B&W Monitor went dead with H-HOLD

Hi,

I had a slightly blurry B&W monitor on a Cube. Wanted to adjust focus and centering.

At the end, I touched the 'H-HOLD' control with a screwdriver, screen went immediately black, and won't come back.

Any idea what went wrong? Any fix?

Hello Fstark: I've had this happen when using a metal screw driver and it grounds on the case.

I just bought this adjustment tool kit https://www.ebay.com/itm/VELLEMAN-VTPT-VTCSS-COMBO-PACK-ALIGNMENT-TOOL-SET-FOR-PC-RADIO-TV-HAM/281929165928  as I did something similar , I tuned the cutoff beyond its maximum by mistake , poof the picture disappears.
http://www.blackholeinc.com/docs/NeXTServiceManualPages1-96.pdf  page 42 for adjusting monitor.

So my hope is to use the kit to adjust the monitor without shorting .

Best Regards Rob Blessin

Hi Rob,

Thanks a lot for the answer. I'll buy a plastic screwdriver set (will try to find one in Europe, shipping cost is $20.34...)

I'm not sure moving the control will do anything as (longer story):

1) I didn't even have the time to move the potentiometer.

2) It actually happend *exactly in the same way* previously on another MegaPixel, as soon as the screwdriver touched the potentiometer, *poof*, the image was gone. But, after disconnecting/reconnecting the screen, it went back on. So I added tape around the screwdriver (not on the tip, but on the shaft), and it went *poof* the same way, and I decided not to touch this anymore. However, when I got my other MegaPixel, I wanted to know if the control was working on this one, and it did the same *poof*, but never went back on.

Note that it isn't that the monitor is dimmed out, it really is a *poof* sound and I could see the beam shutting down.

I'm going to try to re-connect it over the weekend (maybe some gremlins will have fixed the monitor?) and see if it works. As I have two monitors, I may be able to swap parts at some point to see what is going wrong, but I am worried that I will just end up with two dead monitors...

And thx for the link to your website, I already found it when searching for potential solutions on the net. Fun fact: your other PDF http://www.blackholeinc.com/docs/NeXTServiceManualPages1-160_OCR.pdf was the only doc I could find that acknowledge the existence of the "h.hold" button on the MegaPixel (page 150).

I'll keep the forum updated.

Best Regards,

--fred

It sounds like the pot has gone bad.  You can measure it, but it might be better to just replace it.  Touching it puts some mechanical load on the slider that may affect the electrical signal.