19" Emerson - Weird, random fault

[Hemingray]

My 19" Emerson, which I found alongside the road awhile back and replaced a bad cap in the vert circuit, now has a rather interesting new fault:

When first turned on (and at times a few times after), the set makes a loud "SNAP!" sound before shutting off, leaving me only the channel display. Sounds like the HV is suddenly grounding out someplace but where? and why would it suddenly stop after a few tries.

[radiotvnut]

Does that set use the sidemounted chassis or the horizontal goldstar built chassis?

That's going to be a hard problem to fix unless you can see where the HV is arcing from. It could be arcing from around the CRT anode connection, there could be a leak in the HV cable that leads from the flyback to the CRT, the flyback itself could have a tiny crack and arc, there could be arcing at the CRT socket, or there could be arcing inside the neck of the CRT. Also, check the CRT aguadag ground(s). If they are not connected, a charge can build up on the CRT and arc to the chassis.

What is likely happening is when the arc takes place, it is triggering the overcurrent protection circuit; thus, shutting down the set.

You may also want to check the B+ voltage. If it is high, HV will increase and this will increase the chance of arcing. The HV shutdown circuit is supposed to prevent excess HV; but, there's a chance that circuit isn't working properly.

You should probably remove the back and watch for arcing in a dark room. Of course, it won't do it when you need it to.

[Hemingray]

It uses the sidemounted chassis.

Will do this check next time I am in the back shop where it's used at.