As I've already explained in post #20, the chip is powered from the transformer - so you can't do tests with parts removed. In the case of removing the chip you've no supply from the transformer to feed the chip, and it's high because it's startup resistor is fed from the main HT rail, relying on the current the chip takes to keep it low enough.Back after a bit of work. I pulled the 4605 and powered up without it, I'm seeing 26VDC and about 0.045VAC across pins 6 and 4 (supply and ground). About 140VAC between pin 6 and the chassis, and about the same VAC between pin 4 and chassis.
I should put it on the scope but I think the VAC values are probably about right. But 26VDC seems a bit high to me. I'm going to let it discharge a little and go for a ride before checking out the remaining components you mentioned up near the transformer.
160uF and 0.36ohms is probably out of tolerance, and while it may not be causing any issues at the moment it will only get worse, until it does cause problems. However, powering it up without the chip in place won't have done it any good, 26V across a 16V capacitor isn't a good idea, and presumably it was only the capacitor breaking down that prevented it going higher.I'm learning, part of learning is generally looking around to see what's happening in a circuit. I appreciate this mightn't be helpful to those trying to guide me through though.
The only anomaly I can see is that CP09 (an electrolytic which would be C2 on the diagram you provided) is reading on my ESR meter as 160uF and 0.36ohms (out of circuit), whereas the component's value is 220uF 16V. I understand electrolytics can have large tolerances so I'm unsure if this warrants replacement or not. DP04 (which would be D1 on your circuit) seems to be fine. RP04 (which would be R1 on your circuit) also measures well at 12k for a 12k value.