Re: [AH] Fwd: Moog Voyager elusive problem, asking for your advice

From cheater00 .
Sent Fri, May 10th 2013, 14:43

sounds like a cold solder. are you a tech?
try disconnecting the power supply and connect a soupy linear bench
power supply.

try to trigger the bug while observing the voltage rails on the scope
with the original psu.

On Fri, May 10, 2013 at 2:11 PM, System 100 <system100m@gmail.com> wrote:
> Hi all !
>
> I bought a second hand Voyager a while ago and just found it has a severe
> issue... Once I power it on, after a few minutes the overall pitch can
> change dramatically and intermittently for a fraction of a moment and than
> return to normal. I can happen after a few minutes or after half an hours
> after powering it, and it can come and go spontaneously. It can be heard
> when using MIDI or the keyboard, and it happens also when the pitch wheel is
> disabled.
>
> Please take a look at this video, of an RME acting exactly the same as mine:
>
> http://www.youtube.com/watch?v=Ew5DQXc-xko
>
> The guy there says it was sent to moog for repair a few times and it still
> acts the same... Can anyone think of any idea what causes it ?
>
> The voltages are stable and when the pitch changes no change in the main
> voltages is observed. All connectors and ICs are tightened in place... All
> functions performs well and all pots are in good contact...
>
> The only irregular thing I notices was that the 4 transistors on the small
> powersupply board (not the main PS board) are very (very) hot. No heatsink
> was built around them, just thought one of them might have gone bad but
> again, all voltages are pretty accurate.
>
> Will appreciate any help.