80 columns horizontal position

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80 columns horizontal position

I have an Apple II Plus, with a generic videx videoterm clone for 80-column mode, and hooked up to a Monitor III. 

40-column mode looks fine, as you can see:

but 80-column mode is shifted too far to the left:

as you may know, the Monitor III doesn't have any horizontal controls, and neither does the videx.  

Do you know of any good way to handle this? Are there any resistor or capacitor values on the videx I should try to tweak, for example?

 

 

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Suggestion...

Be sure the rings on the back of the neck (picture tube) are not mis-adjusted.

Looking at your 40-column positioning, it looks like it might be.

 

It might be helpful to have a lot of text on the screen when making the adjustment.

 

There also might be a Width adjustment internally, but either solution will require you remove the back of the monitor.

Be careful not to ZAP yourself in the process.  =:-O

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Joined: Apr 9 2022 - 17:05
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Ah, so maybe the 40-column

The width seems fine as when I fill the screen with text in either mode it doesn't go too far to the right. In fact in 40-column mode there is maybe a half inch more margin on the right than on the left, so you're probably right that it is the monitor.

 

Hmm, I still haven't figured out this image embedder. Here should be clickable versions of the original pictures

 

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Although I did tweak the

Although I did tweak the internal adjustments on my monitor a bit, this issue was essentially fixed just by updating the Videoterm firmware to 2.4.

Turns out different firmware has different monitor timings pre-set into them. With a little ingenuity one can even customize their firmware to their monitor (see the "TABLE" section in the code listing, these are the CRTC initialization parameters) 

I think this was actually a service that Videx offered to customers back in the day.

 

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