No output power

Symptom

Phase rotation - red LED on the 'B' supply lights

Fault

• Input phase missing
• Faulty synch assembly
• Faulty 'B' supply

Solution

1. Check for 35v 3-phase at wires 55, 56, and 57
2. To set the phase rotation do as follows: Remove left hand ribbon cable off of control (LM2209) or remove the gate leads from the converter SCRs (LM2100 series). Remove F2, which is in line with wire24. Pull the start button and adjust the phase rotation pot until the phase rotation diode lights. The phase rotation is now set. Re-connect the fuse, ribbon cable, or gate leads.

Symptom

No phase rotation

Fault

• Missing converter or inverter gates
• Check the gates on the board with an oscilloscope
• +15 or -15vdc supply missing

Solution

1. LM2209 converter gates: remove the left hand ribbon cable from the control board and pull the start button. The gates can be seen at the top of the can style transistors 02 at A', B', and C'. They should appear as two double pulses at each transistor. The gates can be checked at the converter SCRs. Re-connect the left hand ribbon cable and remove the gate lead from each SCR. The gate should be a positive double pulse at each block. If the gate can be seen at the board but not at the block, change the CGS.

   LM2016 converter gates: Remove the gate leads from each converter SCR block. The gates can be viewed at the board by attaching a scope to position 9 (common) to position 10 (probe), position 12 (probe), and position 14(probe). A positive pulse should be seen at all three positions. The gates can then be checked at the SCRs. A single positive pulse train should be seen at each SCR. If the pulse can be seen at the board, but not at the SCRs, change the CGS.

   Inverter Gates: LM2209: Remove the left hand ribbon cable from the control board. With an oscilloscope measure at the top of 03 and 06 on the control board (start button pulled). A train of pulses should be seen at each transistor. The pulses can also be checked at the SCR at the white gate lead. Remove the gates at the converter blocks first so no dc bus is generated. Re-connect the left hand ribbon cable.

   LM2100: The inverter gates can be checked with an oscilloscope at the inverter control board at the following positions: position 16 (common) to positions 15 and17 (probe). A train of pulses should be seen at each point. The gates can then be checked at the inverter SCRs at the white gate leads. Before checking the gates at the inverter SCRs, remove the gate leads from the converter SCRs so no dc bus is generated

2. This can be measured at wire 43(+) wire 41 (com) for the +15v and at wire 44(+) to wire 41 (com) for the'-15v supply. If either supply is missing, replace the 'B' supply.

   In the cases above, the frequency cannot be heard.

Symptom

Frequency can be heard

Fault

• Open output at the station
• Feedback assembly

Solution

1. Check outputs
2. See ohm check sheet.