Author Topic: Help Identifying COS6100M Scope Components  (Read 199 times)

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Offline LivermoriumTopic starter

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Help Identifying COS6100M Scope Components
« on: November 06, 2024, 08:03:11 pm »
Hello EEV World! - Looking for help to ID these two old components from a COS6100M Oscilloscope.

RESISTOR - 2BJ (H in diamond) 68 Ohm
TRANSISTOR - NEC C2371 L D 3Z

The Problem - The Trace on the scope is blinding. I adjusted the Sub Intensity Adjustment RV1141, and the trace is still insanely bright. I checked the Power Supply Circuit and found that Test Point 5 should be +150V, but is measuring 63.8V. On the power supply circuit I found some heat damage on the Resistor and Transistor in question (both in pic attached). Going to replace these components, haven't had any luck finding them online, any and all help is appreciated for this, my first post.

I also attached the schematic of the Power Supply Circuit. I adjusted RV1211, the 12V adjustment point which influences all the other power circuits. It was at 12.6V, now nominal.

https://archive.org/details/kikusui_COS6100M_E/page/n3/mode/2up
 

Offline Haenk

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Re: Help Identifying COS6100M Scope Components
« Reply #1 on: November 06, 2024, 08:11:03 pm »
search for 2sc2371 - easily available
the resistor is wirewound, maybe 2Watt, easy to source, too
 
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Offline coromonadalix

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Re: Help Identifying COS6100M Scope Components
« Reply #2 on: November 07, 2024, 01:11:58 pm »
this link is better  full schematics and parts values

https://elektrotanya.com/kikusui_cos6100_oscilloscope_user_sm.pdf/download.html#dl

name the parts placement   

Q1213 is the requested transistor,   who act as a pre driver for Q1211,   2sc 1505,  150vdc  line
R1124  would be your 68 ohms 2watts resistor ?   you have 2x of them for the 12 vdc lines

comment would be for the 150vdc line,  check the zenner CR1213,  C1213, C1214  ...   don't change part(s) hoping it may / will solve your problems,  do proper diagnostics BEFORE
« Last Edit: November 07, 2024, 01:20:15 pm by coromonadalix »
 
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