Problem with 1084 monitor: No blue in RGB mode

[Mr.Amiga500]

In RGB mode (connected to Amiga), no blue is displayed. It is not a problem with the Amiga or the RGB cable - both worked fine with my other 1084 (which unfortunately died recently).

 

I confirmed there is no blue at all by looking at the monitor screen with a magnifying glsss while displaying a palette. No blue elements were on. I tried opening the monitor and adjusting the knob for blue, but nothing happened. (red and green knobs work)

 

In composite mode, there is no problem. This makes me think there is a problem with the RGB connector (or some circuitry related to RGB display only).

 

My question is: what can I do to fix it? Is there a simple thing I missed? Is there any easy fix or am I just screwed?

 

(Or is there anybody in Canada that has a 1084, 2002, 1080 or 2080 monitor they can sell me?)

[ckrtech]

Hey Mr.Amiga500.

 

Make sure that monitor has been discharged if you are working inside of it!

 

All of my monitor work has come from CRTs out of arcade machines. Next to simply having a dead gun, the worst case scenario was having to use a picture tube rejuvenator to bring the gun or guns back to life. The tough thing about that was a: You need a picture tube rejuvenator and B: You need the proper attachment for your particular monitor's guns.

 

Assuming that is the problem, do you have any mom and pop TV repair shops nearby? Sometimes dropping by and just saying "hey i got this monitor that isn't firing blue - do you have a rejuvenator we could zap it with?" might be helpful.

 

Still - there are plenty of other simple items that might be the problem. You may want to check out this link: Notes on the Troubleshooting and Repair of Computer and Video Monitors

[Mr.Amiga500]

Thanks for your response. As I said, in composite mode there is no problem. I'm sure if it was a problem with the blue gun it wouldn't work for composite either. Because the problem is with RGB mode, I'd have to take my whole Amiga setup with me to demonstrate the problem to a TV repair guy. That's assuming there are still TV repair guys out there. I've noticed that these days people don't take TVs to get repaired. They just trash it and get a new one.

 

I don't have any TV repair knowledge, but my theory is that the blue pin on the RGB connector has lost contact from wear. Visibly, the pins look fine, but I think internally it lost contact. If I move the cable up and down, I can make green disappear too and display only red (cable worked fine on other 1084, so cable is not the problem). Unfortunately there's no way to open the connector to check or repair. And it's blocked by a shield on the bottom of the circuit board, so it'd be a pain in the ass to solder in a replacement. Is there a way to repair broken connectors without replacing it? (cram some metal in there to repair connection?)

 

(reminds me of the Airplane 2 quote: "Where am I going to find a piece of metal? Here? In Space? ... At this hour?)

[ckrtech]

Ahh forgive me. I scanned your post too quickly and missed the composite information.

 

It seems like replacing the connector could be one possibility - though one that apparently will cause some frustration. How much of the board does the shielding cover? Do you have a multimeter? Could you eliminate any other potential problems by tracing the "blue circuit?" If you determine all other paths after the connector (and the shielding) are still good, then you're probably going to have to get underneath there.

 

I do not know of any "jam the metal" type of fixes that you could do. Seems kinda dangerous.

 

You can find the schematics for your monitor on this page: http://www.devili.iki.fi/mirrors/4x4.hopto.org/

[BigO]

Did you keep your other 1084 that died recently? Seems like an obvious source for parts if the connector is the problem.

[+poobah]

probably bad/cracked solder joints, gotta pop the shield and touch 'em up.

 

no fun there, sorry

[Mr.Amiga500]

Did you keep your other 1084 that died recently? Seems like an obvious source for parts if the connector is the problem.

 

Yes, I kept it and that's what I was going to use to replace the connector. It looks like a bastard of a job though. I'd have to unsolder the huge metal shield (covers half the monitor's circuitry) from both monitors, unsolder both connectors, then resolder the "good" connector and pray that I didn't screw anything up and that it was actually the connector that was defective.

 

I do not know of any "jam the metal" type of fixes that you could do. Seems kinda dangerous.

 

What if I ran wires from the cable to the connector pins and swapped red and blue to confirm that it is actually the connector that is defective? (...is that any less dangerous? )

 

Damn. I wouldn't have to go through all this if I could just buy another monitor. These monitors were pretty common just a few years ago. Now if I want one I have to get into a bidding war on eBay, then pay $150 to ship it.

 

Maybe I'll just live without the blue. (and get yellow "burn in" on my eyeballs)