Thread: Sharp TRP801
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Old 5th Jul 2020, 6:40 pm   #31
FERNSEH
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Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
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Default Re: Sharp TRP801

Operating that system switch also killed the frame output transistor.
It's a 2SB84, the Radiomuseum suggests the ASZ16 as an equivalent.
As a temporary measure an AD149 has been fitted. Looking at the amplitude of the flyback pulse it's unlikely the transistor will last very long in this application. The collector load consists of a choke and the high impedance scanning coils connected in parallel.
Imagine what the flyback pulse would be without the scanning coils?
The waveform will corrected after the output bias is adjusted. The PNP transistor is cut-off at the start of the scan.

DFWB.
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