A minor Johnson Desk KW problem

[WQ9E]

My usually highly reliable Desk KW finally had a bit of a problem.  I noticed a couple of weeks ago a disconcerting odor of something getting too hot after being in the transmit mode for a couple of minutes.  My first thought was the troublesome drive control in the Ranger being used for a driver since one of my Valiants developed the same odor when the drive control was going out but no happiness.  Since the Desk has been in service for a couple of years I decided it was due for a cleaning anyway so I disconnected everything and slid out the cage which contains all of the working parts out of the pedestal.  After a couple of minutes of transmit there was again a faint odor but no visible smoke.  I shut it down and grounded the power supply outputs and was very happy to find that there was no sign of heat or damage with any of the big iron.  As I was trying to decide whether it was time to pull the plug in chassis that contains the actual RF deck for further investigation I noticed a suspicious "aged appearing" wire.  Lucky me, the only trouble was the original crimp connector which attaches to 1 side of  the main power relay RY-300.  This particular connector supplies one side of the line output of the relay to the exciter and  to the various power transformers.  It originally had several wires crimped together in one connector and over time it appears heating/cooling and corrosion created the problem.  After replacing the single connector with a couple of new (and hopefully better) connectors the only thing getting hot and smelling now is my dummy load.

I don't feel quite lucky enough to buy a lottery ticket but I am glad it was a low ticket repair.  I wasn't looking forward to having to send out a big piece of iron to Gary for rewinding, particularly after Todd's shipping experience!

Looks like the Viking 500/KP-81 will get Labor day weekend off and the Desk KW/HRO-50 will be back in service.

Rodger WQ9E

[WA1HZK]

That's a win!
Go have a beer!!

[Todd, KA1KAQ]

I had a similar issue the 230V outlet and clothes dryer plug. It looked like it was plugged in completely, but wasn't. This impacted it's ability to handle the power being sucked through it and resulted in a smelly, smoking end with charred outlet and plug. Same scenario - I could smell it but not see it. Needless to say, it got my attention and I'm much more careful and certain about these otherwise-simple matters.

Glad to hear it was a simple fix, Rodger. Not always the case with those beasts. Mine is still in need of work and will be for a while with the current schedule and lack of time. As well, I find it a bit more intimidating to work on compared to the big rig. So many potentially lethal points of contact in such a small area.

That's a win!
Go have a beer!!

Have one for me too(or two)! 

[AF9J]

Cool!  Ms. Scout and I hope to QSO with you this weekend.  Work is done (it's been a rough week).  I have to get a relay for receiver muting, and work on the VF-1 VFO (It's a bit rattty, and needs some refurbishing).

73,
Ellen - AF9J

[WQ9E]

I think the beer is a great suggestion; actually I think I will raise that to a bourbon and coke since I did grow up in the deep south   It looks like a great evening so I am going to go relax on the gazebo and I will take my Grundig Satellit 3400 out to monitor 3885.  It is nice to get back to radio and away from my university department's dress code controversy.  We decided that our marketing majors should be dressed at least in corporate casual for their classes but I don't think any of us quite expected the controversy it caused and the number of national media outlets that have taken an interest.  Apparently the student government also feels we have violated their bill of rights so rather than protest the war, genocide, starvation, or other significant matters we have a dress code protest.  Ah, but bourbon is going to make everything better....

The Desk KW mainframe is back in the pedestal and all of the connections to the receiver are back in place.  I blew out the dust and cat hair while I was in there and gave the fans (all 4 of them) a shot of oil while I had it apart.  Hopefully it will be good for a few more years of service now.

Ellen, I look forward to hearing your Scout!

73, Rodger WQ9E

[AF9J]

Evening Rodger,

I don't know how much work I'll be able to do on the relays & the VF-1 for the Scout tonight.  At the request of a couple of my fans , I'm going to fire up Ms. Scout on 3885 (the only crystal I have of course) tonight, and try to scare up some QSOs.  The weather is beautiful, and is supposed to stay that way for the next few days.  That, combined with the cool nights we're supposed to have, should help keep the noise down on the bands.  Well, I'm in the middle of eating supper, and I have to shower up afterwords.  Then, it's radio time. 

73,
Ellen - AF9J

P.S. - the students had a hissy fit over faculty wearing business casual?  That's silly.  Many places (including the place I work at) do business casual for dress.  Go figure.

[W2PFY]

Since we are on the topic of Desk KW's, I recently acquired one but it does not have the original plate transformer or filter choke. Does that in any way detract from the value of said unit?

[WQ9E]

Hi Terry,

It would probably reduce its value a bit in "Ebay" terms but if you decide to sell it through other methods it probably would have little impact.  If the replacement iron is high quality (Dahl for example) then some might value it a little higher than stock.  As long as the replacement plate transformer/choke fit without major mechanical mods and they provide the proper voltages for the low/high power settings and sufficient current then I would be very happy with it.

If you haven't done so already, make sure the contacts on the plate relay are clean and lubricate all of the fans motors.

Enjoy the Desk KW, I really like mine.

73, Rodger WQ9E