Tinitron KV-27S42 Blinking Standby Lights

[DeathByBFG]

Hi Everyone. I'm having an issue with a KV-27S42 Trinitron. It has a BA-4D chassis. The issue is that I turn it on and get two blinking LEDs in succession. According to the service manual it means there's a +B overcurrent and two possible problems is that Q502 is shorted or IC1751 is shorted. I didn't take IC1751 out of circuit as it's on the C board but it doesn't appear to be shorted when checking for continuity or resistance. I took Q502 out of circuit and had some readings that made me think it was a problem. It's NPN and I get the following readings with my multimeter set to diode:
Base to Collector - 0.5V
Base to Emitter - 0.059 V
Collector to Emitter - 0.5V

Then I switched the leads and got these results:
Collector to Base OL
Emitter to Base - 0.059V
Emitter to Collector - OL

Those readings made me think something was wrong with that diode on the emitter side. So I ordered some new diodes of that same model (2SC5426), installed one, and the same problem happened. I measured all of them and they all measured about the same as the one I took out of the A board. So my questions to the forum are as follows:
1) The overarching question is what other components do you advise I check for this problem?
2) How do I properly measure the transistor? I assumed that the Base To Emitter should be around 0.5V. I also assumed that I shouldn't be able to measure from the emitter to base or collector to emitter. I'm also asking this assuming that the transistor replacements I bought are good. I find it unlikely that I got 5 bad ones.

Link to the service manual is below:
https://dn790009.ca.archive.org/0/items ... 105670.pdf

Thanks in advance for any help.

[KPackratt2k]

Measure the voltage of the 5V regulator (Q502 emitter) with the red multimeter probe on the emitter pin of the transistor and the black probe on a nearby ground point in DC voltage measurement mode. If it's less than 5V, then measure the VDD pins of the comb filter chip (IC302 pins 22 and 23) between ground with the continuity feature of your multimeter. If it's shorted or it has low resistance, then the comb filter chip will need to be removed/replaced in conjunction with the 5V regulator transistor (Q502). I worked on one of these that had a similar problem to yours and found that both of those components needed to be replaced to make it work again.

[DeathByBFG]

Thank you for the tips. I think I may be having issues with IC302 as well. But I need to double check the readings. Do you recall what the measurements should be for Q502 when testing it alone? My measurements are when it was out of circuit.

[KPackratt2k]

The collector is connected to the 30V power rail on the TV chassis, so that end of it should read 30V when measured in circuit with the set powered on.