VOGONS


First post, by Shagittarius

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Guys,

I recently aquired a complete IBM PC AT 5170 w/ 5154 Monitor and IBM AT Keyboard in a lot. I knew that the monitor needed repair as the seller told me when he was testing out the monitor it "released its magic smoke". Anyways I was hoping a few caps would be enough to revive the beast so I picked it up. I really should have done this myself but I've never worked on a monitor PSU before and everyone told me that I could kill myself working on it. So I took it to a repair shop.

The owner has had it for a month now and has been slowly working on it, hes not familiar with this old of a CRT so I've been trying to field questions for him to help out. He's pulled and tested a few parts and replaced all the caps but he's not sure what value the resistors should be or what capacity a certain component should be. Does anyone have a schematic for the PSU of a 5154? If not perhaps someone who has one with easy access might take a look and tell me what the values of the following items are:

R37 Two resistors blown, can't tell from the resistors what the values are.

C6, what is the value for this capacitor? He's guessing 250v?

I'm posting pictures below of the board, and the resistors, and maybe someone can help, thanks!

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Thanks guys, I wish I was ready to work on monitors but in the pursuit of safety I decided to let someone else handle it, but I could still use your help.

Reply 1 of 22, by Shagittarius

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I was able to figure out what C6 is here's the cap list incase anyone lands here in the future:

https://docs.google.com/spreadsheets/d/1opYmx … 1nXQ/edit#gid=0

I still don't know what R37 is, I haven't been able to find any pictures of the PSU where I can see this component. I can't even find where it should be on the board. So if anyone knows that would be a big help.

Reply 3 of 22, by keropi

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These pics are not good to identify components not to mention a burned resistor is tricky... Your best bet is the circuit diagram found here: http://minuszerodegrees.net/5154/doco/5154_documentation.htm
I am on mobile and can't check it atm but it seems like it would list component values.

Edit: I see it's a payed dl... Had to do the same to fix my pvm... :\

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Reply 6 of 22, by Shagittarius

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Well, It seems to have everything but I still dont see an R37 in that documentation so maybe the guy mistyped that number. At any rate I sent him the schematics he should know better than I do I hope.

Reply 7 of 22, by Shagittarius

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A Happy Ending!

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Reply 8 of 22, by bjwil1991

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Excellent. That reminds me. I need to fix an old IBM 2115 15" CRT that has color issues (color tone is pink, but still displays the picture without issues).

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Reply 9 of 22, by Shagittarius

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After 10 minutes of running it with an IBM CGA card it smoked again. I'm wondering if this is a different issue than before as it seemed to have a problem with all the half bright colors in text mode. All the colors that were half bright were barely visible and the gray halfbright had a somewhat red hue to it. However all the full bright colors were there and very bright, I had to turn down the brightness the monitor was so bright with those.

I also ran through a few games, Leisure Suit Larry and Police Quest in RGB CGA mode and all those were fine, which again leads me to believe somehow the half bright colors were the problem since there are no halfbright colors for CGA in those graphics modes as far as I know.

I'm going to give the guy a call and take it back to him again and give him another chance to look at it. When I was in the games the monitor looked great, It's too bad it smoked and text mode was a little odd. Maybe next time it will work completely and not smoke almost immediately.

Reply 10 of 22, by CkRtech

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Any updates on this one, Shagittarius? Hoping for a happy ending...

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Reply 11 of 22, by Shagittarius

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Thanks! I took it back to the shop this past weekend but haven't heard from the guy yet. I'm imagining this is a cap he didn't replace that went when I started changing resolutions and testing the monitor. I don't think he's going to be very fast with it so I'm being patient. Meantime I'm running it through VGA, trying to just enjoy the journey =)

Reply 12 of 22, by lowlytech

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Hey fellow 5154 owner. I just got one myself this weekend and am having some focus/brightness issues.

There are two of the X2 caps in the power supply that blow out smoke from what I have found online. They are just filter caps however. Do you still need any part values? I noticed keropi got you the links to the SAMS documentation, but if you need to compare I will be happy to tell you what values I have.

Reply 13 of 22, by Shagittarius

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Thanks a lot lowlytech. The guy has it back in his shop and he has the schematics though hes not going to be able to look till the end of this week. If he has any questions or issues I will take you up on your offer and let you know what might help.

You mention brightness issues...one of the things I saw on my moniotor after the first repair was all the halfbright colors were really dim and somewhat miscolored, this was not true of the full bright colors which were very bright and the perfect colors. Is this similar to what you are experiencing? I've told the repair guy about this and hopefully I will get more of a chance to discuss it with him as well.

Reply 14 of 22, by lowlytech

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I can't find R37 either on my power supply. I took some close up shots of my power supply that has been recapped.

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Reply 15 of 22, by Shagittarius

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Yeah the repair guy I got said that R37 was actually a dual set of resistors, I didn't get a chance to ask him to show me but he said the schematics helped him figure it out. I don't know if that helps you at all.

Reply 16 of 22, by lowlytech

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Well I still have my 5154 halfway torn down, let me skim over the mainboard, crt neck board, and video board too and see if R37 is somewhere on one of those boards

Reply 17 of 22, by lowlytech

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I am sorry Shagittarius, I can't find R37 anywhere at all on any of my component boards. If you knew the physical location of the original part I would be happy to let you know what is in that place on my 5154.

Reply 18 of 22, by Shagittarius

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It's alright, thanks for your help, it might have been an errant request. I'm going to talk to my guy again tomorrow and send him the picture of your 15kV tripler. Where did you get the replacement for that? I think mine probably needs that one replaced too as my half bright text was discolored and dark sort of like yours.

Reply 19 of 22, by lowlytech

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Maybe your tripler just needs adjusted, unless you already tried that. The screen adjustment that also seems to coincide with focus adjustments is that potentiometer that is on the board that connects to the CRT neck.

If that doesn't help, I ordered my part from tedss.com here is the direct link..

https://www.tedss.com/2023000565