Elenco Electronics M-1250K, Assembly And Instruction Manual

Page 1: ...lenco Electronics Inc All rights reserved Revised 2007 REV H 753070 No part of this book shall be reproduced by any means electronic photocopying or otherwise without written permission from the publi...

Page 2: ...9 34k 1 1 4W orange yellow black red brown 153430 1 R5 40k 1 1 4W yellow black black red brown 154030 1 R23 44k 1 1 4W yellow yellow black red brown 154430 1 R17 83 3k 1 1 4W gray orange orange red br...

Page 3: ...Wire 27AWG Bare 65mm 2 55 or two 25 4mm 1 wires 83J400 1 Lead Free Solder Tube 9LF99 1 Test Lead Set 9TL11 Specifications Measurement Ranges Accuracy Remarks DC Voltage DCV All ranges 3 FS Input impe...

Page 4: ...er smoothly indicating a good solder joint Use only rosin core solder DO NOT USE ACID CORE SOLDER Do not blob the solder over the lead because this can result in a cold solder joint 3 CONSTRUCTION 1 S...

Page 5: ...een orange brown R25 18k 1 1 4W Resistor brown gray black red brown R14 6 75M 1 1 2W Resistor blue violet green yellow brown R15 1 8M 1 1 2W Resistor brown gray black yellow brown R16 360k 1 1 4W Resi...

Page 6: ...rown R4 150k 1 1 4W Resistor brown green black orange brown R5 40k 1 1 4W Resistor yellow black black red brown R11 10 1 1 4W Resistor brown black black gold brown R9 97 1 1 2W Resistor black white vi...

Page 7: ...igure C F1 Fuse Clips Fuse 0 5A see Figure J R10 04 Shunt Wire see Figure G Mount the 10k potentiometer to the foil side of the PC board in the location shown Solder and cut off the excess leads Use t...

Page 8: ...Solder the white buzzer wire to point BU on the PC board Solder the green buzzer wire to point BK on the PC board Tin both ends of the 3 5 red wire and solder to point 3V on the PC board Tin both end...

Page 9: ...OVEMENT WIRES TO PC BOARD Tin the ends of the meter wires Solder the red meter wire to M and the black wire to M on the foil side of the PC board see Figure N 8 M M M M Buzzer Assembly Red Wire Figure...

Page 10: ...clip as shown in Figure O Solder the red and white wires from the PC board locations 3V and 3V to the single battery contacts see Figure P Solder the red and yellow wires from the PC board locations...

Page 11: ...reading of 0 4V 40 on 50 scale on the M 1250 meter If a DC power supply or an accurate voltmeter is not available then use a fresh 1 5V battery and adjust R6 to read 1 55V on the 2 5V scale 155 on 25...

Page 12: ...VER AND 0 ADJ KNOB Install the bottom case and mount into place with an M4 x 10 screw as shown in Figure Q Place the 0 ADJ knob onto the front of the unit on the upper right of the panel Figure Q M4 x...

Page 13: ...age reading 1 Check for open fuse Refer to Figure 3 for a better understanding 2 Check diodes D1 D2 for opens and shorts of how the meter works 3 Check resistors R8 R14 R17 for correct values and good...

Page 14: ...the Dial Scale Reading Exercise included with this kit Before starting tests set the meter needle to zero The zero adjust screw is located on the meter face next to the base of the needle With no tes...

Page 15: ...t The hFE of a transistor is read using the six small input sockets To measure the hFE beta of an NPN transistor proceed as follows 1 If you removed the 1 5 volt battery from the multimeter replace it...

Page 16: ...ified diagram of the DC voltage measuring circuit Here resistors are switched in series with the meter to provide the desired ranges Figure 4 Buzzer Test 1 Set the range switch to the BUZZ position 2...

Page 17: ...t On the 250VAC range the input impedance is therefore 2M Figure 5 Resistance Measurement Figure 7 shows a simplified diagram of the resistance measuring circuit Here a known 1 resistor in parallel wi...

Page 18: ...transistor may be read on the hFE scale Figure 8 17 Battery Test Figure 9 shows a simplified diagram of the battery measuring circuit The battery voltage is measured under a 0 25A load DC NULL Test Fi...

Page 19: ...SCHEMATIC DIAGRAM M 1250K 18 Pin out 2SC1815 2SA1015 E C B...

Page 20: ...Elenco Electronics Inc 150 Carpenter Avenue Wheeling IL 60090 847 541 3800 Web site www elenco com e mail elenco elenco com...