Sony Kvx-370 Indextron Color Tv Repair

[John Folsom]

I have been interested in the indextron technology for years. About 5 years ago I bought a Sony KVX-370 on ebay, and it worked well. I bought a second one non-working for spares. When I powered the "good" one up about a year ago, it no longer functioned. I disassembled the set, to see how possible repairs might be. However, it readily became obvious to me this set was likely beyond my ability to deal with small parts and find detail, given my substandard eyesight. I would just wind up wrecking the PC boards, or worse.

So it was with great interest I followed the threads here on AK involving indextrons. And when Andy (Cuffe) repaired Dave A's set, and another, I contacted him to see if he would give my set a try.

I am please t announce that Andy has worked a minor miracle and has BOTH sets working nicely. So don't be put off by the poor reliability of the indextron sets, Andy can fix 'em up! Thanks, Andy!

As has been indicated by Andys other repairs on indextron sets, it would appear most of the unreliable reputation of these sets is due to the poor quality leaky electrolytics used, and not a fundamental desing issue. The set DO run very hot, and this likely agrivated the capacitor problem.

Here are a few photos of the sets operating. The sets really look better than the photos would indicate. The brightness is good, though not exceptional. The contrast ratio is only fair, due to the fact that the CRT beam cannot be fully cut-off, due to the need to illuminate the index phosphor stripes.

The last photo is a close up of a portion of the color bars screen. This give some idea of the precise beam control required to make the indextron concept work. Remember, this set has one gun and NO shadow mask!

One more indextron item: I found a manual for a Sony IDX 5000 video monitor, using a 5" indextron CRT operating at 30KV!! Sure would like to find one of those.

[Eric H]

John, just wondering if the picture on these actually has those noticable bright stripes running from top to bottom or if the camera exaggerates it?

[andy]

...

[John Folsom]

What Andy said.

A little longer exposure on the camera makes the line structure disappear, but results in an overexposed picture. But as you can see from the close-up of the color bars, when saturated primary colors are displayed, the line structure is more apparent, because the space between illuminated phosphor stripes is greatest. But at normal viewing distances the eye integrates most of the artifacts out, and the resulting picture is very pleasing. But it is noticeably less detailed than a comparable fine dot pitch CRT.