Mydel MP-304 Fault

[GDog]

Hi all.
Long time no post and then I expect to be posting quite a bit this week graciously accepting assistance if possible !

My Mydel works, but with no load connected the voltage sometimes drops to 2 volts very slowly.

If I power up with load connected 99 percent of the time it works. With no load, drops to 5 or even 2 volts, plug radio in, radio wont power up. I HEAR a little tick sometimes and the power goes back to 12v on the meter then starts dropping again.

Ive tested the output from the transformer at 22v if i remember rightly, ie... its not faulty as far as I know.

Ive measured across the bridge rectifier, and that voltage drops with the meter reading. Both reading exactly the same voltage.

Disconnecting the psu circuits from the regulator it reads around 17 volts. Right now with a radio connected its rock solid at 13.8 volts.

Ive ordered an LM chip and a new bridge rectifier to test. Its only 8 months old, hardly used, never more than 6 amps out.

If i want to repeat the fauly i just need to connect a radio to it, power off the supply, radio drains the current, disconnect radio wires, power on psu with no load connected, power drops slowly over 60 seconds or more to 2 volts.

Or, sometimes drops to 8 ish volts then goes back up, only to stay at 13.8 or whatever its set at or start slowly dropping again.

Tested for dry joints, refreshed the solder on various components.

Help please if you know this fault and have experienced it before.

Im thinking the ATU of my new radio has caused RF feedback and damaged the LM chip but i could be wrong. GOOGLE, isnt much help.

G

[GDog]

Just to update. Voltage now at zero so failed. Waiting for parts today. Will update results.

[GDog]

Replaced rectifier and now working fine