CurtPalme.com Home Theater Forum

Jeremy112 · Joined: 28 Sep 2006 Posts: 2649 Location: Fond du Lac, WI

Got one of these old beasts from a friend just to tinker with then either give away or good will it...

Works good but I want to get the PQ bit back up to spec, it needs some slight convergence and some focus work..

Theres 3 potentiometers on the main circuit board (one for red green and blue). I would like to know what exactly what they are for? Drive, focus? I assume the magnets on it are only for convergence but this thing is so old that I have no clue...

the only actual number I got off of it for a possible model is HL843357.

If anyone has a schematic, manual etc.. or any advice would be welcome Mr. Green

**Curt Palme** · Posted: Thu May 19, 2011 8:30 pm Post subject:

Post a pix, I worked on 100s of those...

Jeremy112 · Joined: 28 Sep 2006 Posts: 2649 Location: Fond du Lac, WI

Hey Curt, great!

I dont have it hooked up right as of now, I just disconnected everything to move it to a more easily accessable work area, (Sadly its more work to get a pic on this than a new TV, with the TV tuner/cabling etc...)

But heres a pic of the front and back of it, not turned on. If you want pix of it with the back cover off let me know Ill post that as well..

**Curt Palme** · Posted: Thu May 19, 2011 9:36 pm Post subject:

That's a System 3 chassis, a real POS. SUrprised it's still working, those things failed like crazy even when new out of the box. That'll teach Zenith for wave soldering 3 lb transformers by the leads only. Smile

The CRT might be weak, that was right around the tiime that Zenith started cheaping out on the tubes...

Post a pix of the image...

Jeremy112 · Joined: 28 Sep 2006 Posts: 2649 Location: Fond du Lac, WI

Bout the time they started cheaping out? Dang, when I opened it up I thought there was quite a bit of tech in it for such a cheapo (though I did find a leaky capacitor that I had to replace)

Oh well either way Razz

, Sorry bout the quality of pics, but pretty hard to make quick pics of something as old as this TV look good. The picture looks better of course in real life..

Anyway heres the pix of the pic Razz

Jeremy112 · Joined: 28 Sep 2006 Posts: 2649 Location: Fond du Lac, WI

Also... the whole reason I even took it was I had one of these old beasts about 10 years ago and it worked great all the way til I gave it away, doubt its in use anymore, but I couldn't pass this one up when I noticed it sitting under a bunch of stuff in my friends garage... its been sitting thought to be "broken" (turned out it was the TV antenna, it was only VHF!!)

**Curt Palme** · Posted: Thu May 19, 2011 10:24 pm Post subject:

The main power board on the bottom of the set should be pulled out and all suspicious looking solder joints should be redone.

No kidding, I think the winter of 1986, we had to test every System 3 set before we sold it, as we suspected that Zenith ran out of working modules to build sets with, the failure rate was that high, and prices of TVs were dropping, so that everyone with a tube TV was trading it in and buying a new Zenith. Then they all came back after Christmas when they broke down. Smile

Oh, those were the days!

Overalll the image looks OK. I believe those sets had the convergence rings on the CRT neck. Shoot a pix of the inside of the set to remind me.

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Let me just add also that on these type sets the only way to really check focus and convergence is with a pattern generator. The tube should also be degaussed before testing as the onboard degaussing was crap.

Jeremy112 · Joined: 28 Sep 2006 Posts: 2649 Location: Fond du Lac, WI

Pix of the inside as requested Smile

thats pretty shocking, but funny at the same time. Like I said this one is from October of 1984, so it must have gotten lucky and was properly assembled. I will do as you say anyway and pull the main board out and redo any suspicious looking connections. I want to take it out to give it a full cleaning anyway, you can see how filthy the inside is!

I think it even got rained on once... as suggests the sheilding on the TV tuner and the sheilding on the main board... Laughing

Jeremy112 · Joined: 28 Sep 2006 Posts: 2649 Location: Fond du Lac, WI

**Curt Palme** · Posted: Fri May 20, 2011 12:03 am Post subject:

Umm, only if your computer has an RF channel 3 output. Smile

Jeremy112 · Joined: 28 Sep 2006 Posts: 2649 Location: Fond du Lac, WI

well I have an older one that has a composite out, that I can put into a VCR and back out with the coax like Im doing with my HD tuner... would that work??

**Curt Palme** · Posted: Fri May 20, 2011 12:12 am Post subject:

Sure, that will do it, or if you're going to do more of this, grab an AVIA plain DVD off eBay, it's got everything you need on it.

Jeremy112 · Joined: 28 Sep 2006 Posts: 2649 Location: Fond du Lac, WI

I probably should have picked one up long ago anyway, ill do that right away, would save me hassle of computer and so on lol

Jeremy112 · Joined: 28 Sep 2006 Posts: 2649 Location: Fond du Lac, WI

Hey curt, just curious,... this was suggested by a guy I know who tinkers with a lot of gadgetry and robot building, he said I should integrate a digital converter box board in with the TV, would this be possible? I got a few spare bucks to burn on this old thing, and it would actually make it useful again... Very Happy

**Curt Palme** · Posted: Fri May 20, 2011 1:04 am Post subject:

I think he might be talking about the optional 'smart box' for the back of the set. All that was was a video switcher that could be accessed via the remote.

It's a 480i set, that's as good as it gets. Your challenge is to find a working Beta machine and go watch 'Bachelor Party'.

Smile

Jeremy112 · Joined: 28 Sep 2006 Posts: 2649 Location: Fond du Lac, WI

no he was speaking of the little digital converter boxes that you can get at dept stores, was thinking of getting a cheapo off ebay to try this out, hey, it can't hurt right? too much anyway!

And as for Bachelor party, got it on the computer, and on VHS xD great movie!

Jeremy112 · Joined: 28 Sep 2006 Posts: 2649 Location: Fond du Lac, WI

Hey curt, I got a couple pics of the main board you suggested I look over, I went through it pretty thuroughly and the solder connections were pretty good, I did retouch a couple of them and replace a few suspicious looking capacitors.

The reason for the pics is I was wondering if you knew what the RGB pots, and the Yello, Black, White, and Orange pots on the board are for? I know its been eons since you worked on one of these but if you know I what they are for I would appriciate it (so I dont go tinkering in the wrong area!)

**Curt Palme** · Posted: Fri May 20, 2011 6:42 pm Post subject:

I think the RGB are either G2/screen controls or video gain. The rest you don't need to touch. Not sure what they are for, but I never needed to tweak them.

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

The RGB should be for the drive signal for adjusting white balance. The screen control (1 only) and the focus control should be on the flyback. The other pots are for various adjustments such as sub contrast and sub brightness, AGC, phase, vert hold and shift, horz frequency and such. If the board is not marked then you would need the manual or see if there is a decal inside the back cover. A lot of older sets had this decal.