Assembly of the feeding
circuit on the front face |
Control not under tension |
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Created it, 06/10/19
Update it, 06/10/28
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3. - ASSEMBLY OF THE FOOD
Initially, you will assemble some components relating to the food on the printed circuit and fix this last on the digilab. In the second time, you will carry out a control not under tension of the circuit. Lastly, you will carry out the assembly of the transformer and the test under supply voltage.
Proceed to the various operations with much attention and care and conform you to the following instructions.
3. 1. - WIRING OF THE PRINTED CIRCUIT
While referring to you on figure 3, carry out the following operations :
a) Introduce the electrolytique capacitor C1 of 4700 µF - 25 V with the site envisaged on the printed circuit. Respect the polarity of this condenser. Weld then the two terminals of this one with the copper pastilles and cut the surplus part.
b) By respecting the polarity of the electrolytique capacitor with C3 tantalum of 4,7 µF - 10 V, weld it onto the printed circuit.
c) Weld onto the printed circuit the ceramic condenser C2 of 100 nF (or 0,1 µF).
d) Weld onto the printed circuit R1 resistance of 220 W - 1 / 4 W tolerance 5 % (red - red - chestnut - but).
The rectifying bridge comprises four terminals, like illustrated on figure 4.
Two are located by the usual symbol ~ and constitute the entry to which the alternating voltage taken on the secondary of the transformer is applied.
The two other marked terminals (+) and (-) are the exits connected at the boundaries of the condenser of C1 filtering. Sometimes, the rectifying bridge has a flat part of reference mark which indicates the respective position of the terminals (+) and (-).
e) Weld rectifying bridge DR1 standard B 40C 3700 / 2200 onto the printed circuit by respecting the polarity of its two output (+) and (-).
Now, you will cable regulator LM 340T5. It is equipped with three electrodes. Figure 5 represents the regulator seen of face and side.
Pin 1 located on the left is the entry to which is applied the not controlled tension. The central pin 2 is connected to the mass.
Pin 3 is the exit which provides the controlled power. The metal plate connected to pin 2 is pierced with a hole for fixing on a radiator. This last allows the dissipation of heat generated by the integrated circuit.
In this assembly, the radiator will be consisted the metal front face of the digilab.
For the moment, carry out a provisional mechanical assembly of the regulator by conforming you to the following instructions:
f) Prepare the integrated circuit like illustrated into the figure 6-a. Use the flat-nose pliers to fold the three electrodes with 90° side of the frontal face. The line of folding is located at approximately 3 mm of the case of the regulator.
g) Turn over the printed circuit and thread the pins of the integrated circuit on the side of the copper tracks in the holes envisaged. The clamp hole of the regulator must correspond to the hole carried out on the printed circuit as indicated in the figure 7-a. Do not carry out any welding for the moment.
h) Fix the regulator at the printed circuit by means of a threaded hexagonal spacer Æ 3 x 9 mm and two screws Æ 3 x 4 mm, as indicated in the figure 7-b.
Tighten the two screws at bottom ; thus, the metal plate of the integrated circuit will position correctly compared to the printed circuit.
i) Weld the three pins of the regulator onto the copper pastilles and cut the surplus part which arises on the not coppered face of the printed circuit.
To supplement the assembly on the printed circuit, it remains you to weld a connector and some wire of connection which will be useful for connection with the other components of the food.
j) Position the plug connector with 3 pins as indicated in figure 8 and weld the 3 pins onto the printed circuit.
k) Cut two pieces of 0,5 mm² of section and 30 cm length red flex-wire approximately. Strip the ends on 3 to 4 mm, then twist two wire between them. Introduce then wire of an end of the twist into the holes located beside the rectifying bridge (figure 8) and weld them onto the copper pastilles.
l) Cut two pieces of flex-wire of 0,5 mm² of section, one red, the other black, a length of approximately 10 cm, twist them together then strip the ends. Introduce an end of the red wire into the hole located by (+) and an end of the black wire in the hole located by (-), then weld them with the printed circuit.
m) Cut two pieces of flex-wire of 0,25 mm² of section, one red, the other black, a length of approximately 8 cm each one ; twist them between them and strip the ends. Introduce an end of the red wire into the hole located by letter A (anode) and an end of the black wire in that located by the letter K (cathode), then weld them with the printed circuit.
3. 2. - VISUAL MONITORING
Before undertaking the following phase of work, it is desirable that you make an attentive visual monitoring of the assembly carried out by ensuring you of the correct position of each component, in particular of the integrated circuit and the polarities of the electrolytique capacitors while referring to you on figures 7 and 8.
Also check that there are no tracks in short-circuit because of an excess of welding between two close pastilles.
3. 3. - ASSEMBLY OF
THE FEEDING CIRCUIT ON THE FRONT FACE
OF THE DIGILAB
You now will carry out the assembly of the various accessories on the metal front face.
The first operation consists in dismounting the front face on which the matrix is fixed at contacts.
a) Unscrew the four screws retaining the metal panel with the box. Withdraw the two cords of food on the left crossing the hole located in bottom.
b) Unscrew the two nuts on the red casing greenhouse-wire and withdraw the first insulating cylinder.
Then introduce this red casing into the hole located in bottom on the right as represented at the figure 9-a.
Then, thread the cylinder insulating which you previously withdrew on the threaded rod. Thread a disc and block with a nut. In the same way, thread an eyelet with thimble, a second disc whose hole is of 4,2 mm Then block the whole with a nut by respecting the orientation of the eyelet with thimble as indicated in the figure 9-b.
c) In the same way, fix the black casing greenhouse-wire above the symbol (-).
d) While observing figure 10, assemble the fuse holder in the hole located by the inscription “FUSES” and put the fuse of 250 inside mA.
e) Fix then the two-track switch in the hole located by the inscription OFF as indicated in figure 10. Regulate the position of the counter-nut first of all so that the threaded part of the switch comes out from approximately 4 mm. Then, correctly position the disc with the lock pin. Thread the star washer and tighten thoroughly the locknut.
f) Introduce a milled capscrew Æ 3 x 14 mm into the central hole of the matrix located near the higher edge of the panel of the front face and fix, without however tighten thoroughly, a threaded spacer Æ 3 while intercalating between this one and the panel two discs Æ 6 x Æ 3,2 mm as illustrated with the figure 11-a.
g) Withdraw the screw of Æ 3 x 4 mm fixed temporarily on the voltage regulator. Then fix without blocking the printed circuit of food on the front face as indicated in figure 11. The clamp hole of the regulator must be in correspondence with the lower central hole of the matrix. Two screws are necessary, one with milled head Æ 3 x 14 mm, the other of Æ 3 x 4 mm.
h) Block all four screw represented to the figure 11-b. Tighten in first and at bottom the milled capscrew which plates the regulator on the front face. Now, carry out the various connections.
i) First of all, you will proceed to the wiring of the LED. Draw aside the terminals of the LED slightly and cut to them to approximately 7 to 8 mm. Soudez the black wire referred K to the cathode of the LED and the red wire referred A to the anode of the LED. This is indicated to the figure 12-a. The cathode of the LED is located by a flat part.
j) Carry out the assembly of the LED now on the front face of the digilab as illustrated with the figure 12-b. First of all, introduce the sleeve carries-LED in the hole located beside the switch. Then thread the LED in the ring of blocking and finally thread the latter in the sleeve. Then insert the ring of blocking on the sleeve.
k) Weld the loose leads of the other red twist - black respectively onto the thimbles of the eyelets of the casings red (wire red) and black (black wire).
Now, you go carry out the wiring of the switch and the fuse holder. Proceed with much attention while following the instructions below :
l) Cut four pieces of flex-wire of 0,25 mm² of section, two greens and two blacks, approximately 24 cm length.
strip each end on approximately 5 mm
twist the stripped bits of each wire
galvanize each end.
m) Prepare four pieces of soupliso of Æ 2 mm and two pieces of Æ 3 mm each of approximately 1 cm while cutting them in the souplisos that you had in your possession.
n) Galvanize terminals 1, 2, 4 and 5 of the switch as well as the terminals of the fuse holder.
o) Take one of the pieces of black insulated wire prepared previously. Reduce to 2 mm the galvanized end and vertically weld it onto terminal 1 of the switch (figure 13-a). Prevent that tin runs at the base of the terminal.
p) In the same way, weld the second black wire on terminal 4 and one green wire on terminal 2.
Also weld the green wire remaining on terminal 2 of the fuse holder.
q) Cut a piece of green flex-wire of 0,25 mm² of section and approximately 5 cm.
Galvanize the two ends like previously, then weld one of them onto terminal 5 of the switch.
You ensure that there is no short-circuit on the 4 cabled terminals of the switch.
Introduce the four pieces of soupliso of Æ 2 mm out of four wire cabled on the switch and push them until the base of the welded terminals, thus covering the weldings carried out.
r) Introduce a piece of soupliso of Æ 3 mm on the green wire cabled on terminal 5 of the switch, then weld this same green wire onto terminal 1 of the fuse holder.
Cover then the welding while making slip to the piece of soupliso of Æ 3 Misters.
s) Put the second piece of soupliso on the green wire cabled on terminal 2 of the fuse holder.
Twist between them two green wire and two black wire (figure 13-b).
Figure 14 presents the face lower of the metal panel to you (front face) at this stage of the assembly of the food.
3. 4. - CONTROL NOT UNDER TENSION
Prepare the controller for the measurement of resistance and take the measurements indicated in the table of figure 15.
This table indicates the points of connections of the ohmmeter and the values to you which you must obtain.
| N° |
POINTS OF CONNECTIONS OF THE OHMMETER |
VALUES TO BE OBTAINED |
| 1 |
Between the two ends of the red twist of wire |
Higher than 40 kW (after a few seconds) |
| 2 |
Between the black casing and the red casing |
3 to 4 kW |
|
With the switch in position OFF |
||
| 3 |
Between the two ends of the black twist |
¥ |
| 4 |
Between the two ends of the green twist |
¥ |
| 5 |
Between the two ends of the black twist and an end then the other of the green twist |
¥ |
|
With the switch in position opposed to that of OFF |
||
| 6 |
Between the two ends of the black braid |
¥ |
| 7 |
Between the two ends of the green braid |
¥ |
| 8 |
Between the black wire connected on terminal 1 of the switch and the green wire connected on terminal 2 of the switch |
0 |
| 9 |
Between the black wire connected on terminal 4 of the switch and the green wire connected on terminal 2 of the fuse holder |
0 |
| 10 | Between each end of green wire and the black casing | ¥ |
You must imperatively find the values appearing in this table. In the contrary case, it is necessary for you to check wiring to discover the anomaly. Think of checking the fuse. When the whole of control is correct, you will be able to continue the assembly.
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