[WRL] Possible problem source

[Garey Barrell]

I get the best results with a fractional drop of DeoxiT D5L in each 
socket, then reinsert the tube a few times.

I think the problem is a combination of the corrosion on both the pin 
and socket, combined with the small contact area and lower contact 
pressure of the miniature tubes.  The smaller socket "mass" also 
probably make the sockets more likely to "spring" or lose contact pressure.

PLEASE don't "spray" DeoxiT or anything else on phenolic or even 
Bakelite sockets.  I don't know how many I have had to replace because 
they've been "contaminated" with spray cleaners and have developed 
enough leakage between pins to disrupt AGC and other Hi-Z circuits.   It 
seems to soak into the material and won't come "off" even with alcohol 
or other strong cleaners.

73, Garey - K4OAH
Atlanta

Drake C-Line Service Manual
<http://hr99.home.mindspring.com/R-4C_Servicez/>



john.brewer at us.schneider-electric.com wrote:

>Hi Glen,
>
>This seems to be largely a problem with miniature tubes (or quite possibly, their
>sockets). I've rarely seen this in older Octal - type tubes, but I do see this
>quite often in Drake gear. I suspect it's a combination of inexpensive sockets
>(phenolic in both Drake and Heath) and  the smaller pins with less contact
>area, and different pin finish.
>
>That's my guess anyway! I do know, many Drake pieces that cross my
>bench, come back to life with wiggling the tubes in their sockets.
>
>John K5MO
>
>
>
>
>                                                                                               
>             Glen Zook                                                                         
>             <gzook at yahoo.com>                                                                 
>             Sent by:                                                                       To 
>             wrl-bounces at mailman.qth.n         wrl at mailman.qth.net                             
>             et                                                                             cc 
>                                                                                               
>                                                                                       Subject 
>             02/17/2005 12:25 AM               [WRL] Possible problem source                   
>                                                                                               
>                                                                                               
>                                                                                               
>                                                                                               
>                                                                                               
>                                                                                               
>
>
>
>
>Tonight my Heath SB-110A 6-meter rig developed a
>couple of problems.  First of all, I tightened all of
>the screws that hold the printed circuit boards to the
>chassis.  Then I took a paint brush and cleaned
>everything on top of the chassis.  Finally, before
>disconnecting the rig and taking it to the service
>bench I started unplugging and then plugging in again
>the tubes in the circuit "area" that the problem was
>occurring (the push to talk circuit was "hanging" for
>several seconds after releasing the microphone).
>
>When I removed the 6AZ8 that controls the relay the
>unit returned to receive.  Of course I had to return
>the tube to its socket before the unit would operate
>again.  I "wiggled" the tube, I removed and replaced
>it, and so on.
>
>Finally, I actually removed the tube, removed the tube
>shield, and took a good look at it.  Frankly, the tube
>pins had corroded over the years and just were not
>making a good connection to the socket.
>
>Since I keep a jar of Goddard's "Silver Dip" around to
>clean various items (like coax connectors) I "dipped"
>the tube pins in the solution.  After a good rinse at
>the sink and a good dry with a towel I replaced the
>tube.  Problem solved!
>
>I then checked the other tubes and all of their pins
>were showing various signs of corrosion.  Thus, I
>cleaned them one-at-a-time.  Of course most of the
>tubes in the SB-110A are actually original, and since
>the unit works perfectly, I haven't replaced a tube in
>years.
>
>I now plan on cleaning the tube pins, along with
>tightening all of the hardware that holds everything
>in place on any boat anchor that I work on that had
>intermittent problems.  In fact, I really think that
>it would be a good idea to actually clean all of the
>tube pins whenever I work on a unit for someone else.
>
>Corrosion on tube pins is not something that you
>immediately think about when troubleshooting a "boat
>anchor".  But, it certainly can be a source of
>problems.  Often we clean the sockets as well as
>switches, potentiometers, and so forth.  However, how
>often do we think of cleaning the pins on the tubes?!!
>
>Glen, K9STH
>
>=====
>Glen, K9STH
>
>Web sites
>
>http://home.comcast.net/~k9sth
>http://home.comcast.net/~zcomco
>
>
>
>__________________________________
>Do you Yahoo!?
>The all-new My Yahoo! - Get yours free!
>http://my.yahoo.com
>
>
>_______________________________________________
>WRL mailing list
>WRL at mailman.qth.net
>http://mailman.qth.net/mailman/listinfo/wrl
>
>________________________________________________________________________
>This email has been scanned for SPAM content and Viruses by the MessageL
>abs Email Security System.
>________________________________________________________________________
>
>
>
>_______________________________________________
>WRL mailing list
>WRL at mailman.qth.net
>http://mailman.qth.net/mailman/listinfo/wrl
>
>  
>