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Re: 5400 Resistance Readings



Hello Rick, as I recall from memory.....

Another point , the potentiometer DOES NOT have stops built into it, 
like a normal pot.
It will turn continuously. The mechanical gear train DOES have stops in 
it for a max of 180 deg rotation.
0 thru 90 thru to 180.

Set the mechanical gear train to 90 deg or halfway thru its rotation.

Then find the pot position where the wiper is mid way, 250 ohms either 
side of the winding,

The potentiometer will turn continuously and self destruct if turned 
many times. Be careful.

Think about the mechanical assembly and understand how it works

Reassemble and test.

Stan, WA1ECF




Richard J. Lawn wrote:

> I continue to be confused in repairing this 5400B EL rotor and I thank 
> all those of you who have been trying to coach me through the repair. 
> It was suggested that I take readings off EL terminals 1,2 & 3. I have 
> the boom tube removed. I took readings at 0 at the control box 
> terminals with power off and came up with the following:
>
> Pins 1-2 0
> Pins 2-3 3.7 ohms
> Pins 1-3 0 ohms
>
> readings at 90 deg according to the control box meter:
>
> Pins 1-2 243 ohms
> Pins 2-3 210.7 ohms
> Pins 1-3 0 ohms
>
> readings at 180 deg.
>
> Pins 1-2 45.7 ohms
> Pins 2-3 0 ohms
> Pins 1-3 0 ohms
>
>
> Another ham suggested that a good pot will read 0 ohms at 0 deg., 250 
> ohms at 90 deg. and 500 ohms at full rotation to 180 deg.
>
> Another helpful ham reported the following readings from his healthy 
> EL rotor:
>
> 0
>
> Pins 1-2 237.2 ohms
> Pins 2-3 2.8 ohms
> Pins 1-3 235.7 ohms
>
> 90
>
> Pins 1-2 184.5 ohms
> Pins 2-3 172.2 ohms
> Pins 1-3 234.1 ohms
>
> 180
>
> Pins 1-2 24.2 ohms
> Pins 2-3 228.5 ohms
>
> Can anyone tell me what I should be reading from these pins? Am I 
> reading values from the wrong pins? My AZ rotor is working fine so can 
> I compare readings through the same panel meter rotation?
> I wish Yaesu would have been more helpful in the schematic as mine 
> doesn't even show the two stop switches and does not indicate a value 
> for the pot.
>
> Thanks for any additional help.
> Rick W2JAZ
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