[Elecraft] Re: KPA100 - Super problem

[Don Wilhelm]

Bob,

Go back to the KPA100 connected directly to the K2 *after* you replace 
all the diodes in the T/R switch and any resistors that show signs of 
having been overheated.

Once you know that the KPA100 is working properly connected direct to 
the K2, then check the KIO2 (you may have opened some inductors) and 
check the small inductors in the KPA100 too.

I expect that you may have had your cable between the K2 and the KPA100 
wired incorrectly, so check that visually and also (using the 
schematics) check each of the lines from the 10 pin connector on the 
control board for continuity to the KPA100. before attempting to apply 
power with the remote KPA100 connections.

73,
Don W3FPR

F5UL wrote:
> Hi, Don and all the list
> 
> Lasr Sunday, I was page 53 of the KPA100 manual, with every steps OK all 
> the way up to securing the shield  and closing the box!
> I had a very nice output, the KPA100 being direct with the K2 or with 
> the remote EC2 case, Once the shield in place and verified for bad 
> contact and so on, the next power up was a disaster.
> I did not switch to transmit!!!
> The resistors R21, R33 where burned out, RFC also, and after excanges 
> with Don WFPR, diode D12 and D14 where also found in short. R22 and R13 
> where very hot,
> and the curent on the K2 display was about 1.6 A.
> So all off and after replacement and checking i'm at the following stage :
> 
> with only the KIO2 connection or direct connection the curent flow from 
> 12CTRL is around 1 A on the K2.
> Without PA power, only the KIO2 connection I do not get the NO PA PS 
> information when turning on the K2. R13 is still very hot and R21 is 
> hoter than normal. Pin #13 of U shold be at +4.9 V and insteed is at 0.1 
> V, as PIN #14. The 125 V is OK on R11. If I plug on  the PA PS, I can 
> not turn off the K2, his supply being done via 12CTRL line, either 
> through the KIO2 or direct connection to J4. If I try to transmit even 
> at 11 w level, I get a black cloud of smoke with R21 and R13 going "blam"
> 
> I'm lost, Don , I changed the cap for .22µF and it's OK.
> 
> Hoping for help from anybody
> 
> Regards F5UL Bob
>