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Re: xpander dac


 

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Hi Karl !

Great post and good advice.
Thx for compliments too.

After 25 years using the Xpander, my experience is, it?s one of the most reliable machines I ever owned.
The rotarys, some of the switches and the numeric keypad ( especially button #6) are the parts which become unreliable now but I hope it?s only because of dust or maybe because I didn?t use the switches and rotarys too much in the times I used software to manage/edit the Xpanders patches .

In general: Are there any resources/parts numbers for the switches, keypads switches ?

My music DAW died two weeks ago and I started to program my Xpander w/ it?s front panel controls again which was real fun, but I accidently overwrote patches while editing others by using button No.#6 of the keypad during storage,- and I forgot which ones I have overwritten accidently.

I also need a new battery now and cannot find one actually.
There was a dealer at ebay which I bookmarked for the battery, but now it?s gone unfortunally.

Tuning page:

I press "tune all",- autotune works and sometimes immediatedly shows "fail" on voice #1
I press "tune all" again, and the tuning procedure works as it should and all voices show "pass" on oscillators, filters, resonance, VCAs and PW.

Is it a cap or is is it the switch ?

Xpander is in perfect tune after using autotune and it?s also well in tune if I don?t use autotune at all b.t.w.

Some time ago, you?ve sent me a PDF for a rotary replacement which possibly will work,- I lost ist because of a MFT error of one of my ext. USB2 HDs.
Can you please mail me this PDF again ?

thx in advance

PeWe

P.S.:

For all the others here,- don?t panic. Dead OSCs, displays, processors and DACs are very rare cases of failure.
I had ONE CEM multimode filter chip failure in 25 years and these are always available at technology transplant (ebay) and these aren?t expensive.
I?ve had no other failure w/ my Xpander in 25years except these mentioned above.

All my vintage machines, Moog, Roland, Yammies and Obies are much better built devices compared to what you can buy today new and they sound excellent up today.




Karl schrieb:


Hey Everyone,

I have been helping folks fix their Xpanders / Matrix 12s for awhile
here. I can tell you that by far the most failed component is
electrolytic capacitors. A 2.2 uF @ 50V coupling capacitor is used
through out the analog voice boards. This capacitor will fail and
cause numerous voice problems from failed auto-tune to no sound. The
next part would be the encoders. Usually a good cleaning fixes this.
Next would be the VFD displays which are very hard to find. Steve
Lanham is working on an upgrade for this one.
see:


There have been a few cases of VCO ( 3374 ) and VCF filter chips (
3372 ) failing. Not impossible to find, but expensive.
The DAC issue from Takis is the first I've seen of that part failing.
Many times things can be fixed by simply re seating ( pulling out and
putting back in ) the chips. This is easy on the Xpander because
every integrated circuit is in a socket. Finally, many problems are
caused by cold solder joints. Simply re flowing the solder around the
suspect part can fix this. I always recommend doing this first
before replacing parts.

I personally have fixed my matrix 12 (owned since 1987) several times
This included cleaning the key contacts (typical of any keyboard)
Several of the before mentioned capacitors. An analog switch chip
which had it's pin folded under at the factory. And finally, several
74HC14 Schmidt trigger chips which debounce the encoders.

Soon ( when time permits ) I would like to make a better list along
with part numbers etc. that we could all use to trouble shoot these
wonderful machines. I have been collecting capacitors/ battary etc.
to recap mine.

BTW If you have any software issues/questions Tony C. is the man to
talk to, and PeWe is the best expert on sound design / functionality
( on nearly any synth ) I have ever talked to. Actually, all the
folks in this group are sharp characters ( they own xpanders :-)

Best Regards

Karl

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