[sdiy] low supply voltage dual opamp ??? found the offending 8SOIC part number

Jean-Pierre Desrochers jpdesroc at oricom.ca
Thu Sep 29 16:17:53 CEST 2016

In my last post seeking for a replacement
for a noisy small surface mount 8SOIC chip lettered
690 055 used in a Samson AH1 wireless headset..
Well when you don't have any schematic to work with
you have to make some circuit analysis and decision.
The bad IC had supply pins 4=GND and 8=2.5vdc (AAA 1.5v cranked to 
and its final audio output was on pin 7.
Well I decided to go with a low voltage dual opamp
such as the Microchip MCP6002.
So I replaced the bad IC with that but.. no luck..
no sound was present anymore on pin 7..
Fortunately I found a Samson service center and
the guy I talked to was welling to tell that the actual
original 8SOIC part number was... TK10690.
This is an obsolete compressor/expander.
Try to figure out that part number starting with
a partial "690 055" lettering on it !!!!
You know technology does not always get better over time..

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