Magnavox combo problems

[anteater81]

Hello-

I've enjoyed reading the posts on the TV forums here for a while, and everyone seems to be very friendly and helpful. I've been into old TVs, and obsolete technology in general, for as long as I can remember, and it's nice to know there are so many others who share my interests.

Well, now I finally have a reason to post something myself. I picked up a 60s-era black & white Magnavox combo at a thrift store for $5.00 not long ago and it has a few problems I'd like to fix. By the way, it's completely solid state...I was surprised when I took the back off and didn't see any tubes! I have some knowledge of electronics and I've repaired a few old radios, but I don't know much about TVs, so perhaps someone can help me and tell me where to begin.

First, it works well on UHF when the cable is hooked up to it, but VHF is nothing but slanted horizontal lines. Perfect sound, though. When the cable is unhooked and the rabbit ears attached, I get one station on VHF just fine, but nothing else.

The other problem is with the record player. When using the TV or the radio, the sound comes through the left and right speakers as it should, but when I play a record, I only get sound through the right channel.

What could be causing these problems and how can I fix them? I also need the VHF channel selector knob, as the one on this TV is broken. I've heard that's a common problem with these. I've attached a picture if anyone wants to see what it looks like. Any help would be greatly appreciated! Thanks!
JD

[bgadow]

Solid state? That was rare when this was new! I'm pretty much useless diagnosing problems on solid state stuff, but if you can post a shot of that knob I'll be glad to look for one to match.

[Sandy G]

Hey Anteater, where you at? I'm about 30 miles below Kingsport...-Sandy G. P.S.- Nice old TeeVee !!!!

[andy]

Have you tried adjusting the horizontal hold?

[rca2000]

Yes, in 1966, I think, magnavox brought out a line of solid-state BW tv's. The chassis were well built, and if not the first large-scren solid state tv, they were among the first.

If you can, post some pictures of the INSIDE, the chassis of BOTH the tv ,and stereo(for us old tv and hi-fi-nuts,, that is what we like to see, anyway).

[anteater81]

Thanks for all the responses!

I've played with the horizontal hold until it begged for mercy, and I've played with all the other controls I feel comfortable messing with, and still no difference. To add to the troubles, this evening I was watching "Now, Voyager," and the picture started getting jumpy. It jumped for a while, and then it turned into a horizontal white line in the middle of the screen. I'm assuming this means I'm having a vertical deflection problem. Of course, I don't know as much as I'd like to, so correct me if I'm wrong. What do I do? I'm clueless here. I'd like to get this set working. I'd really love to get the phono working right, as it's the only changer I have that seems to function correctly! I need something to keep those Guy Lombardo records going. If I got this one working I could start on the three other old TVs (1955 Zenith cat-eye table model, 1956 Hallicrafters console, and late 50s Olympic combo) sitting around here gathering dust. If anybody wants to see 'em, I can post pictures.

Thanks so much, bgadow, for offering to help with the knob. I'm posting a picture of it here. Not a very good picture, but I hope it'll do. I appreciate your help. And RCA2000, I'll pull the back off tomorrow and get some pics of the TV and stereo chassis. I'm almost afraid to take it off again, as the last time I took the back off, I was attacked by a couple big ol' spiders. As a matter of fact, when I bought it, there was a dead one hanging between the CRT and the safety glass! This thing must have spent a few years in someone's basement or barn.

BTW, Sandy, I'm in Bristol, the "city" that rolls up the sidewalks at 9 p.m, and doesn't have any decent antique or thrift stores! I bought this TV in Johnson City. Thanks, everyone!
JD

[Sandy G]

Awww, Anteater, Bristol ain't so bad...you're close to Abingdon, they've got several antique stores to prowl thru, then there's the ones at Fort Chiswell where I-81 & I-77 meet, remember there was a 10" Admiral bakelite set there year ago Labor Day, Kinda skint up, but the bakelite wasn't broken. It was that oh-so-cute floor model that stands about waist high. Should a got it. -Sandy G.

[jstout66]

Cool set. I was going to suggest you clean the tuner and controls with tuner-cleaner or de-ox it. As for the vertical problem... I have no clue. I can barely work on tube stuff and I'm clueless when it comes to solid-state. I would imagine for your sound issue on the turn-table you probably have a bad cartridge. Your vertical problem sounds like the same problem I'm having with my Motorola solid-state "works in a drawer" set. I got it ALL set up in the living-room and it did the same damn thing! Vertical got jumpy and I lost ALL deflection. Your set has to be somewhat rare. I don't know why ANY makers would have bothered with a solid-state set in a B&W console when EVERYONE was moving to color and a majorityof color was tube untill 1970-1971. I had a 1967 Motorola B&W console that was solid-state as well. It even had a pre-set "Insta-Vue" button that had a pre-set for the brightness & contrast. Wish I woulda kept it, but that was YEARS ago. Maybe you can find some shop in your area that would work on it, or if you have the ability maybe that sucker has plug-in transistors. Good Luck!!

[dewickt]

I would offer to help out but my shop is to small for a console to fit in and work on at the same time, someday if I ever expand I would say bring it down to Knoxville, need a garage in the back yard to store the 35 Woodie then my shop space would double.

[bgadow]

I looked through all the knobs, these are the closest I came up with. If you think one of them might work let me know. The one closest in shape looks like 1/2 of a two piece design. Yours looks like the same knob as Polarman's new Magnavox console.

[polaraman]

I would go with the 1/2 knob. The channel indicator is turned by the tabs at the botton of the knob.

polaraman

[Sandy G]

Terry, you'd have PLENTY of room if your disreputable customers would pick their Junque up promptly, & not bring back more than they come & get...and not bring BIG junk like R-390As & oscilloscopes...Hehehehe-Sandy G

[roundscreen]

JD. clean all the service controls. Vertical height vert lin etc. Also vert hold. Look around for a diagram that explains what the transistor functions are. See if you can find the vertical section transistors. Turn the set on and turn the contrast all the way down. Set the brightness so you see a dim picture. Let it heat up. Tap the board with the plastic end of a screwdriver. If it makes the picture jump around you have bad connections. Get out your soldering gun and re solder the boards. Most problems in solid state sets are connections and bad caps. Heat from the transistors and resistors will crack the solder connections. IF you can, Replace the caps esp if you want to use it as your main tv. The turntable problem may be the cartridge or the wires in the tone arm. Also dirty controls will make a channel go out. If the turntable uses rca cables switch them around see if sound comes on from the dead channel. that way u know the amp is ok. Afc diodes may be the problem with the horz hold. Good luck
ED

[anteater81]

Well, this thread is back again.

I cleaned all the controls, resoldered the pc board, messed around with everything...probably more than I should have messed with. At any rate, I'm getting a decent picture now, although I'm STILL having problems with the vertical. It still jumps and becomes a horizontal white line after watching for a while. Takes longer than it did before, though. I know I'll have to replace the caps. I'll tackle that when I can afford to buy new caps. I've included a screen shot of the set showing a vodka commerical. ) I found a channel selector knob for it in one of the boxes in my basement...I guess all those years of flea market scrounging have paid off.

I managed to get the record changer working, and it sounds GOOD! Apparently, someone had installed a new cartridge at some point, and whoever did that forgot to attach the wires to the left side of the cartridge. I had to do a bit of soldering and oiling, but now the record changer functions as it should and it sounds wonderful. I love the changer in this thing, BTW. It's a Magnavox Micromatic, made by Collaro, and it's the best record changer I've ever seen. I'm thinking now that I should buy one of the portables with this changer in it. I would like to have the original cartridge, but I haven't been able to find one.

Thanks to everyone who helped me! It works as it should much longer now, although the vertical problem is still present. I'll recap it and see if that helps. I love the pictures of all these old TVs, keep it up! Thanks!

JD

[RetroHacker]

Originally Posted by anteater81

At any rate, I'm getting a decent picture now, although I'm STILL having problems with the vertical. It still jumps and becomes a horizontal white line after watching for a while. Takes longer than it did before, though.

This sort of vertical problem was pretty common in the original Macintosh computers (the ones with the 9" black and white screens). The source of the problem was always cracked solder connections at the yoke connection, and/or a failing capacitor in the vertical circuit - IIRC it was a non-polar electrolytic. Since now it takes longer for the problem to appear, and it seems to be heat related, I'd suggest really resoldering the yoke connection. Suck out as much old solder as possile and resolder with plenty of heat and new solder. Remove the connector for the yoke, and clean the pins (if it has a connector). If while the set is showing the horizontal line, if you can jump real hard on the floor and have the picture come back, then it's most likely just a bad connection. Next time you get that line, first thing to do is turn the brightness down to prevent burning the tube. Then try banging on the set a little, jump on the floor, poke the board with a plastic pen, etc. See if it's an intermittent connection. If it pops back to normal, you've still got a bad connection somewhere - double check and resolder anything that looks suspect, and anything that isn't. Cold solder joints are a very common source of problems in solid state sets. Also look for cracked traces - if the board got a little warped, and there are damaged traces, similar symptoms can appear. I'd also suggest resoldering the pins at the bottom of the flyback transformer - those like to crack too. It's the high frequency signal and the heat that does it.

If the problem still persists, then start suspecting electrolytics - replace the ones in the vertical circuit. Check the obvious too - vertical hold control, dirty service switch, etc.

If the problem _still_ persists, the set could be going into HV shutdown - some sets had a circuit to kill the horizontal hold if the HV ran too high, to prevent users from being bombarded with X-radiation. Not seen one that went to a horizontal line, but it's possible - it normally goes to a bunch of angled horizontal stripes. Check the damper, and parts of the associated circuitry.

Replacing the filter caps couldn't hurt either - those can cause all sorts of wonky problems.

If the problem still persists, call in an exorcist. That television may be posessed.

Originally Posted by anteater81

I had to do a bit of soldering and oiling, but now the record changer functions as it should and it sounds wonderful. I love the changer in this thing, BTW. It's a Magnavox Micromatic, made by Collaro, and it's the best record changer I've ever seen.

Yeah - I love those micromatic Magnavox changers too. Good, reliable mechanism, good sound, consistent quality - I've rarely seen one that didn't work. The record changer I use in the shop is one of these, it came out of a trashed Magnavox solid state console. The tone arm was broken in half! I patched it back together, and it works great. It looks kinda naked - I've got it propped up on some scraps of wood - it doesn't have a case, since it came from a console. All I did was patch a power cord onto it, and hooked up the connections to a receiver. These changers were used in most (if not all) of the solid state consoles that Magnavox made. These console stereos are _really_ common, and I find them on the side of the road sometimes. If you find one, you can pull out the changer really easily, I'm sure you found this on yours, just pull the back off, disconnect it, flip the three little catches up, and just pull it up and out. Those were great consoles, but now you can't give them away, especially the later ones with the speakers facing the sides as opposed to the front.

BTW - Very nice find! I've never seen a solid state combo like that with a black and white set - that's pretty cool!

Good luck!

-Ian