crate-gx212 problem need help

[cliff465]

hi guys
i have 2 gx212 guitar amp,both they have same problem
when disconnect speaker,b+ b-are +-40v,and op ic v+ v- are 16.6v as normal
but when it connect to speaker,b+ b- are +-10v and v+ v- are +-3.8v as short.
and it has some hum
the output transistors tip142 147 are ok,but tip142 become hot and the speakers also work fine.

can somebody help me?

[techineer]

It sounds like there is DC voltage being applied to the speaker. When you disconnect the speaker, what does a DC voltmeter read when you connect it across the speaker tabs J4 and J5 on the board?

If it's more than zero, look for shorted output transistors. Also check Q8 and Q14, as well as any resistors below 1K ohm.

[Gtr_tech]

Shorted output x-istors fer sher. Don't just let it sit there with dc on the speaker. it'll toast the speaker's coil.