9100Bs freshly acquired, weird variations

[teenix]

(02-28-2019 02:05 AM)tubenewb Wrote:  Thanks for looking out, Tony. I was splitting apart old all-in-one Macs (Plus, SE, etc.) when they were still in use and VERY conscious of the charges on those CRTs and related caps.

FWIW, here's a photo of the work the last crew did that didn't seem to fix the problem. (that TI in place of the germanium)

Cool, you should be a wiz then :-)

If it is the TIP29B you are referring to, it is a 1.0 A, 80 V 30W NPN Bipolar Power Transistor marked as Q1 in the circuit diagram for that board. Still cheaply available for around $1. It is part of the oscillator circuit around the transformer which looks like it has had better days.

Q1 is listed in the service manual on the HV PCB (09100-66522) as...
TSTR: NPN Si (this would seem to be silicon, not germanium)
MFR. 86658 (???)
PART NO. obd (???)
Not much to go on.

Looks like the circuit track has lifted off the board too.

cheers

Tony