EICO 723 Help Needed

[Jim Simmons]

Alan,
If the choke is open, and you had power applied, did you notice the screen
grid in the final getting red hot?  This occurs when the plate circuit is
open. The screen is drawing all the tube current and it's not designed to do
that.  How about the heater?  Was it glowing?

If it was me, I would check the screen supply line carefully and replace the
final amp along with the plate choke before I powered it up. I would do this
even without checking the tube.

Good luck,
Jim N5MSJ

-----Original Message-----
From: Boat Anchor Owners and Collectors List
[mailto:BOATANCHORS at LISTSERV.TEMPE.GOV] On Behalf Of Alan W. Fremmer
Sent: Thursday, January 24, 2008 10:50 AM
To: BOATANCHORS at LISTSERV.TEMPE.GOV
Subject: EICO 723 Help Needed

Fellow Collectors/Restorers,
 
An EICO 723, bought on eBay and advertised as in "operating condition" is  
not exactly like that.  I get grid current and can hear the oscillator in a

nearby receiver.  There is no plate current.  I checked for plate  voltage
from 
the plate cap to ground and found nothing.  There is a chassis  mounted 
vertical rf choke in series with the plate cap.  A check at the  base of the
choke 
shows 600 volts.  At the top, zero.  A resistance  check of the choke shows 
infinity.
 
I guess the choke is open.  I don't have a schematic nor a parts  list.
Does 
anyone have a suggestion as to what I can use in place of the  apparently 
defective choke.  Sources for same would be most  appreciated.
 
Thanks in advance to all on the list.
 
73, Alan - KB2HEI



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