1084D-S changed the HOT and flyback, new problem

Martinmorv · 16 January 2021, 17:47

Hello,

I had the whistling noise, no high voltage, no power light problem on my monitor.

I changed the flyback and the HOT. First time I’ve done this and I’m glad I lived to tell the tale!

When I power on now, I briefly get the power light and high voltage sound, then nothing. It powers down. If I immediately try to power back on, it’s completely dead. If I wait a few minutes, I can then get the brief power up behaviour.

What could this be? The switch still latches properly so I don’t think it’s that. Caps maybe?

Thanks!

Shadowfire · 16 January 2021, 19:21

All CRT's have a redundant set of safety circuits which are designed to shut off the electron beams (by killing off the high voltage generator) if conditions are such that the voltage is too high, and therefore there is a danger of emitting X-rays. Additionally, the power supplies usually have some sort of short-circuit protection measures as well.

Martinmorv · 16 January 2021, 19:26

Hi, thanks for that. I’m almost certain it’s briefly powering high voltage on as I can hear static around the screen. Under what conditions would the voltages be too high? What
Could cause this?

16 January 2021, 17:47	#1
Martinmorv Registered User Join Date: Sep 2020 Location: SHEFFIELD Posts: 2	1084D-S changed the HOT and flyback, new problem Hello, I had the whistling noise, no high voltage, no power light problem on my monitor. I changed the flyback and the HOT. First time I’ve done this and I’m glad I lived to tell the tale! When I power on now, I briefly get the power light and high voltage sound, then nothing. It powers down. If I immediately try to power back on, it’s completely dead. If I wait a few minutes, I can then get the brief power up behaviour. What could this be? The switch still latches properly so I don’t think it’s that. Caps maybe? Thanks!

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16 January 2021, 19:21	#2
Shadowfire Registered User Join Date: Aug 2001 Location: Connecticut USA Posts: 617	All CRT's have a redundant set of safety circuits which are designed to shut off the electron beams (by killing off the high voltage generator) if conditions are such that the voltage is too high, and therefore there is a danger of emitting X-rays. Additionally, the power supplies usually have some sort of short-circuit protection measures as well.

16 January 2021, 19:26	#3
Martinmorv Registered User Join Date: Sep 2020 Location: SHEFFIELD Posts: 2	Hi, thanks for that. I’m almost certain it’s briefly powering high voltage on as I can hear static around the screen. Under what conditions would the voltages be too high? What Could cause this?

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