[raregtp]

Just picked up a Toshiba 50H12 for free (already realize it's basically the 50H81). Was told that "the crt bulb is broken"....had hoped it was a non-technical users way of describing a convergence issue, however when picking it up this evening, the red CRT is in fact shattered. The guy who gave it to me said he just tried to turn it on one day and it wouldn't do anything....in removing the panel to take a look he found the shattered CRT.

A few questions (and this is my first post in this forum, so be patient!!). I'm more than capabable of repairing electronic devices...have been in the computer industry for many years and am well above average with most aspects of solid state repairs.....including using a soldering iron. But....this is my first go at repairing a television.

1.) What would cause a CRT to shatter on it's own?? Manufacturing defect??

2.) The wood directly below the shattered CRT appears to have had liquid on it. I don't believe anything was spilled on the unit itself as there are no other traces of any type of liquid anywhere on the set....only inside directly below where the red CRT should be mounted. In looking up replacement CRTs, I saw mention of a "liquid coupling chamber". Is that something these CRTs have and could that be where the liquid came from?

3.) Assuming this is something I can repair, is it worth repairing? I know.....sounds like a loaded/trick question, just trying to decide if this is worth my time.

4.) What are the chances of "collateral" damage from the CRT imploding?

5.) Can anyone recommend a good source for replacement CRT's for this television?

I'll stop there for now.....I'm sure more questions will come up as this discussion progresses. Thanks in advance for your time answering this post!!

Matt

 

[raregtp]

Ok, I think I just answered 1,2, and 4 myself. After doing some more reading on the forum and reading through the service manual, I now understand that the CRT's have coolant resivoirs on them. Soo....

1.) The seals failed letting the coolant leak out and the CRT overheated?? Would it shatter from overheating, or (I tend to believe this more) would it have shattered from the coolant running down a hot CRT??

2.) The liquid marks on the wood MUST be from the coolant for the red CRT.

4.) I fully understand the potential for damage to the circuit boards from the coolant. I'll have to do some investigating to see how much it splattered inside the cabinet, however upon initial inspection it appears that most of it landed on the wood directly below the CRT....and there are no circuit boards in this location.

And now for a few more questions.....

It appears the anode cable was sheered off where it attaches to the anode cap.......the service manual mentions replacing this when a CRT is replaced anyway. Is that something that would come with a new CRT normally or not? Also, will a new CRT include the coolant resivoir?? I'm guessing not, but what about the CRT assembly that the service manual mentions?

Thanks again!

Matt

 

[lcaillo]

The coolant probably reached the yoke causing a short which can break a tube. I would look for a used tube which will be more likely to match up with the other two.
Posted via Mobile Device

 

[raregtp]

That's the conclusion I was coming to (or close to anyway).

Another thought that I just had......

Would it be worth my time to part this thing out considering many of the boards are discontinued?? Since it was free it would be money in my pocket. If so, what's the best method to move these parts....ebay??

Thanks!

Matt