Message
Re: [Fairlight-CMI] Faulty light pen issue
2017-09-01 by britt@shapetable.com
Could you try:
- Keep the USB mouse adapter plugged in
- Unplug the lightpen from the Fairlight monitor (VDU)
And see if it still looks like HIT is stuck?
The USB mouse adapter will prioritize the HIT from the lightpen and hide the mouse cursor.
This is so you can switch back and forth between the lightpen and mouse.
If HIT or TOUCH are stuck active, that could confuse the mouse adapter.
Also, if HIT were stuck active, I would expect the entire display to be inverted. HIT works by XOR'ing (so inverting) the pixels that are being drawn.
If you are seeing a normal (non-inverted) display but no HIT, *and* you are on a IIX (not a I or a II), check to make sure that the Q219 connections are correct. The VDU cable has a blue band and goes to the upper connector on Q219, the lightpen cable has a white band and goes to the lower connector on Q219.
The upper Q219 connector *only* has video out, and the lower connector has video AND lightpen inputs. One of the original mouse adapter buyers had never had a lightpen, and those connections were reversed. As a result, he had video (since it is on both), but the mouse could not simulate the lightpen since it was connected to the video-only connector.
Fingers crossed!
Joe