View Full Version : Helooooooooo

01-15-2012, 11:05 PM
Helo guys, I'm obviously new to this forum, and wanted to share my TV and any questions I may have.

I use a Hitachi in my bedroom, as my main TV, and love using it.. It's a very early 80's model.

It's solid state, but there exists an earlier board revision from 78, that for whatever wisdom Hitachi had, used a few tubes in the color decoding and CRT driving (but the rest, solid state).

When I got the TV years ago, it was busted, wouldn't power on, with the completely solid state board. I recapped it, adjusted the flyback, and viola, had not only power, but a decent raster.
(It even says Solid State on the back. I wonder what the hybrid tube model said on it's back)
Yes, the flyback is in rough rusted shape. I don't know how to properly clean it, but it appears to work just fine.
Busted and terribly ugly anode cap.
Cleaned and relubed tuner assembly (though it's useless as I only use Channel 3 now since the digital switchover)
Cleaned and ready to assemble.
Assembled. Notice the cleaned and repaired anode cap.
Ugh, what a weird raster. Turns out I had a problem on one of the caps that was responsible for vertical hold.
Ok, good raster,but now it's green.. Apparently the POTs on the neck board are in terrible shape, and require a LOT of deoxit.


Anyways, here's a video of this TV the day it was repaired and operational.

I have however, changed to the older tube hybrid board though, it's flyback was in better shape, and the board has it's own quality of the color yellow for some reason.. Yellow is a gold color, but you know what, I like it!!

Here's a comparison.

Solid state board:

Hybrid board:

A color test on the hybrid board. Notice the golden yellows:

The TV setup in my room:

And lastly, a video of the TV running on the hybrid board:

Sadly, I didn't take any pics of the hybrid board. But when I get the TV apart next time for more servicing (I need to possibly adjust the focus a little better), I'll be sure to snap a pic..

Keep in mind, while I'm good at this stuff, im new to the terminologies..

Electronic M
01-16-2012, 09:40 AM

I find it interesting that Hitachi still had hybrid color sets as late as 1978.
Most of the major American companies went all Solid State on color between 1973-1975 and soon dropped the hybrid monochrome(meaning black&white) chassis as well, but some mono hybrids stuck around until the opening years 80's. There was one weird exception to use of tubes in color sets though. The all tube (it did use a transistor in the UHF tuner though) GE Portacolor which aside from minor cosmetic changes and a redesigned CRT midway through production stuck around unchanged from 1965-1979 (with some reports of early 80's units being found).

If I was you I would not have hung on to that Hitachi if it did not have that hybrid board as most solid state sets are not collectable. However the hybrid board makes it collectible and very interesting.

It is possible that realigning the color demodulator on your set will cure the gold yellows, but it does not look too bad right now.

There are lots of experienced techs here to give pointers on difficult repairs if you find your self confused working on something.

01-16-2012, 09:53 AM
I only hung on to the Solid State board because it was my second TV repair I had ever done and wanted to experiment on it.. My first repair would be a 90's RCA TV that had a blown transistor..

I would love to have help.. There's only 2 other fault that I know of with this set on the tube hybrid board.. One, is when the contrast is set high, the colors blue seem to "reach" out to the right, like a water fountain, it's really weird. The other, is when the screen flashes white, the picture bounces like it lost vertical hold for one field.

01-16-2012, 10:05 AM
Hmm, I found this site here, and this TV has the EXACT same yellow.

So I would be interested then to know how that's fixed.

01-16-2012, 10:28 AM
More-orange yellows are probably a deliberate design to reduce the variability of flesh tones, and probably not adjustable. My suggestion is to enjoy it as-is.

Electronic M
01-16-2012, 01:13 PM
If the contrast control's range is too far in a given direction look for a control marked AGC and try adjusting it. The AGC (Automatic Gain Control) controls the signal gain of the IF and tuner such that the signal these deliver to the tuner stays at a consistant level, thus eliminating the need to readjust the contrast when switching between weak and strong broadcast stations. It works on a feed back principal where it measures the synch pulse level (which should not vary) in the video signal and adjusts the gain of the tuner and IF to hold that synch value at a constant level. adjusting the AGC control adjusts the level of synch (and the video signal which contains the synch) that the circuit tries to maintain. A misadjusted AGC can either overload the video and synch blacking out the picture or wipeout the video (the synch tends to go first) causeing a blank white screen. The AGC may also affect the synch of the deflection circuits if an overload occurs so it could simultaneously be messing with the contrast range, and upestting the vertical synch as you have described.

On the "reaching" blue problem if you can get a source (ie. testpatern generator, testpatern recordig) for a white cross hatch on a black background then play it on the set and if the bars deviate from pure white, and have either a color fringe or a parallel bar of any of the three screen primary colors then that indicates that the blue issue is a convergence problem which can be solved by preforming the convergence adjustment procedure (convergence is complicated and takes some time to get good at, but one can probably pick it up over the course of a week end).

I believe that your set uses a newer inline gun type CRT which has a different procedure from the deltagun CRTs I'm used to converging.

In your shoes I'd save the SS board too as it is cool to have both versions. What I meant to say was that it is not worth it to save inline gun CRT SS (Solid State) sets unless there is sentamental value attached to a certain set or it is historically signifficant in some way (like the first SS set from a certain brand or the first example of some feature or circuit).

Hybrid sets were made for two reasons. One to save cost over using transistors in a given circuit. And two to use up excess stocks of tubes. Both reasons ultimately boiled down to trying to make the sets cheaper to gain a market edge.

I always love to hear of those oddball later hybrids.

You have got a very cool set there. I'd save one of those any day of the week (though hybrids don't show up much locally).

01-16-2012, 08:26 PM
Yea, I'm fairly certain mines inline, and not a delta formation. I wanted a delta style CRT, but I can never find them around here..

Here's another pic of my setup:

Complete now with my 80's Panasonic VCR.

02-03-2012, 08:01 PM
Hi, I am a new member of forum. Would a newcomer be warmly welcome here? Good day you guys!!!

Suggest you go to the Introductions section instead of this particular thread, then click on "Forum Tools" and post a new thread introducing yourself.
Welcome aboard.

Electronic M
02-03-2012, 08:29 PM
I wanted a delta style CRT, but I can never find them around here..

Here's another pic of my setup:

Complete now with my 80's Panasonic VCR.

I seem to recall you saying that you live in the Seatle area.....If you have the room and want a delta gun roundy with the added benefit of a built in stereo then you may want to read this thread. That is a good price for that set, if the CRT tests good the CRT alone could bring 4 times that to the right person.

02-12-2012, 03:32 PM
I live in Orlando FL, never said Seatle. :/

I went around the local flea market yesterday, and didn't find a single thing.