KPA500 Heat Expansion Pop

[Joe Word]

I changed the screws in my amp yesterday morning and ran it yesterday
afternoon and night, and have not heard any pop since. I used the
3/16" that were extras from a K3 build. I got from the hardware store
4-40 1/2" long flat heads, but the counter-sink angle was different,
so I did not use them.

Here are the basic steps I used to change out the screws: You have to
remove the top cover (do not remove the screw second from the back on
the left (it attaches the safety interlock plunger). Remove the right
side panel and remove the front panel. Remove all the wires attached
to the front of the PA unit, remove the screws that go through the
bottom panel into the Z bracket on the PA unit, remove the two back
screws that go into the Z bracket. Then rotate the PA unit out from
the front so you can get to the screws to be changed. I replaced one
screw at a time, did not tighten them until all were replaced.

Joe  N9VX



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My amp has been "click" free for four days now. To clarify, page 22 Fig.27,
is the area I'm referring to. Change the five 5/16" screws to 3/16" when
mounting the Z-bracket on the PA/LPF module. I also would have preferred to
use 1/4" screws but none come with the kit.
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[Ken Wagner K3IU]

G'morning, all:

In case anyone is keeping score, I shortened the 5/16"
screws that support the PA module on the Z bracket and the
Right Hand Panel, reinstalled them and now  no longer have
thermal expansion "clicks/ticks/pops" of any kind as the amp
heats up(tested to 65C) or cools off. I had previously tried
tightening just the Right Panel screws because they were the
easiest to get at and it really didn't help. Today I opened
up the amp and shortened the five on the Z bracket and now
all is nice and quiet.

73,
Ken Wagner K3IU
K3 #202
KPA500 #108
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[John_N1JM]

Interestingly enough, I just received KPA500 #594 and there is an errata sheet with 1/4" 4-40 screws attached.

John N1JM