FIELD MULTIMETER » EXACTA «
MULTIMETER » E X A C T A « Model 1-20 by H.G.L. (1970's)
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In '60s was an "ULTRON-Family" of MULTIMETERs on the market: The Japan-
made instrument was sold by many companies /LOGOs w. minor differences.
The »ULTRON« became very popular in Germany, because its recommendation
from KOSMOS as addition to their Experimental "RADIO+ELEKTRONIK" Kits.
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The » E X A C T A « has the same housing as the » ULTRON UM201E «
but less ( & different ) DC & AC Ranges. (* see below ...)
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Dimension ( W-D-H ) 85 mm x 118 mm x 28 mm / 3_3/8" x 4_5/8" x 1_1/8"
20 kΩ / Volt ( DC & AC ) 2 Jewels < Ri(I) = 4.5 kΩ >
10 V / 50 V / 250 V / 1000 V ; 50 μA / 250 mA DC Ranges
10 V / 50 V / 250 V / 1000 V AC Ranges
0 Ω ... 60 kΩ / 6 MΩ with 1.5 V »AA« Battery
- 20 dB ... +22 dB ( Output Measurements, see Manual )
R E M A R K S & R E S T O R A T I O N
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A friend ask me for help and repair. He found this instrument on its
WASTE CONTAINER: It came in its original red box with instruction sheet
and its old bill from 1973 ( ATZERT RADIO, BERLIN = 38 DM ) - But there
was NO TEST CABLE SET included! A quick investigation showed: DCV & AMP
worked. But ACV showed only the HALF VALUE. Decision was made: "It is
worth to repair!" ...
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The (Mini-)GRAETZ-RECTIFIER
was defect and had to be
replaced:
Home-made with 4 DIODES
eg. OA-95
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2nd Problem: The LOWER OHM-RANGE was dead. A RESISTOR was burned out.
With trial-and-error we found the replacement value of 270 Ω ...
... Next Problem: No common plug fits into its sockets - We had to make
our own, out of ( sand-down until fitting ) copper-wires - Weeks later
we found the right probes on a FleaMarket tour ...
For expanding the AMP(DC)Ranges of the »EXACTA« ( eg. 5 / 50 / 500 mA )
have a look at the ...
S+H_LAB_AMP_METER & Multimeter "Recycle-Project"
... how to build a 3-SHUNT-BLOCK ...
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SELECTOR | SHUNT | RANGE
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50 μA | 50 Ω | 0 .. 5 mA
| 5 Ω | 0 .. 50 mA
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250 mA | 6 Ω | 0 .. 500 mA
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Have a look at the N E X T VERSION:
» 4-SHUNTS & 4-SERIALS BLOCK «
After a year my friend bought a Digital MM and the »EXACTA« became mine
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(* see above)
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I have SPECIAL MEMORIES
on this type multimeter:
I had the »ULTRON« Model
in my youth and bought
it because its CLEVER
INDUSTRIAL DESIGN!
Observe the DIFFERENCES!
1st I changed the
» OHMS ADJ « wiring,
because it was
in my opinion the
"WRONG DIRECTION"
- HA! -
The »EXACTA« has the
same "wrong" behaviour:
Must be changed too ...
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Have a Look at the Wire Diagram of the » ULTRON UM-201 E «
Have a Look at another "Family Member", the MONARCH » MT-202M «
My »ULTRON« ( recommend by KOSMOS ) was good as a "Hobby Instrument".
My 2nd MultiMeter was "THE-BEST-VALUE" in the '70s, the precise Class 1
» CHINAGLIA « ...
impressum:
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© C.HAMANN http://public.BHT-Berlin.de/hamann 12/17/16
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