CurtPalme.com Home Theater Forum

[jrh_james]

Hi,

I have an ECP 3500. A few weeks ago I was watching it and the picture suddenly went very out-of-focus. The problem affects all three tubes. I have tried adjusting the focussing pots but they seem to make no difference.

My initial thought was a problem with the focus/G2 bias module which I swapped out for a spare, but the problem was the same with the new board. Any thoughts on what the problem could be?

Thanks,
James.

[Curt Palme]

Failure of that focus board is rare, never had it happen, but I guess it can. There's a black lead coming from the HVPS to the focus block that has 12,000 or so volts on it. It could be dead. If you have no HV probe, then don't try and measure it with a regular meter.

Try disconnecting the focus lead going from that board to each tube socket. See if the other two tubes come back in focus. If not, then you have a fault on the focus board or in the HV supply. All you can do is swap them or send them to me for testing, there's nothing you can really do at your end to do further testing.

If you disconnect one focus lead going to one tube socket and the other two tubes come back in focus, then that CRT socket you disconnected has a short in it, and it needs to be replaced. I've got stock.

[Curt Palme]

Failure of that focus board is rare, never had it happen, but I guess it can. There's a black lead coming from the HVPS to the focus block that has 12,000 or so volts on it. It could be dead. If you have no HV probe, then don't try and measure it with a regular meter.

Try disconnecting the focus lead going from that board to each tube socket. See if the other two tubes come back in focus. If not, then you have a fault on the focus board or in the HV supply. All you can do is swap them or send them to me for testing, there's nothing you can really do at your end to do further testing.

If you disconnect one focus lead going to one tube socket and the other two tubes come back in focus, then that CRT socket you disconnected has a short in it, and it needs to be replaced. I've got stock.

[jrh_james]

I tried swapping the focus board and disconnecting the tubes in turn, but with no effect.

It looks like there is a fault with the HVPS. I was able to swap it for a slightly-less-broken one from a faulty spares set, and the focus seems to be okay with the new HVPS.

Unfortunately, the new power supply is also faulty and cuts out every few seconds.

Annoyingly I have spares for everything except the HVPS

Thanks,
James.

[Curt Palme]

I've got one good one left..

[Curt Palme]

I've got one good one left..

[jrh_james]

Well I seem to be having a bad run of luck with ECPs.

My other (working) ECP 4100 has now developed an intermittent fault whereby the tubes briefly go off and on again every 10 - 15 minutes or so. Can't hear any arcing, but I have the feeling that it's another dodgy HVPS at work.

I would enquire about the HVPS you have but I suspect that with shipping to the UK it wouldn't be worth it.

[Curt Palme]

That can also be a bad CRT socket. Disconnect each one one at a time from the wiring harness, and see if you can narrow it down.

[Curt Palme]

That can also be a bad CRT socket. Disconnect each one one at a time from the wiring harness, and see if you can narrow it down.

[jrh_james]

Thanks, I'll give it a try.