Heathkit GR-900 Build Thread!

[N2IXK]

Power applied.

Heaters start warming up, and....

It Lives!!!

First light: June 17, 2016.

After a couple minutes of snapping pictures and sniffing for smoke, I flipped on the built in dot generator and got pretty much what I expected. Could have been cover art for a 60's psychedelic band. Convergence just about as far out as it is possible to be in every direction. Horrible purity, and overall reddish cast with blurry retrace lines, but it makes an image! My visitors seemed puzzled why I was as happy as I was with what we saw. Had to explain the large amount of adjustment and tweaking that needs to be done to a set of this vintage to get everything just right. And that having a picture even this good means that 90% or more of the set is already working properly.

A quick purity setup, static convergence setup and greyscale adjustment produced a nice stable black and white image. A few tweaks of the 3.58 osc and burst phase got a reasonable color image, and tweaking the AGC got it fairly viewable in about 20 minutes.

Today I went through and finessed things in a bit better, and got things as good as the "non instrument" alignment procedure is going to, I think. I plan to follow the full alignment procedure detailed in the final volume of the manual set, and at least verifying that the IF and chroma circuits are lined up. Several coils and traps are left unadjusted when using the simplified procedures, and I think I can squeeze a bit better image out of this thing with a real instrument alignment. Both the color and tint controls have a very limited range of action, right around the center of travel. Color level particularly touchy to set to get reasonable skintones without over or saturation.

It's been a month and a half since I started this journey, and had a great time doing it! Will begin looking for a suitable NOS replacement tube and designing some kind of cabinet for this beast. Any leads or ideas gratefully accepted...