TRS-80 Model 1 - running temperature for Q4

[ColinT]

I have a Model 1 with a G version board and am finding that the main Q4 transistor in the power circuit gets very warm/hot. Should I be concerned?

 

[Eudimorphodon]

Getting hot is what it does. As long as you're getting the right voltages you're fine.

(It's typical for these linear power supply setups to be pretty inefficient and put out a lot of waste heat.)

 

[Trash-Eighty]

This was also a topic on Adrian's Digital Basement (YT) a short time ago:
The Model 1 is fixed and you'll be surprised to find out what was wrong!
at 14:27

 

[ColinT]

Thanks. I'll focus on my video problems instead now. Text seems fine but graphics tend to smear out horizontally.

 

[Eudimorphodon]

The Model I's power supply circuitry is pretty amazing, really. Single-package integrated voltage regulators existed at the time, but Radio Shack used this fistful of discrete pieces because it saved a buck or two over the price of the newer parts. But yeah, if Q4 was cool you'd actually need to worry, it being toasty is how it should be.