Oberheim OB-8 restoration

[Iain McNeill]

Hi,
I'm restoring an OB-8 and was lucky enough to actually meet Tom Oberheim yesterday at the AES convention. He graciously spent some time helping me with debugging a bad voice and his 1st recommendation was to replace the EPROMs.

I've done some searches but can't find any programed parts. Does anyone know of anyone selling replacement programmed EPROMS for OB-8 synths?

Alternatively, is there anyone out there with a working OB-8 who would allow me to clone the EPROMS? In return I'll give you a back up set!

Any links would also be gratefully accepted!

[rderby]

Nice "magic eye" avatar!!

Did you try Kevin Lightner over at synthfool.com?

Good luck with your OB8!

[Iain McNeill]

Thanks!
I tried Richard at Archive Sound with no luck so thanks for the tip, I'll contact him right now.

[Iain McNeill]

Well, I'm still trying to find a source for rev B5 EPROMS for this OB-8. Drawing a blank on all fronts.

Does anyone know if I could substitute a previous rev EPROM? Or would that mean giving up the add-on MIDI board?

Neither Archive Sound or Synth Fool were able to help.
Thanks in advance.

[Kramerguy]

I would try cleaning the sockets and pins on everything before replacing UV or EE or Flash Proms of any variety. Unless they have been subjected to massive ESD or EMP they almost never go bad.

Also If you have Eproms and a programer and they are just flaky you could try copying them yourself and if you lack the tools let me know I have them.

Originally posted by Iain McNeill
Hi,
I'm restoring an OB-8 and was lucky enough to actually meet Tom Oberheim yesterday at the AES convention. He graciously spent some time helping me with debugging a bad voice and his 1st recommendation was to replace the EPROMs.

I've done some searches but can't find any programed parts. Does anyone know of anyone selling replacement programmed EPROMS for OB-8 synths?

Alternatively, is there anyone out there with a working OB-8 who would allow me to clone the EPROMS? In return I'll give you a back up set!

Any links would also be gratefully accepted!

[gain-wire]

Hi Iain,
I sometimes look over different recent posts on diyaudio and once in a while, there's one that catches my attention. I am not a synth player, but having listened to many Van Halen songs and read his interviews, I can guarantee you that he must still have his lying around! I have no idea how to contact him though..

OK SERIOUSLY, I might have a link for you. I decided to check on ebay, I know I know, you must have tried this. In the case that you have not, or possibly overlooked this, check out: http://cgi.ebay.com/ws/eBayISAPI.dll...m=170290424178
The guy is selling the OB8 without Eproms and curtis chips (I have no idea what those are) but he also is keeping them. So, in other words he has them! Maybe you should ask him a question, if he could copy the Eprom chips for you.

Just my two cents.

[Kramerguy]

If the seller had the capability to reproduce those eproms he would be selling the ob8 with them. It could also be that some technician in the late 80s early 90s robbed them out of the device becuase eprom programmer were not very cheap 20 yrs ago.

Either way if someone can find the files and the eprom type I assume most like its is a 2 4 or 8kb hex,Srecord,binary file I can load those up on the some eproms for a few $$$ to cover the costs of the chips+shipping. I sell a number of chips to friends for $5-10 each depends on the chip.

Still i would try cleaning the sockets.

Originally posted by gain-wire
Hi Iain,
I sometimes look over different recent posts on diyaudio and once in a while, there's one that catches my attention. I am not a synth player, but having listened to many Van Halen songs and read his interviews, I can guarantee you that he must still have his lying around! I have no idea how to contact him though..

OK SERIOUSLY, I might have a link for you. I decided to check on ebay, I know I know, you must have tried this. In the case that you have not, or possibly overlooked this, check out: http://cgi.ebay.com/ws/eBayISAPI.dll...m=170290424178
The guy is selling the OB8 without Eproms and curtis chips (I have no idea what those are) but he also is keeping them. So, in other words he has them! Maybe you should ask him a question, if he could copy the Eprom chips for you.

Just my two cents.

[gain-wire]

Yeah, cleaning is definitely a good, inexpensive solution. But how do you clean sockets? I'm a bit perplexed about this...

[Iain McNeill]

Originally posted by gain-wire
But how do you clean sockets?

I think it's more cleaning the pins of the chip (a pencil eraser is good). If the socket has oxidized and re-seating the chip doesn't cut through then its new socket time.

You're right, they're good old D2732A's but I think the problem is getting the musician with the OB8 together with the computer guy with the EPROM reader. Still working on that.

Does anyone have experience working with 25yr old EPROMS and how they keep their data? I've heard rumours that background radiation can flip bits and so over time the image gets more and more corrupt. How many Linn drums are there still out there working??

Thanks for you help, I haven't given up yet.

[Kramerguy]

I reprogram Automotive engine control modules as an occupation. Somtimes I refer to it as insanity for money but nontheless it keep clothes on my back and a roof over my head.

d2732a eproms are easy to come by. How many do you need ? I have hundreds of New ones I got at a Ford Engineering auction some years ago.

as for stability pretty much you would have to seriously ESD those devices I am talking enough milliamps/volts to knock you unconcious and or a nuclear explosion sized EMP event.

I would try some CRC contact cleaner and make sure the Eproms fit snugly in the sockets. You can do this by bending the legs out just a touch so that you have to nest the chips in one side at a time.

If you have Eproms you want copied ship them to me $10 a chip and I send back your originals.

I would be highly dubious of a EPROM failure unless it was left out in direct sunlight for weeks with no UV window block.

Originally posted by Iain McNeill


I think it's more cleaning the pins of the chip (a pencil eraser is good). If the socket has oxidized and re-seating the chip doesn't cut through then its new socket time.

You're right, they're good old D2732A's but I think the problem is getting the musician with the OB8 together with the computer guy with the EPROM reader. Still working on that.

Does anyone have experience working with 25yr old EPROMS and how they keep their data? I've heard rumours that background radiation can flip bits and so over time the image gets more and more corrupt. How many Linn drums are there still out there working??

Thanks for you help, I haven't given up yet.