Museum Hours:

Saturday 10-6

Sunday 12-5



Vintage Television Sets and Colour Television Sets from the Dawn of Television until Now

Echard Etzold's Site


Color Television:

Documentation: General Electrics Portacolor M21THW-1


Click photo to supersize it!
[Text in deutsch]

Motorola VT-71

In 1966 General Electrics offered the first portable color television set in the U.S.A., the Porta-Color. Till that time color television sets were exclusively available as table sets or console TV sets. The PortaColor was a full tube set (with one exception, one transistor in the UHF tuner) and was produced - nearly invariably - till the end of the 1970s. The tv set here is a rather early tv set, similar to the later Porta-Color, but it has not the label "Porta-Color on the front side.

General Electrics, Portacolor General Electrics, Portacolor

The Porta-Color has an economical number of 14 tubes (including CRT). The tubes are multifunctional tubes, called Compactrons. The total power consumption is noted with 200 watts, which is at the lower end of the consumption scale of a tube set. Remember that b/w tv sets of this time need only 20 watts less than this tube color tv set.

General Electrics, Portacolor General Electrics, Portacolor

The circuits are very simple in comparison to table sets or consoles. Many functions which seems to be indispensably for today standards were left because of financial reasons to keep this set cheap. D.C. restoration for the video signal is missing, and an automatic color drive regulation doesn't exist. The bandwidth of the chroma amplifier is very small in comparison to other color tv sets. The tuner is divided into a VHF tuner and an extra UHF tuner.

General Electrics, Portacolor General Electrics, Portacolor

Nevertheless, the Porta-Color was innovative. It has the the first Inline-color picture tube. The electron guns are ordered in a line instead of the Delta electron gun design of the CRTs before. But the shadow mask is taken from a larger, 21" CRT which results in a rather low resolution here in a 12" CRT with the same numer of lines. For adjusting convergence some adjustable permanent magnets are placed on a plastic hold on the neck of the CRT.

General Electrics, Portacolor General Electrics, Portacolor

The line output unit is a small one, dimensioned like a b/w line output unit of this epoch. There is no need for a high deflection current because of the 70° CRT, and the high voltage of 16 KV is in the range of the high voltage for a simple b/w tv set too. No need for a shunt regulator. Left photo: flyback transformer with high voltage rectifier. Right photo: Line output tube and damper..

General Electrics, Portacolor General Electrics, Portacolor

The screenshots of the working Porta-Color showed the poor resolution of this tv set inclusive the moiré, caused by the big-holed shadow mask. This tv set here has no y delay line. The old y delay line was defect and a new one is not available. Therefore the colors on the screen followed the lumance content with some delay. Beside this the picture quality for this tv set is quite good (in the range what one could expect. In the midst 1960s, the German brand Kuba Imperial was bought by General Electrics. GE sold the Porta-Color in Germany too via Kuba. Here are some photos of a Kuba Porta-Color, which is in bad shape: 1, 2, 3, 4, 5, 6, 7, 8.


Download. Scans of the service manual: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, all scans contributed by Joe Sousa


2GK5, 4LI8, 1AD2, 12GE5, 12AX3, 6LT8, 11FY7, 6AC10, 8BU11, 8BQ11, 8AR11, 11BT11, 12BF11, 11SP22.

Photos: © Eckhard Etzold, 2004.



[Text in deutsch] [Zurück]
Stand: 8. Oktober 2004,