Posted by
Don Wilhelm-4 on
Apr 10, 2011; 10:46pm
URL: http://elecraft.85.s1.nabble.com/K2-KPA100-Removal-tp6212794p6259777.html
John
If the board has not been removed a few times, it often sticks on the
screw threads - I suspect that is the problem. I usually use a
flat-blade screwdriver between the heatsink and the board to carefully
nudge it up. Watch where the screwdriver is going (peer between the
board and the heatsink) so you do not damage any of the capacitors
mounted under the board.
Usually when you lift the board, the standoff near the fan is the
troublesome one, but the other center ones can be troublesome at times.
73,
Don W3FPR
On 4/10/2011 2:51 PM, Jon Perelstein wrote:
> Don,
>
> I'm trying to replace D16 and D17 in the KPA100 but I'm having trouble
> removing the heat sink so that I can get at them (it looks to me as if
> I have to remove the heat sink to get at the bottom of the PC board to
> unsolder them).
>
> I have removed the three black pan head screws that attach the rear
> panel to the heat sink.
>
> I have removed the seven standoffs that screw onto the set screws that
> come out of the heat sink and hold it to the PC board.
>
> I have removed the four (2 each) 4-40 x 1/4" screws at Q1 and Q2 (2
> each) that hold Q1 and Q2 to the heat sink.
>
> I have removed the two 4-40 x 1/4" screws that hold Q3 and Q4 to the
> heat sink.
>
> When I try to remove the heat sink from the board, I'm getting
> resistance from the center of the board, near Q1 and Q2. I don't want
> to just pull in case there's something that I've missed removing. Did
> I miss something, or is this one of those cases where a sledgehammer
> is appropriate?
>
> Well, okay, maybe not a sledgehammer...
>
> Thanks.
>
> Jon
> WB2RYV (ex KB1QBZ)
>
> On Sun, Mar 27, 2011 at 4:50 PM, Don Wilhelm <
[hidden email]
> <mailto:
[hidden email]>> wrote:
>
> John,
>
> I believe after you replace diodes D16 and D17 in the KPA100 (both
> are 1N5711), you will find the problems go away.
>
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