Advice about repairing an IBM 5151

1 Sep 2015

...
   Are you sure
TR23 is good. The horizontal output transistor in many monitors
 often fails.  I am not sure. I assume I have to desolder it to check it right?

Yes, but it's only 3 connections to desolder.

Obviously if the 2 junctions don't test properly as diodes, or if the Hfe is much
lower
than it should be then the transistor is dead. But due to the high voltages that should
be around, most transistor testers don't do adequate testing of such transistors. 

-tony

2025

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

1999

1998

1997

Advice about repairing an IBM 5151