Marshall JCM900 2100 SL-X Preamp Problem

[stereomonostereo]

Thanks again for all the help.

R36 checks out ok. ZD2 is reading 2.16k across with no power.

[stereomonostereo]

I'm getting -1.2 and -26.4 on the sides of R36 and 26.4 and 0.7 across R35.

I really loathe this schematic.

[g1]

OK, first off, I had assumed you had +15 but not -15 VDC supply, but you are saying there is neither. You say there is +26 and -26VDC coming out of BR2. But there is basically 0VDC on the zener sides of R35 & R36. So, either R35 and R36 are bad (open), or they are burning up. Or there is some error in measurement.
You want to be measuring DC volts from either side of R35 and R36 to ground. Are those resistors overheating?

[stereomonostereo]

I'm measuring both to ground, DC voltage. And testing the resistors themselves they are showing 1k.

[J M Fahey]

Dear sms, please answer what's being asked.

Are those resistors overheating?

Nice to know they are 1K , anyway, just to confirm that they are not open.
You *might* have almost shorted ZD1/ZD2 or C12/C23 but I much suspect dead ICs.
Pray it's an easy to find TL072, because the M5201 is harder to get.
With power off, *carefully* remove the TL072, clean its holes well, turn amp on and check whether you recovered the +/-15V on pins 4 and 8.
If you did, pop a new TL072 there.
If not, remove the M5201, check that now you have +/-15V and order a new one.
As you see, I left the "difficult one" for the end.
Good luck.
PS: always pamper the board.

[stereomonostereo]

Sorry, i missed that part. The resistors aren't overheating.

I just pulled TL072 and now i'm getting my +/-15v. Replaced it with a new one and she's finally got output!

Thanks a million for the help. I woulda thrown this thing into a tree otherwise.

[g1]

Good call JM picking on the TL072 before the 5201
Glad to hear it's up and running!