzweil 1000).
> > The issue really resides in the digital part during the init phase. Happily, I've got another DX7, in working condition; I can make some comparisons.
> > 
> > 
> > --- In vintagesynthrepair@yahoogroups.com, "z3sound" <z3sound@> wrote:
> > >
> > > 
> > > hi 
> > > there was no complete Service manual for DX7 (first edition)
> > > on the internet.but now it is 
> > > i just upload the complete  DX-7 first service manual in Files
> > > hope it will help......
> > > 
> > > --- In vintagesynthrepair@yahoogroups.com, Kashayar Dashtdar <vdashtdar@> wrote:
> > > >
> > > > Hi my friend.
> > > > 
> > > > Unfortunately there is no complete Service manual for DX7 (first edition)
> > > > on the internet.
> > > > 
> > > > Try these :
> > > > 
> > > > 1- Replace all the electrolytic capacitors in the power supply board.
> > > > 2- Send a fresh sound bank from the PC to the keyboard using a midi
> > > > interface.
> > > > 
> > > > I hope it will make your dx7 work properly.
> > > > 
> > > > Good luck.
> > > > Ciro
> > > > 
> > > > On Tue, Mar 6, 2012 at 8:49 AM, alesisfusion8hd <babouche369@>wrote:
> > > > 
> > > > > **
> > > > >
> > > > >
> > > > > Hi group,
> > > > >
> > > > > I recently bought a first generation DX7 for $ 50. Problem on startup:
> > > > > sometimes starts up OK, sometimes keeps looping, sometimes seems OK but
> > > > > actually frozen.
> > > > > When it starts up OK, I found only garbage in the internal memory, but it
> > > > > works with the cartridge. It does not memorize my settings, and main output
> > > > > seems dead (headphone OK). I've suspected and replaced the battery cell.
> > > > > I was able to run the self tests up to test #5 (analog inputs), but I have
> > > > > no foot controller to complete this stage.
> > > > > I checked the PSU and the voltage source on the main board (+2.5V, +7.5V
> > > > > and +5AV) and everything is OK.
> > > > > I suspect a signal is missing on the sub-CPU (6805), or a defective RAM.
> > > > > I picked up the schematic and the service manual on Dave Benson's site,
> > > > > but it seems to be altered after page 20. All other services manual I found
> > > > > on the web has the same issue. Does anyone have a full copy of it?
> > > > >
> > > > > Thanks,
> > > > > François
> > > > >
> > > > >  
> > > > >
> > > >
> > >
> >
>

>
> Good troubleshooting! Does the 6805 get warm? Since all the resets come from the same timing cap you could try a 22uf and see if the extra settling time helps. I found the 6805 on Ebay. Not sure if it's the same package...  
> 
> --- In vintagesynthrepair@yahoogroups.com, "alesisfusion8hd" <babouche369@> wrote:
> >
> > Just a follow up. I nailed down my issue to the Sub-CPU 6805 (IC 13) which sometimes does not boot up the right way. When I reset it by grounding pin 28, everything runs smoothly.
> > My guess is the condition on power up does not reset the sub-CPU long enough (the 63B03 boots every time; less sensitive? ). That's the best case. The worst case is a defective 6805.
> > I changed the 10 uF cap of the Initial Clear, but no success. I'll take a chance and change the 4700 uF on the PSU, or simply switch it with my other DX7.
> > 
> > --- In vintagesynthrepair@yahoogroups.com, "alesisfusion8hd" <babouche369@> wrote:
> > >
> > > Thanks man, the tuning procedure is exactly what I was missing. 
> > > 
> > > I've cleaned up all the connectors (on main board and sub boards); it didn't solve my issue, but it's a good start. I've also tipped on all chips & components to track any dry joint (I'd this issue on a Kurzweil 1000).
> > > The issue really resides in the digital part during the init phase. Happily, I've got another DX7, in working condition; I can make some comparisons.
> > > 
> > > 
> > > --- In vintagesynthrepair@yahoogroups.com, "z3sound" <z3sound@> wrote:
> > > >
> > > > 
> > > > hi 
> > > > there was no complete Service manual for DX7 (first edition)
> > > > on the internet.but now it is 
> > > > i just upload the complete  DX-7 first service manual in Files
> > > > hope it will help......
> > > > 
> > > > --- In vintagesynthrepair@yahoogroups.com, Kashayar Dashtdar <vdashtdar@> wrote:
> > > > >
> > > > > Hi my friend.
> > > > > 
> > > > > Unfortunately there is no complete Service manual for DX7 (first edition)
> > > > > on the internet.
> > > > > 
> > > > > Try these :
> > > > > 
> > > > > 1- Replace all the electrolytic capacitors in the power supply board.
> > > > > 2- Send a fresh sound bank from the PC to the keyboard using a midi
> > > > > interface.
> > > > > 
> > > > > I hope it will make your dx7 work properly.
> > > > > 
> > > > > Good luck.
> > > > > Ciro
> > > > > 
> > > > > On Tue, Mar 6, 2012 at 8:49 AM, alesisfusion8hd <babouche369@>wrote:
> > > > > 
> > > > > > **
> > > > > >
> > > > > >
> > > > > > Hi group,
> > > > > >
> > > > > > I recently bought a first generation DX7 for $ 50. Problem on startup:
> > > > > > sometimes starts up OK, sometimes keeps looping, sometimes seems OK but
> > > > > > actually frozen.
> > > > > > When it starts up OK, I found only garbage in the internal memory, but it
> > > > > > works with the cartridge. It does not memorize my settings, and main output
> > > > > > seems dead (headphone OK). I've suspected and replaced the battery cell.
> > > > > > I was able to run the self tests up to test #5 (analog inputs), but I have
> > > > > > no foot controller to complete this stage.
> > > > > > I checked the PSU and the voltage source on the main board (+2.5V, +7.5V
> > > > > > and +5AV) and everything is OK.
> > > > > > I suspect a signal is missing on the sub-CPU (6805), or a defective RAM.
> > > > > > I picked up the schematic and the service manual on Dave Benson's site,
> > > > > > but it seems to be altered after page 20. All other services manual I found
> > > > > > on the web has the same issue. Does anyone have a full copy of it?
> > > > > >
> > > > > > Thanks,
> > > > > > François
> > > > > >
> > > > > >  
> > > > > >
> > > > >
> > > >
> > >
> >
>

>
> Hi Narfman,
> 
> no the 6805 doesn't get warn.
> I plugged another 10uF in parallel (giving 20uF), but no change.
> I tried with another power supply (and another keyboard); still the same.
> 
> What buzzes me is /RES seems to reach +5V in 10ms; the datasheet says it should stay low for 100ms. That's why my manual reset works.
> 
> Strange thing: I wanted to sinc my one-trace small scope to the +5V (to precisely measure the time between power on and RES). I made a small BNC cable (coming from an old network cable), but the cable had a short I was not aware of. I took my supply from CN6 (pin 1=+5V, pin 4=GND). When I plugged it to my working DX7, I had the exact same behaviour.
> 
> --- In vintagesynthrepair@yahoogroups.com, "narfman96" <narfman96@> wrote:
> >
> > Good troubleshooting! Does the 6805 get warm? Since all the resets come from the same timing cap you could try a 22uf and see if the extra settling time helps. I found the 6805 on Ebay. Not sure if it's the same package...  
> > 
> > --- In vintagesynthrepair@yahoogroups.com, "alesisfusion8hd" <babouche369@> wrote:
> > >
> > > Just a follow up. I nailed down my issue to the Sub-CPU 6805 (IC 13) which sometimes does not boot up the right way. When I reset it by grounding pin 28, everything runs smoothly.
> > > My guess is the condition on power up does not reset the sub-CPU long enough (the 63B03 boots every time; less sensitive? ). That's the best case. The worst case is a defective 6805.
> > > I changed the 10 uF cap of the Initial Clear, but no success. I'll take a chance and change the 4700 uF on the PSU, or simply switch it with my other DX7.
> > > 
> > > --- In vintagesynthrepair@yahoogroups.com, "alesisfusion8hd" <babouche369@> wrote:
> > > >
> > > > Thanks man, the tuning procedure is exactly what I was missing. 
> > > > 
> > > > I've cleaned up all the connectors (on main board and sub boards); it didn't solve my issue, but it's a good start. I've also tipped on all chips & components to track any dry joint (I'd this issue on a Kurzweil 1000).
> > > > The issue really resides in the digital part during the init phase. Happily, I've got another DX7, in working condition; I can make some comparisons.
> > > > 
> > > > 
> > > > --- In vintagesynthrepair@yahoogroups.com, "z3sound" <z3sound@> wrote:
> > > > >
> > > > > 
> > > > > hi 
> > > > > there was no complete Service manual for DX7 (first edition)
> > > > > on the internet.but now it is 
> > > > > i just upload the complete  DX-7 first service manual in Files
> > > > > hope it will help......
> > > > > 
> > > > > --- In vintagesynthrepair@yahoogroups.com, Kashayar Dashtdar <vdashtdar@> wrote:
> > > > > >
> > > > > > Hi my friend.
> > > > > > 
> > > > > > Unfortunately there is no complete Service manual for DX7 (first edition)
> > > > > > on the internet.
> > > > > > 
> > > > > > Try these :
> > > > > > 
> > > > > > 1- Replace all the electrolytic capacitors in the power supply board.
> > > > > > 2- Send a fresh sound bank from the PC to the keyboard using a midi
> > > > > > interface.
> > > > > > 
> > > > > > I hope it will make your dx7 work properly.
> > > > > > 
> > > > > > Good luck.
> > > > > > Ciro
> > > > > > 
> > > > > > On Tue, Mar 6, 2012 at 8:49 AM, alesisfusion8hd <babouche369@>wrote:
> > > > > > 
> > > > > > > **
> > > > > > >
> > > > > > >
> > > > > > > Hi group,
> > > > > > >
> > > > > > > I recently bought a first generation DX7 for $ 50. Problem on startup:
> > > > > > > sometimes starts up OK, sometimes keeps looping, sometimes seems OK but
> > > > > > > actually frozen.
> > > > > > > When it starts up OK, I found only garbage in the internal memory, but it
> > > > > > > works with the cartridge. It does not memorize my settings, and main output
> > > > > > > seems dead (headphone OK). I've suspected and replaced the battery cell.
> > > > > > > I was able to run the self tests up to test #5 (analog inputs), but I have
> > > > > > > no foot controller to complete this stage.
> > > > > > > I checked the PSU and the voltage source on the main board (+2.5V, +7.5V
> > > > > > > and +5AV) and everything is OK.
> > > > > > > I suspect a signal is missing on the sub-CPU (6805), or a defective RAM.
> > > > > > > I picked up the schematic and the service manual on Dave Benson's site,
> > > > > > > but it seems to be altered after page 20. All other services manual I found
> > > > > > > on the web has the same issue. Does anyone have a full copy of it?
> > > > > > >
> > > > > > > Thanks,
> > > > > > > François
> > > > > > >
> > > > > > >  
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>

----- Original Message -----

From: alesisfusion8hd

To: vintagesynthrepair@yahoogroups.com

Sent: Sunday, March 11, 2012 9:57 PM

Subject: [vintagesynthrepair] Re: Looking for DX7 service manual

Hi Narfman,

no the 6805 doesn't get warn.
I plugged another 10uF in parallel (giving 20uF), but no change.
I tried with another power supply (and another keyboard); still the same.

What buzzes me is /RES seems to reach +5V in 10ms; the datasheet says it should stay low for 100ms. That's why my manual reset works.

Strange thing: I wanted to sinc my one-trace small scope to the +5V (to precisely measure the time between power on and RES). I made a small BNC cable (coming from an old network cable), but the cable had a short I was not aware of. I took my supply from CN6 (pin 1=+5V, pin 4=GND). When I plugged it to my working DX7, I had the exact same behaviour.

--- In vintagesynthrepair@yahoogroups.com, "narfman96" wrote:
>
> Good troubleshooting! Does the 6805 get warm? Since all the resets come from the same timing cap you could try a 22uf and see if the extra settling time helps. I found the 6805 on Ebay. Not sure if it's the same package...
>
> --- In vintagesynthrepair@yahoogroups.com, "alesisfusion8hd" wrote:
> >
> > Just a follow up. I nailed down my issue to the Sub-CPU 6805 (IC 13) which sometimes does not boot up the right way. When I reset it by grounding pin 28, everything runs smoothly.
> > My guess is the condition on power up does not reset the sub-CPU long enough (the 63B03 boots every time; less sensitive? ). That's the best case. The worst case is a defective 6805.
> > I changed the 10 uF cap of the Initial Clear, but no success. I'll take a chance and change the 4700 uF on the PSU, or simply switch it with my other DX7.
> >
> > --- In vintagesynthrepair@yahoogroups.com, "alesisfusion8hd" wrote:
> > >
> > > Thanks man, the tuning procedure is exactly what I was missing.
> > >
> > > I've cleaned up all the connectors (on main board and sub boards); it didn't solve my issue, but it's a good start. I've also tipped on all chips & components to track any dry joint (I'd this issue on a Kurzweil 1000).
> > > The issue really resides in the digital part during the init phase. Happily, I've got another DX7, in working condition; I can make some comparisons.
> > >
> > >
> > > --- In vintagesynthrepair@yahoogroups.com, "z3sound" wrote:
> > > >
> > > >
> > > > hi
> > > > there was no complete Service manual for DX7 (first edition)
> > > > on the internet.but now it is
> > > > i just upload the complete DX-7 first service manual in Files
> > > > hope it will help......
> > > >
> > > > --- In vintagesynthrepair@yahoogroups.com, Kashayar Dashtdar wrote:
> > > > >
> > > > > Hi my friend.
> > > > >
> > > > > Unfortunately there is no complete Service manual for DX7 (first edition)
> > > > > on the internet.
> > > > >
> >; > > > Try these :
> > > > >
> > > > > 1- Replace all the electrolytic capacitors in the power supply board.
> > > > > 2- Send a fresh sound bank from the PC to the keyboard using a midi
> > > > > interface.
> > > > >
> > > > > I hope it will make your dx7 work properly.
> > > > >
> >; > > > Good luck.
> > > > > Ciro
> >; > > >
> > > > > On Tue, Mar 6, 2012 at 8:49 AM, alesisfusion8hd wrote:
> > > > >
> > > > > > **
> > > > > >
> > > > > >
> > > > > > Hi group,
> > > > > >
> > > > > > I recently bought a first generation DX7 for $ 50. Problem on startup:
> > > > > > sometimes starts up OK, sometimes keeps looping, sometimes seems OK but
> > > > > > actually frozen.
> > > > > > When it starts up OK, I found only garbage in the internal memory, but it
> > > > > > works with the cartridge. It does not memorize my settings, and main output
> > > > > > seems dead (headphone OK). I've suspected and replaced the battery cell.
> > > > > > I was able to run the self tests up to test #5 (analog inputs), but I have
> > > > > > no foot controller to complete this stage.
> > > > > > I checked the PSU and the voltage source on the main board (+2.5V, +7.5V
> > > > > > and +5AV) and everything is OK.
> > > > > > I suspect a signal is missing on the sub-CPU (6805), or a defective RAM.
> > > > > > I picked up the schematic and the service manual on Dave Benson's site,
> > > > > > but it seems to be altered after page 20. All other services manual I found
> > > > > > on the web has the same issue. Does anyone have a full copy of it?
> > > > > >
> > > > > > Thanks,
> > > > > > François
> > > > > >
> > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>

>
> At least it isn't trying to cook your breakfast...
> 
> Is ZD1 the 6.2 zener on the power board shorted? Also have you checked the 39k and 82k actual values? Somehow the turn on is way too fast. I worked on a Digitech IVL 7000 Pitchrider for 6 months off and on. (It was mine so no customer blues...) Sometimes it would boot most often not. I ultimately found the factory installed a 2.2k feedback resistor in place of a 22k in the slave CPU clock driver circuit. Red,red,orange not red,red,red. "Missed it by that much!" Agent 86.... Ohhhhhhhh Max!  
> 
> --- In vintagesynthrepair@yahoogroups.com, "alesisfusion8hd" <babouche369@> wrote:
> >
> > Hi Narfman,
> > 
> > no the 6805 doesn't get warn.
> > I plugged another 10uF in parallel (giving 20uF), but no change.
> > I tried with another power supply (and another keyboard); still the same.
> > 
> > What buzzes me is /RES seems to reach +5V in 10ms; the datasheet says it should stay low for 100ms. That's why my manual reset works.
> > 
> > Strange thing: I wanted to sinc my one-trace small scope to the +5V (to precisely measure the time between power on and RES). I made a small BNC cable (coming from an old network cable), but the cable had a short I was not aware of. I took my supply from CN6 (pin 1=+5V, pin 4=GND). When I plugged it to my working DX7, I had the exact same behaviour.
> > 
> > --- In vintagesynthrepair@yahoogroups.com, "narfman96" <narfman96@> wrote:
> > >
> > > Good troubleshooting! Does the 6805 get warm? Since all the resets come from the same timing cap you could try a 22uf and see if the extra settling time helps. I found the 6805 on Ebay. Not sure if it's the same package...  
> > > 
> > > --- In vintagesynthrepair@yahoogroups.com, "alesisfusion8hd" <babouche369@> wrote:
> > > >
> > > > Just a follow up. I nailed down my issue to the Sub-CPU 6805 (IC 13) which sometimes does not boot up the right way. When I reset it by grounding pin 28, everything runs smoothly.
> > > > My guess is the condition on power up does not reset the sub-CPU long enough (the 63B03 boots every time; less sensitive? ). That's the best case. The worst case is a defective 6805.
> > > > I changed the 10 uF cap of the Initial Clear, but no success. I'll take a chance and change the 4700 uF on the PSU, or simply switch it with my other DX7.
> > > > 
> > > > --- In vintagesynthrepair@yahoogroups.com, "alesisfusion8hd" <babouche369@> wrote:
> > > > >
> > > > > Thanks man, the tuning procedure is exactly what I was missing. 
> > > > > 
> > > > > I've cleaned up all the connectors (on main board and sub boards); it didn't solve my issue, but it's a good start. I've also tipped on all chips & components to track any dry joint (I'd this issue on a Kurzweil 1000).
> > > > > The issue really resides in the digital part during the init phase. Happily, I've got another DX7, in working condition; I can make some comparisons.
> > > > > 
> > > > > 
> > > > > --- In vintagesynthrepair@yahoogroups.com, "z3sound" <z3sound@> wrote:
> > > > > >
> > > > > > 
> > > > > > hi 
> > > > > > there was no complete Service manual for DX7 (first edition)
> > > > > > on the internet.but now it is 
> > > > > > i just upload the complete  DX-7 first service manual in Files
> > > > > > hope it will help......
> > > > > > 
> > > > > > --- In vintagesynthrepair@yahoogroups.com, Kashayar Dashtdar <vdashtdar@> wrote:
> > > > > > >
> > > > > > > Hi my friend.
> > > > > > > 
> > > > > > > Unfortunately there is no complete Service manual for DX7 (first edition)
> > > > > > > on the internet.
> > > > > > > 
> > > > > > > Try these :
> > > > > > > 
> > > > > > > 1- Replace all the electrolytic capacitors in the power supply board.
> > > > > > > 2- Send a fresh sound bank from the PC to the keyboard using a midi
> > > > > > > interface.
> > > > > > > 
> > > > > > > I hope it will make your dx7 work properly.
> > > > > > > 
> > > > > > > Good luck.
> > > > > > > Ciro
> > > > > > > 
> > > > > > > On Tue, Mar 6, 2012 at 8:49 AM, alesisfusion8hd <babouche369@>wrote:
> > > > > > > 
> > > > > > > > **
> > > > > > > >
> > > > > > > >
> > > > > > > > Hi group,
> > > > > > > >
> > > > > > > > I recently bought a first generation DX7 for $ 50. Problem on startup:
> > > > > > > > sometimes starts up OK, sometimes keeps looping, sometimes seems OK but
> > > > > > > > actually frozen.
> > > > > > > > When it starts up OK, I found only garbage in the internal memory, but it
> > > > > > > > works with the cartridge. It does not memorize my settings, and main output
> > > > > > > > seems dead (headphone OK). I've suspected and replaced the battery cell.
> > > > > > > > I was able to run the self tests up to test #5 (analog inputs), but I have
> > > > > > > > no foot controller to complete this stage.
> > > > > > > > I checked the PSU and the voltage source on the main board (+2.5V, +7.5V
> > > > > > > > and +5AV) and everything is OK.
> > > > > > > > I suspect a signal is missing on the sub-CPU (6805), or a defective RAM.
> > > > > > > > I picked up the schematic and the service manual on Dave Benson's site,
> > > > > > > > but it seems to be altered after page 20. All other services manual I found
> > > > > > > > on the web has the same issue. Does anyone have a full copy of it?
> > > > > > > >
> > > > > > > > Thanks,
> > > > > > > > François
> > > > > > > >
> > > > > > > >  
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>

>
> I like the smell of a cooking CPU in the morning...
> 
> Just checked the resistor values: OK.
> The Zener : I took the entire power board from my working DX7. Same behaviour.
> I made some comparative measurement on power on between my 2 DX7. My scope is DSO 082, I use external triggering (I trigger on CN6, pin 1=+5V) and I measure IC17 pin 9 (/RES). On the working one, I clearly see a spike and then a /RES frankly going high way later (not sure how long; not able nailed it down precisely, but close to 1 sec).
> On my defective, no spike and /RES slowly going high in 10 ms, with a curious wave in the middle.
> 
> The initial clear is really achieved by a few components; TR2, TR4, 4 resistors, a cap and a Schmitt trigger (IC17). A few bucks. I'll probably change them all. If it doesn't work, I'll give a look to a reset chip as adviced by GB.
> 
> --- In vintagesynthrepair@yahoogroups.com, "narfman96" <narfman96@> wrote:
> >
> > At least it isn't trying to cook your breakfast...
> > 
> > Is ZD1 the 6.2 zener on the power board shorted? Also have you checked the 39k and 82k actual values? Somehow the turn on is way too fast. I worked on a Digitech IVL 7000 Pitchrider for 6 months off and on. (It was mine so no customer blues...) Sometimes it would boot most often not. I ultimately found the factory installed a 2.2k feedback resistor in place of a 22k in the slave CPU clock driver circuit. Red,red,orange not red,red,red. "Missed it by that much!" Agent 86.... Ohhhhhhhh Max!  
> > 
> > --- In vintagesynthrepair@yahoogroups.com, "alesisfusion8hd" <babouche369@> wrote:
> > >
> > > Hi Narfman,
> > > 
> > > no the 6805 doesn't get warn.
> > > I plugged another 10uF in parallel (giving 20uF), but no change.
> > > I tried with another power supply (and another keyboard); still the same.
> > > 
> > > What buzzes me is /RES seems to reach +5V in 10ms; the datasheet says it should stay low for 100ms. That's why my manual reset works.
> > > 
> > > Strange thing: I wanted to sinc my one-trace small scope to the +5V (to precisely measure the time between power on and RES). I made a small BNC cable (coming from an old network cable), but the cable had a short I was not aware of. I took my supply from CN6 (pin 1=+5V, pin 4=GND). When I plugged it to my working DX7, I had the exact same behaviour.
> > > 
> > > --- In vintagesynthrepair@yahoogroups.com, "narfman96" <narfman96@> wrote:
> > > >
> > > > Good troubleshooting! Does the 6805 get warm? Since all the resets come from the same timing cap you could try a 22uf and see if the extra settling time helps. I found the 6805 on Ebay. Not sure if it's the same package...  
> > > > 
> > > > --- In vintagesynthrepair@yahoogroups.com, "alesisfusion8hd" <babouche369@> wrote:
> > > > >
> > > > > Just a follow up. I nailed down my issue to the Sub-CPU 6805 (IC 13) which sometimes does not boot up the right way. When I reset it by grounding pin 28, everything runs smoothly.
> > > > > My guess is the condition on power up does not reset the sub-CPU long enough (the 63B03 boots every time; less sensitive? ). That's the best case. The worst case is a defective 6805.
> > > > > I changed the 10 uF cap of the Initial Clear, but no success. I'll take a chance and change the 4700 uF on the PSU, or simply switch it with my other DX7.
> > > > > 
> > > > > --- In vintagesynthrepair@yahoogroups.com, "alesisfusion8hd" <babouche369@> wrote:
> > > > > >
> > > > > > Thanks man, the tuning procedure is exactly what I was missing. 
> > > > > > 
> > > > > > I've cleaned up all the connectors (on main board and sub boards); it didn't solve my issue, but it's a good start. I've also tipped on all chips & components to track any dry joint (I'd this issue on a Kurzweil 1000).
> > > > > > The issue really resides in the digital part during the init phase. Happily, I've got another DX7, in working condition; I can make some comparisons.
> > > > > > 
> > > > > > 
> > > > > > --- In vintagesynthrepair@yahoogroups.com, "z3sound" <z3sound@> wrote:
> > > > > > >
> > > > > > > 
> > > > > > > hi 
> > > > > > > there was no complete Service manual for DX7 (first edition)
> > > > > > > on the internet.but now it is 
> > > > > > > i just upload the complete  DX-7 first service manual in Files
> > > > > > > hope it will help......
> > > > > > > 
> > > > > > > --- In vintagesynthrepair@yahoogroups.com, Kashayar Dashtdar <vdashtdar@> wrote:
> > > > > > > >
> > > > > > > > Hi my friend.
> > > > > > > > 
> > > > > > > > Unfortunately there is no complete Service manual for DX7 (first edition)
> > > > > > > > on the internet.
> > > > > > > > 
> > > > > > > > Try these :
> > > > > > > > 
> > > > > > > > 1- Replace all the electrolytic capacitors in the power supply board.
> > > > > > > > 2- Send a fresh sound bank from the PC to the keyboard using a midi
> > > > > > > > interface.
> > > > > > > > 
> > > > > > > > I hope it will make your dx7 work properly.
> > > > > > > > 
> > > > > > > > Good luck.
> > > > > > > > Ciro
> > > > > > > > 
> > > > > > > > On Tue, Mar 6, 2012 at 8:49 AM, alesisfusion8hd <babouche369@>wrote:
> > > > > > > > 
> > > > > > > > > **
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > Hi group,
> > > > > > > > >
> > > > > > > > > I recently bought a first generation DX7 for $ 50. Problem on startup:
> > > > > > > > > sometimes starts up OK, sometimes keeps looping, sometimes seems OK but
> > > > > > > > > actually frozen.
> > > > > > > > > When it starts up OK, I found only garbage in the internal memory, but it
> > > > > > > > > works with the cartridge. It does not memorize my settings, and main output
> > > > > > > > > seems dead (headphone OK). I've suspected and replaced the battery cell.
> > > > > > > > > I was able to run the self tests up to test #5 (analog inputs), but I have
> > > > > > > > > no foot controller to complete this stage.
> > > > > > > > > I checked the PSU and the voltage source on the main board (+2.5V, +7.5V
> > > > > > > > > and +5AV) and everything is OK.
> > > > > > > > > I suspect a signal is missing on the sub-CPU (6805), or a defective RAM.
> > > > > > > > > I picked up the schematic and the service manual on Dave Benson's site,
> > > > > > > > > but it seems to be altered after page 20. All other services manual I found
> > > > > > > > > on the web has the same issue. Does anyone have a full copy of it?
> > > > > > > > >
> > > > > > > > > Thanks,
> > > > > > > > > François
> > > > > > > > >
> > > > > > > > >  
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>

>
> Maybe try a few reset chips instead of the cap. You can get them in TO-92 transistor packages and DIP too.
> 
>   ----- Original Message ----- 
>   From: alesisfusion8hd 
>   To: vintagesynthrepair@yahoogroups.com 
>   Sent: Sunday, March 11, 2012 9:57 PM
>   Subject: [vintagesynthrepair] Re: Looking for DX7 service manual
> 
> 
>     
>   Hi Narfman,
> 
>   no the 6805 doesn't get warn.
>   I plugged another 10uF in parallel (giving 20uF), but no change.
>   I tried with another power supply (and another keyboard); still the same.
> 
>   What buzzes me is /RES seems to reach +5V in 10ms; the datasheet says it should stay low for 100ms. That's why my manual reset works.
> 
>   Strange thing: I wanted to sinc my one-trace small scope to the +5V (to precisely measure the time between power on and RES). I made a small BNC cable (coming from an old network cable), but the cable had a short I was not aware of. I took my supply from CN6 (pin 1=+5V, pin 4=GND). When I plugged it to my working DX7, I had the exact same behaviour.
> 
>   --- In vintagesynthrepair@yahoogroups.com, "narfman96" <narfman96@> wrote:
>   >
>   > Good troubleshooting! Does the 6805 get warm? Since all the resets come from the same timing cap you could try a 22uf and see if the extra settling time helps. I found the 6805 on Ebay. Not sure if it's the same package... 
>   > 
>   > --- In vintagesynthrepair@yahoogroups.com, "alesisfusion8hd" <babouche369@> wrote:
>   > >
>   > > Just a follow up. I nailed down my issue to the Sub-CPU 6805 (IC 13) which sometimes does not boot up the right way. When I reset it by grounding pin 28, everything runs smoothly.
>   > > My guess is the condition on power up does not reset the sub-CPU long enough (the 63B03 boots every time; less sensitive? ). That's the best case. The worst case is a defective 6805.
>   > > I changed the 10 uF cap of the Initial Clear, but no success. I'll take a chance and change the 4700 uF on the PSU, or simply switch it with my other DX7.
>   > > 
>   > > --- In vintagesynthrepair@yahoogroups.com, "alesisfusion8hd" <babouche369@> wrote:
>   > > >
>   > > > Thanks man, the tuning procedure is exactly what I was missing. 
>   > > > 
>   > > > I've cleaned up all the connectors (on main board and sub boards); it didn't solve my issue, but it's a good start. I've also tipped on all chips & components to track any dry joint (I'd this issue on a Kurzweil 1000).
>   > > > The issue really resides in the digital part during the init phase. Happily, I've got another DX7, in working condition; I can make some comparisons.
>   > > > 
>   > > > 
>   > > > --- In vintagesynthrepair@yahoogroups.com, "z3sound" <z3sound@> wrote:
>   > > > >
>   > > > > 
>   > > > > hi 
>   > > > > there was no complete Service manual for DX7 (first edition)
>   > > > > on the internet.but now it is 
>   > > > > i just upload the complete DX-7 first service manual in Files
>   > > > > hope it will help......
>   > > > > 
>   > > > > --- In vintagesynthrepair@yahoogroups.com, Kashayar Dashtdar <vdashtdar@> wrote:
>   > > > > >
>   > > > > > Hi my friend.
>   > > > > > 
>   > > > > > Unfortunately there is no complete Service manual for DX7 (first edition)
>   > > > > > on the internet.
>   > > > > > 
>   > > > > > Try these :
>   > > > > > 
>   > > > > > 1- Replace all the electrolytic capacitors in the power supply board.
>   > > > > > 2- Send a fresh sound bank from the PC to the keyboard using a midi
>   > > > > > interface.
>   > > > > > 
>   > > > > > I hope it will make your dx7 work properly.
>   > > > > > 
>   > > > > > Good luck.
>   > > > > > Ciro
>   > > > > > 
>   > > > > > On Tue, Mar 6, 2012 at 8:49 AM, alesisfusion8hd <babouche369@>wrote:
>   > > > > > 
>   > > > > > > **
>   > > > > > >
>   > > > > > >
>   > > > > > > Hi group,
>   > > > > > >
>   > > > > > > I recently bought a first generation DX7 for $ 50. Problem on startup:
>   > > > > > > sometimes starts up OK, sometimes keeps looping, sometimes seems OK but
>   > > > > > > actually frozen.
>   > > > > > > When it starts up OK, I found only garbage in the internal memory, but it
>   > > > > > > works with the cartridge. It does not memorize my settings, and main output
>   > > > > > > seems dead (headphone OK). I've suspected and replaced the battery cell.
>   > > > > > > I was able to run the self tests up to test #5 (analog inputs), but I have
>   > > > > > > no foot controller to complete this stage.
>   > > > > > > I checked the PSU and the voltage source on the main board (+2.5V, +7.5V
>   > > > > > > and +5AV) and everything is OK.
>   > > > > > > I suspect a signal is missing on the sub-CPU (6805), or a defective RAM.
>   > > > > > > I picked up the schematic and the service manual on Dave Benson's site,
>   > > > > > > but it seems to be altered after page 20. All other services manual I found
>   > > > > > > on the web has the same issue. Does anyone have a full copy of it?
>   > > > > > >
>   > > > > > > Thanks,
>   > > > > > > François
>   > > > > > >
>   > > > > > > 
>   > > > > > >
>   > > > > >
>   > > > >
>   > > >
>   > >
>   >
>

>
> Update. After leaving the DX7 getting dust on a shelf for months (leaving my workbench for other synths to fix), I finally found the issue; the 10/16 tantalum close to the battery was open. Once replaced, boots up fine. Tantalums are really the plague of old synths...
> 
> --- In vintagesynthrepair@yahoogroups.com, "GB" <grantbt@> wrote:
> >
> > Maybe try a few reset chips instead of the cap. You can get them in TO-92 transistor packages and DIP too.
> > 
> >   ----- Original Message ----- 
> >   From: alesisfusion8hd 
> >   To: vintagesynthrepair@yahoogroups.com 
> >   Sent: Sunday, March 11, 2012 9:57 PM
> >   Subject: [vintagesynthrepair] Re: Looking for DX7 service manual
> > 
> > 
> >     
> >   Hi Narfman,
> > 
> >   no the 6805 doesn't get warn.
> >   I plugged another 10uF in parallel (giving 20uF), but no change.
> >   I tried with another power supply (and another keyboard); still the same.
> > 
> >   What buzzes me is /RES seems to reach +5V in 10ms; the datasheet says it should stay low for 100ms. That's why my manual reset works.
> > 
> >   Strange thing: I wanted to sinc my one-trace small scope to the +5V (to precisely measure the time between power on and RES). I made a small BNC cable (coming from an old network cable), but the cable had a short I was not aware of. I took my supply from CN6 (pin 1=+5V, pin 4=GND). When I plugged it to my working DX7, I had the exact same behaviour.
> > 
> >   --- In vintagesynthrepair@yahoogroups.com, "narfman96" <narfman96@> wrote:
> >   >
> >   > Good troubleshooting! Does the 6805 get warm? Since all the resets come from the same timing cap you could try a 22uf and see if the extra settling time helps. I found the 6805 on Ebay. Not sure if it's the same package... 
> >   > 
> >   > --- In vintagesynthrepair@yahoogroups.com, "alesisfusion8hd" <babouche369@> wrote:
> >   > >
> >   > > Just a follow up. I nailed down my issue to the Sub-CPU 6805 (IC 13) which sometimes does not boot up the right way. When I reset it by grounding pin 28, everything runs smoothly.
> >   > > My guess is the condition on power up does not reset the sub-CPU long enough (the 63B03 boots every time; less sensitive? ). That's the best case. The worst case is a defective 6805.
> >   > > I changed the 10 uF cap of the Initial Clear, but no success. I'll take a chance and change the 4700 uF on the PSU, or simply switch it with my other DX7.
> >   > > 
> >   > > --- In vintagesynthrepair@yahoogroups.com, "alesisfusion8hd" <babouche369@> wrote:
> >   > > >
> >   > > > Thanks man, the tuning procedure is exactly what I was missing. 
> >   > > > 
> >   > > > I've cleaned up all the connectors (on main board and sub boards); it didn't solve my issue, but it's a good start. I've also tipped on all chips & components to track any dry joint (I'd this issue on a Kurzweil 1000).
> >   > > > The issue really resides in the digital part during the init phase. Happily, I've got another DX7, in working condition; I can make some comparisons.
> >   > > > 
> >   > > > 
> >   > > > --- In vintagesynthrepair@yahoogroups.com, "z3sound" <z3sound@> wrote:
> >   > > > >
> >   > > > > 
> >   > > > > hi 
> >   > > > > there was no complete Service manual for DX7 (first edition)
> >   > > > > on the internet.but now it is 
> >   > > > > i just upload the complete DX-7 first service manual in Files
> >   > > > > hope it will help......
> >   > > > > 
> >   > > > > --- In vintagesynthrepair@yahoogroups.com, Kashayar Dashtdar <vdashtdar@> wrote:
> >   > > > > >
> >   > > > > > Hi my friend.
> >   > > > > > 
> >   > > > > > Unfortunately there is no complete Service manual for DX7 (first edition)
> >   > > > > > on the internet.
> >   > > > > > 
> >   > > > > > Try these :
> >   > > > > > 
> >   > > > > > 1- Replace all the electrolytic capacitors in the power supply board.
> >   > > > > > 2- Send a fresh sound bank from the PC to the keyboard using a midi
> >   > > > > > interface.
> >   > > > > > 
> >   > > > > > I hope it will make your dx7 work properly.
> >   > > > > > 
> >   > > > > > Good luck.
> >   > > > > > Ciro
> >   > > > > > 
> >   > > > > > On Tue, Mar 6, 2012 at 8:49 AM, alesisfusion8hd <babouche369@>wrote:
> >   > > > > > 
> >   > > > > > > **
> >   > > > > > >
> >   > > > > > >
> >   > > > > > > Hi group,
> >   > > > > > >
> >   > > > > > > I recently bought a first generation DX7 for $ 50. Problem on startup:
> >   > > > > > > sometimes starts up OK, sometimes keeps looping, sometimes seems OK but
> >   > > > > > > actually frozen.
> >   > > > > > > When it starts up OK, I found only garbage in the internal memory, but it
> >   > > > > > > works with the cartridge. It does not memorize my settings, and main output
> >   > > > > > > seems dead (headphone OK). I've suspected and replaced the battery cell.
> >   > > > > > > I was able to run the self tests up to test #5 (analog inputs), but I have
> >   > > > > > > no foot controller to complete this stage.
> >   > > > > > > I checked the PSU and the voltage source on the main board (+2.5V, +7.5V
> >   > > > > > > and +5AV) and everything is OK.
> >   > > > > > > I suspect a signal is missing on the sub-CPU (6805), or a defective RAM.
> >   > > > > > > I picked up the schematic and the service manual on Dave Benson's site,
> >   > > > > > > but it seems to be altered after page 20. All other services manual I found
> >   > > > > > > on the web has the same issue. Does anyone have a full copy of it?
> >   > > > > > >
> >   > > > > > > Thanks,
> >   > > > > > > François
> >   > > > > > >
> >   > > > > > > 
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