[Collins] KWM-2 tube socket voltage and resistance charts

[James Liles]

Good morning Glen:

Use a tube extender with the pin tabs to measure --- saves digging around
and you know which tube your working with.

Kindest regards Jim K9AXN



On 3/10/2012 10:34 PM, Glen Zook wrote:
>
>
> I have been "pulling my hair out" working on a particular KWM-2A.  The 
> radio is in excellent physical condition but has some very serious 
> electrical problems.  Of course, it is necessary to measure the 
> resistances and voltages at all of the tube sockets.  However, it is a 
> REAL "pain in the posterior" to go to the resistance / voltage chart in 
> the manual, then to the diagram showing the tube socket locations, and 
> finally digging through all of the layers of wiring that is present in the 
> KWM-2- series.  After making the measurement on a certain tube socket pin, 
> then going back through the charts to get the next value and then 
> relocating the proper tube socket through the layers of wires gets very 
> time consuming to say the least.  Anyone who has worked on a KWM-2- series 
> radio know of which I speak.
>
> Finally, this evening, I decided to make some single page charts showing 
> the tube socket locations and the resistance and voltage measurements at 
> each socket.  Basically, I scanned the under chassis locator diagram and 
> then eliminated all of the components except the tube sockets and a few 
> other components which are very prominent and help locate any particular 
> tube socket immediately.
>
> Someone else may have done this.  However, I can't find any documentation. 
> So, I took the information from the voltage / resistance chart from a 
> fairly early KWM-2 manual and a fairly late KWM-2 manual and made labels 
> for each tube socket.  Those labels were then put on the revised locator 
> diagram with lines drawn to the tube socket to which the information 
> belongs.  There are a total of 4 charts:  1 for early resistance 
> measurements, 1 for early voltage measurements, 1 for late resistance 
> measurements, and 1 for late voltage measurements.  In certain circuit 
> locations there are significant differences in the value of the voltage 
> and in the value of the resistance.
>
> Of course, any particular KWM-2 unit may differ from a certain value for 
> several reasons including factory production changes and in which Service 
> Bulletin was installed.  But, either the early version or the late version 
> chart should be enough to get someone started in repairing their KWM-2 
> transceiver.
>
> The charts are posted on my website at the following URL:
>
> http://k9sth.com/uploads/tube_voltage_resistance_charts.pdf
>
>
> The charts can be downloaded and printed to be used at the repair bench.
>
> Glen, K9STH
>
>
> Website: http://k9sth.com
>
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