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1980s_john
June 23rd, 2014, 03:19 PM
Hi,

I have a CT-64 terminal with a CT-VM monitor. The CT-VM is the matching video monitor, but mine is a bit flaky (wobbly unclear display). I think it came ready assembled rather than a kit, as I don't have a schematic. Can anyone help with a circuit diagram please?

I tried out the CT-64 with another monitor, and it gave a really steady display (16 lines of 64 characters). I think it is set to page mode, as typing produces letters along the top row, and line-feed moves the text down. How do I change mode to scroll mode rather than page mode?

I think that it has some issues, but it is a wonder it works at all as it has so many chips & jumpers. You get spoilt with modern terminals with microprocessor controls!

I had a bit of a problem whilst testing it, I smelt burning and so quickly turned the CT-64 off. However clouds of smoke wafted around the room until I eventually noticed my oscilloscope was making a good impression of a cigar (otherwise known as letting off some magic smoke). Bugger! Always something new to repair, this hobby does get frustrating sometimes.

Regards,
John

1980s_john
July 7th, 2014, 01:21 AM
I have a CT-64 terminal with a CT-VM monitor. The CT-VM is the matching video monitor, but mine is a bit flaky (wobbly unclear display). I think it came ready assembled rather than a kit, as I don't have a schematic. Can anyone help with a circuit diagram please?

I took the cover off the CT-VM, it looks like it is just a generic 9" monochrome monitor in a SWTPC plastic case. I found a label with a Motorola icon, and another with model M2000-355, serial 8155 7749. I think 81 might be date code for 1981. I googled Motorola M2000-355, looks like the right number. I haven't found an exact schematic, the closest I could find was this:

http://www.klieglbros.com/service/consoles/performer/motorola%20vp16/Motorola%20VP-16.htm

which is for the earlier M2000-155 monitor. Hopefully this is good enough, if anyone else has an M2000 manual please shout.




I had a bit of a problem whilst testing it, I smelt burning and so quickly turned the CT-64 off. However clouds of smoke wafted around the room until I eventually noticed my oscilloscope was making a good impression of a cigar (otherwise known as letting off some magic smoke).

I fixed the oscilloscope, luckily it was just one 0.22uF X2 capacitor connected across the 230V mains input which had melted. This was made by Rifa around 1984, seem to always fail eventually, eg BBC B/Master computers. Plenty of examples elsewhere eg:

http://www.vintage-radio.net/forum/showthread.php?t=69128

Regards,
John
PS My camera also stopped working the other week, luckily Canon UK repaired it for free (even thoiugh it is over 3 years old) as it had a design fault - a screw had come loose inside and shorted out a DC-DC board. Thank you Canon for providing a free fix!