VOGONS


Reply 21 of 42, by Scythifuge

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Caluser2000 wrote on 2021-06-02, 20:20:

I use a NEC/Packard Bell 17" FT700 LCD Monitor shared between a AcerAcross 486DX2/50 and my Zenirh 286LP Plus. Has worked on Win3.1, wfw 3.11, OS/2 v3 Warp and of course MS and DrDos.

Thank you! I'm looking for 19+, though I am probably going to grab a couple of 17 inch monitors as well.

Reply 22 of 42, by Caluser2000

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I find 17" the "sweet spot" wrt monitors for 80s-90s stuff.. I've still got a working Dell 19" crt but found that too big when sitting in front of it.

Last edited by Caluser2000 on 2021-06-02, 21:34. Edited 1 time in total.

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Reply 23 of 42, by BitWrangler

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Half of that is the depth of the darn things, you need a 4ft deep desk or your nose is almost touching the screen when you lean in to the keyboard. 🤣

Now if you're talking guaranteed 4:3 support on a widescreen LCD, I think you could do worse than a 21" TV, they're about 20" wide.

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Reply 24 of 42, by Scythifuge

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BitWrangler wrote on 2021-06-02, 21:31:

Half of that is the depth of the darn things, you need a 4ft deep desk or your nose is almost touching the screen when you lean in to the keyboard. 🤣

Now if you're talking guaranteed 4:3 support on a widescreen LCD, I think you could do worse than a 21" TV, they're about 20" wide.

My retro desk was made before they came out with 19" CRT monitors, though I was able to fit it in there - barely. If and when I get this monitor fixed and/or get another one, I'll take and post pics when I make my retro PC show off thread. I was going to do it by next week, but this situation has delayed it.

Reply 25 of 42, by BitWrangler

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Heh, any project involving computers or anything with an engine, this rule applies.. https://en.wikipedia.org/wiki/Ninety%E2%80%93ninety_rule

Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.

Reply 26 of 42, by Scythifuge

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BitWrangler wrote on 2021-06-02, 22:42:

Heh, any project involving computers or anything with an engine, this rule applies.. https://en.wikipedia.org/wiki/Ninety%E2%80%93ninety_rule

That is perfect!

Reply 27 of 42, by Scythifuge

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After checking out the link where the technician solved the pincushion/OSD issue by replacing a capacitor and a diode, and watching a video of a dude soldering a Playstation mode with multiple soldering points, and deciding that paying $600-800 dollars to have the KDS completely rebuilt is not in the cards right now (even if it means having it work for life - I mean, what if it doesn't after spending that kind of money?) I think that I am going to buy a "learn to solder" kit, and work through the exercises. It honestly doesn't look to be too difficult.

In between working on the exercises, I will pull the chassis off of the monitor and start examining and taking pics of the innards, and see if the capacitors are clearly marked and easy to read, and I will post them and get more advice. Once I know what caps I need, I'll order them and complete the soldering exercises. After that, I will attempt to replace the caps. I am also going to try to acquire a couple more 19 in monitors and a couple of 17 inchers, and a couple of the recommended LCD monitors, and keep them on standby. I wonder if it is good to run old electronics now and then, so that the caps get some juice flowing through them. I mean, this KDS never had power run through it once it was boxed up at the factory where it was made, and in less than 20 hours after sitting in a warehouse for nearly 20 years, components failed. I know that KDS wasn't a top-of-the-line brand, though I never had a "brand new" monitor fail so quickly (though my very first LCD monitor I ever bought was DOA, which I attribute to my curse.)

At any rate, perhaps the curse is a blessing in disguise. Reading about retro projects like the AWE64 Legacy, and desiring PCI and ISA combo cards which don't exist, and getting interested in modding consoles and PCs has made me think about learning soldering and has had me reading and watching videos about electronics. Having this monitor crap out is "forcing my hand," so to speak. I don't give up very easily, especially after spending more money than I should on electronics that I can't return. Maybe I "needed" this to happen. After all, after I said I couldn't find a reproduction of the issue anywhere, I found the link where a similar issue happened to a TV and it was a cap and a diode, and the dude fixed it in no time, with before and after examples.

Reply 28 of 42, by yawetaG

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Scythifuge wrote on 2021-06-02, 11:20:

I'm going to use a piece of electrical cable wrapped around a flat head screw driver on one end, with an alligator clip on the other, and discharge the power. I also heard that CRTs at the end had a part that caused most of the power to discharge upon power down.

Unless you got this method from a source that is guaranteed to be correct, and not one where that method worked out for the performer without putting him in hospital or the morgue by accident, you better be very careful with it.
The human body is a very good conductor of electricity if it needs to be, as it often is the fastest connection between ground and the source of the electricity, and due to its anatomy it has an organ that is very sensitive to electricity right at its heart (pun not intended). You get yourself zapped with a high voltage discharge from a monitor tube will at least lead to arrhythmia (irregularities in heartbeat, potentially very dangerous) or get yourself killed, potentially also causing serious burns at the entry and exit points.

Reply 29 of 42, by Joseph_Joestar

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Scythifuge wrote on 2021-06-04, 02:00:

After checking out the link where the technician solved the pincushion/OSD issue by replacing a capacitor and a diode, and watching a video of a dude soldering a Playstation mode with multiple soldering points, and deciding that paying $600-800 dollars to have the KDS completely rebuilt is not in the cards right now (even if it means having it work for life - I mean, what if it doesn't after spending that kind of money?) I think that I am going to buy a "learn to solder" kit, and work through the exercises. It honestly doesn't look to be too difficult.

I don't think you understand the dangers of working on a CRT. The stored charge can get you seriously injured if you even lightly touch something like the anode. And no, watching a YouTube video doesn't mean you have enough training to safely handle a CRT.

By all means, do practice your soldering and repair skills, but do so on a safe piece of hardware like an old network card or something.

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Reply 30 of 42, by Miphee

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Scythifuge wrote on 2021-06-04, 02:00:

After that, I will attempt to replace the caps.

Make high quality photos from every possible angle before you begin (both sides). It helps if you mess something up.
Make this little tool to discharge capacitors.

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Discharge the capacitors with the bleeder. You don't have to discharge all of them if you don't want to, just the high voltage ones.
Be careful when you remove the panel from the tube. Sometimes it's glued on and it's easy to break it.
It's up to you if you want to remove the main panel or not. There are a lot of wires to remember and they are often soldered on the board. If they are not soldered then you are in luck. Just remove everything and put it back together later with the help of the photos you made earlier.
Don't desolder all caps at once or you could lose track.
Desolder one, solder in the new one (observe polarity) and mark it's top with a marker. Onto the next one.
Inspect everything twice when you're done. Polarity!
Put the panels and wires back and test the monitor.

Reply 31 of 42, by Doornkaat

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Joseph_Joestar wrote on 2021-06-04, 06:54:

I don't think you understand the dangers of working on a CRT. The stored charge can get you seriously injured if you even lightly touch something like the anode. And no, watching a YouTube video doesn't mean you have enough training to safely handle a CRT.

Even though the voltage stored in CRTs is very high the capacitance of the tube is very low.
The energy contained in a screen like that is less than an impulse from a lot of agricultural electric fences.
The involuntary movement caused by the shock is more dangerous than the electrical energy itself.
The real danger is either forgetting to unplug the monitor before working on it so there's a constant delivery of power on the flyback or reassembling the CRT in a way that power can get outside of the case after it is plugged back in.
Another danger is accidentally causing the tube to implode.
Also if you discharge the tube wrong there's a good chance of damaging components on the PCB.

A CRT is not a good place to start learning electronics repairs mainly because it requires deeper understanding of analog electronics and often some advanced tools.
If OP wants to be sure not to ruin his expensive CRT finding a retired radio/TV technician and asking him to fix it for a tip is probably the better idea.
But as long as you make sure the monitor is unplugged working on CRT mnitors is not as dangerous as it is often made out to be.

Reply 32 of 42, by Scythifuge

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I watched a bunch of videos where people make a discharge tool with an insulated screwdriver, a wire, and an alligator clip and they insert it under the suction cup. I'll be sure to watch a few more videos about CRT monitor repair.

Reply 33 of 42, by Miphee

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Doornkaat wrote on 2021-06-04, 08:55:

The real danger is either forgetting to unplug the monitor before working on it so there's a constant delivery of power on the flyback or reassembling the CRT in a way that power can get outside of the case after it is plugged back in.
Another danger is accidentally causing the tube to implode.
Also if you discharge the tube wrong there's a good chance of damaging components on the PCB.

AMEN! I'm glad somebody said it.

Reply 34 of 42, by yawetaG

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Scythifuge wrote on 2021-06-04, 11:05:

I watched a bunch of videos where people make a discharge tool with an insulated screwdriver, a wire, and an alligator clip and they insert it under the suction cup. I'll be sure to watch a few more videos about CRT monitor repair.

Darwin Award incoming, I fear. 🙁

Reply 35 of 42, by cyclone3d

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yawetaG wrote on 2021-06-04, 15:37:
Scythifuge wrote on 2021-06-04, 11:05:

I watched a bunch of videos where people make a discharge tool with an insulated screwdriver, a wire, and an alligator clip and they insert it under the suction cup. I'll be sure to watch a few more videos about CRT monitor repair.

Darwin Award incoming, I fear. 🙁

Hah.. I was taking apart CRT TVs before I was 12.

The only time I've been zapped by a capacitor is when I took apart a point and shoot digital camera that was broken. I accidentally touched the apparently still charged flash capacitor. It left a couple black pinpoint sized marks on my finger.

That being said. Just make sure the thing is unplugged and that the capacitors are discharged before doing any actual work on it.

I don't think I would use the short the cap out with a screwdriver method. That just seems dumb and at the very least if you do short a charged high voltage capacitor, then you are likely to damage the screwdriver and possibly the circuit board.

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Reply 36 of 42, by BitWrangler

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Yeah, you can make anything sound really dangerous, park a pickup truck with a full tank of gas within 2 blocks of your house, are you crazy? Don't you know a full tank of gas in one of those has as much energy as 1000kg of TNT, that's two conventional Tomahawk missile warheads, NEXT TO YOUR HOUSE!!!111111oneone.

There are dangers, but they are handle-able by someone of moderate intelligence.

Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.

Reply 37 of 42, by TheMobRules

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Discharging a CRT is very simple, just make sure the screwdriver handle is well insulated and leave the monitor unplugged for a few hours before doing it to be extra safe. And don't just carelessly jam the screwdriver there, do it carefully to avoid scratching the tube coating or damaging the rubber cap.

I would be more concerned about a CRT board being your first soldering project. Even though soldering is not hard, when you're a beginner some accidents are more likely to happen, like destroying pads due to overheating or causing unintended solder bridges. That could lead to catastrophic consequences, at least for the monitor.

And if you decide to do it, please make sure to take detailed pictures before disassembly, at some point you'll have to put everything back together and the spaghetti innards of a CRT monitor can be daunting.

Reply 38 of 42, by Scythifuge

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I appreciate everyone's concern. I will definitely research and practice before I go in there. I am looking for a cap discharge probe with a long needle, but the only ones I see online have short needles. The one YT video I watched has a guy using one with a long needle. Another video had a guy pull the suction cup off and then discharge it directly without probing. I have a 19" Gateway monitor from 1999 that is really dim, so I may practice on that first, buy buying a CRT tester with a rejuvenate option, and by messing with the inner dials and looking for crap caps.

If upon opening these up I see that they are overly complex, I may just take the drive into the city and drop them off with the repair guy who was honest about not having schematics but that he could examine and possibly recap. However, many videos I am watching show PC CRT monitors as not looking too bad.

I can guarantee that I won't stick my hands in there until I have researched the hell out of things and successfully go through the soldering exercises. I have some old socket A Abit boards in storage, and I may practice de-soldering and re-soldering the caps.

Learning this may be good, overall. My Asus P2B is becoming unstable. I bought a NOS 120gb HDD and I am still getting a "Primary Slave Drive Fail" error if I have to reboot, requiring that I power down and back up in order to have it recognized. It doesn't happen if one of my CF/SD/IDE drives is slaved and I have the SSD with SATA/IDE adapter as master. However, when using a CF/SD/IDE drive as a master, I have to power down rather than reboot, or I get the error. I am also getting noise/wavering/shimmering on the characters during post/boot/bio menu screens with this HP lcd, and the P3 600 CPU I bought causes the PC to lock up before I can make it to windows. The mobo may need recapped or replaced.

My curse can suck it - I'm getting these retro machines and displays working, one way or the other...

Reply 39 of 42, by BitWrangler

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Best to practice on Black and White TVs or mono monitors... of around the 12" size, they don't bite so hard... or at least start with smallest monitor you've got.

Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.