Mitsubishi CT-36309 36" CRT Issues
 

Another curbside refugee I took pity on, mostly because I have heard a lot about these larger Mitsu CRTs but never had one. It's pretty clean and appears well cared for. When plugged in, the power supply clicks continuously. After several seconds I noticed a thin whisp of smoke from what I thought was the flyback and unplugged immediately. As it turns out, the flyback was not to blame; it was instead emanating from a small disc capacitor(?) very near the FBT, dead center in the attached photo. Obviously something upstream is causing this cap to throw a tantrum, but what?

The capacitor might be the only problem. This looks like one of the capacitors that connects between the collector of the horizontal output transistor and ground. This capacitor is under a lot of stress and these little blue capacitors are bad about shorting and burning. Replace the capacitor and the set will likely work again.

I would be very happy if that little guy ended up being the only problem! I assume the ratings will be printed on the cap, but as it isn't an electrolytic, it may be some sort of code rather than a plain English rating. Will pull it out and check when I get a chance. Hopefully the rating hasn't been burned off!

The model number is not listed in Sam's; so, hopefully, the value will be on the capacitor.

I have extricated the offending capacitor. It's nice and toasty, haha. I can read the following on its side:

HR R
561K
__KV

Unfortunately the cap is burned over part of the rating for KV. The last digit may be a '2'.

The capacitor's location on the board is C568.

I KNOW a 2KV cap would work fine here.

I have repaired many tv's over the years...of ALL sizes...includiung projos--for this problem. nearly ALWAYS....that is all that is wrong--besides maybe a fuse or possibly fuse resistor on the line open or such.

Now, my only question is how to interpret '561K'. I've mostly dealt with can electrolytics, so am unfamiliar with this nomenclature.

561K is a 560 pf. Probably rated at least 2 KV.

Here is an ebay seller--US--for this cap. 10PCS.

http://www.ebay.com/itm/10PCS-2KV561...item20fd98c37f

Here's a relevant link for you: http://www.robotoid.com/appnotes/ele...-markings.html The K just means +/- 10%, so don't go dropping a "Z" type in (Z is +80%/-20%) unless the value isn't critical to functioning of the unit overall.

Thanks much for that link!

Another question: How critical is the capacitance rating? I have some junk/parts boards laying around with very similar caps on them. Just an idea that may save me some time and money.

You need to use the same value as the original, if at all possible. This capacitor controls the HV and the width of the picture.

Very common fail on 1980's - early 90's sets. Mostly in
MGA, Panasonic, RCA, Quasar, Sony & Panny built GE's.
Usualy all thats wrong.
On Panasonic & Quasar VCR combos it causes a chain reaction
& blows the HOT, STR regulator & a few resistors.
IIRC most used 220pf. On any sets of this vintage is best to
give a good looking at the hoz drive through the hoz out for
cracked caps & cold joints.

73 Zeno:smoke:

There were some late '90's Philips-Magnavox sets where the blue capacitor would short. I remember the 19" Panasonic-built MK chassis GE's that used an orange capacitor that would burn and this would sometimes take the HOT with it.

In some Panasonic sets, those capacitors can drift in value as the set warms up and trigger the HV shutdown circuit.

What is the minimum safe voltage I can use here? I found a 560 picofarad @ 500 volts, but I fear this is too low.

...

19c each:

http://www.talonix.com/shop/item.aspx?itemid=12102
http://www.talonix.com/images/caps/CDC0099.jpg

With shipping, probably under 5 bux.

Cheers,

Success
 

I installed a 560pf 500-volt capacitor today to test, and the whole set sprang to glorious life. Picture, sound, everything! I ran it for about ten minutes. The picture flickers a bit, but I assume this is due to the low value cap. I will order the proper 2KV cap, button everything back up, and use it for awhile before selling it. Thanks again for your help, guys!! :thmbsp:

I hope you can sell it. Around here, I'd be stuck with it from now on (that's why I've pretty much stopped picking up TV's for the purpose of reselling them).

If it doesn't sell for $40 I'll relist it for $5 less until it goes. I would love to keep this set, but it is simply massive and I don't have the room, or a practical place to use it. I'm hoping it will go to a gamer; they're my primary market. I sell a lot of CRTs to them because they don't have the video lag that modern LCDs do, thus making it easier to play games where split-second decisions can be the difference between winning and losing in a tournament. :yes:

In my area, the main ones buying them are people wanting them for their children's room. Even at that, they must be later models and have A/V jacks. Right now, I have a 20" Sony from 2002 listed for sale for $20 and haven't gotten one bit of interest.

Don't run it for long, that's a 2kv rated cap.

At the end we still could sell these sets to collage kids & folks
with camps. Nobody would steal them. The MGA 36 consoles
could even double as a table. Had one up in the Connecticut Lakes.
They took almost everything but didnt even try to move it.
A 40" flat would have been first out the door.

73 Zeno:smoke:

The 36" Mitsu is now running with the proper 2kv cap in place, and it seems happy. It's all clean with a remote and listed for $40. We'll see what happens!