[Boatanchors] AR 88 Discussions

[Rob Atkinson]

The 3 in 1 power supply oil filter cap is rated for 500 v.  When you
switch off the B+ with the front panel rotary switch, (the four
position mode switch, off, on, rec.mod., rec.cw) by putting the switch
one click clockwise from off, you supposedly only have the filaments
on.  But the B+ is actually on, just not connected to the plates of
the tubes.  This means the unloaded B+ soars far above the 250 to 300
v. it is when loaded, to 500 v. or almost that high.  That will do in
one section of the 3 in 1 cap, maybe more.  I learned all this the
hard way.  I put a toggle switch in the power cord along with a 2 A
fuse (incredibly no one had ever bothered to add a fuse in the past 60
years) and power it on with the B+ fully loaded.  The 5Y3 will curb
any in-rush as it comes up to temperature.  Save the 3 in 1 cap; don't
put the set in the unloaded filament only position.

Here's what an 88D looks like:
http://www.ebay.com/itm/RCA-AR-88D-vacuum-tube-communication-radio-receiver-1940s-/151223515636

73

Rob
K5UJ