EEVblog Electronics Community Forum
Electronics => Repair => Topic started by: Jeff eelcr on February 25, 2024, 01:24:46 pm
-
Blaupunkt car radio Bamberg CR stereo 455 7634934210 SN: G5490440, Amplifier 8638710305 SN: 0755865.
The amplifier contains 4 parts I can't ID W700, W710, W720, and W730 all custom IC's?
I need a schematic on this (rare) amplifier or at least pinout of these parts?
These units also came with a UKW Stationwahler 7607127000 SN: F0489781.
Thanks for any help.
Jeff
-
This "W710" ++ are resistor-networks - and yes, they are customer-specific . ( -didn´t go defectiv so often - as I remember)
Have a look to tatalum capacitors !
I found that attached file only - may not fit to your radio.
-
Thats the manual on a very close (useable) radio but not close on the amplifier.
At least I now know what these parts are and they may be OK but signal is clean on one pin (assume input)
and distorted on other.
I only tested tant's for short so far, and the fact someone was in this before me after they hooked it up wrong "twice"
made me want a manual, two blown runs, only one they fixed.
I found they also removed the output transistors insulators and bent the heatsink :-//
Thanks,
Jeff
-
not being rude, ditch this repair
if they were badly played in it .... before you .. you'll have to assume and check all the mess before beig ok to assume now i have the real problem ..
my 2 cents, when i see this i simply move on
-
I feel the same way most times, but antiques tend to be simpler and repairable and I charge more for stupidity.
Jeff
-
Found the problems, same in each channel BC328N shorted (not sure on baseing) middle leg to left leg.
Strange it did not draw more current.
Jeff
-
good + tenacity :-+