Re: Kaypro II Video Problem
- From: Barry Watzman <WatzmanNOSPAM@xxxxxxxxxx>
- Date: Sun, 14 Aug 2005 01:18:28 GMT
One thing that you need to do is turn the brightness up and the contrast down so you can see the "raster", even where it's black.
This is really a tv (monitor) repair problem, and I'd really advise you to seek help from someone familiar with TV or monitor repair. As monitors go, this one is VERY, VERY simple, the entire circuit of interest probably does not have 20 components in it. Doing anything with the deflection yoke was probably a mistake.
Thanks all, This info helps me to narrow down the possible cause(es) and potential solutions. I cruised through other posts and found out about the excellent (Kaypro) pdf at bitsavers.org - my Dealers' Manual is nothing more than a stripped down version. Oddly enough, the manual instructs one to loosen the neck clamp, reach in, and twist the yoke to square the display! <NOTICE: What I describe next is my personal experience. Do not attempt unless you understand there is a risk of *electrocution* and *death* > Reading that and having had previous HV experience, I did try and adjust the yoke, and I already mentioned adjusting the deflectors....I caught a poke off the flyback, 30kV is a tickle compared to my ~60kV homemade Jacob's Ladder. The most dangerous items on the video side of the Kaypro II: CRT :: Treat it like a large capacitor. The amperage is LETHAL. Brightness Pot :: 12V hot, and ground all around Use caution. Yoke windings & Horiz. Width :: Both have abundant RF energy; thus RF burns are a possiblity. Use a plastic tool when adjusting the H. Width, and avoid grabbing the deflection coils directly....they get real warm real quick. The Flyback Xformer :: There's an exposed metal bracket that seems either to carry or induct the 30kV potential....I brushed it and lived, your mileage may vary....
Sorry for the wordy post, but I'm trying to document this process as I go...I googled "kaypro monitor repair" and waded through 26 pages of dead ends.....I'm hoping to save the next guy some the hassle.
Thanks again for your insights. Testing begins sometime this weekend, and I'll post the results.