In this video, I restore a Tektronix 2235 analogue oscilloscope.
Below is all the details of the obscure parts I used:
Schematics and documents:
https://drive.google.com/open?id=1L2ptk_0OeEywzHXIV2jmTQYrtf5IzgIH
Digikey Parts List:
https://www.digikey.com/short/zf0m5b
TekWiki link:
http://w140.com/tekwiki/wiki/2235
Details on parts substitutions:
- Full capacitor replacement. Swapped like for like, except.
- Two tantalums on the attenuator board were upgraded to 50V.
- PSU output caps were upgraded to 1000uF.
- The large silver 450V 75uF cap was upgraded to 120uF.
- Replaced Rifa mains caps with new x/y class caps.
- Installed 60mm fan, swapped the 20ohm resistor to 10ohm to increase fan speed slightly.
- Replaced R888 - R892, R894 with new Metal film Vishay HVR series 1/2W 510Kohm.
- Performed Service update 050-2242-03 with the following details:
- 119-3511-00 Diode-Resistor network built from an 1N4148 and 10ohm 1/4w resistor in series, cathode of diode away from resistor.
- 151-0565-00 substituted with S4010LS2TP (original part in my scope was a C106B2).
- 151-0852-00 substituted with TIP41C (original part in my scope was 476-02).
- 151-1245-00 substituted with IRFBC40LCPBF (original part in my scope was an IRF710 by International Rectifier).
- 307-0456-00 substituted with V250LA20AP (original part in my scope was V250LA15A)