Model 1 Transistor Q3 Very Hot

[troff]

Hi All,

Dug out an ebay purchased model 1 with video issues I've been meaning to look at for a while.
When checking voltages, which all seemed fine using a multimeter (+5V pin 3 Z1, +12V pin 3 Z2, -5V CR2 as per SAMS), I noticed the TIP29 transistor at Q3 quickly got very hot, the transistor at Q4 only got slightly warm even after several minutes.
I replaced the TIP29 with a new one but no change.

I checked Q4 by removing it, measured it, cleaned up pins and re-installed, Q3 still got burning hot.

Can anyone point me in the right direction as to what to check next?

TIA

 

[Trash-Eighty]

Adrian did a video about his Model I repair. Q3 was also very hot. He found out that one Q4 screw had a bad connection to the trace of the circuit board due to oxidation:

 

[troff]

Adrian did a video about his Model I repair. Q3 was also very hot. He found out that one Q4 screw had a bad connection to the trace of the circuit board due to oxidation:

I saw Adrian's video too and thought (hoping) it would be the same problem, but as I said in my post, I removed Q4, tested and cleaned it, checked connections but it didn't make any difference for me.
Thanks anyway.

 

[troff]

Had a spare MJ2955 TO-3 that I could replace the original 2N6594 at Q4.
That solved it, Q3 barely warm now. The original transistor was bad after all. My 'testing' wasn't up to scratch, lesson learnt.