Sony kv20v80 PS Problem?

Hi all, I have a 1998 Sony kv20v80 in shutdown with 2 blinks on the standby led. I think that means the PS section area. I am working off of a Sam's #4134 schematic.

Measured the 115v, 12v, and standby 5v sources and these are ok. The

9v source off of Q605 9v reg goes to 4v before shutdown. As is the 5v source off of Q650 reg, fed from the 9v source. Measured the resistance at the 9v TP to ground and it read 3.5 ohms. Don't know if that's normal or not.

Q502 HOT is a 2sc5426 with internal damper. Seems to check out ok except I do get a reading of 43 in ohms function B to E and 4.3 in diode check function. Reversing the leads gives the same #s. Not sure if the Hot has an internal resistor.

Anyone with pointers on what I should be looking at next or have fixes on similar models.

Thanks , Al

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I don't have the schematic of this set to follow you. It must be at least 8 years since I last worked on this model.

If the HOT is not shorted from E to C, and there is supply volts to the C, then it is possible that there is no drive to it. To properly check the HOT, it must be removed. It is best to check it by replacing it.

At the HOT, check to see if there are drive pulses on the B. If not, follow the path back. Sometimes, the H driver transformer that is driving the B of the HOT can be defective, or the device driving the driver transformer, or the scan gen IC itself can be the fault. There are a number of components used in these areas that can also fail. Don't rule out the flyback assy being defective, and thus causing a safety shutdown. You will have to figure this out from procedure.

As for the 9V source having such a low resistance, I would investigate that as well. I think if the 9V in this set is not working, there may be other issues with the user setup memory, tuner and front end, but I cannot remember details about this one.

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