My 20L5 lose Blue and Red over time on 240p/480i. Need help.

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Reptile
Posts: 6
Joined: Tue Aug 27, 2019 4:25 pm

My 20L5 lose Blue and Red over time on 240p/480i. Need help.

Post by Reptile »

Hi everyone. This will be a long post with a TL;DR at the end. I'm French Canadian so some sentences may sound weird. I'll copy this post on Facebook, Reddit and Shmups in hope to find some gardian angel technicians that may have some solutions for me.

My story:
I love retrogaming, got my first RGB modded consoles early fall 2019 and not long after my first PVM. Got an 20M4 but the lack of multiformat (480p and up) was a little restricting. I wanted to run a dedicated PC with CRT emudriver and Gen6-7 consoles on crisp progressive scan but I wasn't in a hurry. I kept an eye open over the last 2 and a half years and continued to build my dream setup (multiple retro RGB/component consoles wired together to a GCOMPSW with the outputs going to my PVM and OSSC=>LG C9 for maximum retro goodness). Recently I stumbled on a CRT knowledgeable guy in Ontario who was willing to sell his 20L5 at a reasonable price (around 2.3K USD, market price is 3K right now). He lives 12 hours away from me (I live in a somewhat northern region) but since I went on a family vacation in Montreal, I've decided to make the trip to purchase his PVM. I must mention we spent almost 1 and a half hour doing tests to be sure everything was fine. $150 worth of gas later and a whole day of driving, I bubblewrapped the hell of this mofo on my way back from Montreal and plugged it at home to configure the geometry (that was a little lacking in quality, I must admit, but still fine). Then the problem appeared...

The problem:
Everything is working as expected on resolution 480p and up! What is bad is when the PVM is on resolution 240p and 480i. When I turn on the monitor and it hasn't been on for some time, the picture is very red at first. I turn off and on and the picture is now fine except that the blue color is going away over time and afterward it's the red color. Only green remains after 10 minutes. I can even unplug the B and R cable and it makes no difference. But any time I restart the PVM or if I change the resolution, every color comes back but slowing going away again over some minutes. So the picture is all green if I don't turn it off and back on every 5 minutes (which is stupid).

Troubleshooting:
I repeat, the problem isn't present on resolution 480p and over, only in 240p and 480i (ironic since I have a 20M4 that can output 240p/480i perfectly but not higher and now I've got a 20L5 that can go higher but not lower). The problem is present over RGB and component. I didn't try any other input since I don't really care about those (as many of us). Tried almost every console I've got (NES, SNES, N64, NGC, PSP, WIIU, PC, to name some) and always have the same problem. I opened up the monitor to see if some capacitor are swollen or leaking but they all looks perfectly fine. I can't see every capacitor on all the 4 board though since some are hidden unless I disassemble the whole thing. I'm a fairly tech savvy guy, worked in computer support at the beginning of my adulthood and did some small soldering job here and there. I could replace 2 or 3 capacitor if it was that easy but I'm not confident at all disassembling and reassembling a CRT (especially discharging it). I feel like there's way more rusted wire I could break and ways I could destroy something in this monitor than a PC. Let's just say I have many successful stories about electronics repairs and soldering job I'm proud of but some not so successful I don't really want to talk about. I don't want this premium monitor that's worth 6 months of my savings go to waste.

Looking for help:
-First thing first, I sent a message to Savon Pat. He told me a recap should solve the problem. I messaged him again asking him if I could pay him for some technical support, if I may be better to send him the 4 monitor's boards for a recap job or if it was better to send the whole monitor? I ask if he had some documentation I could refer myself to maybe. He never answered me again. I assume he got tired of noobs like me asking him stupid questions over the years.
-Afterwards, since I did every troubleshooting I could, I wrote back to the guy who sold me the monitor and, after a good discussion, I really don't think he was aware of the problem. The guy seems legit and want to help me the best way he can. He'll try to find some pro in his area who could help. We concluded the problem arised during transit, which I still find highly unlikely but not impossible (it was a hot day when I drove back home... maybe some capacitor dropped the balls because of the temperature).
-I looked up a lot of video of the Retro Tech guy over YouTube. This guy is a beast. Maybe I could ask him some advice and maybe a repair service for both my PVM to get them top notch. What is preventing me is shipping. I can't go myself to California only to repair some monitors. Shipping have a high risk to break even more those monitors without talking about the price. It would cost me at LEAST $500 USD only to ship them on a round trip and I may have to pay custom fees TWICE. This is crazy.
-So now I'm writing this post

TL;DR: My 20L5 lose Blue and Red over time on 240p and 480i. I need help.

My choices for now:
-Dump this PVM and forget it ever existed
-Recap it myself and break something
-Disassemble the thing (and break something?) then send the boards for a recap service
-Ship the whole monitor for a recap service (and my other one while being there) and break both during transit, losing even more money on shipping
-Wake up realising it's just a bad dream
-Find some EXPERT in Canada (preferably around the Quebec province) that can get me out of this sh!t
-Resell the monitor at a loss to somebody who doesn't need those resolutions
-Put my house on fire to collect insurance to buy another PVM

Thanks if anybody can give me some advices it would be really appreciated.
Last edited by Reptile on Mon Jul 04, 2022 2:06 pm, edited 1 time in total.
fernan1234
Posts: 2167
Joined: Mon Aug 14, 2017 8:34 pm

Re: My 20L5 lose Blue and Red over time on 240p/480i. Need h

Post by fernan1234 »

Issues like this that come and go as the monitor is turned on almost always point to an issue with caps, which is probably why Pat was so confident that a recap would fix it. I think Steve (Retro Tech) will be much more helpful. Sending him just the boards would be the best thing to do IMO, especially if he has another L5 that he could use for isolating the problem and confirming it fixed. Recapping can indeed lead to problems, especially when not done right, many things can go wrong and you end up more confused about what may be wrong and have no idea what you broke in the process, so it's definitely better for it to be done by someone with experience and with a different monitor of the same model for testing.

Also, you most likely don't need to discharge the CRT if you're simply disconnecting boards. There's probably videos on Youtube of a 20L5 being taken apart (on the RetroTech channel most likely), or you can record the disassembly process to make it easier to recall how to put it back together after the boards are serviced.

It is definitely very strange that the issue only happens with SD resolutions, but that may be the perfect hint to diagnose it by someone who knows more about this specific model.
jd213
Posts: 412
Joined: Mon Feb 01, 2016 9:03 am
Location: Pennsylvania

Re: My 20L5 lose Blue and Red over time on 240p/480i. Need h

Post by jd213 »

I've heard that Pat hates reading long emails and much prefers talking over the phone, so you may also want to try that.

The 20L5/14L5 service manual should also have diagrams showing how to remove the boards.
Reptile
Posts: 6
Joined: Tue Aug 27, 2019 4:25 pm

Re: My 20L5 lose Blue and Red over time on 240p/480i. Need h

Post by Reptile »

fernan1234 wrote:Issues like this that come and go as the monitor is turned on almost always point to an issue with caps, which is probably why Pat was so confident that a recap would fix it. I think Steve (Retro Tech) will be much more helpful. Sending him just the boards would be the best thing to do IMO, especially if he has another L5 that he could use for isolating the problem and confirming it fixed. Recapping can indeed lead to problems, especially when not done right, many things can go wrong and you end up more confused about what may be wrong and have no idea what you broke in the process, so it's definitely better for it to be done by someone with experience and with a different monitor of the same model for testing.

Also, you most likely don't need to discharge the CRT if you're simply disconnecting boards. There's probably videos on Youtube of a 20L5 being taken apart (on the RetroTech channel most likely), or you can record the disassembly process to make it easier to recall how to put it back together after the boards are serviced.

It is definitely very strange that the issue only happens with SD resolutions, but that may be the perfect hint to diagnose it by someone who knows more about this specific model.
Yeah Steve did some videos on his YouTube channel of him repairing a 20L5. Contacting him will probably be my next step. Thank you for your nice tips.
I've heard that Pat hates reading long emails and much prefers talking over the phone, so you may also want to try that.

The 20L5/14L5 service manual should also have diagrams showing how to remove the boards.


It looks like he's a man of few words ahah.
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NewSchoolBoxer
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Location: Atlanta, GA

Re: My 20L5 lose Blue and Red over time on 240p/480i. Need h

Post by NewSchoolBoxer »

You can't just look at capacitors and know if they're good or not. Obviously you can if one exploded or bulged or looks burnt but that's catastrophic failure. The key is measuring the equivalent series resistance (ESR). Somewhat expensive meters exist for this sole purpose. If the ESR is too high then the capacitor needs to be replaced. Its capacitance value would probably also be out of spec.

The key to an ESR meter is you can measure the capacitor in-circuit. If you use regular multimeter and measure resistance (for ESR) or capacitance (to check against rated value), the input and output impedances of chips and other capacitors/inductors in the same circuit screw the measurement up. Simple circuit like an RGB cable then, yes, you can measure the 220uF with regular multimeter. EEVBlog Dave says capacitors at least 10 uF can "usually" be measured in-circuit with a regular multimeter.

You can spend $500 USD and send the board off or you can spend $80-100 USD on an ESR meter and DIY.
gray117
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Joined: Fri Jul 25, 2008 10:19 pm
Location: Leeds

Re: My 20L5 lose Blue and Red over time on 240p/480i. Need h

Post by gray117 »

Make the assumption it's a 50/50 chance of success....

Be ok with the idea that you're now a tinkerer of old tech, be ok with spending a certain amount of time and money and having this fail (BUT there is a good chance this will just be an 'easy' capacitor replacement and nothing more complicated), and accept the risk you may either break this or it may be dead. It sounds like you're pretty much there - but I feel it is important to be clear to avoid disappointment.


i) Replacing caps is a relatively common task, so get the service manual with the components on, draw up the list of capacitors yourself (2 things most people can't be arsed to do for you), and you'll probably be able to find someone local to do just the de-solder/solder for you even if they don't do crts specifically. It's relatively simple and low cost task - but it's very time consuming even for someone skilled. Extremely time consuming for a hobbyist. You will be mostly paying for this time. (And unfortunately unless you do this in stages - tv's have way more caps in total than more basic monitors... so it would be a good idea to try and priortise the boards you re-cap, but be aware it is better to re-cap as much as you can, even if not relevant to your precise needs, to avoid more problematic failures in the future).

ii) If sending this away I would probably disassemble and pack well. The biggest danger in shipping is that you damage the tube/neck of the crt and/or some other part that may not be replaceable/repairable. The added weight of these components just increases the cost and any liklihood of damage occurring. Take your time learning how to disassemble and be very careful around any high voltage components. If you are uncomfortable/unsure take your time and do your research. It's unlikely to be a problem as long as you are sensibly prepared even if you are shocked, but any risk is still a risk, and it'd be a crap way to die. If you are still unsure see i) or give up on the screen and either store or donate it.

iii) DIY: See i) and if you would like to learn how to do this kind of work yourself, store the screen for now, get the (all the) soldering kit (no need for super expensive, but adjustable, flux, cleaners, desolder sucker and wick are all necessary extras to get familiar with before you use), and just get some junk circuit boards to practice on. Watch youtubes, get good (enough - no need for expert level but you want to get a good feel about how to do something right and how to clean up if it goes wrong). Accept the idea you may break what you work on. Be happy that you've learnt a skill even if you break stuff. Learning the skill has to be more important to you than the object you're working on. If it's not, that's perfectly ok, don't feel bad - many of us would rather just be playing the games in our downtime than 'working' - there's nothing wrong if you don't have the time to put into this, or you find that even with the time this just isn't enjoyable (enough) for you
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