Vintage Synth Repair

If you are going to own and maintain a Prophet 10 then is is definately worth having the 
correct drawings for it, so it would be a good idea to get them I think.

--- In vintagesynthrepair@yahoogroups.com, "Frank Simon" <fsimon001@...> wrote:
>
> Steve,
> I got this from someone on the Web. Do you feel I need what he is selling?
> This is his pitch:
> [From what I've been told now, it seems you need the Rev. 3.3 
> Service manual, plus the P10 addendum.
> 
> I can provide the PDF files for the P5 Rev. 3.3 service manual
> and the P10 Service Addendum on my website for you to download for a 
> total of $ 20.]
> 
> 
> 
>   ----- Original Message ----- 
>   From: thirteentech 
>   To: vintagesynthrepair@yahoogroups.com 
>   Sent: Wednesday, April 30, 2008 10:38 PM
>   Subject: [vintagesynthrepair] Re: Prophet 10 repair (was Hi from a new member).
> 
> 
>   It sounds like you know what you're doing, the only way to test the EPROM's (apart 
from 
>   hung data or address lines) is to replace them. Have a look on some of the Prophet 
>   websites to see if anyone has posted the EPROM images, but first eliminate everything 
>   else by thorough faultfinding procedures.
> 
>   --- In vintagesynthrepair@yahoogroups.com, "Frank Simon" <fsimon001@> wrote:
>   >
>   > Steve,
>   > Since I downloaded the P5 service manual (it only goes to rev 3.2) I have a much 
better 
>   understanding of the system. It helps to have a good service manual. Before all I had 
was a 
>   schematic only of the P10. I do have an Oscope and I may borrow a logic analyzer. I 
have 
>   good troubleshooting skills. I have little microprocessor troubleshooting but as long as 
I 
>   understand the flow, I know address and data bus and when a part of the system is 
>   Computer Select from a Memory Address Decoder A10-A12 to take Adress from CPU 
to 
>   output data to Data Bus. So I am going to probe the tune section (since you said that is 
>   first operation) look for CS to the timer and status output then work towards the 
EPROM if 
>   it gets CS. I think I will put a wire on CPU reset to ground instead of cycling power 
switch. 
>   > 
>   > In general I need to know sequence of events but isn't that from firmware 
programmed 
>   in the EPROM. That is where I need help. How do I know it is programmed properly.
>   > 
>   > ----- Original Message ----- 
>   > From: thirteentech 
>   > To: vintagesynthrepair@yahoogroups.com 
>   > Sent: Wednesday, April 30, 2008 6:06 PM
>   > Subject: [vintagesynthrepair] Re: Prophet 10 repair (was Hi from a new member).
>   > 
>   > 
>   > Yes, it sounds like your computer is not running, and you are getting random LED's 
>   when 
>   > you power up. Do you have an oscilloscope and any experience troubleshooting 
>   > microprocessors? If not, you will need someone who can I think.
>   > 
>   > --- In vintagesynthrepair@yahoogroups.com, "fsimon100" <fsimon001@> wrote:
>   > >
>   > > Steve,
>   > > I down loaded a P5 service manual. It is very helpful and much 
>   > > better print than the P10 schematic I have. I can now see the what 
>   > > you meant by the subtractive synthesis gated by the CEM3310. I just 
>   > > need to isolate why the control panel is dead. I have two LEDs light 
>   > > up when I power up but not everytime I power up. I know the CPU is 
>   > > good now. I'm thinking it has to be on the computer system and not 
>   > > the Analog or synth section. Would you agree. Thanks for your help 
>   > > and patience
>   > > 
>   > > 
>   > > --- In vintagesynthrepair@yahoogroups.com, "thirteentech" 
>   > > <thirteentech@> wrote:
>   > > >
>   > > > Well, I can't guarantee that the machine will run OK without the 
>   > > sequencer, but it probably will, and is 
>   > > > worth a try. I see one P10 for every dozen P5's that I service, so 
>   > > unfortunately I don't have a P10 in the 
>   > > > shop to look at directly. 
>   > > > 
>   > > > As for service manuals, Sequential put out a large folder called 
>   > > the "Prophet Synthesizer and 
>   > > > Polyphonic Sequencer System Technical Manual" which has the 
>   > > Prophet 5 REV 3.0, 3.1 and 3.2 service, 
>   > > > programming guide and schematics, the Prophet 10 theory, 
>   > > schematics and parts list, and the Poly 
>   > > > Sequencer theory and schematics, the Prophet 5 remote service and 
>   > > schematics, and update mod info 
>   > > > for the Rev 3.3 update. much of the P10 section refers to the P5 
>   > > schematics.
>   > > > 
>   > > > The basic differences between a P10 and a Rev 3.x P5 are: The 
>   > > P10's master tune is digitized whereas 
>   > > > the P5's is connected directly to the common analog circuit. The 
>   > > P10 also has 6k of PROM compared to 
>   > > > the P5's 2k to allow it to scan the keys and controls better to 
>   > > keep scanning delays down to a 
>   > > > maximum of 11ms. 
>   > > > 
>   > > > So if the machine is frozen, the best thing to do is to just start 
>   > > making sure that every CPU line looks 
>   > > > like it is doing the right thing, and then move on to each device 
>   > > on the data bus and see if it's chip 
>   > > > select input is working. If it is and you have gone through all of 
>   > > the basic troubleshooting that you 
>   > > > would expect to do with a microprocessor circuit, and it all seems 
>   > > to be running, then take a look a 
>   > > > the autotune circuitry, although this is unlikely as your TUNE led 
>   > > is not coming on.
>   > > > 
>   > > > 
>   > > > --- In vintagesynthrepair@yahoogroups.com, "fsimon100" 
>   > > <fsimon001@> wrote:
>   > > > >
>   > > > > Steve,
>   > > > > Thanks. Are these diagnostics tribal knowledge or are they 
>   > > > > documented in a manual. I do not hve the P10 manual. If I find 
>   > > one 
>   > > > > will it give me diags. 
>   > > > > 
>   > > > > I have disconnected the Seq board so obviously your saying it 
>   > > will 
>   > > > > run without it. Great. One system removed. I do have a z80 CPU 
>   > > to 
>   > > > > swap out. 
>   > > > > 
>   > > > > I was thinking the record switch was a microswitch so to enable 
>   > > > > would be a pull down or pull up Res on PCB.
>   > > > > 
>   > > > > --- In vintagesynthrepair@yahoogroups.com, "thirteentech" 
>   > > > > <thirteentech@> wrote:
>   > > > > >
>   > > > > > I am not certain what the P10's last OS revision was, the 
>   > > highest 
>   > > > > that I have seen on a 
>   > > > > > Prophet 5 is V9.3. Looking at the schematics of the 2 machines 
>   > > the 
>   > > > > CPU board is similar, 
>   > > > > > they do have different EPROM and NV RAM chips. Also the P 10 
>   > > has 
>   > > > > different scanning 
>   > > > > > circuitry because it would have an unacceptable scan delay 
>   > > with 2 
>   > > > > keyboards as opposed 
>   > > > > > to the P5's 1 keyboard, which has a maximum delay of 10 Ms. 
>   > > The 
>   > > > > scanner also scans all of 
>   > > > > > the buttons during each cycle.
>   > > > > > 
>   > > > > > For what it's worth (not knowing if it also applies to the P-
>   > > 10), 
>   > > > > to enter the CPU and RAM 
>   > > > > > test on a late rev. Prophet 5, turn off the power, put the 
>   > > record 
>   > > > > switch to "enabled", and 
>   > > > > > jumper test point 304 (MEM TEST) to plus 5V, then turn on. The 
>   > > > > machine starts 
>   > > > > > sequentially flashing it's LED's, to then enter the memory 
>   > > test, 
>   > > > > press TUNE. It runs through 
>   > > > > > 4 tests, counting 1-4 as it does them, and finishes on 0, 
>   > > > > indication no failures. If it stops 
>   > > > > > on 1-4, it is indication a failure of either the scratchpad 
>   > > RAM, 
>   > > > > NV RAM, PROM or 8253 
>   > > > > > timer (1,2,3 and 4).
>   > > > > > 
>   > > > > > I haven't used these tests on a P10, so I don't know if they 
>   > > > > apply, but otherwise maybe the 
>   > > > > > best idea would be to disconnect the sequencer board and just 
>   > > > > start the usual traditional 
>   > > > > > checking of the main CPU lines to see if any of the data or 
>   > > > > address lines are hung.
>   > > > > > 
>   > > > > > 
>   > > > > > --- In vintagesynthrepair@yahoogroups.com, "Frank Simon" 
>   > > > > <fsimon001@> wrote:
>   > > > > > >
>   > > > > > > On Brd 3 there are three EPROMs with the Z80 CPU. The first 
>   > > > > says: 0 TEN 5.0, second 
>   > > > > > says: 1 TEN 5.0, third says: 2 TEN 5.0 on their stickers. 
>   > > > > > > 
>   > > > > > > On Brd 9 there is one EPROM with the Z80 CPU. The sticker on 
>   > > it 
>   > > > > is not too legible what I 
>   > > > > > do see is: SEQ (that part is clear) below it say C1 or C.1 or 
>   > > I 
>   > > > > was thinking maybe 2.1( if 
>   > > > > > upper half of 2 was missing). 
>   > > > > > > 
>   > > > > > > Both Z80s on pin 6 CLK have 2.5MHz clock at about 4v p-p. 
>   > > and 5v 
>   > > > > dc on pin 11. Does 
>   > > > > > the EPROM lose all programming if battery dies? If so how do 
>   > > you 
>   > > > > reload? Will keyboard 
>   > > > > > not boot without EPROM program. My friend today is bringing me 
>   > > a 
>   > > > > Z80 CPU in so I can 
>   > > > > > swap out.
>   > > > > > > 
>   > > > > > > 
>   > > > > > > 
>   > > > > > > ----- Original Message ----- 
>   > > > > > > From: thirteentech 
>   > > > > > > To: vintagesynthrepair@yahoogroups.com 
>   > > > > > > Sent: Monday, April 28, 2008 7:47 AM
>   > > > > > > Subject: [vintagesynthrepair] Re: Prophet 10 repair (was 
>   > > Hi 
>   > > > > from a new member).
>   > > > > > > 
>   > > > > > > 
>   > > > > > > What is written on the stickers on the EPROMS?
>   > > > > > > 
>   > > > > > > --- In vintagesynthrepair@yahoogroups.com, "Frank Simon" 
>   > > > > <fsimon001@> wrote:
>   > > > > > > >
>   > > > > > > > I don't know. How do I find this out.
>   > > > > > > > ----- Original Message ----- 
>   > > > > > > > From: Stephen Jones 
>   > > > > > > > To: vintagesynthrepair@yahoogroups.com 
>   > > > > > > > Sent: Monday, April 28, 2008 12:14 AM
>   > > > > > > > Subject: Re: [vintagesynthrepair] Re: Prophet 10 repair 
>   > > (was 
>   > > > > Hi from a new member).
>   > > > > > > > 
>   > > > > > > > 
>   > > > > > > > Which Rev. Processor board do you have? All the Rev.
>   > > > > > > > 3.1 and 3.2 Prophet 5's have a built in memory test,
>   > > > > > > > and latest software versions also have a basic CPU
>   > > > > > > > test. Which software version do you have?
>   > > > > > > > 
>   > > > > > > > --- Frank Simon <fsimon001@> wrote:
>   > > > > > > > 
>   > > > > > > > > Steve,
>   > > > > > > > > The TUNE LED does not come on. Since I am four
>   > > > > > > > > CEM3310s short, should certain slots be populated
>   > > > > > > > > just to get boot up? All the supplies are up. I am
>   > > > > > > > > suspicious of PCB9 due to the 12v applied and you
>   > > > > > > > > mentioned EQ board. There are a couple IC's that are
>   > > > > > > > > warm on the EQ board but not so hot I can't keep my
>   > > > > > > > > finger on it. Can you offer a couple key
>   > > > > > > > > troubleshooting spots for measurements to help me
>   > > > > > > > > isolate this? I'm assuming I have no way to bless
>   > > > > > > > > the Processor. All I have is an Oscope, function
>   > > > > > > > > generator, and multimeter.
>   > > > > > > > > 
>   > > > > > > > > 
>   > > > > > > > > ----- Original Message ----- 
>   > > > > > > > > From: thirteentech 
>   > > > > > > > > To: vintagesynthrepair@...m 
>   > > > > > > > > Sent: Monday, April 21, 2008 12:21 AM
>   > > > > > > > > Subject: [vintagesynthrepair] Re: Prophet 10
>   > > > > > > > > repair (was Hi from a new member).
>   > > > > > > > > 
>   > > > > > > > > 
>   > > > > > > > > When you turn the machine on the front panel
>   > > > > > > > > should be dark with the exception of the 
>   > > > > > > > > [TUNE] switch. The machine boots into it's
>   > > > > > > > > autotune mode and suppresses all of the front 
>   > > > > > > > > panel lights and controls while it does so. it
>   > > > > > > > > should take 8-10 seconds if the machine is 
>   > > > > > > > > functional, longer if voices are way out of
>   > > > > > > > > calibration.
>   > > > > > > > > 
>   > > > > > > > > Does the TUNE button LED come on when you power
>   > > > > > > > > up?
>   > > > > > > > > 
>   > > > > > > > > --- In vintagesynthrepair@yahoogroups.com, "Frank
>   > > > > > > > > Simon" <fsimon001@> wrote:
>   > > > > > > > > >
>   > > > > > > > > > Steve,
>   > > > > > > > > > I have all power supplies in order. There is
>   > > > > > > > > power to all boards. When I turn it on 
>   > > > > > > > > shouldn't it boot up and LED's cycle on or blink
>   > > > > > > > > or even be switchable? The panel is dead. 
>   > > > > > > > > Does this sound like processor to you?
>   > > > > > > > > > 
>   > > > > > > > > > ----- Original Message ----- 
>   > > > > > > > > > From: thirteentech 
>   > > > > > > > > > To: vintagesynthrepair@yahoogroups.com 
>   > > > > > > > > > Sent: Saturday, April 19, 2008 1:07 AM
>   > > > > > > > > > Subject: [vintagesynthrepair] Re: Prophet 10
>   > > > > > > > > repair (was Hi from a new member).
>   > > > > > > > > > 
>   > > > > > > > > > 
>   > > > > > > > > > Each of the 5 voices on each voice board has two
>   > > > > > > > > CEM3310 envelope generators. One 
>   > > > > > > > > > controls the volume envelope of the voice, and
>   > > > > > > > > the other controls the filter cutoff of 
>   > > > > > > > > the 
>   > > > > > > > > > voice if you bring up the filter envelope
>   > > > > > > > > modulation control. If the 3310's in the filter 
>   > > > > > > > > > control line are faulty it should only manifest
>   > > > > > > > > when you turn on the filter envelope 
>   > > > > > > > > > modulation. If this is off then the voice should
>   > > > > > > > > sound if the VCF cutoff pot is set open. 
>   > > > > > > > > If 
>   > > > > > > > > > you have bad 3310's in the VCA envelpoe
>   > > > > > > > > position, the voice won't sound.
>   > > > > > > > > > 
>   > > > > > > > > > I am assuming that your P10 has Rev 3.x Prophet
>   > > > > > > > > 5 voice boards in it, because in the 
>   > > > > > > > > > Sequential System Technical manual which covers
>   > > > > > > > > all Prophets from Rev 3.0-3.2, the 
>   > > > > > > > > > Prophet 10 and the Poly Sequencer, they all use
>   > > > > > > > > the same basic voice board. So for 
>   > > > > > > > > > instance, in Voice 1 of the voice board, U412 is
>   > > > > > > > > the amplifier envelope generator, and 
>   > > > > > > > > > U417 is the filter envelope generator.
>   > > > > > > > > > 
>   > > > > > > > > > --- In vintagesynthrepair@yahoogroups.com,
>   > > > > > > > > "Frank Simon" <fsimon001@> wrote:
>   > > > > > > > > > >
>   > > > > > > > > > > Steve,
>   > > > > > > > > > > I am pleased to know there is a technique to
>   > > > > > > > > troube this with the bad ICs. I hope to 
>   > > > > > > > > get 
>   > > > > > > > > > to that point soon. If I remember there were no
>   > > > > > > > > LEDs on control panel lit when turned 
>   > > > > > > > > on. 
>   > > > > > > > > > Is there a local spot that isolates that
>   > > > > > > > > symptom? I haven't removed the top boards yet. 
>   > > > > > > > > > Hopefully I can handle that. 
>   > > > > > > > > > > 
>   > > > > > > > > > > I guess I am confused on VCA and VCF envelope
>   > > > > > > > > positions. Can you give me a 
>   > > > > > > > > > explanation of how to determine which state the
>   > > > > > > > > IC is in.
>   > > > > > > > > > > Frank
>   > > > > > > > > > > 
>   > > > > > > > > > > 
>   > > > > > > > > > > 
>   > > > > > > > > > > 
>   > > > > > > > > > > ----- Original Message ----- 
>   > > > > > > > > > > From: thirteentech 
>   > > > > > > > > > > To: vintagesynthrepair@yahoogroups.com 
>   > > > > > > > > > > Sent: Friday, April 18, 2008 6:04 PM
>   > > > > > > > > > > Subject: [vintagesynthrepair] Prophet 10
>   > > > > > > > > repair (was Hi from a new member).
>   > > > > > > > > > > 
>   > > > > > > > > > > 
>   > > > > > > > > > > Well, if you have metered all of the power
>   > > > > > > > > supply rails in the machine, and are 
>   > > > > > > > > satisfied 
>   > > > > > > > > > > that they are all in spec, then go ahead and
>   > > > > > > > > put the voice boards back in. Remove the 
>   > > > > > > > > > > known bad 3310's, and if any were in VCA
>   > > > > > > > > ENVELOPE positions, replace them with 
>   > > > > > > > > > 3310's 
>   > > > > > > > > > > from VCF ENVELOPE positions. This will allow
>   > > > > > > > > you to set up a patch with the VCF 
>   > > > > > > > > > envelopes 
>   > > > > > > > > > > control turned off and still have all of the
>   > > > > > > > > voices audible so that you can hear is all 
>   > > > > > > > > the 
>   > > > > > > > > > > voices are working. 
>   > > > > > > > > > > 
>   > > > > > > > > > > The EQ board on P10's was another source of
>   > > > > > > > > problems too of you don't get any 
>   > > > > > > > > > sound. 
>   > > > > > > > > > > 
>   > > > > > > > > > > As for the sequencer board, the best way to
>   > > > > > > > > test functionality is to get the rest of the 
>   > > > > > > > > > > machine basically playing and then just try
>   > > > > > > > > out the sequencer and see if it loads and 
>   > > > > > > > > > plays 
>   > > > > > > > > > > back notes.
>   > > > > > > > > > > 
>   > > > > > > > > > > Sounds like your power supply lines are the
>   > > > > > > > > most important issue, so as I mentioned, 
>   > > > > > > > > > put 
>   > > > > > > > > > > all your attention on them being correct
>   > > > > > > > > first. There are lots of CEM3310's in the 
>   > > > > > > > > > machine, 
>   > > > > > > > > > > so you can definately get the machine playing
>   > > > > > > > > without 4 of them, just make sure that 
>   > > > > > > > > > there 
>   > > > > > > > > > > are good chips in the VCA envelope positions.
>   > > > > > > > > > > 
>   > > > > > > > > > > Steve.
>   > > > > > > > > > > 
>   > > > > > > > > > > --- In vintagesynthrepair@yahoogroups.com,
>   > > > > > > > > "fsimon100" <fsimon001@> wrote:
>   > > > > > > > > > > >
>   > > > > > > > > > > > Steve,
>   > > > > > > > > > > > Thanks, obviously I have a Rev 1. My
>   > > > > > > > > schematic is a scanned copy and 
>   > > > > > > > > > > > didn't see the note and still don't but I
>   > > > > > > > > know you are correct. What 
>   > > > > > > > > > > > do you think I could have damaged with the
>   > > > > > > > > 12v I put in? Like I said 
>   > > > > > > > > > > > U931 shorted and got hot. I know that may be
>   > > > > > > > > a tough question 
>   > > > > > > > > > > > without personally probing but the board is
>   > > > > > > > > holding the 5v now. How 
>   > > > > > > > > > > > could I verify functionality of PCB9. 
>   > > > > > > > > > > > 
>   > > > > > > > > > > > Also if I put one of the voice boards in
>   > > > > > > > > with 4 CEM3310 missing can 
>   > > > > > > > > > > > I continue troubleshooting? Is there a
>   > > > > > > > > chance I could get confidence 
>   > > > > > > > > > > > from a oscope or panel lights before I buy
>   > > > > > > > > four CEMs.
>   > > > > > > > > > > > 
>   > > > > > > > > > > > --- In vintagesynthrepair@yahoogroups.com,
>   > > > > > > > > "thirteentech" 
>   > > > > > > > > > > > <thirteentech@> wrote:
>   > > > > > > > > > > > >
>   > > > > > > > > > > > > The Prophet 10 service manual shows that
>   > > > > > > > > U603 is a +5V for rev. 1 
>   > > > > > > > > > > > machines, or +12V for Rev. 0 machines. It
>   > > > > > > > > looks like that supply is 
>   > > > > > > > > > > > for either a 5V 
>   > > > > > > > > > > > > cassette drive or a 12V wafer drive
>   > > > > > > > > depending on which version of 
>   > > > > > > > > > > > machine you have, but the schematic also
>   > > > > > > > > shows a note on the 5.6V 
>   > > > > > > > > > > > rail of the PSU 
>   > > > > > > > > > > > > saying: "To PCB 9, Rev 0, not used for Rev
>   > > > > > > > > 1". So depending on 
>   > > > > > > > > > > > whether you have a Rev 0 or Rev 1, there
>   > > > > > > > > will be different supplies 
>   > > > > > > > > > > > on P603 pins 2 and 
>   > > > > > > > > > > > > 3.
>   > > > > > > > > > > > > 
>   > > > > > > > > > > > > 
>   > > > > > > > > > > > > --- In vintagesynthrepair@yahoogroups.com,
>   > > > > > > > > "Frank Simon" 
>   > > > > > > > > > > > <fsimon001@> wrote:
>   > > > > > > > > > > > > >
>   > > > > > > > > > > > > > Hi Steve,
>   > > > > > > > > > > > > > I have a manual I downloaded from
>   > > > > > > > > paintingwithsound.com. It is 
>   > > > > > > > > > > > hard to read. I was a little disappointed
>   > > > > > > > > when 
>   > > > > > > > === message truncated ===
>   > > > > > > > 
>   > > > > > > > 
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