FET's came home yesterday from Germany, new old stock. I couldn't resist so I took a chance and changed the FET's; and guess what, everything is in working order again! :D They indeed where the problem. Changed all of them, took 20 minutes disassembling and everything. Maybe it was a c**p shot, but ...

btw, the parts list says all the FET's are the model 2SK30AY. They where easy to find new old stock from germany.

You'll need a transistor tester, a multimeter (many of them incorporate a tester) an oscilloscope and the service manual, and you'll need to go through the circuit systematically testing all elements. We tried, here, based on the available information, but it looks like not enough info was provided...

HI again! I've replaced it and voltages are fine now. still dont have sound though, only white noise as i turn up the volume of my speaker. Everything is connected according to the operating manual, and there are no signs of harm on the preamp board. Tremolo seems to have an effect also, It slightly...

Before varnish, after sanding and cleaning...

Waiting on a german supplier I found who could send me a new transistor for the board. While I'm waiting I wanted to show you guys the renovation, or rather how it turned out. Unfortunately I dont have progress pictures, only the one from the seller back when I bought it, it doesn't show much though...

Thank you so much guys! I'll keep you posted, in the middle of moving from my apartment. I'll take a look at the transistor within this week! Thank You!!

Hi guys. I'm working on a beat up old CP70. It's been really fun! I'll post some pictures when I'm done with the new finish, it's something quite different! The previous owner had done the passive mod, because the preamp/power supply was malfunctioning. I'm trying the figure out how to get it workin...

The 68E09 on voice board may be defective. I had one Xpander on repair and it had very similar issues. After testing all parts between two CPUs I swapped the CPU from Rhodes Chroma CPU board which I had lying around. The new CPU did the job. The same Xpander (which had multiple problems, failed dis...

SOLVED!!! :D :D :D :D :D :D :D Hello! Very good news for anybody with this sort of problem. It was the very chip itself, the voice processor, the 68B09EP on the voiceboard that was going nuts. It's not a job for every diy tech, the chip has 40 very small pins, and its easy to get frustrated and tryi...

Here is something in the operation manual.
DOnt know if it makes sense, but the last couple of lines mentions what seems to be the problem.

Yes, you are right. I found out right when i opened the package... I guess my research before hand wasn't good enough, but then again, when you pay 3200$ for a functioning xp-1 it's suppossed to be working perfectly, right? I trusted him, also because of the pretty high price. My problem is that I w...

The 68E09 on voice board may be defective. I had one Xpander on repair and it had very similar issues. After testing all parts between two CPUs I swapped the CPU from Rhodes Chroma CPU board which I had lying around. The new CPU did the job. Thank you guys. Really apreciate it. I guys the best opti...

Dear all users of the vintagesynthforum, and especially Oberheim Xpander users. I have a unbearable problem with a recent bought Oberheim Xpander, Japanese version. So, 3 months ago I bought a XP-1 from a japanese ebay-seller for a huge amount of money (at least for me) - In the sellers announcement...