28 Apr
2017
28 Apr
'17
6:07 a.m.
Thanks for the information, Peter. It makes me want to try and test a
few of the components around the flyback.
Thanks again,
Aaron.
Peter Coghlan via cctalk writes:
Hi all,
A colleague and I are trying to get a VT220 working again as it recently
died on us. We are hoping to set up a few items for the mid-80s
(including this terminal) to show the graduands what it would have been
like if they were doing their CompSci degree 30 years ago.
It looks to me like the flyback is dead. There is a lot of soot and
there looks like there is some damage to the top of the transformer,
better seen in the second image.
http://www.cs.nott.ac.uk/~psxasj/sparse/flyback1.jpg
http://www.cs.nott.ac.uk/~psxasj/sparse/flyback2.jpg
I think the soot is fairly typical of what accumulates on high voltage
components in a city environment. I'm not sure this indicates any damage to
it but it may well be faulty without showing any signs of damage.
The terminal powers on and does the usual beeping but nothing is
displayed on the screen. Does anyone have any advice about what to do
here? Are there any sources of compatible flyback transformers?
I have a VT220 which also appears to have a faulty flyback. This results in
it drawing too much current from the power supply. I am not certain the
flyback is faulty but I have eliminated most of the other components which
are likely to be responsible.
I have looked for replacement flybacks or equivelants but I have never found
any. Someone mentioned that they might have VT220 parts available on the list
some time ago but I didn't get anywhere in following that up.
We have a second VT220 which exhibits the same behaviour, hopefully for
a different reason so we can try and cobble two into one.
I have a second VT220 which works and I have used it to compare readings
with my faulty one. I also tried swapping some of the suspect components
but this failed to take suspicion off the flyback. I am reluctant to try
swapping the flybacks over in case I cause damage to the working VT220.
While the two flybacks appear likely to be electrically similar, I am not
certain of this and they are physically different - one is PCB mounted
and the other is chassis mounted with flying leads to the PCB as far as
I recall. They have different part numbers, 16-21181-01 and 16-26299-01.
Any thoughts / advice would be greatly appreciated.
Sorry, I haven't been able to provide much help or hope.
Regards,
Peter Coghlan
>
> Thanks,
>
> Aaron.
>
>
>
> --
> Aaron Jackson
> PhD Student, Computer Vision Laboratory
> http://cs.nott.ac.uk/~psxasj