[ARC5] LM Cloudy Dial Window

William Cromwell wrcromwell at gmail.com
Sat Feb 5 13:53:12 EST 2022


Hi,

I have been working on an old LM-13. It suddenly stopped working one 
fine day. I found a couple of electrical problems including a tube 
socket and repaired successfully. Meanwhile the plastic window over the 
coarse frequency dial is clouded up too much to actually use. I see that 
the window and it's parts are riveted to the front panel. The obvious 
thing would be drill out the rivets and make a new plastic window with 
fiducial and then remount the assembly with small screws. Lots of fussy 
work. Have to remove the coarse dial drum for access. I have already 
made 'witness marks' to get the drum back in place.

I could use an exacto knife to cut out the plastic window from the 
outside. That would need an external bezel with the plastic window 
fitted inside the opening and the bezel holding it in place and glued to 
the outside of the front panel. Removal of the dial drum not required. I 
care less about original appearance than i care about useful function.

It might be possible to clean up the original plastic window with the 
compounds that are sold for cleaning headlight assemblies on our cars. I 
don't expect it to work but is the lest invasive and easiest to try. 
If/when that fails I would get out the exacto knife and try that 
route.As a last resort I would get out the drill bits and use a hand 
tool to drill out what looks like soft metal and take the long route.

I am thinking of adding an LED dial lamp inside behind that window.

I wonder what other LM owners have done about that window.

73,

Bill  KU8H

-- 
bark less - wag more



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