Re: {Collins} 32V-3 5V4 Transformer Killer?



Something just pooped into my mind concerning the 5V4 in the Collins transmitter. The 5V4 may be one of the slow start up rectifiers. Slow starters were made to delay the filament emission until the other tubes warmed up and began pulling current from the supply. As the transformer ramped up the current to the rig, the voltage went down to the manufacture's spec for the particular set. Substituting the orignal rectifier with a standard start rectifier may cause the supply to overshoot. Perhaps beyond the ratings of the circuit components. My home made KWM-1 supply has this situation and I go around it with a B plus switch. I turn on the B plus after about 1 minute of power on to the rig's tube filaments.
Anyway, just thinking out loud here.  It's a slow Saturday night.
73's
Greg
WA7LYO
Kinston NC

----- Original Message ----- From: "John Painter" <johnpainter@xxxxxxxxxxx> To: "Colin Lamb" <k7fm@xxxxxxxxxxxx>; "Mack McCormick" <w4ax.mack@xxxxxxxxx>; "Collins" <collins@xxxxxxxxxxxxx>
Sent: Saturday, March 19, 2011 8:56 PM
Subject: Re: {Collins} 32V-3 5V4 Transformer Killer?


It's a whole lot easier to just build a 'tubester' for the 5R4.

It wastes about 40 watts in the resistors, but what the heck?

John P.
----- Original Message ----- From: Colin Lamb
 To: Mack McCormick ; Collins
 Sent: Saturday, March 19, 2011 6:15 PM
 Subject: Re: {Collins} 32V-3 5V4 Transformer Killer?


This may be one case where a consensus of hams who have used the 5V4 tube would be useful. I still remember the fireworks inside one of my 5R4 tubes. I have never had any problem with the 5V4 and like it because it is indirectly heated and delays application of B+.

I also have memories of my high school buddy who had a DX-40. The fuse popped and he replaced it with tin foil. He left the transmitter on and went away. When he returned, the garage and part of the house had burned down. He gave up ham radio.

I think there may be a more modern substitute, although I do not have my tube manual handy and do not know if the current draw is sufficient or even if the pinout is correct. It is the 5AR4. Check that out.

 73,  Colin  K7FM
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SHARE THE FUN: JOIN THE COLLINS COLLECTORS ASSOCIATION TODAY !
http://www.collinsradio.org/membership/

NETS: Tues & Thur: 3.805 MHz-2000 Central + Fri: 3.895 MHz-2000 Pacific
 SUNDAYS: 14.263 MHz-2000 UTC  +  AM Net: 29.050 MHz-1200 Central
 1st Wednesday AM Net 3.880 MHz-2000 local (ET, CT, MT, PT)

LIST HELP?  ADMIN EMAIL:  collins-owner@xxxxxxxxxxxxx
This ONLY goes to the list admins and does not post to the group!







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