[Boatanchors] LM-13 Frequency Meter

[Dave Brown]

Were the LMs designed for a much higher HT voltage than the BC-221 series?
 I have a couple of LMs here. One is virtually original- complete with 
canvas cover and has not been powered on in a long time but I'm in the 
process of sorting out a power supply for it.  Which raised the 
question-what should the HT supply voltage be?  The other one has a 
'commercial' PSU associated with it of UK origin which delivers 300 volts HT 
and it drifts significantly- possibly as a result of the HT being too 
high-or at least thats what I thought. I know the BC-221 used a battery 
supply around 90 volts for the HT but - what was the original power supply 
arrangement for the LM series and what was the nominal HT?
73
 Dave
ZL3FJ