I had a similar problem and when I studied the circuit board up close I found that a tiny piece of wire shrapnal (from some earlier work) had lodged itself between 2 connections, shorting them. When I cleaned it off, all was well. It probably isnt the case, but check first before you go desoldering any roms.
To: tr-707@yahoogroups.com
From: manneokoko@...
Date: Tue, 8 Jul 2008 20:20:49 +0000
Subject: [tr-707] Need ROM replacement
Hello.
Ive got a TR707 on which the CY is busted. Whenever the sound is
triggered all that comes out is a metalic sound. I guess that the
Cymbal ROM is broken.
So my question is if anybody on this list can burn a replacement ROM
for me
Plese help my poor 707 out!
//Rikard - Sweden