Building Ronja Nebulus

Overview

We are going to build a box with electronics. The box is made of metal and is closed with a lid. We will install mounting screws pointing outward from it and wires leading from it. Finally we'll solder electronic components inside.

Soldering the bottom

Solder one lid to the case so that the case has a bottom. Solder the lid everywhere along the length its edges. (Note: ignore the holes, I just don't have the right photo without holes.)

Contact flaps

Make contact flaps on the lid of the case using tin cutters. Adjust their angle using pliers so that every flap is springed against the case when the lid is closed.

Postscript / PDF / EPS / BIG png / DXF (qcad)

Mechanics

Drill out the case and assemble with 4 M4 bolts and 12 M4 nuts. The bolts are drawn for 130mm optical head. For 90mm they will be adequately shorter. Apply thermal coupling paste on both sides of the insulating pad and install BC139 with insulating pad from inner side of the case using M3x6 bolt, M3 (3.2mm) toothed spring washer and M3 nut. Tighten the M3 nut firmly.

Postscript / PDF / EPS / BIG png / SVG (Inkscape)

Transmitter LED

Put the HSDL-42?0 into the 5.3mm hole in front of transmitter case. Fix it down in straight position using thermal glue pistol.

Postscript / PDF / EPS / BIG png / SVG (Inkscape)

Preparing cables

Cut a 20cm piece of 1.5mm^2 insulated double-conductor cord. Cut a 20cm piece of shielded single-conductor. Strip all ends of these conductors and cover them with a solder.

Postscript / PDF / EPS / BIG png / SVG (Inkscape)

Stubs

Solder two 1-inch 4mm^2 pieces of (uninsulated) copper hard wire on one end of the two-conductor cord. Solder another two pieces on one end of the shielded cord.

Postscript / PDF / EPS / BIG png / SVG (Inkscape)

Cable leads

Put the cable grommetss in place into both holes. Put the bare ends through the grommets as seen in the picture. Solder particular ends to the box as seen in the picture. Seal the cables inside the grommet with sillicone sealant (you can also use thermal glue, it faster).

Note: the pictures are not from Nebulus, but from Metropolis transmitter, and have tiny difference in LED hole size.

Making the coil

Take the 8.5mm bit bit and wind a 10-turn coil on it from insulated copper wire of 0.5mm^2...1mm^2 crosssection.

Postscript / PDF / EPS / BIG png / SVG (Inkscape)

Fucking chips

Solder together the three 74AC04's in stack (like they are fucking), pin by pin, all pins.

Postscript / PDF / EPS / BIG png / SVG (Inkscape)

Key components

Place some key components according to the plan. Fix them by soldering on ground if they are connected to ground or by gluing down with thermal glue gun. Print out the schematic and retrace with a pencil every component and wire you solder in:

U1+2+3 (74AC04)
Q4 (BD139)
C11
Q1, Q2 (2N3904)
LED1 (HSDL42?0)

Pictures of the circuit

You can take up the notion how the components, especially blocking capacitors around the three chips, are going to be placed inside from these pictures.

The LED wires are excessively long in this picture. I don't have a better one. Try to make them short.

There are arrows in the schematic labeled as "P*", where "*" varies. Those are not real components but only virtual measuring points.

		PostScript	PostScript + Gzip	PDF
Color	Dark	nebulus_01.ps	nebulus_01.ps.gz	nebulus_01.pdf
	Light	nebulus_00.ps	nebulus_00.ps.gz	nebulus_00.pdf
	Small	nebulus_02.ps	nebulus_02.ps.gz	nebulus_02.pdf
B/W	Dark	nebulus_11.ps	nebulus_11.ps.gz	nebulus_11.pdf
	Light	nebulus_10.ps	nebulus_10.ps.gz	nebulus_10.pdf
	Small	nebulus_12.ps	nebulus_12.ps.gz	nebulus_12.pdf

nebulus.sch (gschem)

Component lists

Seznamy součástek

Place the components in this sequence:

C20, 21, 22, 23
C24, 25, 26, 27, 28, 29. 22n filtering capacitors. They must be soldered as close as possible to U1+2+3 and ground plane (case) and connected using short, thick (1mm^2) wires. They are critical too.
C12, 13, 14, 15. 100n filtering capacitors. They must be soldered as U1+2+3 and ground plane (case) and connected using short, thick (1mm^2) wires. They are critical too.
C1, C6, C9, C16, C17, C18, C30, C32, C35, R1, R5, R6, R8, R9
C2, C3, C5, C7, C8, C19, C33, C36, R3, R4, R7, R10, Q3
C4, C34, C37, L1, R16
D1, D2, R11, R17
C10, C31, Q5, R2
R18

Correctness check

Take the schematic and a multimeter and do a check. Check that the topology is OK (i. e. the wires lead where they should lead). Measure every resistor with a multimeter (sometimes it will show less if there is a current path around). Check every capacitor visually where the value is visible. Check every diode and transistor junction with diode measuring function of the multimeter. Scrawl out every part and wire you check on the schematic with a pencil.

Small schematic

Print out the small schematic (see above, postscript unders schematic) and shear out the 90x60mm schematic. Overwrite all part numbers that have been installed different than in schematic. Overwrite all resistor values that have been chaged during tuning. Write down amplification factors of both 2N3904 transistors. Glue the paper on the inner side of the lid.

Postscript / PDF / EPS / BIG png / SVG (Inkscape)

Labelling

Print out the Ronja Nebulus label. Fill in and glue on the outer side of the lid.

Washers and nuts

Save the 4 M4 washers and 4 M4 nuts for future mounting.