PCSAT2 INTERFACE BOARD ASSEMBLY PLAN 13 May 2003 --------------------------------------------------------------------------- The board began burn-in testing at 1800 on 30 April 2003 and completed 254 hours at 1500 on 12 May. The board is ready for conformal coating. There are only 3 trim resistors that will be adjusted after final assembly and test. These are R61, R62 and R63 in the middle of the board which set the final transmitter frequencies. MOUNT DTMF DECODERS: Mount the two DTMF decoders in semi-permanent manner. Notice, they have an edge connector and if they need last minute re-programming, they have to be removed and re-programmed. MASKING PLAN: 1) Mask all DB connectors 2) Mask the four corner mounting holes 3) Mask the area around the 3 resistors R61, R62, R63 4) Mask the three 3-pin configuration jumper headers. 5) Stake any tall components, and chips in sockets. CONFORMAL COAT ASSEMBLE 1) Plug TNC-A into the edge connectors on the Intereface board. THis is a stressful process and once done, these two boards may be treated as a unit. 2) Mount TNC-B onto TNC-A, plug in its three connectors, and solidify the stack with the two stand-off's. Now these 3 boards are typically treated as a unit. 3) Assemble in TNC box to check the fit. NOTICE: The screws attaching the DB-25 edge connector to the TNC-BOX sidewall must impart no stresses on the Interface board PCB. ANd the mechanical clamping of the TNC's in the box should also impart no aditional stresses on the PCB or its connectors. FINAL-TEST/TRIM: The Transmitters inside the TX BOX, the receivers inside the RX box and the TNC box are needed together to establish the final values of the 3 resistors. The TNC box will be disassembled to solder in those final values and then reassembled for flight.