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

[Bob Groh]

You need (or maybe should use) a surge resister with your dry rectifier
replacement - pretty much for same reasons - surge limiting for caps and to
make up for (some) reduction in voltage drop with solid state. Although if
it is a single plate selenium, I think the voltage drop is only a couple of
volts(? 1 to 2V per plate??).  Regardless you should have a series
resister.  Or at least in my opinion.

Bob Groh, WA2CKY

On Thu, Aug 25, 2016 at 11:25 AM, WA5CAB--- via Boatanchors <
boatanchors at mailman.qth.net> wrote:

> 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
>
> In a message dated 08/25/2016 09:35:45 AM Central Daylight Time,
> boatanchors at mailman.qth.net writes:
> > Guys,
> > I am reworking a TCS shore power supply and want to get some feedback
> > concerning the 6X5 rectifiers (uses 2). Is it worth solid stating them?
> If they
> > are reliable I was thinking to just leave them in there...
> > Thanks in advance...
> > Bill N3WM
> >
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