SLIM-CB-NV rev C
11-11-08. Add link for LPT Parallel Printer
Port Test in Liberty Basic: testlptport.bas
1-20-09. Change page to reflect that Control
Board is modified to Revision C. The schematic is now rev C, the
parts list is rev C, and the PWB is rev B.
8-11-09. Add revision history
9-27-09. Engineering Change Notice (ECN).
There is an error on the PWB. See Release History, Revision C,
3-14-10. Revised PWB-CB-NV to Revision C.
Control Board, size-C
Use your mouse's "right click" and "Save Link" to download the current
a. SKSLIM-CB-NV.sch rev C
SLIM Control Board, in ExpressPCB software.
b. PWB-CB-NV.pcb rev C
Base artwork for PWB, in ExpressPCB software.
Use this drawing to order the pwb from Express, or use as
Layout to locate
the parts on the SLIM Control Board.
c. PLSLIM-CB-NV.txt rev C ,
Parts List for SLIM Control
Board, in .txt format. Open with Exel or Lotus, etc.
The SLIM-CB-NV Control
Board is the Interface between the
Computer and other SLIMs. It
consists of 4 sections, Latch, Power
Conditioner, Voltage Converter, and Noise
Part #: SLIM-CB-NV Rev 0
Rev 0, Released
Parts List: PLSLIM-CB-NV Rev A
PWB: PWB-CB-NV Rev
Revision A: Released 10-13-2007
Revision A changed nomenclature on the schematic, only.
Part #: SLIM-CB-NV Rev A
Rev A, Released
Parts List: PLSLIM-CB-NV Rev A
PWB: PWB-CB-NV Rev
Revision B: Released 4-24-2008
Revision B is a significant modification to the Voltage Converter
section. This changed the PWB artwork. However, the previous pwb
can be modified for the new changes.
Part #: SLIM-CB-NV Rev B, archived
Rev B, Released
Parts List: PLSLIM-CB-NV
Rev B , archived
PWB: PWB-CB-NV Rev A,
Revision C: Released
Revision C consists of adding
resistors, R13 through R24, and capacitors, C29 through C40. The
resistor/capacitor combination creates a low pass filter to improve the
noise immunity of the computer's LPT signal
lines. This changed the PWB artwork. However, this
RC modification can be performed on the previous
versions of the Control Board, if required. This modification
should be performed if the Control Board has symptoms of inconsistant
commanding from the home computer.
Part #: SLIM-CB-NV Rev C
Schematic: SKSLIM-CB-NV Rev C, Released
Parts List: PLSLIM-CB-NV Rev C
PWB was: PWB-CB-NV Rev B, not archived (since it does have an
Notice, 3-14-09. PWB is now: PWB-CB-NV Rev C.
I made an error when
laying out PWB-CB-NV Rev B. The capacitors,
C29 through C36, do not
have their pads connected to the pins of U1. There is a gap
between the pads of the capacitors and the pads of U1. The ground
end of the capacitor pads are correct. You may modify the pwb by
1. add a wire from each pad to the appropriate pad of U1.
2. or, install the capacitors on the end of the pwb directly from the
pads of U1 to the edge ground. You can do this on either the top
or bottom of the pwb.
This modification is to ensure that the newly designed RC
filtering action will work correctly. Many computer/MSA
combinations do not even need this filtering, but some of the newer
(cheapo) computers are very noisy and do require the filtering.
PWB-CB-NV Rev C fixed this error.
Pictures of Schematic,
SK-CB-NV rev C,
sheet 1 of 4. Click on drawings to enlarge for viewing.
The Latch Section consists of 4 ea,
TTL/CMOS input compatable Buffer Latches with CMOS outputs. The
are from the Computer's Standard LPT printer port, carried on a DB-25
female connector. The outputs of the latchs are accessable on 4
ea, 9-pin connector headers. Note: Connector headers are not
mandatory. Direct wiring to the other modules is optional.
A fifth connector (P5) is a direct connection for four LPT signals that
are "read" by the Computer. Two of these are used by the SLIM
Converter. The other two status lines, PE and SELECT are not used
by the MSA or VNA, but may be in the future.
Revision B calls out a change to add 2.2 K ohm pull
up resistors to these 4 status lines. Some home computers do not
have internal pull-up resistors and if so, these resistors are
necessary. Only WAIT and ACK lines may need these
resistors. Previous versions of the Control Board may need this
revision if connected to one of these home computers. Here is a
test to see if the pull-up resistors are required. Re-boot the
home computer. Use a voltmeter to measure from computer ground to
LPT port, pins 10, 11, 12, and 13. If any of these pins are
showing greater than +2.0 volts, the pull-ups are not required.
All 4 of the latch I.C.'s are fed by the Parallel
from the Computer. The Data will be passed to the latch's output
it's enable line is commanded high. If enable is kept high, the
data will follow the input data. When the enable is brought low,
data will be retained as a latch.
The SLIM Control Board is a generic module that will
be integrated into a higher assembly. Therefore, the signal names
schematic are generic (changed 10-13-07). For example, the data
signal that exits the computer is called D0. It is buffered by
the four latches, U1-U4. The name changes at the output of each
latch, for example, P1D0. This is Data Bit 0 on connector P1 (U1
Once the Control Board is integrated
into a higher assembly, the signals are assigned more meaningful names.