Dell P1110 21" CRT repair thread

[momaka]

Re: Dell P1110 21" CRT repair thread

Yes, that is the thread I was talking about.

Oh. Well, I already gave advice there. Not sure what else to suggest...
You don't have to be that gentle with CRT monitors. They can take quite a beating (though, it really shouldn't take any to open it).

Also, I just saw that you said that the base is attached to the back cover - in that case, you'll need to put the monitor face down to open it. There may also be latches on the side. Try prying with something thin like a big flat heat screw driver. Again, you don't need to be gentle (unless you really care about ruining that smooth beige finish on the monitor ).

Do you mind if I will bother you if something happenned to them?

Yes.
Breaking CRT monitors is considered first degree murder, so don't .

[freaker]

Re: Dell P1110 21" CRT repair thread

I don't see it. This one by any chance?
https://www.badcaps.net/forum/showthread.php?t=14795


Nothing? No clicking or ticking either?
I'm not familiar with the P1110, but I suppose there should still be a clicking sound from the degauss coil relay when the monitor tries to start.

It's unlikely, but the power supply could be bad too. On my second GDM-FW900,the power supply would not come out of stanby *most* of the time (but occasionally it would and would work fine). I wonder if the Dell P1110 have the same issue, given how related these monitors seem to be.
To see if that's the issue, you would need a multimeter to check if the PSU gives the proper voltages when the monitor tries to start.

Well it might have made a sound for a moment. All torn a part until Wednesday when I will have time to do some testing.

It was mentioned that ADP Protect was too high a current coming from the flyback. Is there a way of testing the output?

During the course of checking out flybacks for a part I noticed that the Silcon Graphics seems to be a close match to the Sony CPD-E500

https://cdn.badcaps-static.com/pdfs/...f3f1c89374.pdf

[Behemot]

Re: Dell P1110 21" CRT repair thread

Yes.
Breaking CRT monitors is considered first degree murder, so don't .

I do nothing to them, it just looks like they tend to have malfunctioning organs

[CRockT]

Re: Dell P1110 21" CRT repair thread

Long time bump!!!

So, connecting the dots, i bypassed the drift correct thingy on the P1110. The brightness got significantly lower, i had to adjust G2 value with WinDAS again. The new G2 voltage for the P1110 was almost identical to the one the P1130 wanted. And... NO MORE BRIGHTNESS DRIFT!!!! I can finally have a proper monitor. Well, in fact, now i have two proper monitors.

How exactly did you bypass this? I am new to all this stuff, but did my first solder repair on a Trinitron TV recently; so I am ready to desolder some things off of this P1110 I got from CL a month ago, I just need to know what.

[Th3_uN1Qu3]

Re: Dell P1110 21" CRT repair thread

Been a while but i still have the monitor on my desk, have stripped the P1130 for parts since (screen was badly scratched). I'll dig up the mod tomorrow.

[momaka]

Re: Dell P1110 21" CRT repair thread

See attached image in post #25.

Basically, you need to find the Cut Off Amp first - IC406. It is located on the A board - the board that attaches to the back of the CRT tube. Here's what this board should look like more or less (picture is of my 21" Dell D1626HT, which is an older Trinitron with same board layout)
https://www.badcaps.net/forum/attach...8&d=1361437452
(basically, once you take the plastic cassing off of the monitor, the A board will be under a metal shield).

So find IC406, and then locate Pin 17 (it's an end pin). On it will be attached that self-biasing transistor circiut (labeled as "Drift Correct" on schematic). It is comprised of transistor Q401 and resistors R404 and R405. NOTE: these components are SMD (at least on my GDM-FW900 they were, and that monitor has the same "Drift Correct" circuit on the cut-off amp).

So all you really have to do is connect Pin 17 on IC406 directly to ground. This will bypass the dripft correct circuit completely.

With this mod, you may find that you have to adjust the G2. When I tried this mod on my GDM-FW900, it became a little too dark. Since I didn't feel like playing with WinDAS and messing with the G2, I re-enabled the drift correct circuit again (so this mod is completely safe and reversible!). Later, I added a resistor in parallel with R404 (forgot what value), to make the drift-corect circuit bias "more". This helped to reduce the brightness, but only a little.

The best way really is to do it like Th3_uN1Qu3: disable drift-correct circuit and tweak the G2 accordingly.

[CRockT]

Re: Dell P1110 21" CRT repair thread

Thanks for the explanation, momaka! Sounds easy enough; hopefully I can find the time to do this before the week is over.

Either way, I will update everyone on how the mod works out for me.

[CRockT]

Re: Dell P1110 21" CRT repair thread

Okay, so it definitely sounded easy, but now that I have gotten to the part where I connect pin 17 directly to ground, I just realized I have no idea how to do that. Am I supposed to desolder pin 17 and move it somewhere else? And if so, where? I have a picture of the area if someone can show me what I am supposed to do.

[Th3_uN1Qu3]

Re: Dell P1110 21" CRT repair thread

Just solder a wire from pin 17 to the large metal tab you see under R404.

[Topcat]

Re: Dell P1110 21" CRT repair thread

I had one of these back around 2002. It too had the brightness problem, and abck then, DAS software and cables were nowhere to be found....I cured it with the resistor trick.

[CRockT]

Re: Dell P1110 21" CRT repair thread

Just solder a wire from pin 17 to the large metal tab you see under R404.

So, I am finding it very difficult to solder a wire to the metal tab because it looks like there is some kind of glue stuff that is all over it; the solder will not stick to the tab. Will it be okay for me to try the next closest metal tab? And in case that does not work out, what are my other options?

[goontron]

Re: Dell P1110 21" CRT repair thread

So, I am finding it very difficult to solder a wire to the metal tab because it looks like there is some kind of glue stuff that is all over it; the solder will not stick to the tab. Will it be okay for me to try the next closest metal tab? And in case that does not work out, what are my other options?

Resistor error 404 solder pad not found? can you get a picture of the glue spot? it could just be that the solder won't melt right.

[CRockT]

Re: Dell P1110 21" CRT repair thread

Shot 0645 shows how clean the second closest tab to 404 is; shot 0648 shows how messed up the tab right under 404 is.

[goontron]

Re: Dell P1110 21" CRT repair thread

that is actually cooked rosen left over from when the device was made. all that takes is rubbing alcohol ( or really strong moonshine. dont ask me how i know. ) a toothbrush and a careful hand so is not to damage the tiny SMD chips around it, and use the alcohol and toothbrush to scrub the gunk off.

[CRockT]

Re: Dell P1110 21" CRT repair thread

Thanks! I will give that a go right now!

[CRockT]

Re: Dell P1110 21" CRT repair thread

Okay, so what I had to end up doing was scrape all of that stuff off with my iron because I guess I had already burned the stuff pretty good onto the tab. However, I managed to get all of it off and complete the process! I ended up using stranded copper wire, and the finish was not pretty, but it definitely got rid of the over-brightness.

It seems really dark now, but I am going to be messing with all the settings before I mess with the G2 voltage.

Thank you all very much for the advise and help!

[laser]

Re: Dell P1110 21" CRT repair thread

BUMP

hello guys I have a monitor SUN 21 GDM-5410 , is the same monitor I believe is a sony CPD-G500 manufactured by SUN

long time ago I done a serial > TTL converter and I adjusted G2 several times because it goes out brightness frequently
This fuckiiing monitor is working fine but have the classic warm up time problem, it takes about 1 hour or so from cold start to normal brighntess
even when I turn on the monitor the screen goes totally green and there are big flashes and explosions until warms

OK

regardless the IC 406 - PIN 17 to ground mod

my question are:

1 : how many time takes the monitor to warm up exactly doing the pin 17 to ground mod?

2: you guys are you sure that a big warm up time, part of the problem is not the aged capacitors in the power supply area in the G board ????
Im talking about the big cap 450v 320mf and the ones located near vertical IC ie some of them are 4700 mf 16 volts

[R_J]

Re: Dell P1110 21" CRT repair thread

Its been a very long time since I worked on these but I do remember some that had a bad capacitor for the heater supply voltage. I know the 17" monitors had a problem so check the voltage on cn652 pin #9

[momaka]

Re: Dell P1110 21" CRT repair thread

regardless the IC 406 - PIN 17 to ground mod

my question are:

1 : how many time takes the monitor to warm up exactly doing the pin 17 to ground mod?

None.

With this mod, the monitor will start a little dark, just like any other normal CRT monitor and will take probably about 15 to 30 minutes to warm up to full brightness.

I have a 21" Dell Trinitron D1626HT CRT monitor that is a generation or two older than the CPD-E500 chassis. It does not have this "Drift Correct" circuit at all (actually, it uses discrete transistors instead of a Cut Off Amp IC), so it does not have any overbright issues whatsoever.

2: you guys are you sure that a big warm up time, part of the problem is not the aged capacitors in the power supply area in the G board ????
Im talking about the big cap 450v 320mf and the ones located near vertical IC ie some of them are 4700 mf 16 volts

Unlikely.
The caps in my D1626HT are much older (monitor is a 1998 vintage), and it doesn't have any overbright issues. It does occasionally do the "big flash and cracking" sound, though. But I think that is an unrelated issues, because it does it regardless if the monitor is warm or not (most likely the flyback is going out in mine). The newer Sony CRTs are pretty solid in that regard.

[laser]

Re: Dell P1110 21" CRT repair thread

Unlikely.
The caps in my D1626HT are much older (monitor is a 1998 vintage), and it doesn't have any overbright issues. It does occasionally do the "big flash and cracking" sound, though. But I think that is an unrelated issues, because it does it regardless if the monitor is warm or not (most likely the flyback is going out in mine). The newer Sony CRTs are pretty solid in that regard.

thanks for your reply master

about the "big flash and cracking"... what the hell this could be,?a bad weld ?
the flyback? an aged cap?
I looked at the G board quicly and I don't noted any inflated cap

I will upload a video later showing my monitor starting cold before I make the IC 406 mod, then of course I will make a new video with the mod done to see the differences

if flashes and cracking still persist I will dismantle the G board to look around where is the problem, I'm almost sure the problem is located there