Portacolor Troubles

[zenith2134]

Sandy, that is one of the best vintage-TV stories I've heard! Never occured to me that a crt would float

My port-a-color has definitely seen a LOT of use... Its original owner claims he got it for his 18th birthday.. Now he is nearing retirement. The CRT sticker is marked 52 1966, so, Last week of 1966 I assume? Story checks out. Anyway I don't watch this one much, especially since it pulls 200watts from the wall, and I have to push the brightness too far before It is really watchable. Not to mention the heat this little fella throws. Red is also weak, about 30% weaker than G&Bl. Have the red gain cranked up just to get decent greyscale. Cosmetically I cannot complain. Can't wait to slap the new CRT in it and really see what it can do (I know guys, I won't expect too much out of it).

[Sandy G]

I cleaned that CRT up & kept it for years-Didn't have the heart to toss it...Porta-Colors were Hot Stuff when they 1st came out...A Color TV that was SMALL & portable-Well, "luggable" anyhow...and they were fairly cheap. You gotta remember, rectangular color sets had only been around about a year, & about all the sizes you could get was a funky old 21" roundie-Who wants one of them old ugly obsolete things, anyhow ?- a 23" snazzy new rectangular, or the Porta-Color...The "mid-size" sets, IIRC, were still a year or 2 down the road.

[Whirled One]

Originally Posted by andy

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.

I gotta say, I've never seen a Portacolor with a bad CRT, no matter how beat-up and heavily-used the rest of the set appears.

If you ever actually needed a replacement CRT for a Portacolor, though, I seriously wonder if you could just swap it out (along with the yoke and other neck-mounted stuff) with one from a common 1980's-era 10AA or 10AB chassis GE set. The CRTs look identical except for a shorter neck on the AA/AB sets.
[I should really just try that out sometime just to see if it works...]

[radiotvnut]

Originally Posted by Whirled One

I gotta say, I've never seen a Portacolor with a bad CRT, no matter how beat-up and heavily-used the rest of the set appears.

If you ever actually needed a replacement CRT for a Portacolor, though, I seriously wonder if you could just swap it out (along with the yoke and other neck-mounted stuff) with one from a common 1980's-era 10AA or 10AB chassis GE set. The CRTs look identical except for a shorter neck on the AA/AB sets.
[I should really just try that out sometime just to see if it works...]

I think I checked on that years ago and found out that the pinouts are not the same. Of course, the socket could probably be rewired for the newer tube.

[Kiwick]

Originally Posted by zenith2134

Sandy, that is one of the best vintage-TV stories I've heard! Never occured to me that a crt would float

A CRT is an empty shell and as long as it's intact, it will float...

Larger CRT sets are probably useable as lifebuoys in the event of a ship wreck...

[Chad Hauris]

Originally Posted by Whirled One

I gotta say, I've never seen a Portacolor with a bad CRT, no matter how beat-up and heavily-used the rest of the set appears.

If you ever actually needed a replacement CRT for a Portacolor, though, I seriously wonder if you could just swap it out (along with the yoke and other neck-mounted stuff) with one from a common 1980's-era 10AA or 10AB chassis GE set. The CRTs look identical except for a shorter neck on the AA/AB sets.
[I should really just try that out sometime just to see if it works...]

It seems like the earlier Portacolor tubes used a low focus voltage CRT and the later tube type Portacolors and the solid state sets used high focus voltage...the later model tube sets probably could use the CRT's from the solid state sets.
Also the filament voltage/current may be different on the solid state sets? I can't remember if the portacolors had the CRT on a seperate filament transformer or was it in series with the other tube filaments? There was some set which had a 2.3 or 2.5 volt CRT filament, maybe that was a Predicta?

I actually have seen what appears to be weak CRT's on some of the earlier Portacolors although perhaps it is a video problem?

[dtuomi]

Well, its been a couple of weeks since the Portacolor had a problem. Its been reliable. I suppose its just a matter of time before whatever intermittent part will finally go, but for now its well behaved. I appreciate everyone's contribution, its really going to help diagnose this set once it gets a little farther along in its failure. I might just recap it before it does fail, but for now its working.

David

[yagosaga]

Originally Posted by Whirled One

I gotta say, I've never seen a Portacolor with a bad CRT, no matter how beat-up and heavily-used the rest of the set appears.

Hi Marty,

I have seen three German Portacolors, made by Kuba but with a GE 11SP22. Two of them had no emission on the red gun. Only one has good emission on all three guns. I assume that the 11SP22 was fitted with regular guns like they were used in the large-screen CRTs. Since the screen of the 11SP22 is very small and needs only 0.2 or 0.3 mA to be full illuminated (compared with 1 to 1.2 mA for large screens), their lifetime lasts much longer.

Regards,
Eckhard

[bgadow]

I was playing around with a crt tester the other day and wanted something to hook it up to, so I grabbed a portacolor crt I had in the attic. I think it's a 10VAHP22. This one has a GE label and another that says "made for Montgomery Ward" so I guess it came out of an Airline badged set. The crt tester I have is from the later 60s and didn't have a listing for this tube, but did for the 11SP22. It says the 11SP uses a 12v filament, but the 10v tubes are 6v. (at least this one is) And, of course, older ones are dot matrix.

[fujifrontier]

Originally Posted by Sandy G

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...

that's adorable...

too bad there aren't any portacolours on epay

[yagosaga]

Hello,

I have a GE Portacolor, which only displays a raster. No sound, no picture. At the 11BT11 (AGC keying) I found 5V at the cathode and appr. 5V at the grid. With some adjustment at the AGC control I can get 8V. But it has to be 60V. As a consequence I read at the grid of the first video IF tube (pin 10 at the 8AR11) -50V (it should be .1V). Did somebody had AGC troubles with the Portacolor?

- Eckhard

[peverett]

I had AGC troubles with a 1977 vintage Portacolor. The symptoms were intermittant. What would happen is that the picture and sound would go away leaving just a raster. What I found was that the design of this particular Portacolor had controls with the boost voltage (700 volts if I remember correctly) and the AGC controls in the same assembly. Over time, conductive tracts had built up, allowing the boost voltage to leak into the AGC area.

I fixed the problem by very carefully disassembling and cleaning the control assembly. You must be very careful in bending the metal tabs holding the assembly together or they will break. The set still works fine(at least as good as Portacolor ever did) at present.

As this has been a few years back, I do not remember the voltages that were showing up when the problem occurred.

[yagosaga]

Originally Posted by peverett

I had AGC troubles with a 1977 vintage Portacolor. The symptoms were intermittant. What would happen is that the picture and sound would go away leaving just a raster. What I found was that the design of this particular Portacolor had controls with the boost voltage (700 volts if I remember correctly) and the AGC controls in the same assembly. Over time, conductive tracts had built up, allowing the boost voltage to leak into the AGC area.

Thanks very much. I believe you are alright. I have operated the set with shortened filaments of the 11BT11 (AGC keying), i.e. the 11BT11 not operating. I found 0.6V at the anode. (Pin 9). With heated 11BT11, I found -60V. In a quiet room I hear some muted cracking noise from the AGC control assembly. I will remove it and clean it like you have suggested.

- Eckhard

[peverett]

Be very careful disassembling/re-assembling the control assembly. The metal tabs are easily broken.

[yagosaga]

Originally Posted by peverett

Be very careful disassembling/re-assembling the control assembly. The metal tabs are easily broken.

Before disassembling the control assembly, I want to test it with an extern control. I have only to remove the wire from pin 4 to connect it with an extern homebrew control assembly for test reasons. There are only two resistors and a potentiometer, and this is easily build with some alligator clamps. I want to see whether there are other faults.

- Eckhard