[MRCA] Capacitor issues

Thu Jun 2 14:21:53 EDT 2016

Never mind playing with liquid mercury and watching it skitter around in
a container.

Steve

KA1LHZ

On 06/02/2016 10:37 AM, Mike Feher wrote:
>
> Neither Scott of I suggested draining the rest of the oil. Just seal
> it up properly. I am 71 now and when I was a kid I used to take caps
> apart for fun. Used to swim in PCBs. Who needed gloves. Had asbestos
> lined bench also. Same where I worked as a tech in the late 50’s and
> 60’s. Still here, HI. 73 – Mike
>
>  
>
> Mike B. Feher, N4FS
>
> 89 Arnold Blvd.
>
> Howell, NJ, 07731
>
> 732-886-5960
>
>  
>
> *From:*MRCA [mailto:mrca-bounces at mailman.qth.net] *On Behalf Of *Ray
> Fantini
> *Sent:* Thursday, June 02, 2016 9:31 AM
> *To:* Mike Feher; 'Scott Johnson'; 'mrca'
> *Subject:* Re: [MRCA] Capacitor issues
>
>  
>
> Think if I tried to drain remaining oil it will never all drain and
> always have something that’s a lot like a cross between motor oil and
> tar that will be leaking out so if anything am inclined to do complete
> replacement of innards with the option of cleaning out shell. The
> amount that has leaked is only a small fraction of a once but a little
> bit of that crap goes a long way. The thing about cleaning and sealing
> is the capacitor is eighty years old and in addition to the small
> amount of leakage is it possible that some moisture has entered over
> the last eighty years and contaminated the capacitor? I may try
> connecting one up to two or three hundred volts and seeing if it
> develops more leakage or internal heat. Don’t think this radio has had
> any voltage applied to it in decades. The capacitors like everything
> else in the receiver or RCA manufacture so what the status of PCB use
> was in 1936 is a good question. Years ago had to do PCB removal on
> broadcast transmitter and that was a big deal where you received a
> five gallon can along with apron and gloves and deposited the
> offending capacitors into the can then also the protective clothing
> and everything else into the can and sealed it and sent it off for
> proper disposal, and that was for capacitors that were not leaking.
> Between radium paint and PCB oil wonder how many of us are running
> potential toxic superfund sites?
>
>  
>
>  
>
> Ray F/KA3EKH
>
>  
>
> *From:*Mike Feher [mailto:n4fs at eozinc.com]
> *Sent:* Thursday, June 02, 2016 10:20 AM
> *To:* 'Scott Johnson'; Ray Fantini; 'mrca'
> *Subject:* RE: [MRCA] Capacitor issues
>
>  
>
> That was going to be my answer as soon as your post came up, but, I
> figured you were going to be saturated with replies, so decided not to
> bother. 73 – Mike
>
>  
>
> Mike B. Feher, N4FS
>
> 89 Arnold Blvd.
>
> Howell, NJ, 07731
>
> 732-886-5960
>
>  
>
> *From:*MRCA [mailto:mrca-bounces at mailman.qth.net] *On Behalf Of *Scott
> Johnson
> *Sent:* Thursday, June 02, 2016 9:16 AM
> *To:* 'Ray Fantini'; 'mrca'
> *Subject:* Re: [MRCA] Capacitor issues
>
>  
>
> I would not replace it, most of those old oil caps leak their mineral
> oil, but as long as the capacitor roll is still saturated, they should
> be fine.  I have this same rig, in its entirety, and I cleaned up the
> leaking oil, plugged the leaks around the terminals with varnish , and
> it plays fine.  These caps don’t see much stress in this application. 
> The mineral oil is a sticky mess, but not dangerous. If you have a
> case leak, a little JB weld or solder will fix it after removing all
> traces of the mineral oil.
>
> Welcome to the very small fraternity of people that own one of these
> gems.   (BTW, it is a motor lifeboat radio).  It has two 12V
> dynamotors in the waterproof case, and the TX sits above the RX.  The
> cover fit over the front and is dogged down like a hatch on a ship. 
> It is intended to be remotely operated with a handset.
>
>  
>
> Regards,
>
>  
>
> Scott V. Johnson W7SVJ
>
> 5111 E. Sharon Dr.
>
> Scottsdale, AZ 85254-3636
>
> H (602) 953-5779
>
> C (480) 550-2358
>
> scottjohnson1 at cox.net <mailto:scottjohnson1 at cox.net>
>
> scott.johnson at ieee.org <mailto:scott.johnson at ieee.org>
>
>  
>
> *From:* MRCA [mailto:mrca-bounces at mailman.qth.net] *On Behalf Of *Ray
> Fantini
> *Sent:* Thursday, June 2, 2016 5:55 AM
> *To:* milsurplus <milsurplus at mailman.qth.net
> <mailto:milsurplus at mailman.qth.net>>; mrca at mailman.qth.net
> <mailto:mrca at mailman.qth.net>
> *Subject:* [MRCA] Capacitor issues
>
>  
>
> So a 1936 USCG R-104 receiver followed me home from Dayton, it’s very
> clean and in no way modified and the intent is to build an external
> power supply and case and have it working. One of the problems is that
> it uses two huge square 4 mfd @400 volt capacitors in its power supply
> input along with a filter choke and both of the capacitors have leaked
> a lot of oil out of the can and all over the chassis. In the picture
> you can see one of the offending capacitors that’s been removed and
> cleaned up but I don’t want to put it back in being it will just leak
> more oil over time.  It still checks good with only a small amount of
> leakage but would not trust it anyway. So the big question is what’s
> the best way to open this up and remove the guts and substitute the
> innards with a modern capacitor? It appears that the original can is
> soldered all around but I would prefer to keep the original external
> appearance and finish being everything in the radio matches so heating
> this up with a torch would be issues also don’t know if the oil is
> flammable. Maybe the answer is cutting around the base of the can but
> at this point have no idea on how? maybe a dermal tool with a cutting
> wheel? Is it possible that if the base of the can is heated with a
> torch that the entire contents can be dropped out? Another option may
> be to solder up the small hole on the outside of the capacitors can
> and install it back and keep it original? Have lots of questions but
> no answers at this point. In the past I would have just replaced the
> offending parts with modern ones but in this case wanted to keep the
> receiver looking the same so that’s the source of the dilemma.
>
>  
>
> Ray F/KA3EKH
>
>
>
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