Riddled TV Repair Forum

Fairbanks-Morse · Joined: 25 Dec 2013 Posts: 4 Location: New Hampshire

Mitsubishi 25" TV
Model CK2607R
Chassis UM2-B
Production year 1990

It's completely dead. TV shut off in the middle of watching with no prior warning or symptoms. Remote won’t turn on the TV and using the power button on the front panel does nothing.

The two internal fuses tested good with a continuity test.

Any suggestions would be welcome.

Google

JTS1957 · Joined: 21 Jan 2009 Posts: 2395 Location: Far, Far Away

130VDC across C957?

Fairbanks-Morse · Joined: 25 Dec 2013 Posts: 4 Location: New Hampshire

Suggestion was:130VDC across C957?

I don’t have a background in TV repair (Prior jet engine technician) so I could use some interpretation. Is this suggestion recommending checking the 130VDC power source on position C957 on the main circuit board? Possible cold solder joint or is this a test to identify a faulty power supply?

JTS1957 · Joined: 21 Jan 2009 Posts: 2395 Location: Far, Far Away

You will need to be able to identify the different components, to safely test for voltages at specified points and be able to unsolder, test and/or change basic parts and solder them back. Google and YT should provide guidance.

I got a little ahead of myself. There is NO relay click? Right? Then will be No voltage across C957.
You'll (still) need a DVM (set to DC Volts). Across C3A0? Across C2A0?

Fairbanks-Morse · Joined: 25 Dec 2013 Posts: 4 Location: New Hampshire

Thank you for taking the time to respond to my posts. There is no relay click. There is a transformer mounted to the left of the main circuit board part number 350P43902 TRANSFORMER 24F049HD which I found online here:

http://www.hbfelectronics.com/index.php?action=disp_item&item_id=294136

The transformer is supplied by one pair of thick gauge white wire with an output to two smaller red wires. I suspect this transformer may be dead. I could check both input and output but could you tell me what DC voltage setting to use on the smaller red wires?

Thank you.

Google

JTS1957 · Joined: 21 Jan 2009 Posts: 2395 Location: Far, Far Away

At transformer wires it will be AC VOLTS.
Primary (thicker whites) = 120 VAC
Secondary (thinner reds) = approx 20 VAC

IF you were to have a DVM (set to DC Volts) and measure Across C3A0 (and obtain 21.5 VDC) & measure Across C2A0 (and obtain 12 VDC.)

EITHER will prove the transformer is O.K.

Fairbanks-Morse · Joined: 25 Dec 2013 Posts: 4 Location: New Hampshire

Thanks for taking the time to reply! I slid the main circuit board out of this 23yr old Mitsubishi TV and found a cold solder joint just under the relay. Problem solved! Perhaps it will last another 23yrs so I can will it to my great, great grandchildren.