Some time ago I bought legendary
TS 830 and narrow CW 270 Hz filter. I checked sensitivity and some
other performance of "old machine". It was OK !
How to make a tubes tester
for 6146B / S2001A
You can choosing pair for tubes
in TS 830/820
Measurement Current of plate for variable voltage on Grid
Also can measure current of filament, what is very important
for final unit TS830 (where filament of pair tubes connected
Second CW filter in 1st IF of TS-830
and YK-88CN is good filters for 1st IF of TS-830, but we can
not use both filters. Why ? I made small board with place
for two filters.
I re-wired the DH (I did not use digital
hold) button for choose the second filter on the board.
I can use filter with bandwidth 500 Hz or 270 Hz and check
filter with 600 Ohm resistor (impedance of input/output
Low insertion loss and big
isolation between filters !
I made iambic electronic
CW key with universal keying for negative ( in old tranceiver
such as TS520 TS530 TS820 TS830) and positive (modern tranceiver).
Circuit of key optically isolated to prevent unwanted DC -70V
and RF coupling between keys circuits and circuits of transceiver
supply. Installation in some type of shielded case is recommended,
but the board is quite immune to RF and in many cases will
work in an unshielded case for CW drilling without transceiver
I used potentiometer "VOX
Delay" (250k) for Speed control of key and set new potentiometer
for "VOX Delay" on back panel.
Shielding the cables for "Speed control" potentiometer
on front panel of TS-830 is recommended but may not be required.
If you use shielded cable, you can grounded it only in PCB
of key. The PCB of key can be set near IF unit or transformer.
Jack 3,5 mm and potentiometer "VOX Delay" mounted
to back panel. Supply 12 v for CW key got from pin# 12 of
AF UNIT (X49-1140-00).
Schematic of iambic electronic CW key
can use low cost microphone by Motorola HMN3596A (from GM-300 and
other UHF TRX) for TS830. You will make middle spectrum of your audio
signal from 250 Hz to 2800Hz .