Ed Williams wrote:
HI All,
I have been given a Pyramid PS-26K power sypply that is non-operational
and
I am looking for a schematic for the unit. If anyone has one that they
could email me I would be very thankful. If you can assist please email
me
at the below address.
73 de KN4KL ed
As Mike Terrell has noted, most linear power supplies are based upon the
National LM 723 regulator IC. I would highly suggest that you read.
In my experience, I have avoided Pyramid supplies due to questionable
component quality
and some design issues (adequate heat sink for rating).
Check the bridge rectifier, pass trasnsitors and IC723 regulator.
Dave Metz's WA0AUQ 1996 SEITS article. It provides you all the basic
information
to troubleshoot or rebuild a damaged LM 723 based supply.
http://www.seits.org/features/pwrsup.htm
Schematic of Dave's design
http://www.seits.org/features/pwrsup.gif
Astron Power Supply schematics
http://www.repeater-builder.com/rbtip/astron-index.html
Good Luck
W9GB