Re: [vintagesynthrepair] Brian reveals his Omni problems!
2000-08-04 by Gerry Dahl
Hi Everyone and welcome.
When I do repairs on synths, I will hold the keys down for a long time
to see if the EG is malfunctioning, If it starts to gradualy make a sound
then you know that the EG has a problem, Also the filter cutoff could be
below
audible level (all the way down) and so I try to control it with an LFO to
get some other control voltage to it. Of course the best thing to do is
trace
the signal with a scope. I had a Omni II and it was dead when I got it,
I had to replace the final stage op-amps to get sound out of it, these were
on the back vertical board in the synth. Try to look there.
Hope this helps.
Gerry Dahl
Keep on Moogin'
----- Original Message -----Show quoted textHide quoted text
From: Brian Andrew Marek <bmarek@...> To: <vintagesynthrepair@egroups.com> Sent: Thursday, August 03, 2000 4:35 PM Subject: [vintagesynthrepair] Brian reveals his Omni problems! > First, the good bits: the LED's light up, the power supply is kicking > out a nice, healthy 15 volts, the filters work, all the keys apparently > work in the sense that there is an audible click when they are pressed > and one can hear a low-volume swirl of white noise when they are > depressed. > > The bad news: No string or synth tones. > > What I've already done: Replaced all those nasty tantalum capacitors. > Replaced several 1458's. Replaced virtually every component in the > oscillator circuit. Replaced the 4007 on the upper voicing board. > Replaced a number of 3904 and 3906 transistors. Replaced a bunch of > other comonents that aren't usually mentioned in conversations like this > but I had a hunch they were questionable. Checked the integrity of many > connector ribbons and solder traces. > > And yet, in spite of all this... it will not play. > > Are there any other Omni repair panaceas that I have neglected to > attempt? Obviously there's something wrong somewhere between the > oscillator and the filter. But what??? > > BaM > > -- > Find out more about Rocket Park at the (subliminal banana) home page! > http://www.rocketparkmusic.com/ > > > > > > To unsubscribe from this group, send an email to: > vintagesynthrepair-unsubscribe@egroups.com > > >