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<DIV>Hi John</DIV>
<DIV> </DIV>
<DIV>I have a manual for the HP-1144A which shows the protection system in place
and a schematic for the HP-1144 which has no protection system.</DIV>
<DIV> </DIV>
<DIV><FONT lang=0 size=2 face=Arial FAMILY="SANSSERIF"
PTSIZE="10">73<BR></FONT><FONT lang=0 color=#0000ff size=4 face=Arial
FAMILY="SANSSERIF" PTSIZE="14"><I><BR>Bob</FONT><FONT lang=0 color=#000000
size=2 face=Arial FAMILY="SANSSERIF" PTSIZE="10"></I><BR>Bob F Burns G3OOU,
G-QRP 6907, @BobFBurns<BR>Crystal Palace Radio & Electronics Club: <A
href="http://www.g3oou.co.uk/">www.g3oou.co.uk</A><BR>Technical web site: <A
href="http://www.qsl.net/g3oou">www.qsl.net/g3oou
<DIV> </DIV>
<DIV>
<DIV>In a message dated 04/11/2017 18:19:32 GMT Standard Time,
lhouseparker@livingston.net writes:</DIV>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><FONT
style="BACKGROUND-COLOR: transparent" color=#000000 size=2 face=Arial>On
11/3/2017 11:59 AM, Alexander N. Gerli wrote:<BR>> Hi, folks! I have two of
these PSs, both work fine. But they have<BR>> different regulator
PCBs. Both cases say HP-1144. I thought there<BR>> was an -A version, but
which PCB did that have? My Manual shows<BR>> the PCB with the large
screw-mounted diode. Which one is which?<BR>> Thanks. 73, Sandy
AC1Y<BR><BR><BR>I don't know if there ever were "A" and "B" named versions,
but the <BR>first version of the HP-1144 did not have the "large screw-mounted
<BR>diode". That diode was part of a field update modification kit which
<BR>added crowbar over-voltage protection and modified the regulator
<BR>circuitry; that large diode provides the crowbar's short to ground.<BR>The
mod. kit manual said the PS is model 830-33, Series 00835.<BR><BR>Later
HP-1144's from the factory must have included those <BR>modifications and a
new manual, so if your manual shows the large <BR>3-terminal screw-mounted
diode then you have the updated version. The <BR>field update kit included a
completely new PCB, regulator IC, caps & <BR>resistors, plus a new
manual.<BR><BR>If your other HP-1144 is the old version, then I have its
manual; let <BR>me know if you need some pages scanned. I seem to recall that
the <BR>older regulator IC was somewhat unreliable and is no longer
<BR>available; whether or not the newer regulator IC is still available I
<BR>don't know.<BR><BR>73<BR>John
KE5ZB<BR><BR><BR><BR>_______________________________________________<BR>Heath
mailing
list<BR>Heath@puck.nether.net<BR>https://puck.nether.net/mailman/listinfo/heath<BR></FONT></BLOCKQUOTE></DIV></A></FONT></DIV></FONT></BODY></HTML>