[Boatanchors] 6x5 Rectifiers Used In TCS Shore P/S

[Mike Bracey]

Hi Robert,
I have a PP-380/URR that I'm am beginning to restore. I would appreciate any comments you might have on this unit.
Mike Bracey 
KE5YTV
      From: WA5CAB--- via Boatanchors <boatanchors at mailman.qth.net>
 To: boatanchors at mailman.qth.net 
 Sent: Thursday, August 25, 2016 11:25 AM
 Subject: Re: [Boatanchors] 6x5 Rectifiers Used In TCS Shore P/S
   
They are reliable, as are the pair of either 5R4GY or 5U4G rectifiers that 
are also present. The shipboard and shore AC rectifier supplies are open (no 
cover or cage over the top of the components) so there is no heat build up 
to worry about. I would make sure that one set of spares that may never get 
used are present and leave them be. The performance of the supply or the 
radios will not be improved by changing them. And you will loose the soft start 
characteristic that vacuum rectifiers provide a little of.

However, what you should replace without bothering to determine whether or 
not it is still working is the dry disc 12VDC supply rectifier. It may be 
copper oxide, in which case it may still work. Or it may be selenium in which 
case it most likely does not, or if it appears to work, you aren't yet 
seeing the characteristic decline of front to back ratio and the increase in 
forward resistance. Replace it with a 50 PIV or higher 3 AMP or higher silicon 
bridge rectifier selected for its packaging being the most convenient. If you 
pull the stud that usually runs through a dry disc type, you can mount the 
replacement to one of the el-brackets.

In the unlikely event that you are working on a PP-380/URR, I have further 
comments.

Robert Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480 

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