On 2017/12/27 12:31 PM, David Farber wrote:
whit3rd wrote:
On Tuesday, December 26, 2017 at 2:16:52 PM UTC-8, David Farber wrote:
I'm servicing a Behringer EUROPOWER PMH2000. The + and - 15 volt
regulators need replacing because the leads have failed. The
transistor is mounted to the chassis at a 90 degree angle and then
soldered to the pc board. The problem is that pc board fits very
tightly into the chassis. The leads on the regulators keep getting
flexed with each pc board removal. Anyway, I want to replace them
because a couple of the leads have broken off. They are packaged in
a TO-220 case. The center tab is nonmetallic so it is insulated from
the chassis.
I presume, however, that the tab connects to the chassis for
heatsinking?
Best practice if the strain on the component is breaking wires, is to
use
a strain-relieved wiring connection, like a few-inches pigtail wiring
from the regulator to a female Molex KK socket; this will plug onto
male pins mounted
in the printed wiring board, 0.100" centers spacing just like the
LM78xx.
Those regulators are available in fullpak (epoxy insulated tab),
metal-tab-wth-hole, and short-metal-tab (for soldering to a surface
mount "heatsink").
Yes, the tab is for heat sinking and your suggestion of using the Molex plug
and socket is very clever.
Thanks for your reply.
I would not agree with using a socket if the regulator flexes slightly.
You will run through the insertion limit number of the socket very
quickly. Rather, can you solder a flexible loop to the regulator leads -
assuming the PCB and the heat sink are not well joined so there is some
flex.
I have seen sockets used in similar situations in arcade games and the
failure rate is significant. Connectors are the principle point of
failure after all...
John :-#)#
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