Greetings.
This concerns a failed power supply board on an AB168 stage box.
In our church we have an SQ5 desk linked to an AR2412 with an AB168 slaved off it.
The system has been up and running for about 20 months. Last week the AB168 stopped working. I identified a power failure. Incoming power and fuse all OK.
As it was out of warranty I decided to investigate.
I found that the (1w?) 150k.ohm resistor on the power supply board had gone open circuit. There was no sign of it running hot, simply open circuit. No other components appeared to be faulty. I replaced the resistor and all is now well.
[Warning, for anyone looking in that area, the capacitor following the bridge rectifier sits at 350v DC. The power may be off but if the resistor is open circuit the only place for that energy to go is through you! Discharge it carefully before further exploration].
My questions:
Has anybody experienced the same failure? (Is it common?)
Can a nains power surge have caused it?
Is the mains input well protected against surges and spikes?
Should we be using additional surge-protection?
Many thanks.
Spoons.
Which resistor specifically was it? I’m having the same issue with my AB168.
I will look back to see if I recorded it. From memory It was an obvious high wattage wire-wound. Had gone completely open circuit. From memory soon after the bridge rectifier on the power supply board.
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