Re: {Collins} Rebuild and modernization of the 516F-2 power supply

Good suggestions on the selenium and electrolytic replacement. I've seen
many comments about adding a power relay to save the fragile power switch.
 Where could I find suggestions on the type of relay i.e. coil voltage
115AC or 12VDC (with some kind of rectifier off the filament lines)?  Of
all the kits out there, I've not seen one with a relay in it.


Clark, WU4B

On Thu, Jun 12, 2014 at 8:16 PM, L L bahr via Collins <collins@xxxxxxxxxxxxx
> wrote:

> Tom,
> I would offer you this advice.  You really should service the power
> supply.  Those electrolytics are very old and way past their engineered
> life.  If a cap goes bad, especially in the bias supply, your final tubes
> could "run away" with no bias on them and wipe them out. Old caps could
> also inject unnecessary hum as well.  The selenium rectifier diode
> absolutely needs to be replaced.  Seleniums age even if never used and are
> NOS. I think most everyone would agree the power supply needs refurbishing.
>  It's a question of how and what should be done.  Some "reform" capacitors.
>  I am one who does not believe in this for a 40 year old cap.  Maybe one a
> couple year old which has not been used, but I would never use a reformed
> 40 year old cap. This is playing Russian Runlet  There is also the fact the
> electrolytic can loose moisture and no reforming in the world can ever put
> the moisture back in the capacitor.  Also, electrolytics made today are
> inexpensive in axial form and are made
>   much better today with better chemistry and other modern manufacturing
> techniques.
> Lee, w0vt
> I wanted to thank everyone for their thoughts and suggestions.  Since the
> power supply is working fine at the moment, and based on the consensus of
> almost everyone who responded, I think I won't consider fixing something
> that is not broken.
> I learned something important today about my Collins rig and I appreciate
> it.
> Kindest regards,
> Tom
> On Jun 12, 2014, at 5:16 PM, "Bob Tufts" <rbt@xxxxxxxxxxxx> wrote:
> > I know most people will say to leave it alone (some will even consider
> > it heresy if you mod it!! ;-)
> >
> > But if you do go solid state I would suggest hooking up the now unused
> > filament windings so so they perform a bucking effect to the primary
> > side and thus put the voltages back to where they should be on the input
> > side (the output of course will still be higher without the voltage drop
> > of the tubes, but at least the filaments in the transmitter will be back
> > to normal voltages with today's near 120 v supplied AC mains.)
> >
> > -Just my $.02
> >
> > Bob WA1KPA
> >
> >
> > On 6/12/2014 1:53 PM, Tom Branton wrote:
> >> Good afternoon gents,
> >>
> >> I have returned to ham radio after a long absence and I am in the
> process of putting together an S-line station (my first).  One of my
> thoughts was to have the unmodified 516-F2  power supply modernized with
> diodes and caps.  I wondered if anyone on the board might have a
> recommendation on a particular modification kit that worked well for them?
>  I did see that Radio Farm Projects has a new kit in the works and I
> imagine there are other very good ones on the market.  Also, perhaps a
> recommendation on a good Collins shop to do the work?  I am a pretty good
> CPA but my electronics repair technique is not the best.   I'm located in
> the Houston area.
> >>
> >> Thanks everyone,
> >>
> >> Tom Branton KF5WBS
> >>
> >>
> >
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Clark WU4B

*"It is vain to do with more what can be done with less."-- *William of
Occam (1288 AD - 1348 AD)

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