Crown XLS 802 Power Amp Fault Lights On - No sound

[ID Crisis]

I am working on a Crown XLS 802 power amp. When the amp is powered up, the fault lights on the front panel come on and stay on. There is no output as well. This may have been due to a bad speaker connection.

I've measured for shorts in the output transistors, but they all check ok.

Anyway, the customer needs the amp back by this weekend if possible, so I was hoping someone could point me in the right direction so I can get it back to them quickly. Crown is sending me a schematic.

Any help is greatly appreciated. Thanks in advance!

[Jazz P Bass]

Here is an XLS circuit description.
The protect circuit is described on page 7.

[ID Crisis]

Here is an XLS circuit description.
The protect circuit is described on page 7.

Thank you Jazz P Bass. This helps a lot.

[Jazz P Bass]

I have a Crown CE4000 on the bench.
Fault led's are on.
What an absolute beast!
Want to help with that?

[ID Crisis]

I have a Crown CE4000 on the bench.
Fault led's are on.
What an absolute beast!
Want to help with that?

This situation called for quick turnaround. It belongs to a church and they need it by Thursday. I ended up taking it to the place it was purchased from. They work on Crown amps on a regular basis. Guitar and bass amps are more my thing - none of that protection circuit and fault led stuff. If it had not been an emergency situation, I could have spent more time, but I am keeping the customers best interests in mind.

What I will do is let you know how the service center resolves the issue.

[mozwell]

for posterity
Crown XLS202, 402, 602

Power Supply - The amplifier operates from nominal (off-load) +/- 65V (GB202), +/- 80V (GB402) or +/- 93V (GB602) supplies, with an auxiliary +/- 24V supply for the protection circuitry and the optional AMPSAP card.
To generate the supplies, the mains transformer has one secondary with a centre tap, two 18Vac taps and the usual end taps. The end tap outputs are rectified by BR1 and smoothed by C1,C3,C5,C7 to get +HT and C2,C4,C6,C8 to get -HT (note: not all of C1-C8 are fitted on GB402 and GB202). The +/- 18Vac taps are rectified by D13-D16 and smoothed by C17 to get +24Vdc and C18 to get -24Vdc.

Soft Start System - AC mains enters the board on fastons (Red, Black, Blue) and leaves for the transformer by way of connectors Main1 (220/240) and Main2 (110/120). The soft start components are on the NEUTRAL line and comprise R22, PTC1,
PTC2 and the contacts of RLY1. At switch on, R22 limits surge current and PTC1, PTC2 protect R22 from overheating.
After a few seconds, the protection circuit energises RLY1 coil, closing RLY1 contacts which short out R22, PTC1, PTC2, allowing full power operation.

Crown CE4000

[Jazz P Bass]

The CE4000 was so full of dirt it was going into protect.
What an amplifier.
When I opened it up it scared me!