SB-101 alignment

[Pete]

I posted to the reflector a couple of weeks ago
regarding a problem I am having with my sb-101 with
regard to not getting full output on some bands.  The
consensus of the group was that I should perform the
alignment procedure. Here are the results of that
procedure.

The first step is to check the heterodyne oscillator
output at each band. The reading is to be adjusted to
between -0.5 and -2 volts. All bands were easily
adjusted except for the 29.0 MHz band. On the 29.0 MHz
band, the heterodyne oscilltor voltage was -200 volts
and the coil adjustment had no effect.

The next step was to use the 100 KHz calibrator to
adjust the receiver on 3.5 MHz by adjusting t201,
t102, t103 for max S-meter.  All okay.

Next, I adjusted the driver grid coil and driver plate
coils for maximum calibrator signal on 3.5, 29, 21,
14, and 7. All okay except that 29.0 MHz is completely
dead, no calibrator signal could be heard.  Proper
receiver operation is indicated by calibrator signals
of s9 +20 on 3.700 MHz and decreasing to s6 at 29.2
MHz.  My SB-101 is not quite there with reading of
s9+15db on 80 and down to s6 on 40 already.

On to transmitter alignment.  Adjusted bias to 50 ma. 
On 3.5 MHz, adjust t1 for maximum rf output.  I'm
getting just over 40 watts. (Some times I can only get
a few watts on on all bands, but it seems if I jiggle
v7, it helps)

Next, check the grid current at full rf ouput on 3.5
MHz.  The manual says the grid current should be full
scale. But I get no grid current reading on any band. 
So there must be something wrong with the metering for
grid current.

The next step is to adjust the heterodyne oscillator
coil for maximum grid current on each band, but I
can't do that since I'm not reading any grid current.

So, I'm not sure what to do next. Any suggestions are
appreciated.

Pete
aa9nf



	
		
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