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Old 29th Jan 2016, 12:17 am   #32
FERNSEH
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Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
Posts: 7,444
Default Re: PYE TT1 - First Transistor Portable UK TV

Update on the progress of the restoration of the Pye TT1.
Today the two line output transistors were replaced. Not a very easy job, in fact it's an even more difficult task than the replacement of the two line output transistors that are employed in the Rank A823 chassis. The original Texas 2G221 transistors are impossible to find and for that that reason two of the more common germanium PNP AU113 transistors have been fitted.
I've every reason to believe the new transistors will work satisfactorily because even without the line scan coils connected a -30 volt pulse is present at the collector of the "upper" line OP transistor.
With the line scan coils connected the flyback pulse at the collector of the upper transistor is -60volts, the service manual indicates it should be -75V.
The EY51 EHT rectifier heater is lit and there is an audible ticking noise from the frame output transformer.
Things are looking good for this set.

DFWB.
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