Happy New Year's everyone!

I was given a very nice July 1989 JVC Master Command 3, Model C-2019. I haven't spent much time with this set, but I already like it. It's a 20" Model with a square-edge tube. It has an awesome High End 80's Electronics look, I don't know how to describe it but I love the looks of this set. I was lucky enough to be given the original remote. It's made in USA, the plastic was molded here and the tube was made here. I truly hit the jackpot with this set, IMHO. The 27" Zenith I had fixed before didn't fit in the little cubby hole were my old 13" was, so I had to have the TV on the floor. My mom was always complaining about how it was just laying there and I haven't watched that much TV lately since it's a pain in the posterior to drag it out of it's corner and plug it in. This JVC fits the little cubby hole perfectly, almost completely fills the space. My only complaint is that it has no A/V in, just the tuner, but I mostly just watch cable so no problems there. The tube is very strong, very bright, clear, colorful picture.

There's only one problem, whenever it's on, there's a VERY loud buzzing sound coming from inside. I've only had it on for about 20 seconds because I don't want whatever's bad inside to blow and take out other stuff with it. The sound seems to be coming from around the flyback area, but I can't really tell if it's the Fly. The image on the screen is good, but there's a lot of static (like the type that shocks you, the actual picture is fine). There's these four little weird white formations, 4 appear in the picture when the TV is on, and they are definitely not part of the raster. They look like static buildup, no pics sorry. Any suggestions? There's no schematic on eserviceinfo.com, and a google search shows nothing. Anybody got a Sam's on this set? Hopefully it's not the fly. The buzzing is very loud and sounds like a motor, could the fly do that but the set still has a decent picture?

Also about the Sony computer monitor on my other thread.... I will be ordering the HOT in a few days, right now I don't want to start working on it yet, so update on that in a week or two.

Thanks,
-karmaman

Here's some pics of the TV, the chassis, and the static buildup I mentioned.

That looks like a nice TV!

Um, You might want to pull one of the speakers out and examine the surrounds... see if they're disintergrating. I've noticed on 1980's TV's that the speaker surrounds sometimes start to fall apart after 20 years or so...

I have no clue where the buzzing is coming from, but it's probably not good.

I've seen deflection yokes make a buzzing sound before. It probably won't hurt anything. It will just be annoying to listen to. You might try getting a piece of non conductive tubing and stick one end close to your ear and poke around with the other end to try to pinpoint the noise.

Those JVC's are pretty decent sets. The biggest problem I have with them is the fact that JVC is very proud of their parts. My cousin has a mid '90's 27" JVC that I let him have after I changed the vertical IC. He's been watching it for several years.

The speaker is doing great (there's only one, mono sound). I remembered your post about the 80's Trinitron and it's one of the first things I checked when I opened it. The buzzing sound is definitely not coming from the speakers though.

Radiotvnut, I don't think it's the yoke, the noise it's making can't really be described as buzzing, it sounds more like a small motor. I attached a small MP3 file, it's recorded with my computer mic so it's not so great. Could it be a coil or maybe one of those long, white, non-electrolytic capacitors? Also what do you mean about how JVC is "proud of their parts"?

I can't attach MP3 files, so I added a link to megaupload. Don't worry, the MP3 is completely virus-free. Does it sound like it could be the flyback, or is it impossible for the flyback to do that and still work? If it's the fly, I may as well give up all hope on it right now.

http://www.megaupload.com/?d=3I0DTB8G

"proud of their parts" means they are $$ high $$ as a cat's back!

Oh..... lol! No joke, I looked up the Flyback for this and I found it for $96. That's probably because it's not made anymore and hard to find, but still. Doesn't Sony have hideously priced replacements too?

So what do you think of the buzzing sound, were you able to download the mp3?

EDIT: I just hooked the set up to cable and watched it for a minute or two. It gave me one of the best analog pictures I have ever seen, although there's a small snowy line traveling up the screen (my gut feeling is that it's related to the sound it's making). Even my dad said it's got great picture quality when he walked by, and he doesn't really notice much difference between one TV and another.

The Sams Photofact is 2729-1. I'll look tomorrow to see if I have that diagram. That noise does not sound like any flyback or yoke I've heard. I just fixed a Sanyo for a friend that was making a similar noise. The noise was actually the power relay buzzing and it was caused by a bad electrolytic cap in the standby power supply.

And, yes, Sony loves their parts as well. A guy at my church had a fairly new 36" WEGA flat screen with a bad flyback. My cost was around $250 (can't remember the exact figure) for the part! I convinced him not to have it fixed and asked him to please remove his junk from my property. Even though he paid mega $$ for that set, he would have done better to have bought a Sanyo. Those later Sony CRT sets are very overrated, IMHO.

I try to use generic flybacks whenever I need one. They are usually much cheaper than an original and sometimes a generic will be the only thing available. I was just given an '86 16" Quasar with A/V jacks with a bad flyback and shorted HOT. I can get a generic for around $14.95. The CRT test very strong in this set; so, I'll probably fix it for my use.

I listened to the sound, and it does kinda sound like an electric motor.

Have you managed to pinpoint where it's coming from? (Sounds pretty loud)

The sound seems to be coming from a large coil in the power supply area. Check out the pics. Can the coil do this by itself or is a bad cap or something like that making it do that? I checked the cap right next to it (circled in the picture) and it was fine, tested 10.57uF (It's value is 10uF).

Don't know. Caps are cheap though, so you wouldn't hurt anything by replacing it. At the very least it'll rule that cap out.

At least the noise isn't coming from the flyback, right?

Nope, not the flyback.

I still think it's coming from that relay located right there at the big coil you were talking about. That coil is an AC line filter choke and I can't see it making any noise. The relay is the black thing with 48MB and 48 VDC stamped on it.

I found the Sams. Check C791, a 4.7 mfd, 250 volt electrolytic cap.

It's actually a 4.7uF 350V cap, and it tested 10.1nF. I've never seen a cap test this bad before. Will be going to Fry's later today. Any other caps I should check?

It's actually a 4.7uF 350V cap, and it tested 10.1nF.

There's your problem.

I got that samsung that needs C950 replaced, but I can't find it. I suppose i should take it out and go through the larger caps again...

That was most definitely it, thanks radiotvnut. The set has some slight pincushioning, any suggestions on what cap might be causing that?

This set does not have any type of pincushion correction circuit or any adjustments. There are 3 caps in the horizontal output transistor collector circuit that could have drifted in value and be causing a width problem. These are high voltage capacitors and their values are critical. They should only be replaced with the same value and equal or higher working voltage. Failure to do so could result in HV running above normal. In the '70's, Zenith used a high voltage capacitor in this circuit that was prone to open. The result was the HV running so high that it would arc through the neck of the CRT and literally blow the neck off the tube! Anyway, here are the values.

C524 .0056 uF, 1.6 KV, 3%
C526 .27 uF, 200 V, 5%
C527 330 pF, 2KV, 10%

Thanks, I'll check those. It's not really pincushioning, just bad regulation, sometimes if a bright object is in the middle of the screen it kinda bulges out, so I mistook it for a pincushion problem. Interesting about those 70's Zeniths. I guess that's why it's hard to design something, such a problem would only show up after a few years of use!

Check the voltage at the + terminal of C908 (100uf, 160 V). It should read 130 VDC. The voltage should remain around 130 and should not flucuate with changes in brightness. If the voltage is off or fluctuates, there is a problem in the regulator circuit. C908 could be the cause. Use caution when checking voltages. Most TV's have a "hot" chassis and can deliver a possible lethal shock if you touch the chassis while another body part has a path to ground.

C908 was at a healthy 110uF, so it's good. I didn't measure the voltage at it. I think I'll leave this TV as-is for now, the regulation problem is really non-noticeable as it only shows up every now and then depending on what's on the screen. One thing though, this set has a really noisy flyback. I can hear the whining a lot louder than on most sets. Even my friend who was over the other day noticed it. Is this how it's supposed to be, or is there anything I can do to quiet it down a little?