PVM M series power supply failures question

[netimmerse]

I have a PVM-14M4E that has a faulty power supply (G board, overvoltage on 5V, 15V and 115V rails, getting 5.5v, 18v and 133v respectively) which is quite stubborn in repairs.

The list of the things i have done on it so far, to no avail:
- completely recapped the board
- replaced IC602 (STR-S3115, which was shorted at first)
- replaced IC603, IC604, IC605 (5V and 12V regulators) and PH601 (optocoupler)
- currently waiting for IC601 replacement (STR-M6524) to arrive

Question to anyone who happened to repair M series power supplies - what else i could've missed? What did you have to replace?

 

[hatmoose]

This is a particularly tricky situation because a bad power supply is known to blow the HOT, and a bad HOT is known to blow the power supply, so they are quite hard to fix without a few other similar PVM's and a supply of HOT's.

Made even more tricky by Sonys weird design decisions for these power supplies where they only deliver the rated voltage when they are drawing the expected current so they are quite hard to test without a known good chassis to test them on.

I guess what I'm asking is - Are you absolutely sure this is a bad power supply and not a problem somewhere on the chassis? I normally look for
degauss ping
tube static
neck glow
Before I start suspecting the power

 

[netimmerse]

I guess what I'm asking is - Are you absolutely sure this is a bad power supply and not a problem somewhere on the chassis? I normally look for
degauss ping
tube static
neck glow
Before I start suspecting the power

The monitor itself ran fine, just with the output voltages higher than expected (well, until today - HOT decided to short on a power cycle and blow both the PWM and the controller).
This in turn caused many undesirable effects such as wavy raster and pincushion distortion when switching between 50/60hz.

Speaking of supply of HOT's, the 1881 i had installed as a replacement may have been fake, and so is 1878 i have bought along with it.
I have a PVM-14L4 used for spare parts, but i have no idea of the HOT used in there would be compatible (2SC5450) as it doesn't have a damper diode.

 

[hatmoose]

So many fake HOT's out there, I also have a draw full of them too When I was working on my 20M4 I eventually sourced one from a donor 14M2. Most Sony PVM's from the 53 series all the way through to "M" were very similar, but the L series was a strange bird. iI'm not sure that the 2SC5450 is going to be a suitable replacement outside of the "L" series.

The owner of this thread visits arcade projects reasonably often, but also worth a read in the meantime - it is my go-to for PVM power supply repair
https://www.vintage-radio.net/forum/showthread.php?t=189910

 

[netimmerse]

Update: PSU fixed by replacing PC111 (optocoupler), voltages are stable now.
The problem with pincushion distortion still persists, at this point probably the only thing i can suspect is IC509.

Raster with L509 removed looks like this.