Hi;

I'm trying to repair a Punch 250.
There's 2 shorted output transistors.

These are not mounted to the heat-sink NOT by hardware,
they appear to be glued and- or soldered to the board.

I realize that this may be a tactic to discourage non-factory
repairs. Has anyone solved this problem ?

Thanks,
Rick

I have no personal experience with that amp.

I am am mech engineer for Cisco syst and we use thermally conductive
epoxy to attach heatsinks to asics, power supplies and other SMT
components. The stuff is white. to remove, you have to heat it with a
heat gun. Once it cools back down it is very brittle and the heatsink
will snap off easily.

Perhaps a little heat will do the trick?

Garrett





TA7205 wrote:

Hi;

I'm trying to repair a Punch 250.
There's 2 shorted output transistors.

These are not mounted to the heat-sink NOT by hardware,
they appear to be glued and- or soldered to the board.

I realize that this may be a tactic to discourage non-factory
repairs. Has anyone solved this problem ?

Thanks,
Rick

They are soldered. Two words- Heat Gun! Remove the board from the heatsink
and apply heat they'll come off. Lightly tin the tab on your new fets then
heat the MESHA heatsink module and reflow the new transistors on. Don't use
too much solder as it will squish out from under the transistor and provide
too thick a joint. Heat gun temp should be about 600 deg. F.


--
Jammy Harbin
J & J Electronics, Inc.
227 S. 4Th St.
Selmer, TN 38375
731-645-3311
"TA7205" wrote in message
...
Hi;

I'm trying to repair a Punch 250.
There's 2 shorted output transistors.

These are not mounted to the heat-sink NOT by hardware,
they appear to be glued and- or soldered to the board.

I realize that this may be a tactic to discourage non-factory
repairs. Has anyone solved this problem ?

Thanks,
Rick