The preamp plates have a inner and outer end: the preamps are shifted a little away from the beam plane. The channels are numbered inside-out, so the preamp (and bar, and SiPM) closest to the beam is #1. The SiPMs could be loaded in either of two orientations: we always load them so the pins are closer to the outer end of the plate.

Each preamp is oriented so the 10-pin connector faces the direction in which the cables go. The inner half (1-40 on station 1, 1-24 on station 2) are cabled to the inner end of the plate. The outer half of the preamps (41-80 on station 1, 25-50 on station 2) are cabled to the outer end.

The pigtail cable has three conductors: red insulated, black insulated, and uninsulated. The uninsulated wire is connected to the foil shield, and is grounded to a ground pin of the SMA connector. If you hold the preamp plate with the SiPM pins facing you, and the outer end pointing up, the SiPM pins on the right side are at +Vb (red pigtail wires), the pins on the left side are near ground (black pigtail wires). The preamp has two pads for SiPM connections. The pad further from the SMA connector is +Vb (red pigtail wire), the pad close to the SMA connector is near ground (black pigtail wire).

Steps to prepare a Station 1 (80-bar) preamp plate:

1. Label on both sides: station #1, plate #1-4. Add 80/20 bolts on the ends for feet.
2. Station 1 plates: drill out all the grommet holes to 9/64".
3. Load grommets: push in from the fiber side, then push out from the SiPM side.
4. Dab a little RTV on the joint between each grommet and the plate.
5. Load SiPMs - log the SiPM data in the spreadsheet, and keep the envelopes in a bundle.
6. Add Kapton tape to each preamp hole, where the pigtail crosses the corner.

1. Label on both sides: station #1, plate #1-4. Add 80/20 bolts on the ends for feet.
2. Load SiPMs (remember to match SiPMs 47+49 and 48+50) - log the SiPM data in the spreadsheet, and keep the envelopes in a bundle.
3. Load grommets: smear some RTV on the outside of each grommet, then push in from the fiber side until you feel it hit the SiPM.
4. Add Kapton tape to each preamp hole, where the pigtail crosses the corner.

• SiPM connected: With the grommets facing down, use the multimeter on diode-test mode to check the preamp side of the pigtail. Red probe on black wire, black probe on red wire. Check for a diode drop (short beep), a short circuit (long beep) or open circuit (no beep) is bad. You will have to dig the probe tips in a little to get through the solder flux.
• SiPM isolated from plate: With the grommets facing down, use the multimeter on "beep" mode to check for shorts between the plate and both pins of the 2-pin connectors.
• Preamp ground isolated from plate: With the grommets facing up, use the multimeter on "beep" mode to check for shorts between the plate and the brass SMA connectors. The most likely place for a short is under the mounting holes; loosen the screws and insert Mylar shims to fix.

• Length: 4.2 or 6.8 cm
• Wire on left at the 2-pin connector: black or red
• Long wire: black or red
• Pigtail direction at the preamp: towards or away from the Fermilab logo

1. Use the 16 AWG notch on the blue-handled wire stripper to strip 2 cm of insulation from the end of the reel. This is the preamp end.
2. Use the wire cutter to cut the correct length off the reel.
3. Bend out the drain wire, peel the foil off, push the black and red wires in about 1 cm so they stick out the other side - that is the SiPM end.
4. Use the Jonard wire stripper (set to 24 AWG, 2 mm) to strip the ends of the wires on the SiPM end. Push the insulation+foil+drain wire up so they are a few mm from the SiPM end - this will pull the wires together so they grip the 2-pin connector.
5. Use the jig and the soldering iron to solder the wires to the 2-pin connector: spread the wires around the 2-pin connector and bend in the stripped ends so the pigtail holds itself in place, then add solder.
6. Use the diagonal cutters to trim excess wire and solder. Rotate the 2-pin connector. At the preamp end, trim excess wire so the red and black wires are the same length, and strip both with the Jonard stripper. Bend the stripped ends by about 60 degrees.
7. Use the jig and the soldering iron to solder the pigtail to the preamp. Red and black wires: melt some solder onto the pads, then stick the red and black wires on, then add solder to make good connections. Drain wire: use tweezers to bend it around the SMA connector's ground pin, add solder, use tweezers to pull the wire tight around the pin.
8. Use the diagonal cutters to trim excess drain wire.

1. Use the wire cutter to cut the correct length off the reel.
2. Use the 16 AWG notch on the blue-handled wire stripper to strip 1 cm of insulation off each end.
3. Cut the drain wire off on one end (this is the SiPM end), bend it out on the other end (this is the preamp end). Peel the foil off both ends.

• Lead awareness training (online training) required for soldering.
• Do one preamp all the way through so you learn the right way to do each step, and ask someone else to check it. Then do things in batches so you can do step 1 on a dozen pigtails, then step 2, etc.
• Wear safety glasses when you use the diagonal cutters - the little bits of solder will fly. Regular glasses are OK if you wear those.
• When you're done for the day, brush off the table and dump the scraps in the solder waste bin. If you have finished preamps, put them on the table in the middle of the room, in the bin with the type number.
• The big box of preamps is to the right of the soldering station. Everything else (connectors, wires, tools) should be at the soldering station.
• There are two sizes of 2-pin connectors (the pins are different lengths). You can use either.