[AMRadio] Ranger problem-No joy yet


Jim Tonne Tonne at Comcast.Net
Wed Jan 1 12:24:50 EST 2014




Bob and all:

I have again run the analysis but this time put the
Key Up   and also the   Key Down   voltages on that
keyer schematic.

It is again posted (case-sensitive if you do it manually):

http://tonnesoftware.com/Manuals/RangerKeyerDetails2.gif

Note that all of the voltages except the actual VFO blocking
signal are based on a negative 56 volts out of the bias
circuit.   So if you measure, say, -60 volts there then all of
the voltages will be a bit greater than the schematic shows.

For those that can't get the schematic, here is a table of
voltages:

Bias voltage (one end of R42): -56
Junction of R42 and R43, grid of a 12AU7: Key up=-43,  Key down=0
Junction of R43 and R45 (multiplier blocking): Key up= -38, Key down=0
Junction of R44 and R45 (buffer blocking): Key up=-30, Key down=0
Voltage at top side of C86: Key up=-38, Key down=0

Hope this helps you home in on what is going on.

- Jim Tonne W4ENE







On 1/1/2014 8:40 AM, Robert Sauvan wrote:
>
> I cant thank everyone enough for the suggestions to my fix on the 
> Ranger. I have gone through everyones suggestions with no success yet. 
> All caps check out good, C86, C87, & C89. R39 is the variable resistor 
> to set the keying and that shows to be working on the scope,but, it 
> doesnt seem to be doing anything to affect the radio.What Im saying is 
> by turning the shaft, it does not change the cutoff for the vfo. No 
> change in the radio. Maybe this should be replaced despite the fact 
> that I can see it working on the scope? I was having considerable 
> difficulty getting the radio to reproduce the problem on the 
> workbench. It would work just fine and when I put it back on the shack 
> table it would act up right away. Now, of course, everyone is going to 
> say, "something is different in the shack". My same thought, so I 
> reproduced the same setup in the shack as I did on the workbench. 
> Problem cropped up right away on the shack table. Took it back down to 
> the workbench, problem wouldnt occur. Although I could get it to 
> happen eventually. I even went so far as checking the voltage on my 
> wall outlets to see if they were different and swapped the plug strips 
> to make sure I was reproducing everything exactly. I was using a dummy 
> load and took all antenna relays etc off line and bypassed. So,  more 
> troubleshooting today. This doesnt look to be an easy find.
>
> Thanks-Bob-W0YBS
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