Orion Xtreme 800.4 No Power?

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I've got an Orion Xtreme 800.4 that will not power up. Anyone have any experience with this model? I've got a Fluke 115 DMM to troubleshoot with. Will a 12v computer power source suffice as a power source? Thank you.


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Post a photo of the board. Different revisions of the same model can have different boards.

12v computer supply... Sometimes. Some are too sensitive to the inrush current of some amplifiers.

Have you checked the fuses and confirmed that you had consistent 12v+ across the B+ and ground terminals as the amp tried to power up?
11.61v at 12v+ and B+ :(

PCB board has some information:

0770-5109B 600.4 XTR
05/11/99 CHL

I'll be straightforward, this amp has some rework. The transistors on the 'solder side' get warm to the touch. 30v/-30v on center pins of the large rectifiers.


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The amp is powering up if you have positive and negative rail voltage.

If the LED isn't lit, it may be defective or have a broken lead.

Confirm that you read 120 ohms between the primary ground and the non-bridging speaker terminals.

Confirm that you read 0 ohms between the RCA shields and the non-bridging speaker terminals.

No RCAs plugged in and no power applied for either test
Ok Boss, traced the lead over to U3 in the upper right in the picture and discovered that the two regulators U3/U4 are in the wrong locations... I pulled them. Do I dare reuse them and apply full power? My power supply output: 12.0v @3.5A


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-5.10v on output of 7905CT @ U4
4.88v on output of 7805CT @ U3

And the LED is glowing bright red good sir. Now take a bow. :cheers: Take a break if you wish or shall we keep going? What to test to ensure correct operation?


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Negative voltage on the 7905? Measure with the black probe on the ground terminal of the regulator.

If this amp uses sil-pad material, it's best not to reassemble without adding heatsink compound to the transistors.

You need to clamp all semiconductors to the heatsink before testing for more than a few seconds at a time. You can test to confirm that the amp is producing audio out of the sink but only briefly, constantly monitoring the temperature of all components that would normally be clamped to the heatsink (including those under the board).
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