3 and 4 are good.
Are C7 and C8 originals?
Measure voltages at pins 11 and 5 of IC1.
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Schematics show this as a simple series pass transistor type regulator. Too low of input voltage and the regulator circuit will 'drop out' resulting in glitches or drops in regulated output voltage. Too high of input voltage and the regulator circuit has to dissipate the excess input voltage as heat. Sweet spot for this circuit is near the 12V value but varies depending on your specific 2N6057.
2N6057 is LONG obsolete. Those in the photo would be pretty old stock. For awhile, 2N6059 was the manufacturer recommended replacement part.
As of about 5 or 6 years go, 2N6059 also went obsolete.
Recommended replacement is now 2N6284. You can find these at Mouser -- search for 2N6284G.
Sockets for TO-3 transistors are horrible and have had them cause all sorts of problems in the past.
Not a bad idea to replace socket. Get AMP (TE) part number 8080-1G1-LF which is also available at Mouser.
Chris --
On your webpage, the two 6821s also have another indication on them that shows them to be fakes.
Right side photo of 6821, date code is "0438" (38th week of 2004). Left side photo of 6821 - Jerry's photo, date code is "0640" (40th week of 2006).
Motorola issued a last time buy for 6800 and 6821s with a date of December 1999. Last time deliveries were in scheduled for 2000 but I was told they stretched into 2001. Absolute latest date code for 6800s and 6821s would be 2001.
Jerry's part may have worked but the date says it was made 6 years after it was discontinued. Definitely a remark. And since it misrepresents the age of the part, it qualifies as a counterfeit.
I still have a bit more info on my website - if you want to, copy what you want from that page because I'm not sure how much longer that will be up.
https://www.greatplainselectronics.com/Information.asp?region=133
My favorite is the photo of a 6810 memory at the bottom of the page with the 40 pin package.
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