Mitsubishi CS-20SX1, intermittent start up.

[David Farber]

This Mitsubishi CS-20SX1 randomly decides it won't start up. The relay
clicks, the high voltage comes on, then about two seconds later, the relay
clicks again. You can't attempt to turn it back on until you unplug the set
and connect it again. I have no schematic on this set. It seemed that all it
might need was to redo some intermittent soldering connections or replace
some leaky caps. Reflowing the solder didn't help and the caps look and test
very good. While doing a Google search, I was thrilled to find the following
tech tips on this unit:

http://www.freelists.org/archives/techassist/06-2003/msg00655.html
From Tech Repair CD:
MITSUBISHI\CS20SX1\SHUTDOWNS AT TURN ON IMMEDIATELY* RELAY WILL NOT CLICK
AGAIN
UNTIL MICRO RESET\\\\22/50V CAP MOUNTED UNDER
CIRCUIT BOARD NEAR IC401\\\\\\\\

I noticed that the 22uF 50V cap is not located under the circuit board. The
cap that is in the set now checks ok so I was hesitant to change it. It's
funny that there is no mention of the capacitor's reference number but
there's only one 22uF cap in the neighborhood.

Secondly, I found this tip:

http://www.tipsmaster.ca/1help-QA.html

Brand: MITSUBISHI Type: CTV Model: CS20SX1
Question: Instant shutdown or intermittent start up.
Answer: Replace D715(5.1V zener with 6.2V zener).

I performed that modification and it managed to shift the on screen display
about 1/3 of the screen to the left and also caused the on screen display
colors to be misconverged. Adjusting the osd position control moved it back
where it was supposed to be but the osd colors were terrible. This
misconvergence only applied to the volume, tint, brightness, color,
contrast, and sharpness. It did not affect the channel numbers which appear
in the upper right hand corner of the screen. Reinstalling the original
diode corrected the osd problem.

So I was wondering if any of you had come across this problem and had any
success with the above modifications.

Thanks for your reply.

 

[David Farber]

This Mitsubishi CS-20SX1 randomly decides it won't start up. The relay
clicks, the high voltage comes on, then about two seconds later, the relay
clicks again. You can't attempt to turn it back on until you unplug the set
and connect it again. I have no schematic on this set. It seemed that all it
might need was to redo some intermittent soldering connections or replace
some leaky caps. Reflowing the solder didn't help and the caps look and test
very good. While doing a Google search, I was thrilled to find the following
tech tips on this unit:

http://www.freelists.org/archives/techassist/06-2003/msg00655.html
From Tech Repair CD:
MITSUBISHI\CS20SX1\SHUTDOWNS AT TURN ON IMMEDIATELY* RELAY WILL NOT CLICK
AGAIN
UNTIL MICRO RESET\\\\22/50V CAP MOUNTED UNDER
CIRCUIT BOARD NEAR IC401\\\\\\\\

I noticed that the 22uF 50V cap is not located under the circuit board. The
cap that is in the set now checks ok so I was hesitant to change it. It's
funny that there is no mention of the capacitor's reference number but
there's only one 22uF cap in the neighborhood.

Secondly, I found this tip:

http://www.tipsmaster.ca/1help-QA.html

Brand: MITSUBISHI Type: CTV Model: CS20SX1
Question: Instant shutdown or intermittent start up.
Answer: Replace D715(5.1V zener with 6.2V zener).

I performed that modification and it managed to shift the on screen display
about 1/3 of the screen to the left and also caused the on screen display
colors to be misconverged. Adjusting the osd position control moved it back
where it was supposed to be but the osd colors were terrible. This
misconvergence only applied to the volume, tint, brightness, color,
contrast, and sharpness. It did not affect the channel numbers which appear
in the upper right hand corner of the screen. Reinstalling the original
diode corrected the osd problem.

So I was wondering if any of you had come across this problem and had any
success with the above modifications.

Thanks for your reply.

I was able to find the fault with this set.

C519 100uF @ 50V, even though esr was ok, it was leaking.
C520 1uF @ 50V, esr slightly high. (8.2 ohms)

I replaced both of those caps, cleaned up the leaky stuff, and so far so
good.

 

[[email protected]]

The only thing in my history notes on that model is a distorted audio
problem. A leaky capacitor was the culprit, but the esr also checked
marginally good. Right next to the audio process circuit.