[Elecraft] K2 is dead?

[Bill Johnson]

Dave,  my suggestion:  send it Don who is a fantastic expert. He is very reasonalble in his fees.  While I am technically competent, and have the equipment, he is natural at it.  I have to work at it, because unlike Don, don't do it day to day.  I have sent equipment to him and it is done in no time.  If you have time to do your own work, then give that a shot.  For me, life it too short. 


73,
Bill
K9YEQ



-----Original Message-----
From: elecraft-bounces at mailman.qth.net [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Don Wilhelm
Sent: Monday, February 19, 2018 6:28 PM
To: David Perrin <dbperrin at gmail.com>; Elecraft <elecraft at mailman.qth.net>
Subject: Re: [Elecraft] K2 is dead?

David,[Bill] n

There are several possibilities.
While it is possible that the "serial" cable may have been the the problem, that could have damaged the KIO2 (or KPA100), but it could also have damaged the MCU (U6) on the control board.

Did it go into transmit with no load?  If so, it may be that Q7 and Q8 have been damaged.  Check the resistance from the collector to ground. 
It should start out at about 2k ohms and increase in resistance as the electrolytics charge.  If it is substantially less than that, the PA transistors may have been damaged - that will trip the internal resettable fuse (F1).
To remove 12v power from the PA transistors, you can remove them (do that if the resistance check reveals them to be shorted), or you can remove transformer T3.
After removing 12v from the PA transistors, see if the K2 powers on.

I don't know of anyone who is skilled in troubleshooting the K2 in central FL, but someone may volunteer.

If you remove the PA transistors and do not have adequate desoldering ability, clip the leads at the transistor bodies and remove the leads one at a time.  Clean up with solder wick and if solder remains in the holes, heat the pads and push the solder out with a wooden toothpick.
Replace the PA transistors with the K2PAKIT from Elecraft - it has matched PA transistors.  I can give you some tests to check with the PA transistors out to check whether transistors Q11 and Q13 are OK (they are included with the K2PAKIT).


73,
Don W3FPR


On 2/19/2018 10:20 AM, David Perrin wrote:
> Hi-
> 
> Two questions?
> 
> After 18 years my K2 doesn’t turn on. I did it. I must have incorrectly wired the Serial cable. When it got plugged in - that did it.
> 
> There is power thru the Power button. With the radio disassembled to the main pc board, (sans everything that can plug into the main board) and power applied thru the 1/8” coaxial power connector power doesn’t seem to get beyond that.
> 
> I am not in a place where I can get more parts out on the bench, nor the equipment except for a cheap digital Voltmeter.
> 
> Question 1: Is there someone in the central Florida area who knows this radio and can shed some light on my problem?
> 
> Question 2: Is there someone in central Florida who repairs the K2?
> 
> Thanks for reading.
> 
> 73 de Dave
> 
> k1opq.4 at gmail.com
> 
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