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TRS-80 M1 Monitor rejuvenation

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So, I have decided to 'set up' my old TRS-80 and now I have to go through and clean up everything so that it can be safely evaluated. I am reasonably comfortable with the motherboard and probably as comfortable with the expansion interface. Less so with the disk drives, but not completely uncomfortable. The monitor is another matter. These were all working in about 1982-1984 (as I recall) and were stored (not necessarily under ideal conditions) since then.

I am aware that these monitors represent a high voltage hazard. I respect this hazard and I am not interested in exploring the boundaries of this hazard.

To cut to the chase, I want some hand holding.

I have opened up the monitor -  see pics. I am looking for obvious problems like burned portions, burst capacitors, water damage and the like. I am not seeing that at first look over.

Next I have to clean. I plan on using air spray and at a distance since it is quite cold. Then a general bath with non-residue cleaner. Are there areas that I should completely avoid?

One question concerns the vertical and horizontal holds (back) and the brightness and contrast pots (front). Do I uses a healthy amount of cleaner there as is my inclination? I may have some tuner spray which has a lubricant - I have stayed away from that in the past and am inclined to continue to do so - right?.

I want to get to the point where I can plug it in - much like this fellow

although he did not have a lot to say about it.

Do you see anything in the pics of concern? Do you have some general advice/guidance? Why did I schlepp this stuff around for so many years when more normal people would have introduced them to a dumpster at some point? OK, forget that last question :)

I see nothing alarming in the photos, it's a bog standard mid-70s monochrome CRT display. The lack of an insulator over the anode terminal is unusual but it doesn't appear to have been messed with. What is wrong with the monitor? If it will turn on, then a photo showing the symptoms would help a lot for diagnosis. For cleaning I would just take it outside and blow it out with compressed air, it doesn't even look particularly dirty, just dusty. There's no need to have it sparkling clean, the HV will attract dust in no time anyway.


--- Quote from: james_s on December 07, 2021, 12:30:03 am ---/--/
 What is wrong with the monitor? If it will turn on, then a photo showing the symptoms would help a lot for diagnosis.

--- End quote ---
I don't know and did not say anything about having a problem with the monitor. I will find out if it turns on after so many years now that I have it cleaned up - will try powering up tomorrow. Thanks.

Just power it on, no reason to mess with it ahead of time as long as it doesn't have a dead rodent or something inside it. It's always good to have a baseline before you do anything anyway.

It's a "hot chassis" design, so assume mains is everywhere if you power it up with the back off with no isolation transformer.

Don't touch the pots if they don't prove problematic.

I'd be a bit wary of that big can capacitor by the flyback, they do occasionally pop.

Goes without saying but stay far away from that exposed anode connection. I generally leave them alone, but that's one I might discharge and keep a shorting jumper on before working in there.


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