Mitsubishi TriniScope Color TV

[John Folsom]

HI VKers.

Its all true. While Bob was down visiting a couple of weeks back, we did some restoration work on the Mitsubishi trinescope TV.

First job was for Bob gave me an excellent course in can re-stuffing, which I had not done before. These were clamp mount type cans, with a lug on the top for each section and an additional lug for the common ground. After unsoldering and unmounting the cans, the can was cut around the body where the cut would be hidden by the clamp when it was remounted. Placing the can in a vice, a heat gun was used to soften the pitch which surrounds the capacitor elements. Then pliers are used to pull the guts out of the can. A little cleanup with mineral sprits, and the empty can is ready fro re-stuffing. A small hole is drilled beside each lug in the top of the can to allow the wires from the new capacitors to feed up and attach to the lugs. For the two can which had four sections, there was not enough height to install the four capacitors needed. Fortunately, we had a little head room above the cans, and could take advantage of the clamp mount to extend the height of the can just enough so the cut would still be hidden by the clamp. A donor twist-loc can of he same diameter was sacrificed, cutting off the required amount of its bottom (the end without lugs) to extend and complete the original can. Once all four of the single sections electrolytics were wired in and soldered to the lugs, the new bottom of the can was held in place with clear tape while the reassembled can was remounted into the clamp and the wires from the TV soldered back to the lugs. The two cans which only had a single section were a bit easier, as they did not have to be made taller, but the process was the same.

Next, with two people working at it, replacing all the original caps with yellow-wrap mylar types was pretty quick work.

Then we powered it up on the variac, noting the nominal 100VAC operating point of the TV AC input. The set came up and work well right from the start. We spent some time tweaking up the electrical height, v. linearity, and v and H centering for the 3 CRTs. Blue is used as the reference image, and red and green are converged to align with it. When completed, we had a very good looking picture.

The Japanese channel assignments are a bit different. Here are the pairings we were able to make; US/Japan channel assignments 13/11, 2/12, 12/10, 11/9, 10/8,9/7, 8/6, 7/5. Channels 4,3,2, and 1 on the trinescope could be tuned to receive a signal from the cable, but these were cable channels which did not line up with the standard US 2-13 assignments.

I wish to thank Bob Galanter very much for his help in restoring this fascinating little set. The color pictures are extremely bright, crisp and beautiful. When the red CRT is viewed directly, it appears to be very orange in color. The dichroic mirror filters out most of the yellow and green to produce a respectable red. There is some notable spotting on the mirrors, but it is not too objectionable, and trying to find replacement dichroic mirrors is probably difficult and expensive. First one would have to characterize the mirrors in the set, as there is no published data on them that I am aware of.

If I can find a reasonable way, I will bring it to the next ETF convention.

The first two photos show the main chassis after the recap, and the second is a tube layout drawing I made as the set had no tube layout chart. About 2/3 of the tubes appeared to be original Mitusbishi branded, with 1964 date codes. The last two photos do NOT do the TVs performance justice. The perceived color and sharpness is much better than these photos would indicate. This probably says a lot about my photographic talents.

I had posted some additional photos to the ETF website:

http://www.earlytelevision.org/mitsu...trinitron.html

My set is a model 6CT-333, while the set which Jerome showed above is the very similar 6CT-338. The schematic which came with my set is for the 6CT-338, and does have some minor electrical differences from my set. But the main difference is in the styling of the two models. Both sets use the same 6" red, blue and green cRTs.

Coming soon.... restoration of the 15" Admiral Color TV. Stay tuned to VK!

[Robert Grant]

Originally Posted by John Folsom

HI VKers.

<snip>

The Japanese channel assignments are a bit different. Here are the pairings we were able to make; US/Japan channel assignments 13/11, 2/12, 12/10, 11/9, 10/8,9/7, 8/6, 7/5. Channels 4,3,2, and 1 on the trinescope could be tuned to receive a signal from the cable, but these were cable channels which did not line up with the standard US 2-13 assignments.

<snip>

Japanese channels 1 through 4 were/are actually broadcast channels.

1, 2 and 3 are particulary notable for being 90-108 MHz (in the FM broadcast band in most of the world), which explains why Japanese FM is 76-90 MHz.

This was likely done because sporadic-E skip is especially frequent in Japan. The occurrence of sporadic-E drops off dramtically with increasing frequency, and analog television (AM video) is considered less robust under interference than FM radio.

[tubesrule]

Cool set John. I hope you are able to bring it to next years convention.

BTW, your WC-01 has the Japanese RF channels programmed into it under "System M3" so you should be able to provide a signal for all channels on the set.

Darryl