faulty wharfedale R2004 mixing desk. Need schematics!
i have a wharfedale pro R-2004 passive mixing desk used for community open mic and jam sessions, now i began to get an intermittent problem whereby it would power up ok but the moment one peaked on the mic it would switch off. i had 4 of the smaller caps replaced and had it tested and it seemed to work great. just that this week i switched it back on and it blew again with the same symptoms appearing.
this time i noticed that the larger cap including the small one blew..
please can someone guide me.. i live in a small town in new zealand. no one here has a circuit diagram and i cannot seem to find one on the net either.
i have a wharfedale pro R-2004 passive mixing desk used for community open mic and jam sessions, now i began to get an intermittent problem whereby it would power up ok but the moment one peaked on the mic it would switch off. i had 4 of the smaller caps replaced and had it tested and it seemed to work great. just that this week i switched it back on and it blew again with the same symptoms appearing.
this time i noticed that the larger cap including the small one blew..
please can someone guide me.. i live in a small town in new zealand. no one here has a circuit diagram and i cannot seem to find one on the net either.
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Well C8 (or is that C6? - bottom right hand corner of the PCB) looks ready to go as well as the Big cap next to it.
R1 and R2 may be slightly toasty or it could just be shadows on the picture.
personally I would change all the capacitors (that you haven't changed already) as they have obviously all been toasty and warm.....
I can't make out what those ICes are in your picture, but I would guess maybe a couple of LM317/LM337 types and fixed 78xx and 79xx regulators with probably a TL783 for 48V Phantom power.
if so the circuitry should be pretty simple if you know what the supply rail voltages are meant to be, although offhand I can't work out why there are so many diodes?
Could you list the part numbers on the To220 devices please?
R1 and R2 may be slightly toasty or it could just be shadows on the picture.
personally I would change all the capacitors (that you haven't changed already) as they have obviously all been toasty and warm.....
I can't make out what those ICes are in your picture, but I would guess maybe a couple of LM317/LM337 types and fixed 78xx and 79xx regulators with probably a TL783 for 48V Phantom power.
if so the circuitry should be pretty simple if you know what the supply rail voltages are meant to be, although offhand I can't work out why there are so many diodes?
Could you list the part numbers on the To220 devices please?
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