UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - PYE TT1

FERNSEH · 16th Jul 2012, 11:56 am

The internal battery is an essential part of the power supply of these receiver,
it serves as a smoothing element and a stable voltage reference.
It is missing in my set so I'll have to make up a substitute battery pack or engineer in an alternative 10 volt supply stabilising arrangement. Of course it is lot easier nowadays to do circuit modifications but back in 1960 when the set was designed there was a limited number of specialised components available for the designers of transistorised TV sets.
The video output transistor presented problems. Special high voltage devices were not available. The TT1 employs a special CRT which can operate with only 15 volts of video. A few years later the AF118 became available.
Remember that the 1967 Thorn 2000 all transistor TV employed two stacked transistors in the RGB output stages. Of course that was from a >200 volts HT supply unlike the 40 volts video output stage supply in the TT1

DFWB.

16th Jul 2012, 11:56 am	#9
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: PYE TT1 - First Transistor Portable UK TV The internal battery is an essential part of the power supply of these receiver, it serves as a smoothing element and a stable voltage reference. It is missing in my set so I'll have to make up a substitute battery pack or engineer in an alternative 10 volt supply stabilising arrangement. Of course it is lot easier nowadays to do circuit modifications but back in 1960 when the set was designed there was a limited number of specialised components available for the designers of transistorised TV sets. The video output transistor presented problems. Special high voltage devices were not available. The TT1 employs a special CRT which can operate with only 15 volts of video. A few years later the AF118 became available. Remember that the 1967 Thorn 2000 all transistor TV employed two stacked transistors in the RGB output stages. Of course that was from a >200 volts HT supply unlike the 40 volts video output stage supply in the TT1 DFWB.