Need help with ctc169. High voltage at B+

You need only measure the voltages on cr4116 and cr4118 with the tv turned OFF in standby. The 15 volt line should be 13.4v-15v and the

If those are high then the standby regulation stage is bad in the main smps and nothing else you check will matter. Typically the 2.2uf cap near the smps ic is the culprit if both voltages are reading a bit high.

If the 143V line is high and the 15v line is low, then cr4118 is bad.

Be aware that if this is the rptv, then the high voltage turn on attempts probably damaged the high voltage splitter and it may need replaced, but fix the supply first.

Thanks for the response. I will go check this now. I will post my findings. I hope that you can help me resolve this issue. I really appreciate it.

Shallowrunner

dkuhajda,

I measure across diode cr116u (I assume this is 4116 since it is in the

I think I may of measure cr117 instead. I placed my leads across cr118u and plugged in the set. I mentioned that I hear the clickings sound when I plug in the set....well cr118u spiked to around 13 vdc with every click. Once the clicking stopped...then the voltage of cr118u went to zero volts. Does this sound right. cr118u is at the top left corner of T4102.

Shallowrunner

I am not sure what you are measuring because you should not be measuring across any of the diodes as those will always be 0.7-0.9v the forward voltage drop of the diode.

If the tv is trying to trun on and going into protect shutdown, then everything will go to zero. You need to make sure the tv is not trying to turn on at plug in.

Change these first! Then continue!

CR4118 should always be changed if it's the original one...it will check good but break down under load.

See this list of part that must be changed on these for reliable operation & is considered a general tune up for any CTC169 chassis......this is a good place to start.

--------------------------------------------------------------- Text pasted from WinSTIPS 2.0

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RCA CTC169

When Working On Any Of The Ctc169 Chassis Replace The Following If They Are The Original Parts. Cr4118 (Ecg580 Or Equiv) C4102 2.2uf 100v C4104 15uf 63v C4108 47uf 50v ( Sometimes This Is A 39uf)

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-- ========================== Jeff Stielau Shoreline Electronics Repair

dkuhajda...I was measuring at TP4101 for B+. I was looking for 3403 ground but could not find it so I used the cathode side of a diode. Not sure if this is right. . I also measured TP 4103 for +15 volts and used a diode cathode as ground. I had the same results. B+ spiked to

Thanks for you help.

Shallowrunner

Thanks Jeff, I will try that and post my results. Am I checking the B+ correctly? I am using test point 4101 and using the cathode side of a diode. I could not find a ground pin persay.

Shallowrunner

Update....

Let me tell you what I did...and then maybe you can tell me what I need to do next. For some reason...the B+ was spiking to 220 volts and drifting to zero. I measured this at test point 4101 and I also measure the +15 and it was no where near there. I used the negative leg of an electrolytic cap for ground. I replaced cr4118, c4102, c4104 and c4108. I then rechecked B+. It was at 139 vdc standby and at 141.5 when I turned the unit on. Well....Let me rephrase that. I have the box out of the projection tv. I used the remote to turn the unit on and it sounded like it came on. However, I had no picture or sound (sound I guess because of no speakers) and no picture because I am thinking that the spike in dc voltage damaged the HV splitter. Am I correct on all this? What would be the next step? I would think that replacing the HV Splitter is all the unit would need left, but then again, I am not TV technician just someone who likes a challenge and a do it yourselfer. I sure would like to be cuz this is cool (and dangerous). Can you please help me finish this unit up?

Clip your ground lead to one of the RCA jacks ground ring or the CRT ground strap.

-- ========================== Jeff Stielau Shoreline Electronics Repair