[Milsurplus] R-390 hints

[GENE BALINSKI]

Dave,

Get the DeOxiT DL-100 in the little red needle-nose bottle. A little goes a LONG way. The needle allow for very controlled application. It is the last bottle you will ever have to buy.

While you are at it, get a bottle of the FaderLube in the green needle-nose bottle. Great for cleaning all POTS.
Caig, the manufacturer of both, also used to sell lint-less swabs and cloths. They work very well to clean switch contact and related

73
K1NR

> On October 7, 2019 at 10:13 PM David Olean <k1whs at metrocast.net mailto:k1whs at metrocast.net > wrote:
> 
> 
>     Wow, I received at least three valuable tips on fixing up the
>     receiver.   I have some pretty good contact cleaner and lube but it is
>     not DE OXIT. I'll get some DE Oxit and compare it along with the WALMART
>     offering.   I was not aware of the R-390 archives on QTH.net wither.
>     Thanks!!   The syringe idea is pretty good too, and I see that you can
>     get DeOxit in several forms, not all are in a spray can.
> 
>     I tried washing the crystal switch with contact cleaner and it has
>     gotten much better..almost great, and with more use will probably clear
>     up entirely. I have DeOxit on order!
> 
>     Thanks for all the input. The receiver is coming along just fine. At the
>     moment, I have the PTO out and am getting ready to attempt to fix the
>     end point adjustment. It is off by 7 kHz, which seems like a lot, but
>     this is an early Collins R-390 from the original order I think!  Old
>     ferrite was not so good I suspect.  I spent a bunch of time aligning the
>     entire radio, starting with the IF strip. I was impressed with the
>     ultimate sensitivity of the 455 kHz stages. Some of the RF bands needed
>     an alignment badly. Others not so much. I have not done an MDS
>     measurement yet, but I can tell it is now a hot receiver.  A -73 dBm
>     (S-9) signal shows as 55 dB or more on the signal meter. A 1 uv signal
>     at the input raises the diode load voltage by about 7 volts.
> 
>     If I get the PTO perking accurately, I will have a winner for sure.
>     Thanks for all the tips.
> 
>     Dave K1WHS
> 
>     On 10/7/2019 2:08 PM, KD7JYK DM09 wrote:
> 
>         > > "I used a small syringe with de-oxit to get to the contacts."
> > 
> >         I've recently discovered, and been using QD Plastic/Sensor Safe
> >         Electric Contact cleaner, from WalMart, in a red can, to hose down
> >         things I can't easily get to, without any ill affects.  Initially, I
> >         was nervous, because I've destroyed, or melted far too many things
> >         over the decades, but I have yet to find anything this damages, other
> >         than grease, dirt, dust, grime, et cetera.  I've used this product
> >         dozens of times, over several years, on wiring harnesses, motors,
> >         circuit boards, bearings, plastic connectors of many, many types,
> >         plastic case, screens, paints, things you usually wouldn't want to
> >         expose to much more than just air, with no problems at all. It's
> >         something to take into consideration.  I would NOT, personally, try
> >         soaking an item, I'm sure everything has a failure point, but to
> >         blast, and hose out, I've yet to see an issue.
> > 
> >         Kurt
> > 
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