Eberline ESP-1 - Page 64

(c) High voltage breakdown.
(d) Input sensitivity (discriminator set too sensitive).
(e) Noisy low voltage supply.
Loose or bad ground connections are best detected by visual inspection. Check for:
(f) Damaged PC board.
(g) Broken wire(s) in ribbon cables.
(h) ΤΙ frame is not properly grounded.
If the high voltage is too high, try readjusting it (HV control). If it will adjust and control,
then check with the detector to prove the fix. If the high voltage does not adjust and/or
control, go to "Repairing the High Voltage Supply," section V.C.2.d.
Breakdown or arcing of the high voltage is normally caused by a dirty PC board, damaged
component, or dirty/bad detector connector.
Input sensitivity can easily be checked using an Eberline MP-2. Check it with reference to
the table in section IV for the detector being used. If the input sensitivity is too high, reset
it to the proper value and check instrument operation. If it is still noisy, proceed.
Check the low voltage (V., +V) using a scope. The ac component should be less than 10
mV. If not, the probable causes are:
(i) А101 inoperative (if noise is on V,).
(D ALI inoperative.
(k) 0101 defective.
() Leaky filter capacitors.
d. Repairing the High Voltage Supply
NOTE
All measurements of the high voltage require a voltmeter of 1000
МО or greater input impedance. Use an electrostatic voltmeter or
a special high voltage arrangement such as a Fluke model 8020A
with 80k-40 high voltage probe.
It is normal that the high voltage will fluctuate around the control point (+ 5 percent). Adjust
the high voltage by using the INTERNAL НУ control on the PC board.
ESP1.MAN/February
1992
5-15