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Thread

Diagnosing non-functional Emax

2014-02-17 by David Sotnick

Hi all,

Now it's my turn… I'm sad to report that my beloved Emax SE Rack which I upgraded to SCSI and slim floppy is no longer booting.

Symptoms are: PSU voltages look good at the drive power connector. All LEDs on the front panel come on at power-on except load and enter. No LCD display and no floppy or CF reader activity. :-(

I have re-seated all cables but have not yet removed and re-seated any socketed ICs. It has just been sitting in a rack, so nothing has been jostled.

Any suggestions on where to start?

-Dave

p.s. even more frustrating: I missed out on a $60 working Emax SE on a local Craig's list ad which posted the day before I discovered my Emax was dead. :-(

Re: [emax] Diagnosing non-functional Emax

2014-02-17 by jammie

sounds like you have lost the 5v connection

the lcd uses 5v the cf card reader uses 5v and the floppy uses 5v

i would check the 5v rail on the psu

Show quoted textHide quoted text

  ----- Original Message ----- 
  From: David Sotnick 
  To: emax@yahoogroups.com 
  Sent: Monday, February 17, 2014 4:25 PM
  Subject: [emax] Diagnosing non-functional Emax

  Hi all,

  Now it's my turn… I'm sad to report that my beloved Emax SE Rack which I upgraded to SCSI and slim floppy is no longer booting.

  Symptoms are: PSU voltages look good at the drive power connector. All LEDs on the front panel come on at power-on except load and enter. No LCD display and no floppy or CF reader activity. :-(

  I have re-seated all cables but have not yet removed and re-seated any socketed ICs. It has just been sitting in a rack, so nothing has been jostled.

  Any suggestions on where to start?

  -Dave

  p.s. even more frustrating: I missed out on a $60 working Emax SE on a local Craig's list ad which posted the day before I discovered my Emax was dead. :-(

  No virus found in this message.
  Checked by AVG - www.avg.com
  Version: 2014.0.4335 / Virus Database: 3705/7098 - Release Date: 02/16/14

Re: [emax] Diagnosing non-functional Emax

2014-02-17 by David Sotnick

Hi Jammie,

Thanks for the suggestion, however I think the PSU is fine. I read 5.04v on yellow, 12.3v on orange and -11.89v on violet coming off the PSU harness at the CPU PCB.

-Dave

Show quoted textHide quoted text

> On Feb 17, 2014, at 8:30, "jammie" <jammie.emma@...> wrote:
> 
> 
> 
> sounds like you have lost the 5v connection
>  
> the lcd uses 5v the cf card reader uses 5v and the floppy uses 5v
>  
> i would check the 5v rail on the psu
> ----- Original Message -----
> From: David Sotnick
> To: emax@yahoogroups.com
> Sent: Monday, February 17, 2014 4:25 PM
> Subject: [emax] Diagnosing non-functional Emax
> 
>  
> Hi all,
> 
> Now it's my turn… I'm sad to report that my beloved Emax SE Rack which I upgraded to SCSI and slim floppy is no longer booting.
> 
> Symptoms are: PSU voltages look good at the drive power connector. All LEDs on the front panel come on at power-on except load and enter. No LCD display and no floppy or CF reader activity. :-(
> 
> I have re-seated all cables but have not yet removed and re-seated any socketed ICs. It has just been sitting in a rack, so nothing has been jostled.
> 
> Any suggestions on where to start?
> 
> -Dave
> 
> p.s. even more frustrating: I missed out on a $60 working Emax SE on a local Craig's list ad which posted the day before I discovered my Emax was dead. :-(
> 
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 2014.0.4335 / Virus Database: 3705/7098 - Release Date: 02/16/14
> 
>

Re: [emax] Diagnosing non-functional Emax

2014-02-17 by jammie

check the 5v at the floppy power connector 

and the invertor input

Show quoted textHide quoted text

  ----- Original Message ----- 
  From: David Sotnick 
  To: emax@yahoogroups.com 
  Sent: Monday, February 17, 2014 4:48 PM
  Subject: Re: [emax] Diagnosing non-functional Emax


    

  Hi Jammie,


  Thanks for the suggestion, however I think the PSU is fine. I read 5.04v on yellow, 12.3v on orange and -11.89v on violet coming off the PSU harness at the CPU PCB.


  -Dave

  On Feb 17, 2014, at 8:30, "jammie" <jammie.emma@...> wrote:


      
     

    sounds like you have lost the 5v connection

    the lcd uses 5v the cf card reader uses 5v and the floppy uses 5v

    i would check the 5v rail on the psu 
      ----- Original Message ----- 
      From: David Sotnick 
      To: emax@yahoogroups.com 
      Sent: Monday, February 17, 2014 4:25 PM
      Subject: [emax] Diagnosing non-functional Emax


        
      Hi all,

      Now it's my turn… I'm sad to report that my beloved Emax SE Rack which I upgraded to SCSI and slim floppy is no longer booting.

      Symptoms are: PSU voltages look good at the drive power connector. All LEDs on the front panel come on at power-on except load and enter. No LCD display and no floppy or CF reader activity. :-(

      I have re-seated all cables but have not yet removed and re-seated any socketed ICs. It has just been sitting in a rack, so nothing has been jostled.

      Any suggestions on where to start?

      -Dave

      p.s. even more frustrating: I missed out on a $60 working Emax SE on a local Craig's list ad which posted the day before I discovered my Emax was dead. :-(

      No virus found in this message.
      Checked by AVG - www.avg.com
      Version: 2014.0.4335 / Virus Database: 3705/7098 - Release Date: 02/16/14



  
  No virus found in this message.
  Checked by AVG - www.avg.com
  Version: 2014.0.4335 / Virus Database: 3705/7098 - Release Date: 02/16/14

Re: [emax] Diagnosing non-functional Emax

2014-02-17 by David Sotnick

I will check those voltages when I get home this evening. Here's a theory:

I replaced the LCD with an OLED about 6 months ago. I never removed the inverter from the CPU board. Is there a chance that the inverter fried itself by not having a load (EL backlight) to drive?

I will try removing the inverter as it's obviously not necessary with an OLED display.

-Dave

Show quoted textHide quoted text

On Mon, Feb 17, 2014 at 11:30 AM, jammie <;jammie.emma@...> wrote:

check the 5v at the floppy power connector

and the invertor input

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

From: David Sotnick

To: emax@yahoogroups.com

Sent: Monday, February 17, 2014 4:48 PM

Subject: Re: [emax] Diagnosing non-functional Emax

Hi Jammie,

Thanks for the suggestion, however I think the PSU is fine. I read 5.04v on yellow, 12.3v on orange and -11.89v on violet coming off the PSU harness at the CPU PCB.

-Dave

On Feb 17, 2014, at 8:30, "jammie" <jammie.emma@....uk> wrote:

sounds like you have lost the 5v connection

the lcd uses 5v the cf card reader uses 5v and the floppy uses 5v

i would check the 5v rail on the psu

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

From: David Sotnick

To: emax@yahoogroups.com

Sent: Monday, February 17, 2014 4:25 PM

Subject: [emax] Diagnosing non-functional Emax

Hi all,

Now it's my turn\u2026 I'm sad to report that my beloved Emax SE Rack which I upgraded to SCSI and slim floppy is no longer booting.

Symptoms are: PSU voltages look good at the drive power connector. All LEDs on the front panel come on at power-on except load and enter. No LCD display and no floppy or CF reader activity. :-(

I have re-seated all cables but have not yet removed and re-seated any socketed ICs. It has just been sitting in a rack, so nothing has been jostled.

Any suggestions on where to start?

-Dave

p.s. even more frustrating: I missed out on a $60 working Emax SE on a local Craig's list ad which posted the day before I discovered my Emax was dead. :-(

No virus found in this message.
Checked by AVG - www.avg.com
Version: 2014.0.4335 / Virus Database: 3705/7098 - Release Date: 02/16/14

No virus found in this message.
Checked by AVG - www.avg.com
Version: 2014.0.4335 / Virus Database: 3705/7098 - Release Date: 02/16/14

RE: [emax] Diagnosing non-functional Emax

2014-02-17 by S. Kühnl

I also had the LCD on my Emax replaced with an OLED display, and the technician said he removed the inverter.

I'm not tech savvy enough to be able to support your theory, just a hint. I'd very much like to know what you'll find out. My mod was done very recently, I can't speak about it in the long term yet.

To: emax@yahoogroups.com
From: sotnickd@...
Date: Mon, 17 Feb 2014 12:39:21 -0800
Subject: Re: [emax] Diagnosing non-functional Emax

I will check those voltages when I get home this evening. Here's a theory:

I replaced the LCD with an OLED about 6 months ago. I never removed the inverter from the CPU board. Is there a chance that the inverter fried itself by not having a load (EL backlight) to drive?

I will try removing the inverter as it's obviously not necessary with an OLED display.

-Dave

On Mon, Feb 17, 2014 at 11:30 AM, jammie <jammie.emma@...> wrote:

check the 5v at the floppy power connector

and the invertor input

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

From: David Sotnick

To: emax@yahoogroups.com

Sent: Monday, February 17, 2014 4:48 PM

Subject: Re: [emax] Diagnosing non-functional Emax

Hi Jammie,

Thanks for the suggestion, however I think the PSU is fine. I read 5.04v on yellow, 12.3v on orange and -11.89v on violet coming off the PSU harness at the CPU PCB.

-Dave

On Feb 17, 2014, at 8:30, "jammie" <jammie.emma@...> wrote:

sounds like you have lost the 5v connection

the lcd uses 5v the cf card reader uses 5v and the floppy uses 5v

i would check the 5v rail on the psu

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

From: David Sotnick

To: emax@yahoogroups.com

Sent: Monday, February 17, 2014 4:25 PM

Subject: [emax] Diagnosing non-functional Emax

Hi all,

Now it's my turn… I'm sad to report that my beloved Emax SE Rack which I upgraded to SCSI and slim floppy is no longer booting.

Symptoms are: PSU voltages look good at the drive power connector. All LEDs on the front panel come on at power-on except load and enter. No LCD display and no floppy or CF reader activity. :-(

I have re-seated all cables but have not yet removed and re-seated any socketed ICs. It has just been sitting in a rack, so nothing has been jostled.

Any suggestions on where to start?

-Dave

p.s. even more frustrating: I missed out on a $60 working Emax SE on a local Craig's list ad which posted the day before I discovered my Emax was dead. :-(

No virus found in this message.
Checked by AVG - www.avg.com
Version: 2014.0.4335 / Virus Database: 3705/7098 - Release Date: 02/16/14

No virus found in this message.
Checked by AVG - www.avg.com
Version: 2014.0.4335 / Virus Database: 3705/7098 - Release Date: 02/16/14

Re: [emax] Diagnosing non-functional Emax

2014-02-17 by jammie

no its just a tswitching transistor and a step up transformer

the transistor switches like a square wave 0-5 volts theres some smothing caps that makes it a small sin signal this signal then is turned into a high voltage ac with very low current via a step up transformar because the signal is a magnitised through the coils via inductance the windings pick up this ac sin signal then transforms it to a biger signal

the reason for whinning when the efoil dies is bigger resistance and the transformers windings can become lose

but when no efoil is connected it has no load so is an open circuit

you can do away with it as it serves no perpose i always remove them when fitting an oled

also on racks i also remove the angle circuits

as the capaciters are being charged but not discharged as they are open circuit no load

Show quoted textHide quoted text

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

From: David Sotnick

To: emax@yahoogroups.com

Sent: Monday, February 17, 2014 8:39 PM

Subject: Re: [emax] Diagnosing non-functional Emax

;

I will check those voltages when I get home this evening. Here's a theory:

I replaced the LCD with an OLED about 6 months ago. I never removed the inverter from the CPU board. Is there a chance that the inverter fried itself by not having a load (EL backlight) to drive?

I will try removing the inverter as it's obviously not necessary with an OLED display.

-Dave

On Mon, Feb 17, 2014 at 11:30 AM, jammie <jammie.emma@....uk> wrote:

check the 5v at the floppy power connector

and the invertor input

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

From: David Sotnick

To: emax@yahoogroups.com

Sent: Monday, February 17, 2014 4:48 PM

Subject: Re: [emax] Diagnosing non-functional Emax

Hi Jammie,

Thanks for the suggestion, however I think the PSU is fine. I read 5.04v on yellow, 12.3v on orange and -11.89v on violet coming off the PSU harness at the CPU PCB.

-Dave

On Feb 17, 2014, at 8:30, "jammie" <jammie.emma@...> wrote:

sounds like you have lost the 5v connection

the lcd uses 5v the cf card reader uses 5v and the floppy uses 5v

i would check the 5v rail on the psu

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

From: David Sotnick

To: emax@yahoogroups.com

Sent: Monday, February 17, 2014 4:25 PM

Subject: [emax] Diagnosing non-functional Emax

Hi all,

Now it's my turn I'm sad to report that my beloved Emax SE Rack which I upgraded to SCSI and slim floppy is no longer booting.

Symptoms are: PSU voltages look good at the drive power connector. All LEDs on the front panel come on at power-on except load and enter. No LCD display and no floppy or CF reader activity. :-(

I have re-seated all cables but have not yet removed and re-seated any socketed ICs. It has just been sitting in a rack, so nothing has been jostled.

Any suggestions on where to start?

-Dave

p.s. even more frustrating: I missed out on a $60 working Emax SE on a local Craig's list ad which posted the day before I discovered my Emax was dead. :-(

No virus found in this message.
Checked by AVG - www.avg.com
Version: 2014.0.4335 / Virus Database: 3705/7098 - Release Date: 02/16/14

No virus found in this message.
Checked by AVG - www.avg.com
Version: 2014.0.4335 / Virus Database: 3705/7098 - Release Date: 02/16/14

No virus found in this message.
Checked by AVG - www.avg.com
Version: 2014.0.4335 / Virus Database: 3705/7100 - Release Date: 02/17/14

Re: [emax] Diagnosing non-functional Emax

2014-02-17 by David Sotnick

> On Feb 17, 2014, at 13:19, "jammie" <jammie.emma@...> wrote:
> 
> but when no efoil is connected it has no load so is an open circuit

Sort of. The circuit on the secondary side of the step-up transformer is clearly open, however the transistor/capacitor are still driving the primary side of the transformer even with no load on secondary.

I have heard from suppliers of EL wire that I use for projects that you can burn out battery powered EL wire drivers if they are powered up without a closed circuit on the EL wire.

Regardless, I'll find out later today if the inverter is causing a short on the 5v line or if I'm in for more serious procedures to resurrect my Emax.

-Dave

Re: Diagnosing non-functional Emax

2014-02-18 by David Sotnick

Well I opened up the Emax again, all PSU voltages were good at the floppy and inverter.

Taking a scientific approach, I went over all the mods I made, pin by pin and found some cold solder joints on the new OLED display I installed.

Fixed those and she's back!!!

*phew*

-Dave

Show quoted textHide quoted text

> On Feb 17, 2014, at 8:25, David Sotnick <sotnickd@...> wrote:
> 
> Hi all,
> 
> Now it's my turn… I'm sad to report that my beloved Emax SE Rack which I upgraded to SCSI and slim floppy is no longer booting.
> 
> Symptoms are: PSU voltages look good at the drive power connector. All LEDs on the front panel come on at power-on except load and enter. No LCD display and no floppy or CF reader activity. :-(
> 
> I have re-seated all cables but have not yet removed and re-seated any socketed ICs. It has just been sitting in a rack, so nothing has been jostled.
> 
> Any suggestions on where to start?
> 
> -Dave
> 
> p.s. even more frustrating: I missed out on a $60 working Emax SE on a local Craig's list ad which posted the day before I discovered my Emax was dead. :-(

Re: [emax] Re: Diagnosing non-functional Emax

2014-02-18 by wandamusic@...

Well success is great!

Are there service manuals for these instdruments?

In a message dated 2/17/2014 11:49:21 P.M. Eastern Standard Time,  
sotnickd@... writes:

Well I opened up the Emax again, all PSU voltages were good at the floppy  
and inverter.

Taking a scientific approach, I went over all the mods I  made, pin by pin 
and found some cold solder joints on the new OLED display I  installed.

Fixed those and she's  back!!!

*phew*

-Dave

> On Feb 17, 2014, at 8:25, David  Sotnick <sotnickd@ddv.com> wrote:
> 
> Hi all,
>  
> Now it's my turn… I'm sad to report that my beloved Emax SE Rack  which I 
upgraded to SCSI and slim floppy is no longer booting.
>  
> Symptoms are: PSU voltages look good at the drive power connector.  All 
LEDs on the front panel come on at power-on except load and enter. No LCD  
display and no floppy or CF reader activity. :-(
> 
> I have  re-seated all cables but have not yet removed and re-seated any 
socketed ICs.  It has just been sitting in a rack, so nothing has been 
jostled.
>  
> Any suggestions on where to start?
> 
> -Dave
>  
> p.s. even more frustrating: I missed out on a $60 working Emax SE on  a 
local Craig's list ad which posted the day before I discovered my Emax was  
dead. :-(

Re: [emax] Diagnosing non-functional Emax

2014-02-18 by Ted Summers

Yes.

They are still copyrighted, and avallable from musicparts.com I believe.

-Ted

On Feb 17, 2014, at 8:56 PM, wandamusic@... wrote:

Well success is great!

Are there service manuals for these instdruments?

In a message dated 2/17/2014 11:49:21 P.M. Eastern Standard Time, sotnickd@... writes:

Well I opened up the Emax again, all PSU voltages were good at the floppy and inverter.

Taking a scientific approach, I went over all the mods I made, pin by pin and found some cold solder joints on the new OLED display I installed.

Fixed those and she's back!!!

*phew*

-Dave

> On Feb 17, 2014, at 8:25, David Sotnick <sotnickd@...> wrote:
>
> Hi all,
>
> Now it's my turn… I'm sad to report that my beloved Emax SE Rack which I upgraded to SCSI and slim floppy is no longer booting.
>
> Symptoms are: PSU voltages look good at the drive power connector. All LEDs on the front panel come on at power-on except load and enter. No LCD display and no floppy or CF reader activity. :-(
>
> I have re-seated all cables but have not yet removed and re-seated any socketed ICs. It has just been sitting in a rack, so nothing has been jostled.
>
> Any suggestions on where to start?
>
> -Dave
>
> p.s. even more frustrating: I missed out on a $60 working Emax SE on a local Craig's list ad which posted the day before I discovered my Emax was dead. :-(

Re: [emax] Re: Diagnosing non-functional Emax

2014-02-18 by jammie

i bet you used lead free solder

Show quoted textHide quoted text

  ----- Original Message ----- 
  From: David Sotnick 
  To: emax@yahoogroups.com 
  Sent: Tuesday, February 18, 2014 4:49 AM
  Subject: [emax] Re: Diagnosing non-functional Emax


    
  Well I opened up the Emax again, all PSU voltages were good at the floppy and inverter.

  Taking a scientific approach, I went over all the mods I made, pin by pin and found some cold solder joints on the new OLED display I installed.

  Fixed those and she's back!!!

  *phew*

  -Dave

  > On Feb 17, 2014, at 8:25, David Sotnick <sotnickd@...> wrote:
  > 
  > Hi all,
  > 
  > Now it's my turn… I'm sad to report that my beloved Emax SE Rack which I upgraded to SCSI and slim floppy is no longer booting.
  > 
  > Symptoms are: PSU voltages look good at the drive power connector. All LEDs on the front panel come on at power-on except load and enter. No LCD display and no floppy or CF reader activity. :-(
  > 
  > I have re-seated all cables but have not yet removed and re-seated any socketed ICs. It has just been sitting in a rack, so nothing has been jostled.
  > 
  > Any suggestions on where to start?
  > 
  > -Dave
  > 
  > p.s. even more frustrating: I missed out on a $60 working Emax SE on a local Craig's list ad which posted the day before I discovered my Emax was dead. :-(


  
  No virus found in this message.
  Checked by AVG - www.avg.com
  Version: 2014.0.4335 / Virus Database: 3705/7103 - Release Date: 02/18/14

Re: [emax] Re: Diagnosing non-functional Emax

2014-02-18 by David Sotnick

No, I used leaded solder, and a digital soldering iron.

The problem was a broken trace from when I desoldered the old LCD. To fix it, I had to expose some of the trace and build a tiny bridge to the OLED pin that was not connected.

I guess this connection just failed over time as it worked for 6 months before failing.

-Dave

Show quoted textHide quoted text

> On Feb 18, 2014, at 5:13, "jammie" <jammie.emma@...> wrote:
> 
> i bet you used lead free solder

Re: [emax] Re: Diagnosing non-functional Emax

2014-02-18 by jammie

yes you have to desolder very carefully i have had several screen boards with totally burnt out pads i have to through hole rivet them because customers tried to desolder them

and solder the traces to the rivets

its a timely job

but the glue they used for the copper clad is really bad on the screen boards and they looked like they were wave soldered to hot

Show quoted textHide quoted text

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

From: David Sotnick

To: emax@yahoogroups.com

Sent: Tuesday, February 18, 2014 2:37 PM

Subject: Re: [emax] Re: Diagnosing non-functional Emax

No, I used leaded solder, and a digital soldering iron.

The problem was a broken trace from when I desoldered the old LCD. To fix it, I had to expose some of the trace and build a tiny bridge to the OLED pin that was not connected.

I guess this connection just failed over time as it worked for 6 months before failing.

-Dave

> On Feb 18, 2014, at 5:13, "jammie" wrote:
>
> i bet you used lead free solder

No virus found in this message.
Checked by AVG - www.avg.com
Version: 2014.0.4335 / Virus Database: 3705/7103 - Release Date: 02/18/14