[R-390] OT Strange 5R4

[Barry]

Perhaps you need go to get one of these:

http://www.myvintagetv.com/testers/r404.jpg

Regards,
Barry - N4BUQ


 On Thu 01/12/11  8:03 AM , k2cby k2cby at optonline.net sent:
> I recently acquired a Viking 1-1/2 transmitter (that's a Viking I with
> theTVI suppression and audio mods from the Viking II).
> 
> 
> 
> Before I fired it up - and before I re-fastened the umpteen 6-32 screws
> thathold the top shield in place - I thought I ought to check the tubes on
> mytrusty TV-7.
> 
> 
> 
> The power supply uses two 5R4 rectifiers.
> 
> The first one I popped in tested fine.
> 
> The second one didn't move the needle at all - not a flicker.
> 
> I said to myself "Well, that's obvious: open filament."
> As I reached over to pluck the tube out of the TV-7 and throw it in the
> trash I got a surprise - it was hot and glowing.
> I then figured maybe there was a solder fault in one of the base pins, so
> Isweated all of them and applied additional solder - no cure.
> 
> 
> 
> I never heard of a rectifier with a good filament that wouldn't conduct
> atall.
> 
> 
> 
> Did 5R4s have an internal fuse?
> 
> 
> 
> Any other ideas?
> 
> 
> 
> 
> 
> 
> 
> Miles B. Anderson, K2CBY
> 16 Round Pond Lane
> Sag Harbor, NY 11963
> Tel.: (631) 725-4400
> 
> Fax.: (631) 725-2223
> e-mail: k2cby at opt
> online.net 
> 
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