Marshall AVT150 TDA7293

[lowell]

Replacing these output ICs. Testing the supply rails to make sure everything's functional before powering up. I have both main rails for the TDAs, however, on Pin 3 of CON1/2, which is the output connection for the TDA, I have ~ +80Vdc. Not sure why this is, or if this is correct. Of note, I don't have the output board connected at all. There is no load on the supply rails in regards to the power amp. So both rails are ~ +/-40Vdc. Finally, The speaker jacks have +80Vdc on them... with no power amp modules IN.

http://music-electronics-forum.com/a...-schematic.pdf

[lowell]

I figured why not connect a speaker and see if the DC remains. Glad I did. 0Vdc.