Sony HDM-20E1J overload

[Retro Mecano]

Hello,

I have a sony HDM-20E1J which has an overload issue. At start up i can hear the loud magnet buzz but after 2 or 3 sec, ot goes directly to Overload. Screen does not power up.

Not really a specialists at crts, I have spent months reading BVMs manuals and trying different things (due to the huge similarities between HDM and BVM).

Complete clean up
Reseated boards
Recapped PA board
Partial recap on G board.
Checked GA and GB miniboards.

With no result.

With more digging, i suspect the defflection board (E board) having a short somwhere, but i am not sure how to identify it. Found 2 resistors and a diode having full continuity, and following up the rail is a nightmare.. besides that, i am not sure if it's the cause of the overload or it's a completlely different isssue.

Does anyone have experience with HDMs willing to guide me through this 2 years darkness?

[Retro Mecano]

Everyone advised me to seek help in shmups..
Is there anyone who could support here??

[Mantrox]

Sent you a PM.

[Retro Mecano]

Everyone advised me to seek help in shmups..
Is there anyone who could support here??

Small update if anyone by chance is reading this dusty thread...

Went up testing all the damn SMD components on the PA board, and after a long time i found out that smd resistor R526 was open. Didnt have the exact same value (62kohm) so i replaced it temporarly with 65kohm.

Now the CRT behaviour slightly changed.

The monitor starts to get beam on it and i can barely see some light on the upper half of the screen (may be due to some vertical circuit issues) before it goes to overload again.

The problem is that i dont have the bkm controller to try reducing contrast so it will turn on longer.

Any idea what to check next?

[SuperSpongo]

Which control unit does it need? BKM-10R?

EDIT: Just looked it up in the service manual and indeed it does need the BKM-10R.

There are a couple of ways to replace the BKM-10R with other stuff. Somebody wrote a python script to be able to control monitors from the PC:
https://github.com/144a/EmuBKM-10r

Also, I built a replacement for it using a Pi Pico and a display (but that would be more of a side project) :
https://www.youtube.com/watch?v=oZMb17oDjyI

[Housematt]

Mine has the same problem, adjusting contrast using BKM-10R did not improve the situation for me.

I'm sure you've already seen this, but consolemods has an enormous Sony document dump with many service notes and etc (none of the service notes helped me, but they might help you)
https://consolemods.org/wiki/CRT:BVM-20E1U

So my next step is to refer to the service manual here - this is a new scan of the service manual and the diagrams are actually clear this time.
https://consolemods.org/wiki/File:BVM-1 ... Manual.pdf

The ABL overload detection function is spread across BK board and PA board
BK ABL overload detection circuit on 3-1
PL ABL overload detection circuit om 3-12

After checking the components in that chain I'll follow the beam current protector check/adjustment procedure on 4-13