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Repair of ancient monitor - Teleray model 7R circa 1988

I have been given the challenge to fix the above old monochrome monitor, a Teleray model 7R made by Research inc, which is completely dead. It consists of a tube, CRT drive circuit board, PSU board and a big logic board (it displays only text, is not a 'picture' monitor). I have been unable to find any service information for it , even using web searches for the manufacturers. It seems to have a PSU fault, again each board is long obsolete without any info I can find on the web. Although I can do some fault finding, the PSU is switched mode and relies on feedback from the other boards to operate, and also needs to be loaded, so it's like finding the break in a contionuous circle. Added to that fact is that I live in Saudi Arabia and the monitor had been taken to a local repair shop so I can't even guarantee the components are the correct ones without service data. This monitor is part of a larger old test station and there are no compatible newer monitors due to the age/programming of the rest of the test station.

So if anyone knows of anywhere I could get such information, I would be very grateful.

Reply to
Steve
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I think KME in the UK do a new product designed to be replace non-standard old monitors. ie it can be set up to accept any non standard video signal. if you can work out the spec of what you have to inteface to, I think this would be more reailstic than trying to get the old monitor working. If the rest of the system is alive then you can just scope it to get the hoizontal and vertical sync frequencies.

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Reply to
Luke Siemaszko

Hi A document I found at

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gives this information about the Teleray monitors:

#### Teleray # # Research Incorporated # 6425 Flying Cloud Drive # Eden Prairie, MN 55344 # Vox: (612)-941-3300 # # The Teleray terminals were all discontinued in 1992-93. RI still services # and repairs these beasts, but no longer manufactures them. The Teleray # people believe that all the types listed below are very rare now (1995). # There was a newer line of Telerays (Model 7, Model 20, Model 30, and # Model 100) that were ANSI-compatible.

Unfortunately I wasn't able to find any useful info about Research Inc. The only company by that name I found makes heating systems etc. Good luck with your challenge. :)

Bob

Reply to
Bob Parker

Weren't they just glass teletypes aka dumb RS232 terminals?

Reply to
budgie

On Sun, 07 May 2006 09:52:12 +0800, budgie put finger to keyboard and composed:

That was my experience, at least with one particular terminal. I suspect that just about any ANSI-compatible A/N terminal should do the trick, unless the interface is using some proprietary current loop system.

- Franc Zabkar

--
Please remove one 'i' from my address when replying by email.
Reply to
Franc Zabkar

Thanks for the info Luke but no one will pay for this repair/modification, even though I'm only the user (it belongs to the Saudi Air Force) they expect it to be repaired magically without cost. I know what the obvious answer should be but I'd like to keep my job. I am quite willing to repair existing equipment if I can do it relatively cheaply for 'smartie points' at work but major mods/replacements are a no-no. I have also contacted research Incorporated by email but have had no response so far. Currently I am testing individual components on the 2 VDU PCBs as they are quite basic, the only suspect item I have found so far is the PSU chopper transformer but I have no way of testing it as I don't know what pins are connected to what windings.

Reply to
Steve

If it's got one or more high-value startup resistors, at least check those for correct value because they often go open circuit.

Bob

Reply to
Bob Parker

Thanks, Bob

I've checked all the resistors by measurement out of circuit, all the capacitors the same way including ESR tests on the electrolytics. Have checked the semiconductors using a Peak Atlas semiconductor tester and what I think is the chopper transistor by substitution. I do have a close up photo of the PCB I'm currently working on if anyone's interested, it's quite small but, as I said earlier, without a circuit diagram to check out the chopper transformer or know how to load the circuit and simulate feedback, I still don't know for sure that it's this PCB causing the fault. I still have 3 or so 3 pin devices to check as soon as I'm released from 'look after the baby' and shopping duties. I have also contacted the manufacturer of the chopper transfromer and PSU PCB with no replies so far. The only 'success' I have had is that the primary side of the PSU is OK, ie the mains diode bridge DC output is correct with minimal ripple.

Reply to
Steve

It can only help if we can have a look at one or more photos of the board. Where can we see it/them? :-)

Regards Bob

Reply to
Bob Parker

Hi Bob, I have 4 pics, each 865KB but haven't seen pics posted on the group, possibly because they use too much bandwidth. I don't exactly know how to make them available other than posting them to someone's E mail address. If you know how I could post them I'll do it.

Thanx

Steve

Reply to
Steve

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