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PET 2001-32N has slightly tilted screen

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Denniske1976

Experienced Member
Joined
Jan 17, 2011
Messages
480
Location
The Netherlands
Hi guys,

I have this CBM 3032 to accompany my PET 2001-8 that has a slight problem. Not very disturbing but it tickles my OCD a bit when I'm in front of the screen... It's kinda slightly tilted as you can see from the picture:

pet3032-tiltedscreen.jpg

Is there anything I can do to fix that?

Thanx again for helping out,

Dennis
 
i believe you can twist the tube image slightly to level it up but beware , you must disconnect & discharge the CRT first (or it may kill you :)

someone here will know better, i haven't tried.
 
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If it's anything like on my TRS-80 model II or my VT100 (edit: looking at the link above, it is) you do not need to discharge the high voltage to make the adjustment. A metal clamp and screw on the deflection yoke is loosened and you can rotate it either direction you want to straighten the image. I recommend you have something on the screen when you do this in fact so you are not constantly adjusting, turning the machine on, turning it off and adjusting again.
 
It's very simple, just be careful and don't get jittery. You're lucky it's monochrome: no convergence magnets to alter :)
 
So uhm, would that be #1 or #2 to be loosened?

pet3032-tiltedscreen02.jpg

And can I actually do this powered on? Because it's ever so slightly tilted, so it would be handy to do this with the computer powered on (without BASIC ROMs installed so it generates a garbage screen) ;-)

I'm not too familiar with messing around in powered on devices...
 
I can't really see your picture from here but it's the bigger one. The smaller one may be focus or astigmatism, not sure.

Loosen the clamp and carefully break the yoke free. It Will be very stuck in place. There may even be glue which you can cut. Be very careful not to torque the neck the wrong way and break it. I really like to wear safety goggles when doing that. I've done it hundreds of times and never had a problem but you never know.

Do that with the power off, discharge the second anode if you feel safer that way but it's not really necessary.

With the power on, make your adjustments. You can tighten the clamp with the power still on if you want, or not.

Whatever you do you'll do it about ten times and might never be fully satisfied with the results. Also, when you break the yoke free, you might misalign the yoke side to side or top to bottom. There might even be shims in there that may fall out, watch for that.
 
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Loosen bolt 1--not all the way, but enough so that it's not clamping the yoke assembly onto the CRT neck. Leave 2 alone. Be gentle and avoid off-axis forces on the neck.
 
YESSSSS!!!! I've fixed it!! So happy now... such a little misalignment but it was really disturbing me :oops:

You guys are the best!! Thanks so much... now to replace the old BASIC chips. I have to figure out where they go, because there's some wird kind of Tonkar BASIC chips in there now (or Tonker BASIC or something). I want the original BASIC chips in there and see if they work with the 3040 drive I have with it, it came with the machine so it should work (I also got the 8050 and 8052 drives with it and that 3022 matrix printer) :)

Dennis
 
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