24 Nov
2025
24 Nov
'25
5:05 p.m.
I would scope it , Then pull vcc and check current, what is hot? check
resistance across the chip, maybe internal shorts?
Sorry if seggested and answered, TL/DR all of it.
On Mon, Nov 24, 2025 at 2:52 PM Peter Coghlan via cctalk <
cctalk(a)classiccmp.org> wrote:
Sorry if I wasn't clear in my earlier reply, but there were some answers
inline. The summary is that Vcc looks fine, there does not seem to be any
short on the outputs of the shift register and the chip seems to be
working
correctly. It just gets hot and I wonder if this
could be due to the CLK
input being a bit spikier on the VT100 than on my VT102? Could this be
why
later revisions of the VT100 introduced an
inductor on the DOT CLK output
from the DC011?
Perhaps one way to test the hypothesis would be to insert an inductor like
those used on the later revisions in the DOT CLK output and check whether
a) everything still works and b) the shift register runs cooler?
Regards,
Peter Coghlan.