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Home›Repair guides›MAINTENANCE

Cummins/Onan Instapac — MAINTENANCE

For the Cummins/Onan Instapac.

Applies to: Cummins Onan Instapac

Before you start

  • Except for continuous operation models, terminal 7 is
  • Carefully guide wires through rubber
  • When removing wires from transistors, be certain not to
  • Use only enough force to provide a
  • DON'T ATTEMPT TO DISASSEMBLE THE FILTER - ALL
  • New battery op-
  • The above procedures is for lead-acid

Procedure

  1. (Stand-by Mo-
  2. INVERTER
  3. Remove battery cables.
  4. Remove inverter unit backplate and top cover screen.
  5. Disconnect the inverter unit wires from terminals 6, 7, 8, 9, and,
  6. Disconnect the two heavy wires to T, and Tg on T B 5 ; then pull
  7. LOOSEN the four 7/16" nuts securing the inverter unit to the front
  8. Lift the inverter unit up 1/2" and pull it away from the mounting
  9. to remove the heat sinks, unscrew the 4 machine screws holding
  10. Remove the defective transistor and thin (.001) mica insulating
  11. If available, lightly coat the copper base of the transistor and
  12. See Fig. 14 for replacing transistors.
  13. Check to see transistor is not shorted to heat sink. Use highest
  14. When soldering leads do not overheat. Use a very hot iron and do
  15. Make sure of proper polarity when replacing diodes. When solder-

Tools required

  • socket
  • SOCKET
  • SOCKET
  • socket
  • wrench

Source: manual:962-0004 Onan VA Series Instapac UPS Manual (4-1963).pdf. Figures and steps are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.