Synthchaser

www.synthchaser.com
/ thesynthchaser
We install the Synthchaser OB-8 Voice Board Rebuild kit, which replaces the dried up electrolytic capacitors, dodgy trimmer pots and noisy resistors that can prevent an OB-8 from autotuning and sounding consistent from voice to voice.
Parts used in this video are available at my website. I also repair and restore Oberheims and other vintage synths for customers around the world.

[@sawsquaresinetube]

This looks like a fun upgrade! Those trimmers with the top board soldering made my heart race, but I can see the benefits 😊

[@andreasmoll_0924]

What an experience you must have to understand all this. Its a miracle. Looks to me like memorize a telephone book with millions of numbers in your mind

[@supercrazydogs1312]

What a fabulous synth, maybe the best i ever worked with. Thanks for the video !

[@bcastromusic]

another quick note folks may want to check all the ECO's and make those changes as well if not done already. There are some important ones for reliable autotune and stability. They sprinkled ECO's throughout the entire life of the product for both A and B Revs of the voice boards so on most units there's a good chance some are not completed.

[@bhorv67]

Which series of OB had single voice cards mounted vertically?

[@TonyB1522]

I have an old OB8 (it’s so old that the MIDI option was added later) and because of old age & lack of use it is now a paper weight. I’m not a tech but have done tons of soldering in the past...usually stuff like changing capacitors & burnt out 6550 tube sockets, etc and was wondering if someone like me could attempt what you just demonstrated on your video?

[@Synthchaser]

If you've got soldering skills, I don't see why you couldn't do it. I've got a kit with the part you'd need on my site.

[@venusiansky]

Nice work. I used the Bourns 3296Y trim pots as replacements. Looks like you are using 3296W? The Y style has an offset wiper lead that provides a little more length to the top hole. IMO, upgrading the filter trimmers is more beneficial than the VCO v/oct trimmers. The single-turn seems good enough for calibrating v/oct, though I did replace all of mine anyways. For the VCF though, multi-turn trimmers made a big difference for calibrating resonance and initial frequency. The old ones in mine were so crusty and sensitive, it was impossible to get accurate tuning between each voice. Another plus to using these new trimmers is that they are sealed.

[@Synthchaser]

Sounds like your're binge watching my videos. Very brave of you!

[@venusiansky]

Synth Chaser LOL. Yeah, I like these type of electronics repair videos. I’ve learned many tips from them. I am self-taught when it comes to this type of work and have been able to service my own gear, to a degree, probably saving me hundreds. Thanks for sharing.

[@TotallyNuss]

venusiansky Thanks for that info. I'm self-taught myself. Do you know if a parts list is available somewhere? With all these ICs it would be nice to see a list with location numbers. Also, did you have to replace any of the polystyrene caps on the voice boards? Did you use old stock polystyrene caps or something contemporary? What DACs will work in place of the hard to find original? Thanks!

[@TotallyNuss]

Bourns 3296Y-1-104 (100K) and 3296Y-1-103 (10K) are the trim pot part numbers. You can find bulk lots on eBay for cheap from U.S. sellers.

[@pnnielsen]

Does nobody make small "adapter pcbs" for the trimmers? If not, I guess I should make some and sell them...

[@KevinStCroix]

What desolder tool is that? It seemed effortless to take out the components.

[@Synthchaser]

It's a Hakko FR-300

[@KevinStCroix]

Wow, are there any that are a little cheaper that do a good job?

[@Synthchaser]

Not that I'm aware of. I had tried some of the Hakko knockoff products and they quickly broke, so I've been sticking with the real deal.