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John_BS · 5th Feb 2020, 4:47 pm

You've already changed the TL094?

Just check the voltage between 1+2 and 3 in case the voltages were on the move when you measured them both relative to ground.

Then have a look with a scope to make sure there's no ac/ripple on the +12V rail, and ditto any ac on the other end of R21. If IC5 is OK you should be able to put the 470 ohms back. Has C12 been changed?

John

5th Feb 2020, 4:47 pm	#14
John_BS Octode Join Date: Dec 2008 Location: Wincanton, Somerset, UK. Posts: 1,784	Re: Another Quad FM4 problem You've already changed the TL094? Just check the voltage *between* 1+2 and 3 in case the voltages were on the move when you measured them both relative to ground. Then have a look with a scope to make sure there's no ac/ripple on the +12V rail, and ditto any ac on the other end of R21. If IC5 is OK you should be able to put the 470 ohms back. Has C12 been changed? John