[Amps] Yaesu FL-1000

[peter.chadwick at Zarlink.Com]

Steve said:

>I have an old Yaesu FL-1000 sweep tube amp ( four 6JS6's ). Does anyone
>have a manual/schematic for this amp? Also, is it worth while, or even
>possible, to convert one of these to a better tube?


My father had one. It's a carcass on the floor of the workshop at the
moment, awaiting resurrection - as it has been for about 17 years! A
weakness is the variability of 6JS6s. They need a separate bias pot each.
Conversion to 6LQ6s was well worthwhile, again with a separate bias pot for
each tube. The fan is too small, and fitting a decent fan helps, although
it raises the noise level.

A bit of a labour of love, but fairly easy to work on. The transformer is a
bit short on volts to do anything with for other than sweep tubes, as there
isn't really room for the extra electrolytics for a voltage doubler -
although it might be possible with a bit of ingenuity. As I recall, it
really does need step start, too.

There is no provision for input tuned circuits, which limits it a bit too.

73

Peter G3RZP