I picked up this 19" Zenith system 3 with zoom space command, which was made in May of '78. This set uses the short lived system 3 chassis that came out before the 9-160 based sets. This one uses a 9-153 HV module and a power transformer type power supply. The set came to life; but, I could hear something frying and I detected an odor. The sound and smell was something similar to a cap that was about to blow. I'll have to turn it on with the back removed and maybe I can tell what's getting hot. Unfortunately, I don't have the remote; but, I think this set uses the 7 button battery operated ultrasonic remote.

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I had this exact model. It was a pretty good performer in terms of overall pix quality. I know many people feel that the system 3's early in-line trifocus tube was a step down from the CCII tubes, and they're probably right,, but the truth is that they're actually not half bad

when they are right,you produce as fine as chromacolors sets.they tend to fade out much faster.for some reason,all i have known lose the green gun.still worth saving

I am not a technician but I know that the old TV sets with vacuum tubes had about 16 different circuits to control the picture and then when they switched to solid state they had like 8 modules, as in Zenith's Chromacolor, then they reduced them to 3, then 2 and I am really wondering if this lack of many circuits in new TVs can affect their performance.

During the '70's and early '80's, the trend for many solid state color TV's was modular construction. That way, the technician could isolate the trouble to a certain module and quickly fix the problem. This was especially helpful to the tube guys who didn't know much about solid state troubleshooting. In the early '80's, most companies started going to single board chassis designs and the technician was expected to troubleshoot the set to the component level. I think Zenith was the last one to offer a modular chassis TV. In later years, that "module" was the complete chassis; but, it was designed to be replaced. Whenever possible, I tried to repair these modules to the component level, especially when the cost of a new module got excessive. When I first started fooling with TV's, a Zenith 9-160 module was around $50 for a rebuilt module. They ended up costing over $100 just before they became NLA. Now, there is almost no market for them.

I think there were two reasons that companies went from modules to single board designs. One was to cut cost and the other was eliminate problems that were caused by the interconnect system that was used with modular sets. In most brands, a common source of trouble was the connectors where the modules plugged in.

With the new flat panel TV's, things are going back to replaceable modules. With all the surface mounted stuff in these newer TV's, I'd hate to have to repair one to the component level.

I really don't think they reduced the number of circuits in newer TV's. They just made them smaller. By the '90's, there were usually two large IC's in most TV's. One IC was the microprocessor and the other IC contained the majority of the TV's signal processing circuits on one chip. Some of the later TV's even had the microprocessor and signal IC's combined into one large IC.

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That set brings back memories, I changed out a lot of those modules back in the day, mostly under warranty.

Seems like every other Sys3 Zenith that went out the door at that time came back for repairs.

The interconnect cables weren't all that great either, the plastic tabs would break pretty easily though it always seemed to work OK with only one tab.

The earlier upright chassis were better but had a lot of problems with the module contacts, on some of the more stubborn ones we'd just solder them to the pins.

Regarding 9-160's, I've replaced a lot of flybacks on those; but, they all came off of a junk board. Those flybacks were known to break down and arc and burn violently.

I looked at this set a little closer tonight and I don't know what was frying, as it's not doing it now. It was humid the last time I checked it and it was probably HV hissing. Anyway, after making some adjustments, this set produces a decent picture on channels 7-13. Channels 2-6 are dead and can't be fine tuned in. Hopefully, it will only be bad solder connections inside the tuner. I seem to remember Zenith tuners from this time having this problem. I tested the CRT and it test almost like new. This set looks to have been used very little. Also, the color sentry preset controls need adjusting, as it appears that someone has been playing with them.

I found a used 9-151-01 tuner/IF module in a box of junk and the set still has a dead VHF-lo band with that board installed. That tells me that the problem is in the front panel controller assembly. I think that control unit has several IC's on it and there's a good chance one of them is bad.

I picked up this 19" Zenith system 3 with zoom space command, which was made in May of '78.

That's the month and year my BSEE degree was made! Syracuse University. One of the profs there said that he thought that TV was a completely mature technology, and all that was left to do is to figure out how to make it cheaper. :D

Well, a few years later I got a job at RCA Sarnoff Labs, and invented a bunch of patents in TV technology, and later on HDTV came out. :D

Really a wonderful set!!! Is there anyone around who is willing to sell a similar tv to me?
I'd love to own one of these soooooo much!!!

RadioTVNut, In the 2nd picture, I see the coax disconnected from the antenna input board. Are you running VHF with the twinlead connected on the left side?

When cable came along, I just hooked it up to the F connector on the wire at the set.

I also repaired a bunch of these sets... lots under warranty. We did repairs at component levels, too. I always had a list of parts to replace when I would find something wrong, like the Hz output transistor.

I rarely had callbacks on Zenith sets I repaired. We rarely had problems with those board interconnect cables, unless one of the lock tabs was broken. I say this looking back, now, as most of the sets I repaired were under 5 years old. I havn't worked on a System 3 set in 15 years or more, now.

I connected the cable directly to the coax connector on the TV. The vhf high band produces a good picture, while the vhf low band produces nothing. When I get a free spot on my bench, I'm going to dig into the tuner control assembly.