If similar ones don't get hot, I'd suggest pulling the part from the board. Use 
a 250 ohm resistor to ground on the outputs. If anything goes higher than 0.4V, 
there is a problem with the load. You want the part removed so you are not 
looking at the part pulling up. With the part still removed, it should also go 
over 1 Volts with a high impedance voltmeter or scope.
Dwight


________________________________
From: Rob Jarratt via cctalk <[email protected]>
Sent: Wednesday, December 24, 2025 3:47 PM
To: 'General Discussion: On-Topic and Off-Topic Posts' <[email protected]>
Cc: Rob Jarratt <[email protected]>
Subject: [cctalk] Re: Hot Video Shift Register on VT100


I just double checked and on the other unit it is a 74S299N, identical to the 
one that gets hot in the VT100. I suspect it is OK for it to get hot and maybe 
I should just stop worrying about it. But it is puzzling as to why this one 
gets hotter. I will get my VT101 back soon and I can see how that compares.

Thanks

Rob

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