Eico 232 User Manual

Intermittent operation on all functions
1. Loose or bad connections in probe or cables.
2. Wiper contact on SlB or SlC defective.
3. Loose or bad connection in bridge circuit wiring, including meter
terminals. With power
applied, probe wiring and components with insulated
probe.
4. Yl defective. Replace as described under "Tube Replacement."
5. CRl Intermittent.
Instrument
fails to operate on OHMS; works normally on ac and dc voltage
measurements.
1. Battery exhausted or not making
contact.
2. Defective wiper contact on switch section S2C.
3. "OHMS" contact (terminal 7) on SlB defective.
4. Open circuit In resistor network or burned out resistor around switch
section
S2C. Check continuity of network R5 through Rll. NOTE: This net-
work Is made up of resistors which are added in series as switch is rotated.
Therefore, one faulty resistor
may cause improper operation on one or more
ranges.
5. Loose or broken "Ohms" contact on switch section SlC (terminal 1)
OHMS ADJ. fails to give infinity setting on "OHMS" scale.
1. Battery exhausted.
2. OHMS ADJ. potentiometer, R30 defective.
3. Yl defective. See "Tube Replacement".
Resistance readings Inaccurate on
some or all "ohms" ranges.
1. One or more resistors in network around switch section S2C have changed
value.
2. Excessive leakage In "ohms" circuit. Check switch wafers on S2C
and SlB fordlrt or damage. NOTE: High humidity may cause leakage and in-
accurate readings on high ohms scales. Bake out Inside of Instrument with
light bulb. ,J
3. Shorted wiring In resistor network around S2C.
4. Fau Ity or high-resistance connections In "ohms" circuit.
Instrument falls to operate on anyac voltage range; works normally on OHMS
and DC VOLTS.
1. Y2 defect ive. See "Tube Replacement."
2. AC volts contact on SlA, SlB, SlC, or S2B defective.
3. Faulty wiper contact on S2D.
4. Open or short In circuitry associated with Y2. Check out wiring and
components values with ohmmeter.
5. C 1, C2, or R29 open; C3 shorted.
·12·
Meter pointer moves off zero when ranges are changed.
1. "AC
Ba lance" potentiometer R27 out of adJustment. Readjust as de-
scribe under "AC Yoltmeter Balance Adjustment. " If adjustment cannot be
made, then
2.
R28 or R27 Is defective. Check value with ohmmeter.
AC vo I tage readi ngs I naccurate on some or a II ac anges; performance on ohms
and dc voltage ranges is normal.
1. Defective contacts or wipers, or excessive leakage In S2B. Check for
loose or dirty contacts.
2. Y2 defective. Install new 6AL5. See" Tube Replacement."
3. C2 or C3 leaky.
4. R29 changed in value. Check with ohmmeter.
If Instrument is Inaccurate on 500 and 1500 volt ranges only, check contacts
10 and 11 on S2D and also R2, R3, and R4. If inaccurate on 1.5 volt range
only,
replace Y2. See "Tube Replacement."
Instrument fails to operate on any range of
"+YOLTS'" or "-YOLTS"; works
normally on ohms and ac volts. . .
1.
UNI-PROBE resistor is open. Try applying low dc-voltage with UNI-
PROBE set at "AC-OHMS". If reading Is obtained (about 10% high), replace
UNI-PROBE resistor.
2. DC voltage contacts on switch sections S2A, Sl B, or SIC are de-
fective. Check for loose or broken contacts.
Yoltage readings Inaccurate on
"+YOLTS". "-YOL TS", ac voltage and re-
sistance readings are correct.
1.
R31 out of adJustment. Reset as described under "DC Yoltmeter Cali-
bration. "
2. UNI-PROBE switch Is shorted, resulting in readings about 10% high
on all +DC and -DC voltage ranges. Use ohmmeter to check for short be-
tween input and output of probe at "DC" position as well as "AC-OHMS"
position.
3. Resistances in network around S2A has changed value. Check with
ohmmeter and replace defective resistors.
EICO Repair Service
If your instrument fails to function properly and the cause of the trouble can
not be found with the trouble shooting information provided,
you may return
it
tothe EICO repair department where It will be repaired at a charge of $5.00
plus the cost of parts. If your Instrument has been built from the kit form,
refer to the complete statement of the
EICO servicing policy in your con-
struction book. (Note: PleaseincludeUNI-PROBE when returning instrument
for
repair.)

Eico 232 Specifications

General

Brand	Eico
Model	232
Category	Measuring Instruments
Language	English