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This page last changed on Sep 24, 2009 by kgomes.
pH Meter Assembly Instructions
- Don't cut the leads on the Temp sensor AD22103 - Mount standing up with 0.25" leads to insure close proximity to housing. Use a 0.25" Teflon sleeve on the center leg.
- Teflon sleeves on the outer row of the right angle 2x7 JTAG connector (prevent shorting to housing)
- Lift pins on U21 - 3 and 6. Bend straight out.
- Stuff 1x10 header on pH meter / controller board, do not solder header to analog front end board (deliver as two pieces)
- Implement the following Engineering Change Notifications (ECN's)
- ECN #1
- Schematic Mistake on U8 LM337 to fix VAAiso- connection to Vin of LM337 (should be Vout)
- Cut trace under C34 going to the non-stripe end of C34
- Drill hole on pin 8 J17, tube the hole with teflon tubing
- Connect U8 - pin 1 to J17 - pin 8 and non-stripe end of C34
- ECN #2
- Silk screen on rev 1.0 shows opposite polarity for C66 - stuff backwards to silkscreen
- ECN #3
- Connect U14- pin22 to U14 - pin 30
- ECN #4
- Connect C60 Anode to C54 Anode
- ECN #5
- C32 and C33 have wrong polarity on silkscreen stuff opposite
PCB Fabrication
- MATERIAL TYPE: FR4 or 370HR
- UNIT DIMENSIONS: 08.500 By 01.400
- MATERIAL THICKNESS: 0.062"
- ARRAY DIMENSIONS: 00.000
- BOARD FINISH: SMOBC
- ARRAY NUMBER UP: 0
- COPPER WEIGHT: 1 oz
- ARRAY QTY: 0
- INNER COPPER WEIGHT: 1.0
- TAB ROUTE: YES
- SOLDER MASK SIDE: Both Sides
- SCORING: NO
- SOLDER MASK COLOR: Green
- E.TEST OPTION: NO
- LEGEND SILK SCRN: Top Side
- 5% OVERAGE: yes
- LEG SILK SCRN COLOR: White
pH Meter Board House Package
- Schematic and Parts Placement diagrams
- Bill of Material
- Parts Kit with PCB
- Deliver to Indtec
pH Meter Board Inspection
- Visual inspection: compare against 'example board' for missing or mis-placed parts
- Errors found on Indtec board #1
- Some tantalums are missing (6 of them)
- ECN for tantalum reversal not done (in backwards)
- ECN #1 not done correctly - trace not cut underneath C34 (V- measures -15v)
- Tantalum caps are missing (spares not retured from Indtec or lost or obscounded)
- R79 not stuffed (assembly error) - causes no clock to processor
- R69, R70 need 10 ohms, schematic incorrectly has 100K
- JTAG connector stuffed on wrong side of board - JTAG Emulator can't see device, USB FET sees low voltage
- Connect +12v, GND, RX and TX to controller board external interface (next to metal band)
- Connect a 4.5 Digit voltmeter to VPH and GND on controller board external interface
- Connect "Calibrations Inc" voltage standard to VPH and GND on J17
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