Compaq Systempro processor board repair
tothwolf at concentric.net
Sat Jan 3 03:05:11 CST 2015
I have a Compaq Systempro 486DX2/66 processor board (Spare No. 133825-001)
which I'm trying to repair that is missing some SMD components on the
solder side of the board. Does anyone happen to have one of these in their
collection and would be willing to read the component markings so I can
repair this one? Thankfully Compaq used SMD capacitors with readable codes
on them which indicate their values.
My board is missing R135, C227, C178, and C153.
Looking at the solder side of the board with the card edge connectors
facing towards you, R135 and C227 are towards the top left corner, about
1" from the top and 1.5" from the left. They are opposite U54 which is on
the component side of the board. I /think/ R135 is supposed to be 56 ohms
and C227 0.047uF (based on some similar looking circuitry on the board)
but I have no way to verify if those are the correct values.
C178 is about 1/4" from the top edge of the board and just to the left of
U511 (ATT7C174J). It is opposite U43/U60 which is on the component side of
C153 is just above the longest card edge connector, about 1" from the
leftmost contacts. It is opposite U32 which is on the component side of
I salvaged this board out of a scrap bin many years ago and have already
made lots of repairs to it, but I've never quite finished it. I'm about to
order some other SMD parts for other projects, so if I can figure out what
value these parts are supposed to be, I can pick up a few extra reels of
components and finally finish this board.
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