VM-AI1i Assembly step by step

This page show how to correctly assembly the VM-AI1i kit (elaboration unit), step by step.

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The PCBs

Figure 1 shown the two PCBs that are the mechanical support of VM-AI1i. As you can see, are two-layer PCBs, with double side ground plane and star ground (elaboration unit). A state-of-art PCBs, obviously Made in Italy!

The kit parts

Figure 2 shown the parts that compose the VM-AI1i kit. All components are first class, only the best of the best: metal-film 1% resistor from Vishay, audio grade and low-esr electrolytic capacitors from Nichicon and Kemet, film capacitors from Wima and Panasonic, Op-Amp from Texas Instruments, MCU from Microchip, leds from Avago and Kingbrite, mechanical (header, sockets) parts from 3M etc etc…

Bill of Material

Below there is the bill of material of the elaboration unit of VM-AI1i kit.

Resistors

Name	Value	Notes/Color code
R1, R10 (2X)	50kΩ	1/4in Trimmer
R2, R11 (2X)	49.9 kΩ, ¼ W, ±1%	Yellow White White Red Brown
R3, R12, R19, R21 (4X)	6.65 kΩ, ¼ W, ±1%	Blue Blue Green Brown Brown
R4, R5, R6, R8, R13, R14, R15, R17 (8X)	20 kΩ, ¼ W, ±1%	Red Black Black Red Brown
R7, R16 (2X)	10 kΩ, ¼ W, ±1%	Brown Black Black Red Brown
R9, R18, R23 (3X)	100 kΩ, ¼ W, ±1%	Brown Black Black Orange Brown
R20, R22 (2X)	1 kΩ, ¼ W, ±1%	Brown Black Black Brown Brown
R24…R29 (6X)	2.2 kΩ, ¼ W, ±1%	Red Red Black Brown Brown

Capacitors

Name	Value	Notes
C1, C4 (2X)	1uF, 50V	Electrolytic, Audio Grade
C2, C5 (2X)	120pF	Ceramic
C3, C6 (2X)	1uF, 50V	Polyester film
C7 (1X)	470uF, 25V	Electrolytic
C8, C9, C11, C13, C15, C16, C19 (7X)	100nF, 63V	Polyester film
C10 (1X)	10uF, 25V	Electrolytic
C12, C14 (2X)	100uF, 25V	Low-ESR Electrolytic
C17, C18 (2X)	220nF, 63V	Polyester film

Discrete Semiconductors

Name	Value	Notes
D1…D8 (8X)	1N4148	Switching diode
D9 (1X)	SB140	Schottky barrel diode
T1…T6 (6X)	BC337	NPN g.p. transistor

Integrated semiconductors

Name	Value	Notes
IC1 (1X)	TC1044S	Charge pump
IC2 (1X)	TL072	Dual low-noise operational amplifier
IC3 (1X)	LM7805	5V Voltage regulator
IC4 (1X)	TL074	Quad low-noise operational amplifier
IC5 (1X)	–	VM-AI1i v3.5/2013 Preprogrammed MCU

Mechanical/spare parts

Name	Value	Notes
JP1E (1X)		8 Pin Male header
JP2E, JP3E (2X)		3 Pin Male header
JP4E (1X)		6 Pin Male header
S1, S2 (2X)		N.O. Tactile buttons
		2X 8Pin 2.54mm/0.1in IC socket
		1X 14Pin2.54mm/0.1in IC socket
		1X 20Pin 2.54mm/0.1in IC socket
JP1D (1X)*		8 Pin Female header
JP2D, JP3D (2X)		3 Pin Female header
JP4D (1X)		6 Pin Female header

* In italics there are the display units mechanical parts.

Ok, let’s go to start!

Step #1

Bend the resistors (ALL resistor; the picture show how done this step using a bending tool).

Step #2

Separates the diodes.

Step #3

Bend the diodes.

Step #4

Solder the eight 1N4148 (D₁…D₈) diodes. Notes the direction Anode-Cathode (the side with the black band painted).

Step #5

Solder the six 2.2k (R₂₄…R₂₉) resistors.

Step #6

Solder the two 49.9k (R₂, R₁₁) resistors.

Step #7

Solder the eight 20k (R₄…R₆, R₈, R₁₃…R₁₅, R₁₇) resistors.

Step #8

Solder the three 100k (R₉, R₁₈, R₂₃) resistors.

Step #9

Solder the four 6.65k (R₃, R₁₂, R₁₉, R₂₁) resistor.

Step #10

Solder the two 1k (R₂₀, R₂₂) resistor.

Step #11

Solder the two 10k (R₇, R₁₆) resistor.

Step #12

Solder the SB140A (D₉) Schottky diode.

Step #13

Solder the two 50k (R₁, R₁₀) trimmers, the two 120pF (C₂, C₅) ceramic capacitors and the seven 100nF (C₈, C₉, C₁₁, C₁₃, C₁₅, C₁₆, C₁₉) film capacitors.

Step #14

Solder the two 220nF (C₁₇, C₁₈) film capacitors and the four sockets (two 8P, one 14P and one 20P), looking carefully the references.

Step #15

Solder the two buttons (S₁, S₂).

Step #16

Using a nail, bend the pins of uA7805 regulator…

Step #17

…in this way!

Step #18

Solder the uA7805 (IC₃) voltage regulator.

Step #19

Look carefully this capacitors: there are two 1uF/50V capacitors and only one 10uF/50V.

Step #20

Solder the 10uF/50V (C₁₀) capacitor.

Step #21

Solder the two 100uF/25V (C₁₂, C₁₄) Low-esr capacitors and the two 1uF/50V (C₃, C₆) film capacitors.

Step #22

Solder the two 1uF/50V (C₁, C₄) audio grade capacitors.

Step #23

Solder the 470uF/25V (C₇) filter capacitor.

Step #24

Join the headers with the sockets.

Step #25

Finally, solder the headers. After, using a flux cleaner, we can remove the excess flux.

Step #26

Ok, now we can measure the voltages (I’ve used a 12Vdc power supply source). Point #1 – Cathode of D₉, expected value: 11.8V.

Step #27

Voltage measuring. Point #2 – out of IC₃, expected value: 5V.

Step #28

The linear ICs. There are one charge pump (IC₄, TC1044SCPA) voltage converter, one dual-low-noise (IC₁, TL072) operational amplifiers and one quad-low-noise (IC₂, TL074) operational amplifiers.

Step #29

Insert the charge pump IC (IC₄, TC1044SCPA) . Look carefully the reference (pin #1).

Step #30

Voltage measuring. Point #3 – pin #4 of IC₁, expected value: -11.8V.

Step #31

Voltage measuring. Point #4 – pin #11 of IC₂, expected value: -11.8V.

Step #32

Voltage measuring. Point #5 – pin #1 of IC₄, expected value: 5V.

Step #33

Voltage measuring. Point #6 – pin #8 of IC₁, expected value: 11.8V.

Step #34

Voltage measuring. Point #7 – pin #4 of IC₂, expected value: 11.8V.

Step #35

Ok, after correctly inserting the linear integrated circuits and the preprogrammed MCU, the heart of VM-AI1i, we are ready to the final test (I’ve used the old display).

Step #36

…and that’s it! Enjoy!