Portacolor Troubles - Videokarma.org TV - Video

dtuomi · #1 09-29-2007, 07:19 PM

I have a portacolor, made about 1968 or so. Its original, never having been serviced. Its in use everyday about 12-14 hours a day. it produces a nice picture, I've posted a screen shot elsewhere and can link to it here. The problem I'm having is that its moody. I'll be watching it and every once in a while it will lose vertical hold. Its not all the time. It can go days without problems. Someone elsewhere said to test the vertical hold pot, but it seems to be within spec. The tubes are stable, all checked good. The caps seem to be healthy. I'm at a loss as to what its current problem is, or more particularly what makes it fail. it doesn't seem to be temperature, as its in an air conditioned office, and keeps at a fairly even operating temperature (no over heating and no tube scorch on the PCB). Anyone have any ideas of what to look for next?

David

peverett · #2 09-29-2007, 07:35 PM

In my Portacolor which was built in 1977, the boost voltage(several hundred volts) is on some of the rear adjustment controls. These controls are in a common package, with some controls seeing the boost, some not. This caused carbon tracking in the controls. In my particular set, the AGC control was affected. The TV would work, then the AGC would overload. Then it would work again.

After I took the ganged rear adjustment control apart a cleaned it completely, the problem disappeard. This is a tedious process as these are crimped together in my set and care must be taken not to break the metal tabs when unbending/rebending them.

andy · #3 09-29-2007, 07:53 PM

Did you replace that big cap next to the HOT? It's a paper cap and I've seen a few bad (exploded) ones. Even 10 years ago I always replaced that cap when I got a Portacolor. I think it's in the B+ boost circuit, so that would affect the vertical.

bgadow · #4 10-01-2007, 12:42 PM

I would second both suggestions, as I've seen both problems. I had one of those caps blow. Funny, the set kept right on chugging away, but with a messed up picture. I think it's one of those El-Men-Co ceramic tubular caps.

Those 3-in-one controls were a favorite of GE and are trouble. I have had a couple Portacolors with intemittents related to these.

Kiwick · #5 10-01-2007, 03:47 PM

Quote:

Originally Posted by dtuomi

I have a portacolor, made about 1968 or so. Its original, never having been serviced. Its in use everyday about 12-14 hours a day

David

Hmmm isnt 12-14 hours a day a bit too much for a 40 yrs old tube set?

the portacolor's CRT is likely going to get weak pretty quickly this way.

Sandy G · #6 10-01-2007, 03:57 PM

That's the thing about Porta-Pottys...THEY don't know they're cheap, nasty, & not-sposed-to-work after 40 years, they just keep chuggin' on...

Dave A · #7 10-01-2007, 06:55 PM

If anyone is ambitious and needs a 11SP22 CRT for a Portacolor, PM me with a post to let me know. It's NOS and available for shipping costs. First in gets it.

Dave A

radiotvnut · #8 10-01-2007, 07:14 PM

Quote:

Originally Posted by Kiwick

Hmmm isnt 12-14 hours a day a bit too much for a 40 yrs old tube set?

the portacolor's CRT is likely going to get weak pretty quickly this way.

A friend of mine who had an antique / junk shop back in the '90's had a late run portacolor (11/76, I think) and he ran it all day for a couple of years until it died one day. He gave it to me and all I did was solder the mess out of it and got it back going. No, I don't still have it. I guess I should have kept it since it was a later tube set. Of course, if I find another '76 or later model; I'll probably get it for keeps this time.

Dave A · #9 10-02-2007, 10:40 AM

The 11SP22 winner is Zenith2134 at 11:09pm Monday night. I will PM you back tonight. Got my hands full with playoff baseball today.

Dave

dtuomi · #10 10-02-2007, 06:33 PM

It would appear that I've opened a monster here. I took off the forum for a couple of days for my birthday (9/30) and returned to a lot of messages.

I'm gratified that everyone has an opinion on my Portacolor. I've had a few people to mention that it might not be wise to run one so much. But, it runs at my work, and makes my day a little happier. So, I think its worth having around. My only problem is keeping it going.

As far as the CRT strength, I've noticed no degration in the picture brightness. Its not exactly the brightest of sets to begin with, but its still as bright as when I got it.

I'm going to have to go back and study some of the replies. A few of them are complex, although intriguing. I actually didn't know the Portacolor had an AGC circuit in it. I know it has no DC restoration. I got a schematic from a guy on how to fix that problem. But, I figure one thing at a time.

Thanks,
David

Kiwick · #11 10-03-2007, 03:47 AM

Keeping the brightness and contrast low is the key for CRT longevity...

Turn them up just a little and your CRT will last half as much...

andy · #12 10-03-2007, 11:41 AM

Quote:

Originally Posted by Kiwick

Keeping the brightness and contrast low is the key for CRT longevity...

Turn them up just a little and your CRT will last half as much...

That's probably why the portacolor CRT lasts so long. It has a huge electron gun, but a tiny screen. Even at high brightness, it's running under less load than a full size CRT.

bgadow · #13 10-03-2007, 12:16 PM

One of the portacolors I had, which I have since sold, spent years demonstrating nintendo games at a flea market. Despite lots of long days it still looked fine. I don't guess spare crts are too hard to come by. I have a pair of them in the attic, for instance.

fsjonsey · #14 10-03-2007, 06:32 PM

Did any other manufacturers use the same CRT?

Sandy G · #15 10-03-2007, 06:51 PM

I have a buddy who had a houseboat that developed a leak & sank...He had a Porta-Color on board; THAT particular one floated. We fished it out, took it home, I got the CRT out of it, but didn't have any way then to test it. It still had vacuum, the getter was nice & silver. Betcha a nickel it woulda worked...