Marshall Valvestate VS30- Hum/No Output

[glstarr]

thanks

Thanks for the reference. I did pick up some sockets and got the ics ordered!! This sure is different than working on hard wired tube stuff. Do you guys use a magnifying glass to work onthese circuits? I'd swear it seems the solder points touch each other they're so close together!!!

[glstarr]

Can't find M5201 chip

My parts store can't cross reference a m5201 ic. does anybody know where to get ahold of one of these??? !!!

[Enzo]

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[Pleb]

Hi Enzo!

Hi there Enzo, you seem to have a good knowledge of electronics, you've definitely helped me with my Marshall MG15CDR, which had the same symptons as this VS30. I replaced the output amp and took notice of your warnings that something else could be blown. It works fine now, thanks. I was looking at the schematic and saw that there are two diodes on the input of IC1a which are connected to + and - 15volts. Can you tell me what these diodes are for as I've never seen this arrangement on an amplifier before?
Thanks in advance Bub,
Pleb.

If it has that TDA2050, and there is a loud hum, check for DC voltage across your speaker. There should not be any. Or watch the speaker copne. When you power on, does it move one direction and stay there? That would be DC. It will burn up a speaker, so don;t leave it on.

And if there is DC there, then just replace that TDA2050.