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[R_J]

ZD907 (likely ok) is NZX24B 24v zener diode
D902B (likely ok) UG1004 or UF1004-T
C904B (likely ok) 1nF 50v
Seems like IC902 was the problem, ST9S101-t6G or IN1M101 not available from mouser or digikey etc. China, aliExpress, $bay
With IC902 removed and all other parts in place, It is likely you will get the standby voltage and the tv may even turn on. IC902 is more for brownout protection, and the board should work for a test to see if anything else is wrong.

[R_J]

The link to the softpedia file seems to be ok and the file itself seems to be fine as well

[R_J]

The last file (EB.zip) seems to have a virus Trojan:Script/Wacatac.B!ml Severe...

[R_J]

I found this if it helps Intel DQ965GF (Guardfish) - The Retro Web Bios version 6100
Check manufacturers other than intel that used this board , they may still have the bios

[R_J]

So, you isolated the vcc pin from the rest of the circuit? well now we know ic901 is working to produce startup vcc, this where the transformer would start to supply the run vcc, so I suspect something is dragging down the vcc line. possibly ic902?

[R_J]

The ic should be able to charge the vcc capacitor before anything else would be detected, it should be able to charge the cap with about 1ma of current. If you can isolate the vcc pin from the rest of the circuit and only connect a 10~47µf cap from H-ground to only that pin and see if the ic can charge the cap, or try removing one end of ZD907 (it may be zenering at 1 volt?) and try to isolate ic902 vcc pin if you can (careful not to break pin) I would also remove one end of D902B in case it is leaky and loading down the vcc line.
It is possible the ic is defective
IC902 is likely...

[R_J]

Richtek RT6256BGQUF

[R_J]

Looks like it could be a NJM78L05UA regulator ic if that is 8C...

[R_J]

I did not know that you had parts removed when you did this test, with D911 and D912 you would not get the + or - 12v. You seem to have more than one problem; I was just looking at the missing -12v on C912 that you posted....

[R_J]

When you say it only hums when using tapes, which tape deck, 8 track or cassette? or both? As for the FM, what are you using for an external antenna? try touching the FM ANT screw and see if that helps, you may need to connect a length of wire to act as an antenna

[R_J]

Why are you checking R901, you should be checking R912, if you have no -12vdc R912, L912 or D912 are likely open. Or the transformer winding between pins 8 and 9 may be open.
R901, C903 will not cause this fault, my guess would be open L912...

[R_J]

The ground is not an issue, but all that black carbon will need to be removed, or it will likely arc with 167vdc, also water may have entered the panel around the connector, hopefully not.

[R_J]

R907A = 4R70 4.7Ω
R907B = 3R92 3.9Ω
in parallel = 2.13Ω
I believe they are metal film 1 watt 1% resistors

[R_J]

Looks like richtec RT9711AGB

[R_J]

I will wait for op to reply....

[R_J]

The power supply is OFF because it has no standby voltage

[R_J]

Did you check the source resistors R907 A & R907B? make sure they did not open. when the internal mosfet in the ic shorted it may have damaged the source resistors, if it did the ic will likely not start. The ZD909 zener is more for spike suppression than regulation.

When power is applied ic901 will have 165vdc on its drain and it will internally supply a small current to the vcc pin, this will charge C904B, once charged to about 12~16v the ic starts to switch, then the transformer will suppliy the vcc voltage via R908A~C and D902B to about 25vdc.

Once the standby...

[R_J]

it won't turn ON when ic901 is the standby ic which ALSO provides VCC for the PFC drive ic, NO standby = NO pfc vcc, no optocoupler voltages etc....

[R_J]

Are you sure ZD909 was shorted, or did it check shorted in circuit? ZD909 is across source resistors R907A & R907B which are low values, likely under 1Ω
IC901 has an internal startup cell that creates a startup vcc voltage of around 12vdc to charge c904B so you should replace C904B and C907 as well....

[R_J]

If it is Brand New, just return it under warranty