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David Farber David Farber is offline
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Default LM7815A and LM7915A metal tab or no metal tab?

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.
--
David Farber
Los Osos, CA