My neighbour has a Soudlab G097F amplifier that no longer functions.
The symptoms are that everything seems to power up ok but the "protect" indicator lamp remains lit resulting in no output, whereas normaly it would only light up for a couple of seconds at power on before hearing a click and extinguishing, then fuction as normal.
Could anyone suggest where I might start fault finding?
Thanks.
-- t@k (Invalid return address. Please reply to newsgroup).
First two places to look are for an external short across the output - ie a faulty speaker or wiring whisker, or someone having driven a nail through the speaker wire, and then look inside for an open fuse. If either supply rail is missing, it will stay in protect. However, any sign of a fuse being blown violently - blackened glass or metal beads - would indicate more serious trouble in the output stages. No signs of distress at all, could indicate a problem with the fault detect / relay drive circuit itself, or even possibly something as simple as a bad joint. What is your level of experience at working on this type of equipment, and what test equipment do you have ?
Arfa
Thanks for your reply Arfa.
I am an electrician by trade, but I have a basic knowledge of electronics although I only have a half decent multi-meter to hand.
The fault persists with the speakers disconnected which themselves show no evidence of shorting,both the two glass fuses on the circuit board are fine and ther is no visual signs of overheating that I can see.
The cooling fan comes on immediately at power on, but my neighbour insists this has been so since purchase.
One thing I have found, is the sensor on the heat-sink is closed circuit in the amp's present state (cold) - should this be the case?
(Sensor at bottom left corner of image 5 at
-- t@k (Invalid return address. Please reply to newsgroup).
NOTE: disconnected from board when tested.
-- t@k (Invalid return address. Please reply to newsgroup).
I would say that the thermoswitch reading closed, is correct. There are both open and closed types, but closed types in this application are by far the most common. I have looked at the images, and C210 leapt out at me ( heatsink away from you, left side of board, just in front of centre connector ). This cap looked as if it had a domed top. I have looked at this from all the angles that I can, with the photos zoomed up, and it definitely looks as though it is. If it is domed, then that would be the very next thing that I would try with a replacement. I don't know how much actual electronics knowledge that you have, but faulty electrolytic caps are very very common, and a domed top is usually a red-flag giveaway. If it is, and you decide to have a go and replace it, note that these caps are polarised, so must be fitted the correct way round ( sorry if I'm treating you too dumb here ). The board may be marked with a "+" symbol, but more likely from what I can see, a bar at the "-" terminal. This corresponds to a stripe, usually marked "-" on the cap body itself.
Arfa
Where yoo gon?
Did you get any success with it ?
Arfa
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