[Central-Electronics] 20A project

[Curt]

Got to look inside the 20A.   This is the rack mounted one, "2nd" gen 
with the 6U8 Master Osc/aud driver and had tar around TR-1. Well, it had 
suffered a catastrophic failure around the 6U8. Cathode and Osc plate 
Res burned open.  the 2 coupling Res to the PS-1 burned.  The 6U8 had a 
suck-hole thru the side and was massively shorted internally.    TR-1 
measures OK so it may have survived long enough to burn out the cathode 
resistor in the audio half of the tube.   I found some disconnected 
parts and loose repair/mods at that tube and suspect  the tube ran away 
and melted down.   (Found the grid resistor on the osc half 
disconnected). Stuff got real hot for quite some time to melt the pitch 
out the bottom of TR-1.   PS-1 looks OK as does the coils after it.  
Crystal is OK.   I might bite the bullet and remove the whole tube 
socket etc because the socket pins might be trashed.    I don't think I 
can post pics here but I will post updates with pics on the Vintage 
Amateur Equipment BA Facebook Group.

Curt,  KU8L