EICO 232, 249 Service manual
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10033 R19
1003•• R2!S
1040-\ ~28
10406 R20,21"
10407 Rl
10503 R26
10520 R24
10521
10524 R29
11025 R2
11026 R15
11037 R9
11038 RB,
11039 R7
11043 Rll
11044 RIO
11045 R6
11046 R5
11047 R13
11048 R14
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VOLTS (RMS) MIASURED ACIOSS 600 _ OHM IIS'STlYI LOAD
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Fig.l
REPLACEMENT PARTS LIST
DIICIIIITION
Rill.
I
:l.3MO
I
l;2W, 20%
".7MQ ,1/2W, 20% 11050 Rl7
"
02MQ, I/2W, 10%
"
"
"
"
R23
"
"
"
"
"
"
"
"
"
..
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"
"
*Model249 only
6800,
lMO,
33K,
68K,
47K,
lBMO, 1/2W, 5%
150KO, 1/2W, 1%
2001<,
9000,
9KO,
90KO,
9.70,
90Q,
9001<0, 1/2W,
9MO,
2MO, 1/2W,
7001<0, 1/2W,
I/2W, 10%
1/2W, 10%
1/2W,
1/2W, ~%
1/2W, 5%
1/2W,
1/2W,
1/2W,
1/2W,
1/2W,
1/2W,
1/2W,
-r-
1-
1""
2 1 4 S ""
11
5% 11701
1%
1%
1%
1%
1%
1%
1% 72004 Ml meter, 4Q()ua
1%
1%
1%
'7
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-t.
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,
,
4 S ,
101
_THoNG. IVM.
11049
R16
11051
R18
11052 R3
11700 R4
R12
16000 R22,30
18014 R31,32
18015 R27
20003 ct
20007 C4
20012 C2, C3
23010 C5
56000 BT1
"
"
"
"
"
"
n
1. '1000
DISCItIIlTION
70KO,
20KO,
10KO,
1/2W, 1%
1/2W,
1/2W,
325KO, 1/2W, 1%
9001<0
7MQ,
pot., 2 KO, linear
pot., 2 KO, linear
pot., 1OKO, linear
cap., .1 mf- loo0V
cap., .003mf-400V
cap., .025mf-400yr
cap., elec. 10mf,150
battery, 1 1/2 V
60024 52 switch, range
60025 51
90013 VI
90017 V2
92000 11*
93003 CRt
swItch, function
tube, 12AU7
tube. 6AL5
bulb, '47
rect.,35ua
.:.'.::
1%
1%
lW, 1%
iw,
1%
general description
""l'"
-.'. :;'Ex.preuly designed for TV servicing, the Model 232 (249) Peak-to-
,.P,
~Pe1!kVTVM features. a full-wcve , high frequency rectifier circuit that re-
sponds to and measures' the peak-to-peak voltage value of complex and sine
waveforms even when DC is present. It also reads the rms voltage of sine
waves (on a separate scale), de voltage values, and resistance values. For
consistantly high accuracy, there are seven non-skip ranges on a II functions
to provide a uniform 3 to 1 scole ratio between adjacent ranges.
The input resistance on all dc voltage ranges is 11 megohms, which
, is high enough to prevent loading error and yet not so high as to Impair the
stabilityof the instrument. The dc voltage ranges may be extended t030,000
volts (with accessory High Voltage Probe HVP-l or HVP-2) and may also be
'used for RFvoltage measurement up t0250 mc (with accessory RF Probe Model
PRF-ll). The frequency response ofthe ac voltage ranges extends from 30 cps
to 3 mc. for a source of 100 ohms or less.
Facilities that Increase the accuracy, versatility, and ease of oper-
ation include zero- center Indication for discriminator alignment and bias
measurements; zero adjustment unaffected by changing function or range;
separate scale for low ac voltage measurement; electronic protection against
meter burn out; adjustment of all calibration controls without cabinet removal;
and UNI-PROBE, a single unit probe used for all functions. ••
The Model 232 (4 1/2" meter) and the Model 249 (7 1/2" meter)are
identical electrically. Where portability Is desired, the-Model 232 is pref-.
erable because of Its extremely compact design. The Model 249 is an ideal
bench instrument, having extra long scales to minimize reading errors. and per-
mitting permanent placement of the equlpmentat a practical working distance.
Both instruments are ruggedly housed, professional in appearance, and highly
dependable and trustworthy measuring devices that will prove extremely val-
uable in television, fm-om radio servicing, and many industrial applications.
speclfl catlo ns
DC VOLTMETER:
Ranges .•.•..•............•.. 0 to 1.5,5, 15,150,500,1500 volts
Input Resistance ..•.•..•.•..••. 11 MQ
Accuracy ...•...•.•...•.••.••• ±3% of full scale or better.
Range extended to 30,000 volts with High Voltage Probe HVP-l or HVP-2
(l 090 MQ Multiplier resistor recommended).
AC
VOl, TMeTER:
RMSvcslues of Sine Wave •..... 0 to 1.5 volts on separate LOW-AC scale
o
to 5,15,50,150,500,1500 volts
Peak-to-Peak Valuesof Sine .. , 0 to 4 volts on separate LOW-.AC stelle
&
Complex Waves 0 to 14,42,140,420, 1400, 4290;;yoIts ,
Input Resistance&Capacity •.• , 1 MQ, shunted by 60 rnmf"
Accuracy ..•.•••••.•••.•.•• ±5% of full scale or better:", "',,:,. ,',
Frequency Response •••••...•. 30 cps to 3 Mc(source Z 100 Q or less} . '"
RFvoltage measurement to 250 Mc (accuracy ± 10%) with ~F Probe PRF""11
OHMMETER: 0 to 1000 Megohms in 7 ranges- RXl;RXW,
RX10K,RX100K,RX1Meg (10 ohms center scale on RXl range)
TUBECOMPlEM ENT: 1-6AL5 twin-diode as full-wave peak-to-peak rectifier"
1-12AU7 twin-triode in vacuum-tube balanced bridge circuit
, OWER SUPPLY:
II.
POWI.R
OVERALL
WEIGHT: Model 232-7
CASE: Steel cabinet, aroy wllnklll flllhh, .,dIIlMollllt1l1lulll peno l, doop ..etched
used for all functions and ranges) and ground lead.
RrOlJIRrMINIS, 10
SIL.!:,
MOII,,17a~"1\
and rub-proof
IJPpilod
complete with UNI-PROBE (combined isolating and direct probe,
I?S volts AC, 50-60
1/)"11,
rid., MIlII,,1~4')-? pounds
Ionium ructlfleri 1.5 volt flashlight
CPSi
~11'Wi
S"dl Model
249 -
(apRro!<'. )
RX1
0
9
,RX1000
drain: 5 watts
81/2 'h ; 13"w
15"~
.r
....
the worm-up period.
4.,
Short the UN I-PROBE to the Ground Coble and set the meter pointer
at the I~ft:'hand zero with the ZERO ADJ. control. If turning the FUNCTION
selector J~~!(;l.PC VOL TS
the ~ec~ankgl zero of the meter as described under MAINTENANCE.
5. SetA~e FU~CTION selector at "OHMS", the UN I-PROBE at "AC-
OHMS", and the RANGE selector at "RXl 0". Separate the UNI-PROBE from
Ground Coble , The meter pointer should move to approximately full scale.
-1
,
'
6. Use the OHMS ADJ. control to position the meter pointer on the last
j'graduation of the scale.
7. Set the FUNCTION selector at "AC VOLTS". If the meter pointer
does not read zero volts when the RANGE selector is at "1.5 V", refer to the
':'!AC Voltmeter Balance Adjustment" and "AC Voltmeter Calibration"sections
under Maintenance.
Note: Although the meter is protected against burn-out under ordinary over-
loads, repeated overloads may impair the accuracy of the movement. For this
reoson, in the following Instructions the operator is advised to first make a
trial measurement at a range setting higher than the voltage expected.
DC VOLTAGE MEASUREMENT
1. Set the UNI-PROBE at DC and the FUNCTION selector at either
"+DC VOLTS" or "-DC VOLTS", depending upon the polarity of the voltage
to be measured with respect to ground.
2. Set the RANGE selector at a position considerably higher than the
voltag~ to be measured.
i
'
changes the position of the meter pointer, readjust
operation
PRELIMINARYADJUSTMENTS
1. Connect the UNI-PROBE to the VOLTS-OHMS terminal, and the Ground
Cable to the GND. terminal.
2. Plug the line cord into an outletsupplying 105-12SvoltsAC, So-60cps.
3. Set the FUNCTION selector at "+DC VOLTS" and the UNI-PROBE at
"DC". Allow several minutes for the instrument to warm up. If necessory,
use the ZERO ADJ. control to set the meter pointer within scole limits during
-2 -
3. Connect the Ground Coble to the ground side of the voltage being
,.,..
..
:
measured and touch the UNI-PROBE to the high side.
4. Reset the RANGE selector to the position which gives a reading near-
est to fuII sea Ie and read the dc vo Itage on the meter.
ZERO CENTER INDICATION
Zero-center indication permits observation of either positive or negative
vo Itage excursions without resetting of the function selector. To prepare the
instrument for zero-center Indication, simply set the FUNCTION selector ot
• "+DC VOLTS" and turn the ZERO ADJ. control (with no voltage applied) un-
-3- '
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