[Heathkit] SB-200 Whacky Test Results

[kb0nly]

Ok, i put a dummy load on the output, just for the heck of it i don't think it makes a difference, and i put a piece of cardboard carefully between the relay to hold it to the transmit position, then i connected my MFJ-259 to the input of the amp.  Probably sounds stupid to the guys with thousands of dollars worth of test gear but this is the best i got and i was trying to replicate what the radio is seeing on transmit since some suggested i check the relay, some said check the input jack, etc etc..

On 10m i noticed it was subject to being bumped, that is bumping the chassis slightly by accident caused the needles to jump around on the 259.  I found a bad solder joint on the capacitor from the coil to the ground tab.  Touched that up and it improved a bit but still only a good input impedance on one spot of the band.

10m 28.647Mhz 1.5:1, i swept back and forth from 28.3 to 29.7 and found its about 120-45ohms respectively.

15m Infinite SWR, 21.2-21.450 30-35ohms respectively.

20m Infinite SWR, 500ohms across entire band.

40m, now this is weird, because while the 259 shows infinite SWR and 200-300ohms across the band i can get the radio to put out 100w and it doesn't complain.

80m 4:1 to Infinite SWR, 200-40ohms across the band.  Yeah i know, that does include 50ohms at one point in the band but the 259 doesn't dip below 4:1 SWR and so the radio won't transmit full power to load it.

So unless i can find some caps to try the replacement values shown on that website or someone else can suggest a miracle cure, this dumb thing will go on the shelf as a paperweight until i can find another Yaesu 2100.

73,

Scott