17 inch crt montitor died - RIP

[Spike]

I'm now using my 14" backup CRT. I was happily watching tv when I heared an electrical crackle, and then an electrical "crack!". I heaered it about 1 second later, and then every second after. I turned around and could see a bright spark with each bang through the vents of the bottom left corner of the monitor, with each crack, the picture shrank into the correct size on the monitor screen (ie, from expanded beyond screen width). with each crack, the display dissappeared, and then shrank back into view... crack... bang... snap... It was quite a spectacular lightshow! lol

The question is... ...is it worth getting this thing looked at? I mean, it still shows a picture in proper colour, all the chips myust be good - it's an electrical short of some kind - It's not like the coil has gone (or has it?) Or should I just send it o silicone heaven and get another one?

 

[zephead]

unless it's still covered by warranty, you should have a look inside, looking for burnt parts. touch at your own risk, because monitors can retain charges in certain components. perhaps you are fortunate enough to have a repairable problem. i mean, the thing's already busted so why not give it a shot?

 

[Spike]

very true indeed. I just know the voltages inside monitors, and 2kv or more travelling up my arm isn't a nice prospect. lol. 3 pairs of rubber gloves it is then

seriously though - is there any way of ensureing the capacitors are discharged before sticking my hands in there?

 

[PFJ]

Hi Spike,

you've probably solved the problem by now or just thrown it out - Oh! I mean recycled it.

There are as mentioned high voltages remaining for several days on some capacitors but the biggest is the tube itself. Though this information may not now be of interest to you but the best way to dischagre a CRT tube is by using an EHT probe. This is simply a resistor with a high wattage/voltage characteristic and of ~1Gohm. One end of the probe MUST be grounded to earth/chassis or CRT braid while the other end is inserted beneath the high voltage cap attached to the CRT.

NEVER stick a screw driver under the EHT cap with a piece of cable attached to ground in order to discharge the tube because it will damage the sensitive semiconductors on board. Neither should this method be used to discharge the smoothing capacitors - use a resistor with high voltage capabilities of between 120kOhm to 470kOhm. The discharge time is slow even using this method but removes the nasties.

The most critical areas that would exhibit your symptoms are the mains input/ line scan coil plug-socket. Not so much a short as a component not soldered correctly or not enough applied during the solder bath/flow process in high current areas.

What ws the outcome?

Regards

PFJ