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-   -   Oscilloscope schematic? (http://www.diyaudio.com/forums/equipment-tools/72612-oscilloscope-schematic.html)

DigitalJunkie 26th January 2006 12:34 AM

Oscilloscope schematic?
 
Hey guys,

The #2 channel in my scope is dead (has been since i got it,for cheap at a yard sale.) and I finally want to fix it..

The scope is a B+K Precision 1471B

Wondering if anyone has a schematic,or any tips for repair,before I go order the schematic/parts list online..

I've popped off the little metal can cover on the 2'nd channel,and compared some voltages to the good #1 channel,it appears something is whacked in the front end (as I suspected)..There's a dual FET for each channel,a Sony (2S)K58..on the second channel the voltages on one of the dual FET's are all low,as in -V!
I think on the good circuits there was (SGD) +4.7V / 0V /+0.8V and on the "bad" FET they were about +4.7V / -7V /-6.4V !

There's a couple transistors and other things nearby that might be bad also,or perhaps part of the problem.. More investigation is needed,but i'd like to see if I could get a schematic first,hopefully with the correct voltages,etc. listed.

Anyways,Thanks! Pat.

Stocker 26th January 2006 03:12 AM

Is it not identical to the other channel? Be careful about ESD and compare directly if they are the same.


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