Brian, just a note that crystal spacers are *not* needed on the RF
board, synth, REF oscillator, and crystal filter modules. I shrink the
exposed pad area in all my designs on the top side of the board so the
crystal can't short to the pad. Solder mask is an excellent insulator.
tnx
W
On Nov 20, 2007, at 2:33 PM, Brian wrote:
ECO Number: 00507 K3 DSP PCB BOM Changes to Make
Production Rev B1
Date submitted: 11/20/2007
Originator: Brian Broggie
Attention: Wayne B., Lyle J., Bob F., Eric S., Group7,
Synergetics
EPN's Affected: E850233 K3 DSP PCB BOM
Applicability: Applicable immediately to all assemblies for
E100234 DSP PCB rev B.
Special instructions:
Please make the following changes to BOM E850233:
Add E700155 "Mylar Insulator for Xtals" (add ref
HDWR)
set Qty to 1. Vendor is DigiKey Part #
492-1039-ND.
Reason for change: Prevents Y1 from shorting leads to ground.
<E850233-B1 K3 DSP BOM.xls>Assembly: E850233 K3 DSP PCB Assembly
This Document Rev: D
Last Revised: 11/20/2007
Revised By: B. Broggie
Connectors P31 and P32 are installed on the component (top) side of
the PCB.
Connectors J1, J52, J53, and J54 are installed on the component (top)
side of the PCB.
Connectors J50 and J51 are installed on the solder bottom side of the
PCB. These
are the *only* parts installed on the bottom side of the PCB.
Connectors P57 and P59 are not installed.
The holes for P57 must be kept free of solder!
Pins 17, 18, 19 and 20 of J51 must be trimmed FLUSH to the PCB before
soldering, and
inspected post-solder to ensure proper wicking of solder. There mus
be no more than
0.005" of pin extending past the surface of the PC board. This is to
ensure there is
no shorting between pins of the VFO-B encoder PCB on the FP board and
pins of J51 on
the DSP board.
1 3 5 7 9 11 13 15
o o o o o o o o
------------------------
o o o o o o o o
2 4 6 8 10 12 14 16
Y1 requires a grounding wire from the case to the ground pad just
above it.
There are no removed male pins (polarizing) or insterted female pin
blocks (polarizing)
on this PCB assembly.
Ensure the J1 headphone jack is mounted square to the surface of the
pc board.
*******************************
New this rev:
Insert a nylon insulator under Y1 prior to inserting it onto the
PCB.
*******************************
==== End ====
---
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