Moog Taurus I note not working, not a contact...

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WhinyLittleRunt
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Moog Taurus I note not working, not a contact...

Post by WhinyLittleRunt » Wed Jan 06, 2010 4:11 am

Trying to fix one note on a Taurus I; took entire unit apart and cleaned all key contacts. The problem is with the E key (pedal); it will work when you power it on and play for a minute or so, but will stop working after that. If you shut it down and power back up, it will work temporarily again.

Also had intermittent and now absent LEDs on 2 of the 3 presets.

Anything to look for? This unit is foreign to me as of yesterday...
I like vintage synths....

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Re: Moog Taurus I note not working, not a contact...

Post by Maschinengeist » Wed Jan 06, 2010 6:40 am

My time in the repairshop is limited these days but I'll try to find time to think about your problem. Remind me if I forget to come back to you in the next few days.
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Re: Moog Taurus I note not working, not a contact...

Post by Stab Frenzy » Wed Jan 06, 2010 7:48 am

Could be a hairline crack on the board or cold solder joint that opens up when the unit warms up. I'd be checking that first.

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Re: Moog Taurus I note not working, not a contact...

Post by WhinyLittleRunt » Wed Jan 06, 2010 9:53 pm

Hmmm..

I also noticed that if it is working, by touching or moving, say, the glide slider inside, it will immediately cause the note to stop. weird...

Also sometimes on immediate power recycle it still won't work unless you wait longer.
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Re: Moog Taurus I note not working, not a contact...

Post by atkbg » Thu Jan 07, 2010 12:16 am

Check the solder joints as mentioned.

Also, what is IC 101? A SIP?
Hit IC101 with can of compressed air. That'll cool it down and see if its an intermittent IC/SIP.

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Re: Moog Taurus I note not working, not a contact...

Post by Synthaholic » Thu Jan 07, 2010 1:21 am

If it's the E note that isn't working, check the solder joints/continuity at J2 pin 5 to the pedal contact on the E pedal; J2 pin 5 to IC105 pin 6; make sure IC105 is seated properly if it's socketed.

Since the pedal board feeds into a resistor ladder to generate the pitch CV/gate, if just one note isn't working, it has to be the connection between that one note's pedal and the resistor ladder (IC105).

As for the preset LEDs, those are probably a loose connection to the LEDs, if the presets themselves are working. If the presets aren't working, check around IC901 and IC905.
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Re: Moog Taurus I note not working, not a contact...

Post by WhinyLittleRunt » Thu Jan 07, 2010 3:58 am

Great advice everyone.

Synthaholic - thank you so much for the detailed diagnostics. Either you know the Taurus like the back of your hand or you just went totally out of your way to get that info. Either way that was much appreciated :) Got some poking around now to do tomorrow.
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Re: Moog Taurus I note not working, not a contact...

Post by Synthaholic » Thu Jan 07, 2010 1:07 pm

WhinyLittleRunt wrote:Synthaholic - thank you so much for the detailed diagnostics. Either you know the Taurus like the back of your hand or you just went totally out of your way to get that info. Either way that was much appreciated :) Got some poking around now to do tomorrow.
The correct answer is #2. I found the schematic on http://manuals.fdiskc.com/flat/

Of course, I would rather have #1 be true, since that would mean owning one. :)
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Re: Moog Taurus I note not working, not a contact...

Post by WhinyLittleRunt » Thu Jan 07, 2010 3:10 pm

If it makes you feel any better I don't own it either! My associate purchased it but I typically give the stuff a once-over or a complete dis-assembly and cleaning, which is what I had to do in this case because they were just filthy.

Well thanks again for getting that info - I had previously downloaded that schematic as well but I really have trouble following them...
I like vintage synths....

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Re: Moog Taurus I note not working, not a contact...

Post by WhinyLittleRunt » Thu Jan 07, 2010 9:34 pm

Synthaholic wrote:If it's the E note that isn't working, check the solder joints/continuity at J2 pin 5 to the pedal contact on the E pedal; J2 pin 5 to IC105 pin 6; make sure IC105 is seated properly if it's socketed.

Since the pedal board feeds into a resistor ladder to generate the pitch CV/gate, if just one note isn't working, it has to be the connection between that one note's pedal and the resistor ladder (IC105).

As for the preset LEDs, those are probably a loose connection to the LEDs, if the presets themselves are working. If the presets aren't working, check around IC901 and IC905.

Thanks a million, man... you were 100% correct it was a broken leg on IC 105.. Go figure. I'd never have thought to look for that without your help. Also replaced the bad LED's and this thing is functioning great now. Thanks again!
I like vintage synths....

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