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OBXa diagnostic EPROM needed

OBXa diagnostic EPROM needed

2012-12-05 by Thomas

Hi guys,

thanks for approving my membership to this list :-)

I'm restoring an Oberheim OBXa 8-voice and looking for the diagnostic EPROM with paperworks for it. A BIN would be fine.
It's REV C mainboards and has a Numera Midi interface installed.
Will probably remove the Numera first to get the machine up and running and see if it's the Numera that's causing trouble.
Fortunately all the voiceboards are fine.
Any help would be great and appreciated :-)

Best regards,

Thomas

Re: [vintagesynthrepair] OBXa diagnostic EPROM needed

2012-12-05 by Roger J

What are the issues that you are trying to correct?  There are built in aids like calibration and no op.
Show quoted textHide quoted text
>________________________________
> From: Thomas <troperecordings@...>
>To: vintagesynthrepair@yahoogroups.com 
>Sent: Wednesday, December 5, 2012 3:51 AM
>Subject: [vintagesynthrepair] OBXa diagnostic EPROM needed
> 
>
>  
>Hi guys,
>
>thanks for approving my membership to this list :-)
>
>I'm restoring an Oberheim OBXa 8-voice and looking for the diagnostic EPROM with paperworks for it. A BIN would be fine.
>It's REV C mainboards and has a Numera Midi interface installed.
>Will probably remove the Numera first to get the machine up and running and see if it's the Numera that's causing trouble.
>Fortunately all the voiceboards are fine.
>Any help would be great and appreciated :-)
>
>Best regards,
>
>Thomas
>
>
> 
>
>

Re: [vintagesynthrepair] OBXa diagnostic EPROM needed

2012-12-05 by Thomas Heckmann

HI,
it's powering up, but just a few LEDs are on and no sound or response from the keys to the voiceboards.
The Z80 is fine, too.
Thanks,
Thomas

On Dec 5, 2012, at 1:27 PM, Roger J wrote:


What are the issues that you are trying to correct? There are built in aids like calibration and no op.

Show quoted textHide quoted text
From: Thomas <troperecordings@t-online.de>
To: vintagesynthrepair@yahoogroups.com
Sent: Wednesday, December 5, 2012 3:51 AM
Subject: [vintagesynthrepair] OBXa diagnostic EPROM needed

Hi guys,

thanks for approving my membership to this list :-)

I'm restoring an Oberheim OBXa 8-voice and looking for the diagnostic EPROM with paperworks for it. A BIN would be fine.
It's REV C mainboards and has a Numera Midi interface installed.
Will probably remove the Numera first to get the machine up and running and see if it's the Numera that's causing trouble.
Fortunately all the voiceboards are fine.
Any help would be great and appreciated :-)

Best regards,

Thomas





Thomas P. Heckmann
Trope Recordings - AFU Limited - AFULAB - trope mastering




Re: [vintagesynthrepair] OBXa diagnostic EPROM needed

2012-12-05 by Roger J

Been a couple of years since I did an OBXa.  One of the ways to work on issues related to a CPU that will not run is to ground the data bus of the CPU.  This will cause the address bus to auto increment, and with an o-scope, one can do a lot.  As I recall , there is a slide switch that will do this.  There is also a switch to engage the calibration routine.  

Do you have the calibration document?  As I recall it talks about the no-op too.
Show quoted textHide quoted text
>________________________________
> From: Thomas Heckmann <troperecordings@...>
>To: vintagesynthrepair@yahoogroups.com 
>Sent: Wednesday, December 5, 2012 4:32 AM
>Subject: Re: [vintagesynthrepair] OBXa diagnostic EPROM needed
> 
>
>  
>HI,
>it's powering up, but just a few LEDs are on and no sound or response from the keys to the voiceboards.
>The Z80 is fine, too.
>Thanks,
>Thomas
>
>
>On Dec 5, 2012, at 1:27 PM, Roger J wrote:
>
>  
>
>
>What are the issues that you are trying to correct?  There are built in aids like calibration and no op.  
>
>
>
>
>>________________________________
>> From: Thomas <troperecordings@...>
>>To: vintagesynthrepair@yahoogroups.com 
>>Sent: Wednesday, December 5, 2012 3:51 AM
>>Subject: [vintagesynthrepair] OBXa diagnostic EPROM needed
>> 
>>
>>  
>>Hi guys,
>>
>>thanks for approving my membership to this list :-)
>>
>>I'm restoring an Oberheim OBXa 8-voice and looking for the diagnostic EPROM with paperworks for it. A BIN would be fine.
>>It's REV C mainboards and has a Numera Midi interface installed.
>>Will probably remove the Numera first to get the machine up and running and see if it's the Numera that's causing trouble.
>>Fortunately all the voiceboards are fine.
>>Any help would be great and appreciated :-)
>>
>>Best regards,
>>
>>Thomas
>>
>>
>>
>>
>
>
>
>Thomas P. Heckmann
>Trope Recordings - AFU Limited - AFULAB - trope mastering
>
>
>
>
>
> 
>
>

Re: [vintagesynthrepair] OBXa diagnostic EPROM needed

2012-12-05 by Thomas Heckmann

In the meantime I have repaired a faulty OBSX. The Z80 was gone...

I will probably forward the OBXa to my technician, as he's pretty good with all the computer stuff.
I'm more into the analog :-)

But thanks for your help and best,

Thomas

On Dec 5, 2012, at 1:56 PM, Roger J wrote:


Been a couple of years since I did an OBXa. One of the ways to work on issues related to a CPU that will not run is to ground the data bus of the CPU. This will cause the address bus to auto increment, and with an o-scope, one can do a lot. As I recall , there is a slide switch that will do this. There is also a switch to engage the calibration routine.

Do you have the calibration document? As I recall it talks about the no-op too.




Show quoted textHide quoted text
From: Thomas Heckmann <troperecordings@t-online.de>
To: vintagesynthrepair@yahoogroups.com
Sent: Wednesday, December 5, 2012 4:32 AM
Subject: Re: [vintagesynthrepair] OBXa diagnostic EPROM needed

HI,
it's powering up, but just a few LEDs are on and no sound or response from the keys to the voiceboards.
The Z80 is fine, too.
Thanks,
Thomas

On Dec 5, 2012, at 1:27 PM, Roger J wrote:


What are the issues that you are trying to correct? ; There are built in aids like calibration and no op.

From: Thomas <troperecordings@...>
To: vintagesynthrepair@yahoogroups.com
Sent: Wednesday, December 5, 2012 3:51 AM
Subject: [vintagesynthrepair] OBXa diagnostic EPROM needed

Hi guys,

thanks for approving my membership to this list :-)

I'm restoring an Oberheim OBXa 8-voice and looking for the diagnostic EPROM with paperworks for it. A BIN would be fine.
It's REV C mainboards and has a Numera Midi interface installed.
Will probably remove the Numera first to get the machine up and running and see if it's the Numera that's causing trouble.
Fortunately all the voiceboards are fine.
Any help would be great and appreciated :-)

Best regards,

Thomas





Thomas P. Heckmann
Trope Recordings - AFU Limited - AFULAB - trope mastering








Thomas P. Heckmann
Trope Recordings - AFU Limited - AFULAB - trope mastering




Looking for Oberheim OB-SX voicecards

2012-12-05 by Thomas Heckmann

Hi again,

so as I repaired the OB-SX today (besides trying to fix the OBXa) I'm now looking for more voice cards for the OB-SX.

Mine only has a poor one installed, so at least two more would be great :-)

I really like the sound and somehow it feels a bit ballsier than the OBXa. Probably from the X-Mod from the OBX ?

Don't need the Curtis chips, only the cards.

I know some technicians used them to pull the CEMs, so maybe someone here has some in the scrap box ?

Thanks and best,

Thomas


Thomas P. Heckmann
Trope Recordings - AFU Limited - AFULAB - trope mastering




Re: [vintagesynthrepair] Looking for Oberheim OB-SX voicecards

2012-12-05 by Roger J

All of the parts  and test fixtures that were in the Obie service department went to the National Music Center in Calgary, Alberta, Canada.  Contact John at john.leimseider@...

Some of the test fixtures are in Tacoma, Washington in storage.
Show quoted textHide quoted text
>________________________________
> From: Thomas Heckmann <troperecordings@...>
>To: vintagesynthrepair@yahoogroups.com 
>Sent: Wednesday, December 5, 2012 8:15 AM
>Subject: [vintagesynthrepair] Looking for Oberheim OB-SX voicecards
> 
>
>  
>Hi again,
>so as I repaired the OB-SX today (besides trying to fix the OBXa) I'm now looking for more voice cards for the OB-SX.
>Mine only has a poor one installed, so at least two more would be great :-)
>I really like the sound and somehow it feels a bit ballsier than the OBXa. Probably from the X-Mod from the OBX ?
>
>
>Don't need the Curtis chips, only the cards.
>I know some technicians used them to pull the CEMs, so maybe someone here has some in the scrap box ?
>
>Thanks and best,
>
>Thomas
>
>
>
>Thomas P. Heckmann
>Trope Recordings - AFU Limited - AFULAB - trope mastering
>
>
>
>
>
> 
>
>

Re: Looking for Oberheim OB-SX voicecards

2012-12-06 by synthparts

I have some OB-SX voice cards.

Doug 
synthparts.com

--- In vintagesynthrepair@yahoogroups.com, Thomas Heckmann <troperecordings@...> wrote:
Show quoted textHide quoted text
>
> Hi again,
> 
> so as I repaired the OB-SX today (besides trying to fix the OBXa) I'm now looking for more voice cards for the OB-SX.
> 
> Mine only has a poor one installed, so at least two more would be great :-)
> 
> I really like the sound and somehow it feels a bit ballsier than the OBXa. Probably from the X-Mod from the OBX ?
> 
> Don't need the Curtis chips, only the cards.
> 
> I know some technicians used them to pull the CEMs, so maybe someone here has some in the scrap box ?
> 
> Thanks and best,
> 
> Thomas
> 
> 
> 
> Thomas P. Heckmann
> Trope Recordings - AFU Limited - AFULAB - trope mastering
>

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