[Elecraft] K1 with Issues

[cstoverva at aol.com]

 Hi Don,

You nailed it!? Lesson learned on my part.? 

There was a difference in voltages between pins 4 and 5 of RP5 and pin 5 of U1.? I cleaned up around RP5, R19 and R20 and reflowed the solder connections with no real change in symptoms.? I lifted the key jack from the board.? Although I could see nothing with my eyes on the board, when I swabbed the area with a Q tip and Isopropyl the Q tip turned bright red.

The loss of transmit I noted turn out to be a loss of both transmit and receive.? I was on the dummy load so didn't notice how quiet the receiver was until I switched to an antenna.? Apparently a relay got hung up in all the electronic commotion.? I cycled the band switch and everything popped back to life when I came back to band 1.

I disassembled the rig and gave each board a good cleaning and didn't find anymore red stuff.

It's all back together now and working fine.

Thanks.

Chuck K4QS


 


 

-----Original Message-----
From: Don Wilhelm <w3fpr at embarqmail.com>
To: cstoverva at aol.com
Cc: elecraft at mailman.qth.net
Sent: Thu, 16 Apr 2009 9:38 am
Subject: Re: [Elecraft] K1 with Issues









Chuck,?
?

Flux cleaners are *not* recommended for that very reason.  The flux 
residue by itself is non-conductive, but when combined with a cleaner, 
it can create high resistance (leakage) paths unless it is completely 
removed.  Flushing an area with cleaner is almost certain to cause 
trouble, and can result in 'mysterious behaviors' that are hard to track 
down and expensive repairs.?
?

If a builder finds a need to remove the flux, it is best done using a 
cotton swab (Q-Tip) and denatured alcohol or rubbing alcohol working 
only in small areas at a time.?
?

73,?

Don W3FPR?
?

cstoverva at aol.com wrote:?

>  Hi Don,?

>?

> Your comment about using flux cleaner struck a nerve with me.? I didn't have any cleaner at the time of completion and obtained some a while back.? I don't remember exactly when.? I had an idle mind and hands one day and opened up the K1 to spiff things up.? I let it dry for a week and put it back together and it worked fine.?

>?

> The keying misbehaved a little during the previous use of the K1.? I cleaned the paddle contacts and reseated the plug and all seemed well.? Problem solved, or so I thought.? These two events probably relate.?

>?

> At first opportunity I will make the voltage checks and take a look under the key jack. I'll post the results.? Right now I'm off to install an antenna on my Volunteer Fire Departments new utility truck.?

>?

> Thanks.?

>?

> 73,? Chuck K4QS?

>   
>?