From: wa2ise@cbnewsb.cb.att.com (robert.f.casey)
Newsgroups: rec.radio.amateur.misc
Subject: PS50 fix
Message-ID: <1991Dec10.043500.26138@cbfsb.att.com>
Keywords: mod
Sender: news@cbfsb.att.com
Organization: AT&T Bell Laboratories
Date: Tue, 10 Dec 1991 04:35:00 GMT
Lines: 41


copied from packet:
 Msg# TSF  Size #Rd  Date  Time From   MsgID        To
 8740 BF   1561   0 07-Dec 0501 KD2EJ  28375_WB2QJA INFO@ALLBBS ()
 Sb: PS-50 IMPROVE VOLTAGE SURGE

**************************************************************
Info sheets downloaded from Kenwood BBS in California.
Permission has been granted as stated in the READ.ME file on the BBS
for anyone to relay these bulletins without requesting compensation.

These bulletins have not been modified in any way.

* COPYRIGHTED KENWOOD CORP. U.S.A.
***************************************************************

SB-916
PS-50 Improved Voltage Surge Protection                 5-23-86


We have received a few reports regarding the loss of transistor Q4,
resistors R2, and R3, and zener diode D4 on the AVR UNIT.  Apparently a
voltage surge on the power input might cause D4 to short.  If this occurs
the surge current thru resistors R2 and R3 could be high causing the
failure of the two resistors and Q4.

Procedure:

On the AVR unit X43-1520-00 open or remove diode D4.

If you receive a unit with no output voltage check D4, R2, R3 and Q4.  You
should replace R2, R3, and Q4 if there is any sign of damage to any of
these components.

This change applies to serial numbers before 7040001.

Time required for this change is 1/2 hour or less.

(c) 121589TKC
========================================================================
I haven't tried or verified this, proceed at your own risk.  WA2ISE