Philips Magnavox Cooling Fluid Headache
 

Thus begins my first thread on the new forum...:D

So I rescued a model year 2000 55" Philips Magnavox rear-projection television set two nights ago, fully five minutes before the trash truck came rolling by. I couldn't bear to see the TV suffer the same fate as the nearby range, you know me. :D

So I get the beast situated outside the garage the next day. I plug it in and immediately get HV whine and sound. However, as soon as the screen is bright enough to see, I am horrified to see the infamous fuzzy picture associated with bacterial growth in the CRT cooling fluid in these sets. :dammit: Off goes the back cover.

Being relatively inexperienced with how to actually deal with this problem, I proceed to remove the lens from the blue CRT (it was surprisingly the only one with growth in the fluid), not realizing that the same screws that hold the lens on also secure the fluid tank seal. Cooling fluid goes everywhere, including all over the mainboard. :gigglemad Realizing my grave error, I immediately replace the seal and lens, then set about using the nearby leaf blower to banish the fluid from the circuitry. I hope I got most of it off, as I have been told that it will not evaporate.

So after waiting about ten minutes, I plug the set back in and try it. Sound, but no picture at all. :bs: I can hear the HV but there are no CRT filaments burning. Five minutes later I get faint wisps of white smoke coming from somewhere over the mainboard, so I freak out and unplug the set again. So now I have a 30 percent loss of cooling fluid in one CRT AND no picture. Worse than what I started with! :finger: Is there hope, or should I just part out the set and get it over with? :thumbsdn:

Another thing: The cooling fluid (Glycerol, apparently) is nowhere to be found. I was able to locate exactly one supplier online that had it, and they had discontinued it and were out of stock. I have been told that the process of replacing the cooling fluid is long and tedious, but as I need only replace one CRT's worth, I might try. Help! :banana:

000

If you have waited any length of time to clean the boards that were spliied on you will experience repeated failures as the glycol is very(!) corrosive. It will eat the board up slowly. We don't take them in any more because it is a sure comeback once the corrosion starts.:thumbsdn:

Thanks for the info, guys. I really hope it's not too late for me to remove the Glycerol! (it's been about two days now) Also, andy, would one bottle be adequate, and will I need any special tools to inject the new fluid?

P.S.--You mention removing the old fluid by using water. Should I be careful, or do you recommend a special way to do this? I mean, I shouldn't be just removing the board and spraying it with the hose, should I? :eek:

000

Good learning experience here. It's be a miracle if you get it going again. Keep us posted!

I was dreading that phrase. :D Well, it's DUMPING rain here right now, so there's no way I can get into the set now. (don't worry, it's covered!) I really hope I can get it working again...:))

we use windex and water it works 100% of the time in getting coolant off. then use a heat gun or hair dryer on the board.........

Just spray the board down with Windex, let it sit for a few seconds, and hit it with the water?

Update
 

I removed the board today and sprayed the entire thing down with the 'mist' setting on my garden hose. I covered the openings on the flyback and HV distributor so as not to let moisture in. Then I used a combination of a hair dryer and leaf blower to dry the board thoroughly(hair dryer wasn't moving enough air!). Thank God they numbered all of those zillions of wires connecting to the board, by the way. :D

So it's all back together. Now I try it again. When I hit the power button for the first time, the flyback (I think) makes a buzzing like a bug stuck in a zapper, so I unplug the set. I also notice a good amount of smoke coming from behind a side panel that I can't tell what's on the other side of. I remove said panel and thankfully can't find anything charred or smelly. So I try it again. (bad idea?) This time I hear a low-pitched whine for about a second, then the flyback tries to start up but cuts off within a quarter second. No smoke at all this time. I try this several more times always with the same result. My guess is that there is some moisture inside the flyback that is causing a short, which in turn is causing the power supply to shut itself off to prevent damage. Do you think that if I give it some time, the moisture in the flyback will evaporate and I might get better results?

I know that others have said that using water on electronic circuitry is not harmful, but I would never have done that on purpose - there are circuit board cleaning and degreasing sprays that are non-conductive and they evaporate very quickly so that they can be sprayed on live powered circuitry with no danger or damage at all. Since you did use water, it would have been a good idea to let them dry completely for a few days before trying to power them up.

Unfortunately, you let the smoke out of at least 1 or more components - and even though nothing looks burnt, they are damaged and will no longer work properly, or even within critical safety specifications. On all manufacturer service documentation, and even third party service manuals, critical safety components are usually identified as such with at least an exclamation point symbol.

If you do attempt to continue troubleshooting this set, PLEASE proceed with extreme caution from this point on.

This is not encouraging. I needed to use water because the coolant was everywhere, and probably would have been near impossible to completely remove otherwise. I'm not sure where the smoke came from, but I will take a closer look tomorrow. It seemed to emanate from the general vicinity of the audio amplifier. Hopefully, it's something simple(capacitor, resistor, etc.).

Does anyone know of a place where I might find schematics for this set? :scratch2:

P.S.--Is that a CRT from a video camcorder viewfinder in your avatar? :D

The MSDS for the replacement coolant says that it is about 75% ethylene glycol and 25% glycerine. I'm not sure there's much besides water that would have worked.

While letting it dry longer might have been prudent, any damage done probably occurred when you turned the set on right after the leak.

You could try partsrruss.com for the service info or use google with the the model number and "service manual" as the keywords.

John

000

I guess I should have stated the little detail that the set was up and running when the spill occurred. FWIW, nothing wrong AT ALL happened until I turned the set OFF. :D

andy, I'm still hoping that if I let it dry for a few more days, I'll get somewhere. If not, it's looking more and more like the scrap heap for this set. :sigh: