Orion 2150gx repair

[punch45x2]

Hey guys repairing an Orion 2150gx I have read all related posts on here and I am not getting any where. The amp currently snaps a 10 amp fuse with just power and ground hooked up. No blown transistors on ps or output side. Any ideas?

 

[Perry Babin]

What's the resistance across the red and black power wires?

 

[punch45x2]

368 ohms

 

[Perry Babin]

Does it try to build any rail voltage when you apply power?

Does the voltage on the remote wire remain at 0v when power is applied?

 

[punch45x2]

No voltage on remote. It builds almost 5v dc on rail.

 

[Perry Babin]

Desolder one wire on the thermal switch. Does it still try to power up?

 

[punch45x2]

Yes still trying to build rail voltage

 

[Perry Babin]

Is there a standing 2n6488 standing in the power supply section? If so, pull it. Does the amp still try to power up?

 

[punch45x2]

Yes there is. It is still trying to build rail voltage

 

[Perry Babin]

What's the DC voltage on the emitter pad for the 2N6488 that you removed?

 

[punch45x2]

With the unit on board or removed

 

[Perry Babin]

Unit? If you mean the 6488, with it out of the circuit.

 

[punch45x2]

.5 vdc. But the current is pulling voltage down to 1vdc.

 

[Perry Babin]

What's the resistance between the B+ wire and the RCA shields (nothing connected to the amp)?

 

[punch45x2]

Open

 

[Perry Babin]

In post #13, did you mean that it was pulling the 12v supply voltage down to 1v?

 

[punch45x2]

Yes. unless I use a battery to back it up. Then the voltage will drop to 8v. With a charged battery hooked up.

 

[Perry Babin]

When you checked the 2N6488s on the heatsink, in the power supply, did you check them between base and collector?

 

[punch45x2]

For shorts on the ps transistors?

 

[Perry Babin]

Yes. What was the resistance reading B-C?