On 12/23/2017 5:34 AM, Mattis Lind via cctalk wrote:
2017-12-23 13:32 GMT+01:00 Mattis Lind <mattisl...@gmail.com>:
Yes, the oscillator seems to work. But it is a pain to work with the VT52
since the print set has very little information. Where is the component
list? I cannot verify which PROM should go into what location. And the damn
boards doesn't have any component designator anywhere, nor is there
anything on the component placement info in the print set on the data path
board.
The PROMs in my machine are: 23-124A9, 23-125A9, 23-126A9 and 23-127A9. Is
this the same as your VT52? Apparently there is an earlier PROM set as
well.
It would be very nice if you could tell me the location of the PROM chips
as well.
/Mattis
I did some more research into the terminal after I put the christmas ham
steak into the oven and christmas rice pudding on the stove.
There were nothing going on at the microprogram outputs. All high. It
turned out that the CE input for the PROMS was high for ALL banks!
Impossible! A 7400 at E34 was not doing well. After replacing that there
are some life in the microprogram and I have some random klicks from the
key klick relay. But still not working as it should. So more interesting
fault finding ahead! 20+ years sitting in a cold attic probably is not good
at all.
I've been tinkering with a VT52 at the museum. I found that the sockets
for the PROMs are of poor quality and were not making good connections.
This may not be a problem in your case, but it's something to take a
look at if you haven't already.
- Josh
cheers,
—FritzM.
