UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Retired Texas TI99/4A engineer needs help please.

Boater Sam · 21st Oct 2018, 3:18 pm

Switching regulators are not my favourite things.

PG 1992 equivalent is listed as 1N4148 so I'll replace it with one of these.
Is 1N4148 as fast as the original? We are dealing with bits designed in 1980 here.

Maybe it is working OK but the TIP31 gets warm damn quick, it has a clip on heatsink but looks to be not very efficient.
I know that the area on the console where the power supply board is gets warm normally, but...........
How hot can a TIP31 run safely?

Everything stays cold until I connect to the logic board.

21st Oct 2018, 3:18 pm	#4
Boater Sam Banned Join Date: Dec 2013 Location: Middlewich, Cheshire, UK. & Winter in the Philippines. Posts: 3,897	Re: Retired Texas TI99/4A engineer needs help please. Switching regulators are not my favourite things. PG 1992 equivalent is listed as 1N4148 so I'll replace it with one of these. Is 1N4148 as fast as the original? We are dealing with bits designed in 1980 here. Maybe it is working OK but the TIP31 gets warm damn quick, it has a clip on heatsink but looks to be not very efficient. I know that the area on the console where the power supply board is gets warm normally, but........... How hot can a TIP31 run safely? Everything stays cold until I connect to the logic board.