TDA7294 - high current on Stdby-Gnd (PIN1)

B

Bruno Willi

Guest
Hi,

I'm stuck repairing a JVC compact system. Problem is the power-amp pcb
with a TDA7294; supply-voltages (pos and neg) seem to be ok; PIN1
(Stdby-Gnd) is connected via a R4.7 to ground; Stdby and Mute are
connected via a 47k to 20V;

When switching on the system, R4.7 (... and the TDA) is getting hot;
on the output are about 20V DC (... which isn't that good for the
speakers...)
I replaced the IC with a new one, but the same behaviour; I also
replaced the most surround caps. Nothing helped.
Maybe someone out there can tell me, what causes such behaviour; is
there a way to test this IC (maybe a characteristic input-resistance
or something like that.).

Bruno
 
Bruno Willi wrote:
Hi,

I'm stuck repairing a JVC compact system. Problem is the power-amp pcb
with a TDA7294; supply-voltages (pos and neg) seem to be ok; PIN1
(Stdby-Gnd) is connected via a R4.7 to ground; Stdby and Mute are
connected via a 47k to 20V;

When switching on the system, R4.7 (... and the TDA) is getting hot;
on the output are about 20V DC (... which isn't that good for the
speakers...)
I replaced the IC with a new one, but the same behaviour; I also
replaced the most surround caps. Nothing helped.
Maybe someone out there can tell me, what causes such behaviour; is
there a way to test this IC (maybe a characteristic input-resistance
or something like that.).

Bruno
Try news:sci.electronics.repair
--
10 days!


Michael A. Terrell
Central Florida
 

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