View Full Version : Repair of one of those cheap "last gasp" B&W TV's


radiotvnut
06-23-2012, 06:45 PM
Someone gave me one of those 5" Chinese B&W TV's that are so common and I wasted some time this afternoon getting it going. Here's the video of it:

http://www.youtube.com/watch?v=I7VlSPyArqA

lnx64
06-23-2012, 06:57 PM
My grandfather has one of those, in black..

I used to have a blue translucent black and white TV that was sold by Target.. It's CRT clamp broke and caused the picture tube to fall into the TV.. I miss that TV, it was so awesome looking..

Eric H
06-23-2012, 07:54 PM
I've fixed a few of those, one had a bad "Jungle" chip, it had no reception but would light up.
Another had a bad Flyback, got one from a donor and fixed it.
A third one came with a broken CRT, fixed with one from the donor set.

They have a really good picture for what they are, I don't recall any buzz in the sound on any of them.

AiboPet
06-23-2012, 09:18 PM
These are EXACTLY what my little "sub-collection" is. I have about a dozen of these in different cabinet colors and some with A/V in (both RCAs and 1/8").

Most of these just suffer "abuse"...and generally don't see them fail on their own. ALOT of them do have that buzz in the audio (still dunno where that is coming from). When you can find one with good clean audio...has the 3" speaker rather than the 2" one, these usually DO dial in quite well. I have a couple that have PHENOMENAL picture geometry and sharpness...and are QUITE watchable.

I've scrapped ONE set that had a real mysterious horizontal instability after like a minute (likely caps, but never could find which one). That set gave it's life though to save four other sets of that same general "reference design":

Flyback/HOT.....rescued one with the board cracked for like 3" across...ended up having a bad flyback that then killed the little HOT next to it. Works after carefully dremelling and bridging all the traces..replacing the flyback and hot from the doner set.

CRT......One had a perfectly fine picture, but I didn't like the very odd "cool" bluish CRT it had. It didn't match all the others. The doner set's CRT did match the others.

Yoke.....One set had a picture in the shape of a "parralelogram"..and I couldn't figure out WHERE that was coming from. Turned out it's yoke looked like someone tried to twist it off without loosening the clamp. Doner set's yoke gave it a perfectly square crosshatch again.

Cabinet.....Doner set's cabinet was used for a funny "paint project". I'm part of a car forum (soulhamsters.com)..and the question came up about those cans of "chrome" and "gold" cans of spray paint. Doner set's cabinet was painted half chrome and half gold with a little red pinstripe....just to see what these two colors REALLY looked like (don't bother). The set DID come out fun though...and that cabinet ended up being home to one that was REAL busted up, but working perfectly.

The pics are of a little over half of 'em (all that would fit in a neat little row on that Ikea credenza thing)...with one pic of the one I did the chrome/gold treatment to. I keep them ALL tuned to my little in-house transmitter, so one push of a remote X-10 controller will have them ALL on with the same picture. I know...WEIRD, but I think it looks cool :-P

I'll take better pics of this someday when I can have ALL of them in one place. This collection is fun to see when ALL of them are together and on. I think I have like 14 now, and they all don't fit here unless I start crowding 'em.

It's nice to have someone bring up the point that these were sort of the VERY last reference design for B/W TV sets. I didn't really know how to classify this little part of my collection, because it was an "accidental" collection. I find these...buy them for real cheap if I notice an unusual one. Find them in SORRY condition and use them to practice my TV repair "kung-fu"...and then suddenly, I have a COLLECTION of them :-)

AiboPet
06-23-2012, 09:43 PM
And yes Eric.....ALOT of those sets end up with mismatched Wall-warts. If it's anything less than 12VDC and about 500ma...It'll come on but not be at all happy. I've bought plenty at swap meets and the like...that they just found some converter that simply fit the plug, and it's a 6V/200ma or something that would do almost EXACTLY that picture AFTER you fixed the cap. The plug is DEAD common, so REAL easy to end up with the wrong one if not careful.

Also, these tended to be plugged in and forgotten. The wall wart ends up between the wall and some BLANKETS next to someone's bed, etc. I bet ALOT of them melted or just died from heat. You see there isn't much to 'em. If that transformer gets hot and the windings start shorting because the insulation melts....it's toast, and you can't do much about it unless you feel like REWINDING the transformer :-P

Also watch for these to end up with "charger" wall warts. You end up with 12VDC at a kosher current rating....but it's REAL dirty because it was meant to charge NiCads in a cordless drill or something. It won't have the caps inside to take the ripple out. You end up with a set that comes on, but the picture is wavy and you get LOTS of 60hz buzz. I used to think the buzz was from this...but you will notice it changes frequency with the vertical.

I keep at least one "known good" wall wart on my bench JUST for these sets...so I won't mis-diagnose something because of the power supply. I obviously run across these sets WAY more often than you do, so I do sorta have a specific space set aside for working on these.

Eric H
06-24-2012, 12:15 AM
Well Aibo, I'm glad to see I'm not the only one who likes these things, they make great colorful displays.
I once joked about them becoming valuable like Catalin Radios, maybe I wasn't joking!

I have a lot more still new in their boxes, I pick them up when I find them cheap, I have gone looking on eBay to find specific colors (Purple is difficult), I find lots of White Black and Silver, I sometimes pick them up for parts.

I have a few of the really small 4.5 inch models NIB that are really weird two tone colors like Pink and Green or Aqua, those are really nice but I leave them in the boxes.

If I had the skills and tools I would like to build a 1/4 scale 1950's 21" console using one of these for the chassis, complete with knobs and safety glass, at 5" they are just perfect for that scale.

ctc17
06-24-2012, 12:32 AM
If its mass produced there will be a forum, club, user group, magazine, news letter,....something. Something devoted to it and the pattern problems associated with it.

lnx64
06-24-2012, 12:51 AM
You know what, I got one hell of a 5" black and white set to show you guys. Mine is one inherited by my family. It's an old Unisonic, from I think the early 80's, with a PLASTIC CRT screen. (I think it's protector on front, because I can't imagine a CRT having a CRT screen built in, without imploding very easily).

Has 3 TV position modes, VHF-L, VHF-H, and UHF, and runs on AC and DC power.. But I find using DC power, works better than AC for some reason (may be aging capacitors).

EDIT: Here it is!

radiotvnut, any info on these? I remember this TV in the family since I was a baby, and the thing STILL works with ZERO service.

http://img.photobucket.com/albums/v395/Evilweredragon/IMG_0743.jpg
http://img.photobucket.com/albums/v395/Evilweredragon/IMG_0750.jpg

AiboPet
06-24-2012, 09:55 AM
COOL Eric!!

I have a few other small sets as well (Mine IS a "micro" collection). Those little 4.5" sets are neat because I like the high deflection CRTs. The sets are nearly cubes. I have a couple Magnavox "Shadow" sets. ONE of them had become a paint project because I guess the whole front of these is just a piece of real thin lexan or something. I got one from ebay that arrived in TERRIBLE condition and pretty much needed to be "re-imagined". (It's the red one here in the pics). This one is actually VERY much in use. It's in the loo and pretty much stays on at a very low volume any weekend I'm staying home. Gets alot of grins when company comes over and notices I have a set in the loo...tuned to whatever is on in the front room.

I do also have a couple "transparent" versions of the set in this thread. One is blue, and the other is indeed PURPLE. Also managed to find a purple one that wasn't transparent. I got in a weird mood and mounted colored LED modules inside the clear purple one...so it looks EXTRA annoying when turned on :P Friends call this my GAY set, because it just looks like something from a Gay Pride parade. I do sometimes put C batteries in this one and take it places just for a laugh. The LED modules are connected up to the TV side of the power switch on the left, so they come on any time the TV is on....AC or DC. I do keep forgetting that these sets don't get anything but Spanish stations when away from the apartment though. Someday I'm gonna put a transmitter in the little Kia and confuse everyone at the coffeehouse watching my little gay TV :-P

I love those YELLOW ones you have. That is deffinately a color I have NOT seen yet. I could paint up one of the white ones to be yellow, but that would be cheating. The white ones tend to get REAL bad looking if they were in smoking households or in a kitchen window for YEARS. You have that REAL bright blue Pacific Technologies set that I had started this collection with. I have one but the case was all busted up like someone THREW it down the street, and then into the dumpster I found it in (It is now the "open" set on my coffeetable).

Eric H
06-24-2012, 12:53 PM
Those are cool looking sets.

I've noticed they come in dozens of different brands and even though they look similar almost no two are exactly alike inside, close but always some small differences.

When I changed the Fly in the one set it looked the same but I had a difficult time installing it because the pins weren't quite lined up.

Trance88
06-24-2012, 01:13 PM
I've fixed a few of those, one had a bad "Jungle" chip, it had no reception but would light up.
Another had a bad Flyback, got one from a donor and fixed it.
A third one came with a broken CRT, fixed with one from the donor set.

They have a really good picture for what they are, I don't recall any buzz in the sound on any of them.I've had a handful of those little generic 5" B&W TV's in my teens. I remember fondly getting my first one at a garage sale back in the summer of 2004. I watched the Summer Olympics that year on it on car rides. It stopped working not too much longer after that.:tears:

A few weeks after it broke (early 2005), I noticed Walgreens had almost identical sets for a measly 30 bucks or so. Man, that thing was a piece of crap. The audio hummed like a bumble bee was trapped inside. I eventually took that thing back to Walgreens and got a GPX branded one at another store with a cooler looking looking casing. It was a much better set overall. I ended up selling that one off at a garage sale a year or two later.

I currently have a 5" Tenkai brand B&W set from 1986 near mint in the box. I occasionally use it for playing video games on or to see if I can pick up any of the remaining analog stations during power outages.

Sandy G
06-24-2012, 01:20 PM
I scored a 3" Unisonic "All-In-One" that has a still working cassette recorder/player & AM/FM that actually ain't half bad...The volume control is Shazbat, despite several cleanings, but if you can get it in its "Happy Place", the little bestidge has decent sound/tone. Never have bothered to hook up the TV, it works, & still gets a bleed-off signal from the cable. Cyoot widdle unit, reasonable heavy & robust, especially considering what it is.

radiotvnut
06-24-2012, 01:39 PM
I have a Realistic (Radio Shack) version of that Unisonic TV and it appears to be a well-made set.

I would like to find one of those later model sets in a transparent case.

AiboPet
06-24-2012, 01:41 PM
One of those is on ebay here:

http://www.ebay.com/itm/221051021938?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

I've been "watching" it...but really out of curiosity. Almost $90 opening bid (and shipping), so a little beyond the $50 or so I would pay for it. My VERY first TV I ever owned that i saved up and bought was a Unisonic "briefcase" style 5" combo cassette thing. I do still have that, and it's still going. I've rescued it's vertical at least once since I got it in 1981. I have one that is IDENTICAL to it that is by TMK, and I think TMK (ToyoMenKa) was an actual manufacturer. I pay attention to Unisonic simply because of that first set I still have. I remember playing a CASSETTE of Buckner and Garcia's Pac-Man Fever on that 5" Unisonic when I was like 14 :-)

I also found and bought a JVC 500CX which was the 5" COLOR version of this thing. I got it recently, and SIMPLY because I remember not even HOPING to buy one when I was 14. I felt it was just one of those sets I "had" to find...so I could say I won :-P

lnx64
06-24-2012, 02:06 PM
I couldn't find a good picture of my old Spectra black and white.. This is about the best pic I could find.

http://img.photobucket.com/albums/v395/Evilweredragon/phone.jpg

I had it connected to my Atari/Mitsubishi video phone, as the built in screen has let the factory smoke out. Vidicon tube still works though..

Anyway, here's the Unisonic again.. This was a video but for some reason I lost the connection during the upload when I went to sleep last night.

This is the power that the Unisonic needs:
http://img.photobucket.com/albums/v395/Evilweredragon/tvback.jpg

I however don't have a high enough amp/voltage adapter. All I could find is this:
http://img.photobucket.com/albums/v395/Evilweredragon/adapter.jpg

It's a Japanese power adapter for a SEGA SG-1000. In america it puts out nearly 16v:
http://img.photobucket.com/albums/v395/Evilweredragon/voltage.jpg

I'm fairly certain this TV would have a good voltage regulator anyway, as it's designed to have the DC input plugged into a car, which would fluctuate on voltage a little bit.

Turns out I was right, works just fine:
http://img.photobucket.com/albums/v395/Evilweredragon/2tv.jpg

Both these TV's are being fed a signal from my Blonder Tongue, transmitting over a short range VHF signal, so these TV's can pick them up on their own built in antennas.

Sandy G
06-24-2012, 02:08 PM
I bought a CX-500 "back in the Day" new, & it served WELL for nearly 25 yrs, til, stupidly, I sold it. It was my "Car Wash" TV...I'd take it outside & play the radio/tape while washing whatever steed I had during those days. We also took it "Up on the Hill", a place outside of town where they had all the ginormous antennas for the cable TV system, & would watch "Hill Street Blues"...Hey, somethin' to do in a small Southern town....AMAZING how many TV stations the l'il guy would pick up there...Quite a few that we DIDN'T get on cable. I got a "knockoff" CX-500 back since- 4.5 color set, AM-FM, cassette, & it brings back happy memories...Too bad we CAN'T "Go up on the Hill" anymore.

AiboPet
06-24-2012, 03:15 PM
My CX-500 needs some little attention. I got it from someone who admitted they messed with "some knobs inside"...and then they did a perfect job of putting it all back together. It looks like they messed with the "screen" drives or something and weren't sure what they were doing. Has a great sharp picture, but it's a bit bright, and I can only BARELY get it to go completely dark with contrast and brightness all the way down. It's also just barely tinted green if you turn the color all the way down. Whatever is giving it too much brightness is likely also where I'm seeing a little loss in contrast. Either he found and played with a "sub brightness", or there are some gain controls he screwed with. My guess...whichever knobs most resembled "bright shiny object" knowing this guy :-P

Looks like a VERY minor fix....involving me just finally getting INTO it and dialing it in with a proper crosshatch and color bars. I've just not done it yet.

It sure FEELS like a good sturdy set. It's MUCH heavier than any of my other briefcase B/W sets...and it DOES have a big green NiCad battery "pack" instead of all the D batteries. It DOES appear to run CX-500 for around two hours after charging all night (has it's own charger). I cycled that pack a few times, and after about a week....noticed it would run just about two hours.

Eric H
06-24-2012, 05:07 PM
I would like to find one of those later model sets in a transparent case.

I have one of those Prison sets I found at Salvation Army, this one is Color though and about a 13" screen.

It's very clean (most I've found have been beat to hell, Prison's a rough place I guess) other than some Tape residue (that's going to be hard to clean off) but the Camera and the dust make it look bad here.

It has the all important Inmate Serial Number to give it "Street Cred"
Maybe I can find the Inmate and invite him over to autograph it? (or not :no: )

AiboPet
06-24-2012, 05:23 PM
Seen and ALMOST bought a couple of those off ebay, but they sorta stray from my "micro" theme. The biggest sets I have are the rescued 8" Quasar...and the 8" Sony 301.

I do have a blue and a purple "transparent" version of these little chinese sets though. Would be pretty cool if there is an actual CLEAR one of those out there somewhere.

Eric H
06-24-2012, 05:36 PM
Would be pretty cool if there is an actual CLEAR one of those out there somewhere.

Look closely at my picture!

Also there is a Clear 4.5" set available, Rhapsody Brand among others, somewhat hard to find, I have one but it's not in great shape.

AiboPet
06-24-2012, 05:49 PM
Yeah...saw the little "egg shaped" one. You also appear to have one of the little Magnavox "Shadow" sets (small white one) up on the shelf next to whatever the two "hat box" looking items are. Are those two round things old 45 record cases? It LOOKS like you may have an old 45rpm record player on the top shelf.

The little Rhapsody sets I see on ebay do look almost EXACTLY like the Magnavox Shadow sets I have...from what I seen of them anyway (I have no Rhapsody set yet). I like how they are almost cubes.....like the Indextron "apple" tube is supposed to look (can only DREAM of one of THOSE)

lnx64
06-24-2012, 07:01 PM
Here radiotvnut, I made this video for you last night, was only just able to get it to upload just now.

http://www.youtube.com/watch?v=LxZnCvLdhgg

That's my unisonic and TG&Y together.. My only black and white screens.

AiboPet
06-24-2012, 08:04 PM
That Unisonic set is pretty cool!

Sandy G
06-24-2012, 08:27 PM
Hehehehe...Somewhere, in an alternate universe, maybe, they made Plexiglass cabinets in 1950, & THEIR Zenith put Porthole sets in 'em...And later on, you could buy Roundie color sets in clear cabinets...And in that wondrous Alternate universe, I have an R-390A in a Mil-Spec CY-979 clear case- and my Rohde & Schwarz EK-07's "Haus" is clear, too.....Shit, a boy can DREAM, can't he ?!? (grin)

AiboPet
06-24-2012, 08:49 PM
Actually.......

I wish I could FIND the thing, but my TV repair class in Hong Kong...we had a "learning set" in the classroom that WAS a huge 25" plexiglass console color set. Even BETTER than what you imagine it looks like, it also had "fail modules" and switches allover the chassis to "induce" problems. I so wanted to HAVE one of those!

You could "crack" different parts of the yoke with pushbutton switches, kill the HOT....take caps "out of circuit", etc. What was REAL cool was the pushbuttons were POPO...so you could NOT tell what position the switches were in. This thing made a PHENOMENAL tool for testing us pupils. Profesor would configure the set in some failed mode...and pupil gets to try and figure out whats up.

Had NO idea what sort of chassis it was, but we had two of those sets. One of them was a tube set....both color. The solid state set had most of it's silicon in SOCKETS so these things must have cost a FORTUNE with all the identical little "fail modules"

ChrisW6ATV
06-24-2012, 09:54 PM
Hehehehe...Somewhere, in an alternate universe, maybe, they made Plexiglass cabinets in 1950, & THEIR Zenith put Porthole sets in 'em...And later on, you could buy Roundie color sets in clear cabinets...And in that wondrous Alternate universe, I have an R-390A in a Mil-Spec CY-979 clear case- and my Rohde & Schwarz EK-07's "Haus" is clear, too.....Shit, a boy can DREAM, can't he ?!? (grin)
Ever since I was a boy in the late 1960s or early 1970s and I saw clear-case phones in the telephone exhibit at the Museum of Science and Industry in Chicago, I have loved anything in a see-through cabinet.