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Old 05-15-2021, 12:21 PM
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M3-SRT8 M3-SRT8 is offline
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Join Date: Oct 2007
Location: Worcester, Mass
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Quote:
Originally Posted by Notimetolooz View Post
I replaced two electrolytic caps and a 5 V regulator IC. (So far.)
The big 450V cap on the supply to the Drive Amplifier (sweep drive output) was bad. If I remember right two other supplies were just out of spec. Hum and voltage level. Looking at my notes, both caps were on the main supply, the regulator was on the meter supply. There were also some resistors that looked like they had been replaced but did not match the schematic value or wattage.
This might mean someone tried to correct a problem elsewhere.
The Maintenance manual will be uploaded to BAMA shortly. It has the locations on the board to check voltages and lists the supply limits. That manual has much more in the way of tests and checks, although it looks like you need things like a vector scope for some checks.
There is a main supply board (#900) and another board for the meter and ringer supply (#1900).
Watch those board connectors!
My VA-62A appears to be a virgin. No repairs that I could see. All the big lytics appear to be fine, no buldging, leaking, etc.

Which DPDT Switch did Zenith specify for the mod? Can't tell from the picture.
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