Found an Entertainment Center

[Eric H]

Wow, came across this full featured AM/FM/Cassette/TV combo today.
It takes up far less room than a Curtis Mathes combo!

The TV is dead on this one, hopefully an easy fix.

I wouldn't have given $10 for it but it was 70% off day so it was only $3, probably still got ripped off.

The same store had a Panasonic Quintrix color portable, probably a 12" dated Sept 1977, neat little Moderne plastic set, had a dot matrix CRT, worked, I almost bought it but had second thoughts due to overcrowding.

[zenith2134]

Wait... You took the GPX and left the Quintrix?? Haha.

That's one darn nice entertainin' center ya got there! Once you wash the sharpie off the tube...

Seriously, it could just be a fuse or something very simple. I've seen switches break or go bad in these cheapies too.

Or it could need a flyback. Where the heck would you find one for it? Parts set is likely your only bet....

[MRX37]

Originally Posted by Eric H

The same store had a Panasonic Quintrix color portable, probably a 12" dated Sept 1977, neat little Moderne plastic set, had a dot matrix CRT, worked, I almost bought it but had second thoughts due to overcrowding.

So... you passed up a working 30 year old TV for a non working 5 year old GPX TV?

[Sandy G]

The only thing that l'il POS is good for is to Roof Test it off th' top floor of the Fest hotel next year...

[wa2ise]

After next Feb 2009, you'll need a box, or cable or satellite to feed it....

[Eric H]

Originally Posted by Sandy G

The only thing that l'il POS is good for is to Roof Test it off th' top floor of the Fest hotel next year...

Sandy, you're so right but I've got the bug, I have a dozen of these little jellybeans now, fortunately they all fit on top of my CM console.

[bgadow]

It will take some time, but I have a feeling Eric will get the last laugh.

[Eric H]

OK, this may actually have a bad Flyback, or something else is shorted.

I pulled it apart this morning and found a 2200m@16V that was bulging at the top, that gray cap is the replacement, I also replaced a 3.3@50V right next to it, this made no difference in the operation.

The unloaded voltage from the 13.5v wall wart is around 18v, a bit high but the set should run on it. The radio is fine as is the tape player, when the switch is thrown in the TV position is when the trouble starts.

I'm getting a low hum from the speaker, the big transistor next to the Fly is getting pretty warm but it doesn't check shorted, the fuse is OK, the Fly also has a slightly warm feel on the side after letting it run for a bit, I'm not sure if the fly is bad or if the horiz oscillator just isn't running. None of the pins on the fly has more than 5 volts on it.

Would pulling the fly and seeing if the load goes away be a useful test?
I could even swap the fly from one of the other sets if I had to, they are all pretty much the same chassis with minor variations.

[zenith2134]

If the flyback pins show no voltage, the horizontal probably isn't running. Is that a burn on the fly's side or is it just the sticker? On such a small pcb/simple design I'd just start pulling components and testing at that level, until you find the culprit. If you could ring the fly or scope the horizontal section somehow that would tell us alot. Maybe the horiz out is toast?

Much credit given in getting this set going, I admire that you take the tv hobby to the next level by working on these little buggers!! Good luck

[Eric H]

I'm going to say the Fly is bad, I removed it and the short went away, sound came on strong (white noise at least).

Pin 10 seems to be the problem area, pushing the fly back into the board and making connections with a screwdriver it kills the B+ when pin 10 is connected, an ohm check shows it's about 1 ohm to just about every other pin.
All the diodes in the area check OK as does the HOT.

I may be taking the hobby to the next level but I suspect it's a lower level.

[radiotvnut]

Originally Posted by Eric H

I'm going to say the Fly is bad, I removed it and the short went away, sound came on strong (white noise at least).

Pin 10 seems to be the problem area, pushing the fly back into the board and making connections with a screwdriver it kills the B+ when pin 10 is connected, an ohm check shows it's about 1 ohm to just about every other pin.
All the diodes in the area check OK as does the HOT.

I may be taking the hobby to the next level but I suspect it's a lower level.

I've never seen a TV quite like that with a tape player on top. The front looks like the almost current $19.99 specials at the discount stores.

I've seen flybacks in various B&W TV's (and a few color sets) from the '70's and '80's do what yours is doing. I think the windings short or the internal HV rectifier diode shorts.

[Eric H]

Picked up a battered but working set today, newer and branded Memorex but the fly looks like it'll fit, I'll pop it in when I get home and report back.

[Sandy G]

Acouple o' years back, they were selling the "TV Only" version of this for $9.99 at the local CVS drugstore. Unreal. I HAD to buy one-Last time I checked it still worked.

[Findm-Keepm]

Originally Posted by Sandy G

Acouple o' years back, they were selling the "TV Only" version of this for $9.99 at the local CVS drugstore. Unreal. I HAD to buy one-Last time I checked it still worked.

Why buy one? Go listen to a sales spiel at any Timeshare Resort and get one free - remember Bentley TV's ??

Cheers,

[Eric H]

It was the Flyback!


Soldered in the new one, it was a little larger and has a ferrite core instead of the completely sealed style of the old one, it's resting partially on top of a diode but it works.

Now the hard part, putting it all back together!

Note: it's back together now.