Sick ProTrack-Over Voltage Warning.

Started by jvthorsley, September 23, 2016, 11:17:35 AM

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Over the last few months my ProTrack has started claiming an over voltage has been applied.
The fault then became solid on power up and all that happened was that both channel LED's flashed and the ProTrack never got out of the initial diagnostic mode, plus no trace on the CRT.
I found the cause of the problem was caused by acid coming out of capacitors 112,113,114, & 115 (47uf 25 V.) on the main circuit board.
Especially C115 where the acid had eaten through track making the connection from L4 to input of U46 (7905) open circuit.
I suspect these capacitors leaking acid and inherent high ESR may have caused a few other spurious faults in the past such as the set ranges occasionally changing on their own without me touching the controls.
**L4 is just above L3 shown on my attached photograph, but because of the size limitation on this web site I had to crop the photograph.**
Take a closer look at the photograph to see what havoc the acid has done.


Ah. Electrolytic caps. Always a suspect!
The most important troubleshooting tool is your eyes.


Thank you, I better go check mine and recap anyway before things happen