"It's Broken Again!" - let's diagnose a monitor using my new Ring Tester

[@MikesArcadeMonitorRepair]

Hard to get reliable parts for CRTs nowadays unfortunately. Current flyback reproductions are hit and miss, even from reliable sources. It actually depends on the time of year the flybacks are made. Summer months are better because the potting that separates the windings/rings and keeps them from shorting sets up better in warmer temps. Flybacks produced during colder months fail at higher rates because the potting doesn't fully cure and they develop shorts between the windings/rings. Just something we have to deal with, given these parts are not highly sought-after anymore. Another great job on this Tony.

[@tony359]

Interesting thanks for the insight!

[@rodhester2166]

Thanks for showing the process and tester.. cheers

[@tony359]

You’re very welcome!

[@Epictronics1]

Great tool! I wasn't aware of the project

[@tony359]

You should definitely get one, you have more CRTs than me! :)

[@gpamob]

-then why are you doing it? - I dunno. This is hilarious!!

[@tony359]

You mean the fact that I didn’t finish the repair? I thought I explained it at the end? The monitor was not mine, maybe I didn’t make that clear.

[@gpamob]

Hi Tony, no, not at all. I just loved the scene when you were speaking to yourself in the beginning. Love the video, not all repairs go as planned, and nevertheless I learned from this one too, so thank you very much!

[@tony359]

Oh apologies! I misunderstood you! Thanks for watching!

[@gpamob]

Thank you very much for your videos, I am a big fan!

[@aleksandardjurovic9203]

Thank you for the video! You haven't repaired but you figured out the cause! That's the most important part. I also liked funny beginning with two of you!

[@tony359]

One Tony is enough!!! Thanks for watching!

[@minombredepila1580]

Thanks again for an amazing video. I always learn a ton from you. Wasn't aware about this project, and I'll give it a go. Cannot wait to know where was the fault on the monitor !!!!

[@tony359]

Me too, I hope I can find out 🤞

[@bitsundbolts]

A cliffhanger Tony?? Haha! Please give an update once you know if this flyback was really the issue. So weird how the housing bulged. I never want to touch CRT monitors - they are too dangerous for me and my abilities. Thanks for the nice video - and enjoy your vacation!

[@tony359]

Thanks! I might never know the outcome but if I did, I'll definitely let you know! :)

[@sokoloft3]

Awesome, thanks for sharing!

[@tony359]

You're welcome!

[@TheDefpom]

I think C476 might be bad, I think that was right next to that hot resistor, so you may have been assuming the resistor is what is getting hot when in fact it was the capacitor & resistor.

[@tony359]

it could be but looking at 24:13 it really looks just the resistor - but I cannot be sure. I wish I had a chance to work on that monitor a bit more! Thanks for watching!

[@Stoney3K]

I suspect the 'clicking' sound you heard in the previous video was the excessive high voltage arcing through the CRT which may have damaged the tube or the rectifiers inside the flyback. You have to be very careful with high voltage circuits in a CRT, because if the high voltage becomes too high, you have a serious risk of the CRT generating X-rays. If you replace the flyback, it's essential to measure the HV output with a proper meter and adjust it accordingly for safety reasons.

[@tony359]

Yes, apparently it's the X-Ray protection... Also apparently those flybacks come set to maximum from the factory which feels weird. Yes there is a chance some damage happened when I did that, though it was only for a few seconds before I realised. One day I'll get my HV Fluke probe I left home in Italy, back then I never felt brave enough to use it! :D

[@jbinary82]

I'm not sure if you already said, but there's any desoldering gun good enough for a casual use (Europe sellers)? I won't spend like 250€ to use twice a year

[@tony359]

Mine is an Aoyue and I am not sure I'd recommend it. The one I'd like to try is the one @Epictronics is using, it's sold under many names but I feel it's better than the one I have. It might need some tweaks out of the box to make it better. Should be around the 150 euro range? The name is Pro'sKit SS-331

[@kpanic23]

I have a cheap ZD-985 and can highly recommend it. It's usually around 65-70€, I managed to snatch mine for 50€ some years ago from an Italian eBay seller, with EU-wide free shipping.

[@tony359]

I think they are all clones of each other 🙂

[@michael5380m]

I have the ZD-915 and can recommend it, got it in the Komerci rebrand. 4 years ago it was like 80€, now its like 120€ but still recommend it for that price.

[@bbjunkie]

16:30 if there was an open circuit in the secondary wouldn't the primary read ok?

[@tony359]

What the tool is reading there is an internal short. Say you have 1000 windings, if two touch together, the inductance will change drastically and that's usually enough to cripple the "ring" the instrument is sending. At least this is my understanding! Thanks for watching!

[@bbjunkie]

@@tony359 I think you misunderstood my question. You said If the primary is working the secondary is working as well. Couldn’t the secondary still be open circuit even if the primary is reading ok?

[@tony359]

Ah, I see what you mean. If the secondary winding is broken inside (not shorted), the flyback wouldn't work but the ring tester would not show an issue. I am not sure but I think you're right. What I meant was that if the primary reads ok, then the secondary is not shorted - I probably worded it incorrectly! Thanks for that!

[@bbjunkie]

@@tony359 👍 thought I was missing something 😁 thanks for clarifying. Just found your channel, great content - keep it up!

[@jemglen]

Thank you for the video. Do you have the gerber file(s) for the ring tester? The link to Bob Parker's website only has PDFs.

[@tony359]

Thank you for watching! I've just downloaded the file and it contains the gerber in the PCB folder.

[@jemglen]

@@tony359 Wow, thank you for a super-swift response. I'll download again -- no doubt user error!

[@tony359]

You're very welcome, let me know if you fine all you need! :)

[@martin_soerensen]

New subscriber here - just discovered your channel and I ended up spending half a day binging your videos. 🙂 This video was of particular interest to me since last year I was working on a monitor with pretty much the same symptom as this one. It was the Commodore 1084 branded version but otherwise the same Philips model (except maybe configured with different inputs). Like in your case, all voltages from the PSU was about half of what they should be and I spent quite a lot of time checking the PSU but could not find a problem there. If I removed the HOT (which was good), the PSU would output the correct voltages, indicating to me that either 1) the PSU was too weak for some reason, 2) there was an internal fault in the (original) flyback transformer or 3) something on the secondary side of the flyback was drawing too much current. I ended up concluding that the transformer was probably at fault, but since I did not have a replacement I ended up parking the monitor on the shelf. This particular monitor was quite sooty inside so I think it has a lot of hours on it, so I did not want to spend a not insignificant amount of money on a new flyback transformer which might even be of questionable quality (not personal experience - but based what I have read online). Perhaps I will stumble upon a working flyback somewhere, i.e. an identical 1084 with a dead CRT and then I would have the parts to revive it. 🙂 Edit: The concept of the ring tester was interesting and I might check the flyback in my 1084 using this method. I don't see a reason to build this this specific device though since it is basically measuring the Q of the inductor and any ESR meter can do that. Could probably also make a small circuit based on a 555 with a transistor on the output to generate those short pulses and then watch the ringing on an oscilloscope. But I guess for someone without an ESR meter or a scope, the ring tester could be useful.

[@tony359]

Thanks and welcome! Yes I agree with you. It’s too bad those flyback can be of questionable quality. I don’t know what happened to this very monitor unfortunately, I don’t know whether the flyback fixed the problem or not. I am restoring another small CRT, video will be up soon, but on the second channel.

[@DjMarik78]

Hi. Flyback transformers are in fact magnetically coupled inductors! This is the basic rule for any flyback, and this helps allot, because you measure the inductance of an inductor with an inductance meter ( RLC meters are best ). Even if you do not have a working transformer for reference you can still get some values and search info on the on the internet. If you do have a working transformer for comparison, then THE BEST way to test a flyback transformer is with an RLC meter, it let's you set the testing frequency, making the measurement way more accurate, and it gives you the best possible results. That is because if any of the windings are shorted ( or partially shorted ), then the inductance will be way smaller then it should, that is a dead give away of a shorted transformer ( the best and most precise way ). Cheers!

[@DjMarik78]

In fact, is the same with any transformer, of any topology, starting from the basic 50Hz transformer and ending with the most sophisticated switching supply.. That's because any winding of any form is an inductor, with the inductance value given by the number o turns and the core's AL, so if it is a short in them then the number of turns will simply be less, thus the inductance will be smaller. Even if you do not have any good power transformer to compare the values with, and you can find no info on it, you can still very easy know if that unit is good or dead simply by measuring it's inductance. Knowing that in AC any inductance is in fac a resistor directly proportional with frequency, you calculate it's reactance at the given frequency for that transformer, then you add that reactance to the measured DC resistance, and you get a precisely measured impedance at that frequency, which will be the load for the primary voltage of that transformer. From there it is easy to determine if that impedance is acceptable or not, thus it's easy to know if that transformer is good or bad. See, electronics is fun :)

[@tony359]

Thank you for the insight! I think the ring tester is the cheap way to do so - you're right that an LCR meter would be the best tool. I think LCR meters usually also test capacitors as well if not mistaken?

[@DjMarik78]

@@tony359 yes, inductance, capacitance and resistance, they are all well tested with an LCR meter ( with advanced secondary parameters as well, plus different testing conditions ). I have a Hantek LCR meter and it's great for the price.

[@tony359]

@@DjMarik78 Thanks! Might be a good tool for my toolbag :)

[@DjMarik78]

@@tony359 Hantek 1803C, it's cheap and very usefull. You are very welcomed!

[@incandescentwithrage]

To me it's unusual for even the initial fault to be the flyback itself. I worked on many (slightly later) CRTs back in the day, and the majority of the time it was either shorted Horizontal Output Transistor (usually due to bad capacitors supporting it), or cracked solder joints. Granted, I didn't see as many as someone working on full time CRT repair, but I can't recall a single case of a bad flyback in isolation

[@tony359]

My experience is very limited so I don't know. But when it comes to "new" flybacks it seems that the quality is very much hit and miss nowadays. I cannot say though, I wish I had a chance to finish that repair! Thanks for watching!

[@tassdesu]

Thank you! Cool joke about CRT danger

[@tony359]

I’m getting carried away 🙂

[@peddersoldchap]

Hi Tony. What is that spectrum analyser app?

[@tony359]

I think I removed it from my mobile but it should be called DB-X?

[@chainq68k]

Second Tony appearance be like: "Always two, there are. No more. No less. A Master and an apprentice."

[@tony359]

Still lots to learnt I have!

[@stevegorkowski3246]

Not all replacement flyback transformers are the same. I have replaced them under warranty. The yellow glue over the years will become conductive. Many poorly designed displays over the years.

[@jeremywh7]

What spectrum analyzer app are you using?

[@tony359]

I think it was "Decibel X", I might have removed it from that old phone... Any RTA would work though.

[@general23cmp]

Great video!

[@tony359]

Thanks for the visit

[@SobieRobie]

Brave man dancing with CRTs!

[@tony359]

or crazy :)

[@Pulverrostmannen]

So I would need to watch the whole video to the end before getting to know it would be a no fix, Even if the actual Title say lets FIX a monitor using the ring tester. I would call that a fair bit misleading

[@tony359]

I’ll change to ‘diagnose’ if that sounds better? Personally I don’t expect every repair videos on YT to be a success but…

[@Pulverrostmannen]

@@tony359 yes that is a more fitting title :)

[@magnusboman1576]

missed opportunity to not call the video "fix it again, tony" hehe

[@tony359]

I’m sure this won’t be the last time 😉

[@JamesPotts]

Makes me wonder if something on the board is drawing too hard on one of the flyback's outputs, causing the winding to overheat. (Probably just defective, but ¯⁠\⁠_⁠(⁠ツ⁠)⁠_⁠/⁠¯.)

[@tony359]

That’s also an option though I didn’t see anything very hot on the PCB. If it’s the high voltage getting driven too high, it’s either the flyback or the CRT itself I think but feel free to correct me as I am no expert 🙂