[R-390] PTO extender cable

[Flowertime01 at wmconnect.com]

In a message dated 4/4/05 10:17:27 AM Eastern Daylight Time, n4buq at aol.com 
writes:

Anyone have a source for connectors to make some extension cables for the
PTO?  I want to do some linearity checks and would like to do it outside the
frame on the bench. 

Thanks,

Barry - N4BUQ
-------------
Barry

Thousands of old ASA 33's worked on these R390 and R390/A for years all over 
the world for years and never even seen an extender cable. Not one Nota. Old 
school knowledge was the extender cables introduced more problems in feedback, 
loss of shielding, flaky connections than was gained by the extra working 
space.

Stand the receiver on it end. Use a 2x4 to level the back of the receiver 
with its front panel. Pull the PTO connector bracket loose from the chassis so 
you have some wire harness freedom. It is still a short leash. Set the PTO on a 
small cardboard box so it does not have to hang on its wire harness.

This setup was used to set the 10 turn end point adjustment.

If you just need to run the liner deviation, pull the Standard BNC to Mini 
BNC adapter off the 455 output on the rear panel and use it on the end of the 
R390/A PTO. The R390 is a bit more creative as it has the B+ on the coax. You 
need to isolate the frequency counter from the B+ on the R390. Leave the PTO in 
place and use the dial read out to count PTO shaft turns. Set one end at 455 
and zero the dial. Start rolling off turns. At each 100 on the dial counter 
record the frequency counter reading.

Just hanging the PTO out the up ended receiver and using a pencil mark to 
index to, we would get the end points to within 10 cycles or so. Considering the 
counters and power company (Viet Nam, Korea, 69-75) we knew we were kidding 
out selves with those numbers. But you can do it.

If you were really going to go into a PTO and try to adjust the bank of 
little shins all stacked up along the PTO guide assembly, spring for the connectors 
from Fair for the PTO harness. You likely have the coax BNC adapter and can 
extend that cable to the counter with no problem.

I have seen PTO that would not make end point spread and needed work. I have 
not seen one that was considered so non linear as to warrant an adjustment of 
the shin stack.

However, these items are much older now and who knows what would do them some 
good.

Good Luck with this

Roger KC6TRU