RCA PTK169PGA chassis repair help

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Old 11-03-13, 04:43 PM
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RCA PTK169PGA chassis repair help

This TV died suddenly. I found the main fuse blown and the chopper transistor (Q4101) shorted. There was also a bad solder joint that showed evidence of arcing. I suspect this is what killed it. I fixed these issues and now when I plug it in, nothing happens.

I have not been able to find any other bad components. Is there a way to check the regulator IC (U4101)? Any tips appreciated.
 
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Old 11-03-13, 05:33 PM
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Are you working off a service manual ?

Power supplies like that are a series of loops that can be difficult to service.
You need to check for main B+ power of around 150 vdc.

The IC below is the standby regulator. Be sure to check capacitors around it for issues.

TEA2261 datasheet, Pinout ,application circuits SWITCH MODE POWER SUPPLY CONTROLLER
 
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Old 11-03-13, 08:07 PM
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I have the schematic of the power supply. The standby supply does not seem to be working. I cannot find any shorted or open parts, so I think the regulator is likely. I will order one and then go from there. I am assuming here that the cause of the failure would have killed some component(s), and I am not dealing with the bad caps and leaky diodes this chassis is known for.
 
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Old 11-08-13, 01:05 AM
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I replaced the regulator IC. Now it makes a little noise when plugged in. When in standby, I am getting 14-15 volts on CR4118 but nothing on CR4116 (B+). Does this mean the supply is working and there is a short on this line (HV splitter maybe)? Or could this still be a power supply issue?
 
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