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If the Green LEDs of the A8 are not All ON
The green LEDs along the top edge of the A8 post regulator are normally on.
Flashing LEDs on A8 indicate that the shutdown circuitry on the A8 post
regulator is protecting power supplies from overcurrent conditions by
repeatedly shutting them down. This may be caused by supply loading on A8 or
on any other assembly in the analyxer.
Remove A8, Maintain AlSWl Cable Connection
1. Switch off the analyzer.
2. Remove A8 from its motherboard connector, but keep the A15Wl cable
connected to A8.
3. Short A8TP2 (AGND) (see F'igure 5-3) to chassis ground with a clip lead.
4. Switch on the analyzer and observe the green LEDs on AS.
If any green LEDs other than +5VD are still off or fia&ing, continue to
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"Check the A8 Fuses and Voltages"
If all LEDs are now on steadily except for the +5VD LED, the Al5
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is excessive loading somewhere after the motherboard connections at A8.
Continue to "Remove the Assemblies"
Check the A8 Fuses and Voltages
Check the fuses along the top edge of A8. If any A8 fuse has burned out,
replace it. If it burns out again when power is applied to the analyxer, A8 or
1. Remove the A15Wl cable at A8. (See F'lgure 5-5.)
2. Measure the voltages at A15WlPl (see F'lgure 5-6) with a voltmeter having a
small probe.
3. Compare the measured voltages with those in 'lhble 5-2.
If the voltages are not within tolerance, replace A15.
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