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Showing posts from May 4, 2020

FT225RD, FT902 repair

Old rigs of s.k. Eltje PA3CEE  here for check and repair The rig's looked like they have been working in a brown cafe for years He was a real smoker ... the "tank"  FT902DM  very heavy rig permeability tuning  very well build equipment. Plug-in modules.  The standard twin 6146 PA seen in most most older transceivers until 30 years or so ago shown under power with filaments on. Dangerous  be aware !  950V  and 350V are also present at the ACC  backside socket for external use  In the age of SSPA used to low voltages where  touching a working circuit is safe. Working with high voltages is extra dangerous nowadays. The socket board of the PA the brown C looks high-quality is a known issue of the FT902. This 100pf /1kV is to separate 350V  12BY7 driver ANODE  from the delicate  6146 grids -100 150 !  practical a wire direct from the driver anode is leadingto this C1   If shorted the PA wil blow the fuse shortly after the heaters are switched in


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