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

[Glen Zook]

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