Orange TH30 Channel Switching

[Steelwitch]

Hi, I have another post about this in the electronics subforum. I have an orange TH30 that is switching unreliably from the front panel switch only without the footswitch plugged it. I thought it may have been the relay, but if it was, it probably wouldn’t be working at all. Just wondering if anyone has any ideas of what it could be. I know a faulty jack could cause something like this. It’s a 3 tab cliff style jack. It says on the schematic that all 3 tabs should be grounded when there isn’t anything plugged in, but the middle one doesn’t ground at all. It’s probably a very simple fix but it’s been kind of confusing. I’m not too familiar with these amps and their common issues. Thanks!

Here’s a schematic: https://music-electronics-forum.com/...3&d=1521589896

[g1]

It says on the schematic that all 3 tabs should be grounded when there isn’t anything plugged in,

I don't see that anywhere on the schematic you posted?
The relay or the switch could still be intermittent. Or a shaky solder connection.

[Steelwitch]

Sorry, I misunderstood the schematic diagram. After looking around a bit more there’s only 1.5vDC on the supply. I’m thinking C8 and C9 may be faulty. I’m going to replace them and see if the supply voltage looks closer to what’s stated

[g1]

I’m thinking C8 and C9 may be faulty.

Also C7.

[The Dude]

You can measure AC on the rectifier side of C8 and C9 to verify AC is getting to the rectifier without having to shotgun the caps.

[Steelwitch]

Replacing C8 and C9 did it. Supply is back up to 5V. Thanks y’all!