I give up!

[buzzyreed]

I am so sick of dealing with my Allen MOS 120C crackling problem, I've decided to hack it up and sell the boards on ebay to finance a swift "HAUPTWERK-ification" for this sucker. I got a different DAC board in today and for the first few seconds it only crackled about 1/8th as much as the old one. So I got frustrated and put the old one back, which didn't make any crackles for about three minutes then it got worse and worse so I put the newer one in (which, oddly enough is acutally older) and it started to make sounds like a person blowing through an aluminum foil trumpet after each key press from a flute or pedal division stop.

I give up. It's almost as if it's building up a potential charge and then all hell breaks loose. Is there something I don't have grounded correctly???

Be looking for a good deal on MOS boards in the near future on ebay....

[searchinferu]

Buz,

Have you cleaned 'all' the contacts on the connections, taking them apart, checking for, removing corrosion, applying petroleum jelly and them reattaching them. Not just the rca plugs, but the little ones that you may find in the middle of a board here and there? Have you exercised all the potentiometers back and forth a few times to clean bad spots? Have you tried disconnecting the swell, gain, and crescendo pedals? Changed speakers? And a lot of other pointers others have made here?

Yes, u can modify the 120 to accept MIDI outputs, but you won't be able to control the stops or expression without constantly referring back to a keyboard or screen.

Have u talked with a tech and seen what a home visit might cost. If one is nearby, perhaps it would be cheaper to trailer it over to him or her. You have a nice piece that just needs a little something. Give it a rest for a few days and then go back at it. Perhaps all you need is a new perspective. My 2160 has been giving me the willies over something that I had fixed months ago. But, it was a simple fix then and probably will be again.


Just a thought......Bi;;

[Guest]

Hello, I had an Allen 201 which had a low level crackle which was intermittent .... happened for years ... finally found the bass pot on the DAC was the culprit ... simple cleaning... dead silence. Clean ALL pots being careful to make where there were set (if the control's function is unknown).

[OrgansR4Me]

Did you use fader lube for the pot cleaning. I read recently that other cleaning agents can strip the lubrication needed within pots?

[geoelectro]

For delicate work I use DeOxit D-100. This is not the standard D-5 people use. D-100 is 100% and it has a metered spray so easier to keep from putting too much in. It will not damage any lubricant. I use it in sliders as well. Sliders have lubricant that if removed, render then unusable. For regular pots D-5 is fine. You can probably use it on your pots. I tried Fader Lube recently on a vintage synthesizer and it nearly killed a slide pot. Went back with D-100 and all was well.

Geo

[Bob Pierce]

(sorry, never mind... didn't read carefully)

[buzzyreed]

If it were the pots, that wouldn't explain why both the old and the new DAC cards cause cracking. I suspect there something wrong with the MOS board. There are two chips that have an unusual slight silvery spot on them, perhaps they have been fried. I give up. Maybe I'll exchange one of my System 600 double computer organ's MOS board for this one since I never use it.. or I'll just give up on this little @#$#@$ and start writing the MIDI.

[searchinferu]

Geo!

I have a similar distortion problem with a 2140. Exercising the small plastic housed pots made it go away, but now its back. You can feel a grittiness as you turn one of them. So, obviously it's part of my problem. Would the D100 be safe to use on these plastic housed pots? You just spray at the shaft while exercising the pot? Would run off carry contamination onto the rest of the board, as these are at the top and right edge of the board as it is mounted in the cage?

Hmmm. I sound like an infomercial gone bad with all these questions. BUT WAIT THERE'S MORE!

[geoelectro]

You won't hurt it. The spray is metered meaning it just puts out a quick burst each time you press. Some pots just need to be replaced eventually. I would try it first, then replace if necessary.

Geo