previous by dateindexnext by date
previous in topictopic listnext in topic

Subject: Re: Osc 2 mod issues on just one voice

From: Eric Frampton <eric@...>
Date: 2013-02-26

It ended up being a couple of random things. Right out of the gate, ID10T fault: I was poking at the wrong voice channel.

When I started probing at the correct channel (d'oh!), everything up to the input of the 3374 was clean as it could be on the scope. So I tried re-seating the 3374, and voila, the output cleaned right up.

I then started exploring the filter section and discovered another voice not tracking the keyboard like the others. Re-seating to the rescue again, this time the 3372.

This is one of those units that was/is in such dodgy shape that, the more I dig into it, the more little things I find. It literally sat outside in a shed for years - I pulled leaves out of and cleaned rodent poo off of it. Wish I'd done before/after pix. If Paul hadn't come up with those new membrane panels (thanks again Paul!), I"m sure this thing would've just become parts for somebody.

Next up: Glide and Osc 2 Vibrato don't track slider moves like the rest of the parameters do. Details as I discover them...

e

On Feb 25, 2013, at 11:47 AM, Paul D. DeRocco <pderocco@...> wrote:

 

> From: Eric Frampton
>
> Unfortunately, I don't have any spare ADC0804's to toss in
> there. Where would I find one now?

I wouldn't bother with an ADC0804. That won't fix something that only
affects one voice.

I suspect there's a hardware problem somewhere in the voice, which will take
proper diagnosis with a scope. You can't always fix things by blindly
swapping socketed ICs, although it's usually a good thing to try first.