[Boatanchors] BC-1004, Bringing up BA Slowly via Variac

[Philip Atchley]

Hi All,

Well Finally!  After some months of overhauling this Hammarlund BC-1004 
for a friend it's in the process of "bringin' 'er up slow" <grin>.

For some reason, I'm not sure why, the re-cap and overhaul of this set 
has taken FAR longer than any BA that I've ever done.  Perhaps the sheer 
size and weight of the set AND it's outboard power supply has been 
intimidating.  Who knows.

Anyway, I haven't been into the power supply at all.  The owner of the 
radio had already brought it up and tested it.  HOWEVER, I am still 
bringin' 'er up slowly.

The owner said that he ALSO replaced the 5Z3 with silicon units. I'm not 
sure why, if he were going to go to the trouble, he didn't replace BOTH 
tubes with silicon rectifiers.  On the same subject.  The schematic I 
downloaded doesn't show a 5Z3, it shows a 5U4 and 5Y3 tubes,

I realize that the remaining tube rectifier won't start conducting till 
it's filaments reach a certain temperature.

A couple quick questions.

1.  At about what point (percentage of rated line Voltage) can I expect 
this to begin to occur?

2.  Do I need to worry about the filament of the tube being
stripped" by having Voltage (al-be-it below normal) on the plates while 
the filament is still too cool to "squirt electrons"?
73 de Phil,  KO6BB
991 Different NDB's heard to date.

http://www.geocities.com/ko6bb/
Merced, Central California, 37.3N  120.48W  CM97sh