I have 2 of these boards now.
I bought another one to replace the failed one, few months later that went too...
I have had the power pcb repaired on one of them and I'll do the same thing on the other one, but both output stages will need to be repaired, but until I buy a oscilloscope and a soldering station I'm dead in the water.
The tech guy that fixed one of the power boards said: it's a really poor design of circuitry layout and if I get them repaired that they would more than likely fail again weeks, months later, so the circuit needs to be redesigned for much better performance as there is not really any failsafes on the boards, once 1 thing goes bad, other things blow with it.
My question is, if I repair the damage, could I modify something so if it were to blow again, only 1 thing blows? And not the whole darn power and output stage?
I bought another one to replace the failed one, few months later that went too...
I have had the power pcb repaired on one of them and I'll do the same thing on the other one, but both output stages will need to be repaired, but until I buy a oscilloscope and a soldering station I'm dead in the water.
The tech guy that fixed one of the power boards said: it's a really poor design of circuitry layout and if I get them repaired that they would more than likely fail again weeks, months later, so the circuit needs to be redesigned for much better performance as there is not really any failsafes on the boards, once 1 thing goes bad, other things blow with it.
My question is, if I repair the damage, could I modify something so if it were to blow again, only 1 thing blows? And not the whole darn power and output stage?
For what it's worth (service manual):
YAMAHA YST SW800 SUBWOOFER Service Manual download, schematics, eeprom, repair info for electronics experts
That being said, looking at the schematic, despite it using MOSFETs for the outputs, i'm almost positive that's NOT a class-D amplifier.
It does contain a protection chip (which, at least in theory, should detect overcurrent and output-DC-offset events), but sounds like that's not doing its job all that well.
Power supply's a bit on the janky side though, some sort of self-oscillating half-bridge job.
YAMAHA YST SW800 SUBWOOFER Service Manual download, schematics, eeprom, repair info for electronics experts
That being said, looking at the schematic, despite it using MOSFETs for the outputs, i'm almost positive that's NOT a class-D amplifier.
It does contain a protection chip (which, at least in theory, should detect overcurrent and output-DC-offset events), but sounds like that's not doing its job all that well.
Power supply's a bit on the janky side though, some sort of self-oscillating half-bridge job.
Hi Khron, yeah, I just do not know where to start first on the output stages, the power rails, the pieces of metal connecting 1 thing to another, 1 of them is even burnt in the middle of it, so I'm guessing that is quite rare? If so, most probably alot of components on the output stage are also damaged?
Funny enough though, only 1 of the mosfets is defective. I've been advised not to pull out so many components as they can be tested "in circuit" ? As for caps, they must be pulled out, discharged to test properly?
Shall I post some pics?
This is all on the backplate that has not had it's power pcb repaired.
Funny enough though, only 1 of the mosfets is defective. I've been advised not to pull out so many components as they can be tested "in circuit" ? As for caps, they must be pulled out, discharged to test properly?
Shall I post some pics?
This is all on the backplate that has not had it's power pcb repaired.
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