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Revised 2-9-94

SIMCHECK is normally supplied with an external power supply which provides unregulated 9VDC/1A. This unregulated source is further regulated by SIMCHECK's three internal precision regulators. However, you may need to replace the power pack when you have to use SIMCHECK on an exceptionally noisy or unstable AC line source (usually with the Automatic SIMM HANDLER). This document outlines the replacement of the original power pack with an external switching power supply such as the 9VDC/2.3A model UPS20-10P. This unit may be purchased from your SIMCHECK dealer and it has a universal 100-240V AC input.

NOTE: the UPS20-10P is also a part of the 40-BIT PORT package (INN-8484). Users of the 40-BIT PORT have the option to perform the replacement outlined in this document (without voiding the warranty), or to use the UPS20-10P through the AUX power jack.


1) Cut the output (9V) cord of the UPS20-10P as close to the plug as possible. Tear out about 1.25 inch of the outer insulation to expose the internal wires of the cord. The ground shield is not used. Trim 1/4" of the insulation at the ends of the two internal wires. Plug the UPS20-10P to the AC lines and use a voltmeter to verify that the red wire is indeed the +9V. Unplug the UPS20- 10P from the AC lines.

2) Cut the old power pack output cord at about 2" from SIMCHECK and trim about 1/4" of the insulation. Connect the old power pack to the AC lines and use a voltmeter to verify that the (+) is the wire with the white strip.

3) Solder the UPS20-10P (+) to the (+) line from the SIMCHECK, and solder the UPS20-10P (-) line to the (-) line from the SIMCHECK. Use good electrical insulation tape to cover all exposed wires and to complete your work.

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