Hartke LH500, no sound

[psycle_1]

So I received a Hartke LH500 to repair. Owner accidentally used an instrument cable instead of a speaker cable to plug the amp into a cab, no output. I checked the power amp board and I don't see any damaged components. Checked all the output transistors, none were shorted. I can hear the speaker relay engaging, but I'm wondering if there might be an internal fault with it. I haven't investigated it further. Any advice as to other things to look at would be great!

[g1]

Just because you hear the relay click does not mean the switching contacts are good.
You need to verify that the relay switch contacts are closing when engaged. (or bypass them as a test)

[psycle_1]

Resistance between contacts is .3 ohms when the relay is engaged.

[52 Bill]

I doubt that the instrument cable damaged the amp.

Have you tried the usual things like jumpering the power amp in preamp out jacks? Sending a signal into the power amp in jack?

[psycle_1]

Tried both, nothing.

[The Dude]

If neither the preamp out or power amp in work, I would start by checking your power supply- +&-15V, +&-80, etc. I'm with Bill. I doubt the instrument cable damaged the amp, unless it was shorted. It's not recommended, but normally won't hurt anything.