1990 Zenith System 3
 

Hey guys, a friend gave me a Zenith System 3 27" TV, with a manufacture date of January 1990. When I plug it in, a green LED labeled "Stereo" starts blinking nonstop. When I push the power button, nothing happens. If I hold down the power button, I hear a click inside the TV, the green LED stops blinking for a split second, then the LED starts blinking again and nothing happens.

Any ideas? I'm OK at soldering, good at following instructions, and have a multimeter. This TV is old to me (I'm only 15) but it's kinda cool-looking, but I'd love to fix it. It's sorta cool having a TV older than you.

What's the model number? I'll look and see if I have a diagram on it. It sounds to me like bad capacitors in the power supply.

The model No. is:
SF2589W

1990 sounds awful new...then I get doing the math. I graduated in '90. That TV is now 17 years old. When I was 15, a 17 year old set was a '70 model...hmmm, that's just the age set I was dragging home!

I'm sure no expert on sets this age, but caps are the place to start. Good luck!

I pulled the Sams Photofact on your set (2811-2) and I see that you have the dreaded "dual module monster" chassis. However, there is a capacitor in the power supply that has a high failure rate and can cause the problems you're having. Looking at the back of the set, you will notice two large boards next to each other. The board on the left is the main module. The board on the right is the power supply / sweep module. On the far left hand side of the power supply module; you'll notice a large electrolytic capacitor (680 uf, 200 v) Now, look directly behind & to the right of that capacitor and you'll notice another smaller capacitor (100 uf). Directly to the right of this cap is an 8 pin IC (ICX3401). I have seen that 100 uf cap bad several times. Take note that this is a polarized capacitor and the new one must be installed just as the old one was. Electrolytic caps can and will explode if installed backwards. If that cap does not do it; let us know and we'll see what else we can come up with. BTW, if you have access to a CRT tester; check the picture tube. '90's Zenith tubes don't hold up that well and it would be best to know what condition the tube is in before you dig into the power supply too much. I use a B&K 480 CRT tester. If you can find a B&K 467, 470, 480, 490, or a sencore Sencore CR70 tester; you might want to get it if the price is right. These are often on ebay at a reasonable price.

Hey guys, thanks a ton for the info. Unfortunately, I won't be able to get into the set until late tomorrow or Friday afternoon (due to the astronomical amount of homework my merciless teachers have given me), but I'll be sure to take pics of the TV and the chassis. Is the 100 uf cap available locally (Radio Shack)?

Thanks for the help!

This sounds like my main set, which I would call the end of the line for 'good' Zenith sets. Mine had the same problem, and same fix. Great picture if you can fix it, much better than any recent crt junk.

Yes, you should be able to get that 100 uf cap at Radio Shack (of course, you'll probably have to find it yourself since most of the dorks working there now don't even know what a capacitor is). You should also be able to get one from any electronic parts house (if you still have one left in your area). Just make sure the working voltage of the new cap equals or exceeds the working voltage of the original. Even though those chassis could sometimes be a pain to fix; I'll still have to agree on that set being one of the last decent Zenith's. If the CRT is still good; it will probably last a long time.

Yeah, Radio shack should have 100UF caps. God help you if you need something a bit less common though. Usualy the Radio Shack person will scratch their head, then try to sell you a phone.

I had a Radio Shack salesman try to sell me a new digital multimeter back in the early '90's when all I ask him for was a connector so I could make a probe for a VTVM I had. Radio Shack has gone down the toilet since the 80's and early '90's. Back then, I could walk in and say "I need..." and the employees knew exactly where to look.

Those Zeniths are good sets. I liked how they standardaized the chassis. Once I upgraded a 20" set with a video board from a larger set (added s-video and some other features).

Radio shack is a pain because they still ask what you're looking for as soon as you walk in the door. I like to be left alone when I'm shopping.

Holy Cr@p! That was it! THANK YOU GUYS!!!!!! I had a hard time getting the old cap out (couldn't figure out which pins on the bottom of the board belonged to the capacitor on top) and I had to have my dad pull on the cap with pliers while I heated up the solder on the bottom of the board. I pulled out the old cap and headed to Radio Shack, they had a 100uf 35V cap for $1.25. The original was 25V. I got back home, put the new cap in (making sure I had the correct polarity of course!), put some solder on the pins, snipped them to the right length, put the chassis back in the case, plugged it in and crossed my fingers. The first thing I noticed was that the power LED was not blinking anymore, but completely off. I pressed the power button. I heard the CRT degauss, and then.... it worked! The picture was really dim though, but I went into the menu and the "Picture" option was halfway. I turned it up all the way and now I get a bright, colorful picture! I can see the scan lines, but text shows up a little soft. No matter though, It still looks good and the tube seems to be in good shape. I will post pictures tomorrow (my camera is charging right now, but it takes all night). I also bought an universal remote control at Wal Mart for $8 and it works great!

Thanks a ton to everyone, but especially to radiotvnut. Without your instructions, I would have never been able to fix this set. Amazing how many decent "broken" TV's get thrown away because some $2 component inside failed.

If you're getting scan lines, that tube is probably weak.

I don't think the "bad" Zenith tubes started until about '93-ish, so maybe yours just had some serious hours. Mine saw lots of use for the first 10 years, now not as much (as TV has gotten more sucky, the set gets used less).

Glad to hear you fixed it !! :thmbsp::thmbsp:...

Here's what I did with mine:

http://img.photobucket.com/albums/v6...r2/TVstart.jpg

http://img.photobucket.com/albums/v6...2/TVduring.jpg

http://img.photobucket.com/albums/v6...r2/tvafter.jpg

Before anybody hates me, that porthole Zenith was long gone before I got the cabinet.

Glad you got it going. It would have been nice if Zenith had roadmapped those boards. I think they intended on those sets to be repaired by swapping modules. You may can play with the G2 and focus controls located on the flyback transformer (the thing with the large red wire coming out of it that goes to the crt) to help improve the picture. This set employs AKB (automatic kine bias) and has no cutoff or drive adjustments. Yes, I'll agree that there are TONS of nice TV's (both old and newer models) that are thrown away because something minor went wrong and the owner didn't want to invest any money in it. You might consider placing a wanted ad in the paper advertising "free pickup of non working TV's." I've done that over the years with good results. Here lately, all I've gotten is '80's and newer sets. I hope some tube and early solid state sets will find their way over here soon. You could also ask around your local TV shop. There's one here that gives me all their junk so they don't have to dump it. A good bit of it is fixable. They are just sets that no one wants to spend money on. The ones that are going to cost a lot of $$ to fix get scrapped for parts.

By scan lines, I mean that when I look close I can see the individual lines that make up the picture and I can follow them with my eyes as they go down. Every single tube TV I've ever seen does this, I know it's normal but I don't know what it's called. Anyway, this will become my main set. I can finally replace the Orion 13" I've been using for so long! To think I was about to buy a trash Durabrand from Wal Mart.... I knew they were garbage, but thought it was my only option for getting a large TV for my room.