SWR Workingman's 15 Combo humming...

[acorkos]

Lowish output, distorted/crackling, and hum.... +HV is 48V, -HV is -74V. this doesn't seem right...does it? if not, what could be causing this? thanks for your help...

http://music-electronics-forum.com/a...-amp-rev-1.pdf

[The Dude]

Check the AC content on the +HV rail. I suspect, you likely have a filter capacitor that is either defective or has broken loose from the circuit board. You should probably also unplug the speaker until you get it sorted.

[acorkos]

check the ac content on the +hv rail. I suspect, you likely have a filter capacitor that is either defective or has broken loose from the circuit board. You should probably also unplug the speaker until you get it sorted.

24vac @ +hv....0vac @ -hv

[The Dude]

C1 is not working. It is either defective, or has come loose. Check the solder joints on this cap. Give it a good wiggle. Sometimes hairline solder cracks are hard to see.

[acorkos]

C1 is not working. It is either defective, or has come loose. Check the solder joints on this cap. Give it a good wiggle. Sometimes hairline solder cracks are hard to see.

solder joints are good....cap must be bad. thanks!

[The Dude]

If you don't have a cap to sub, you can swap C1 and C2 and see if your AC problem goes to the -HV side. Might be good to verify before you order parts.

[acorkos]

found 2 x 6800uF/63V caps locally...installed them, and all is good. thanks again!