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