Re: Re: WG 6100 Brightness / Focus Issues

Thanks guys. I haven't had a chance to experiment with it but I will try over the weekend.

From: Rodger Boots
Sent: Thursday, July 22, 2010 1:09 AM
To: vectorlist@vectorlist.org
Subject: VECTOR: Re: WG 6100 Brightness / Focus Issues

  If you run a CRT marginally below it's nominal anode voltage (18.4KV vs. 19.5KV), and proportionally lower the cathode, focus and screen voltages, how will it change/impact the warm-up process? The complaint being, as the CRT "warms up" (over ~15 minutes), the change in display intensity is so dramatic, that you go from no picture when cold, to visible re-trace when warm. This results in continual (frequent) adjustment of the screen voltage during the first 15 minutes of operation.

I seriously doubt that a small (less than 5 KV) change in high voltage would have a noticeable effect in brightness. If high voltage and focus voltage don't track each other you would see a focus shift. Of course high voltage dropping WOULD change screen voltage and THAT would change brightness.

Another thing that would cause a slow change in brightness is not enough heater voltage to the CRT or a weak CRT. But if changing the HV module fixes the problem it wouldn't be either of these.

On this particular monitor I'd be looking at the video B+ (181 volt) line to the neck board. I've seen too many bad ZD902 zeners in the past to ever start trusting that part. I'd just stick a new NTE5100A in there and see what happens.

  Thanks,
  -Mark

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Received on Thu Jul 22 07:43:39 2010