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PT.2: By MAURO GRASSI DSP Musicolour: putting it together In last month’s first part, we described the circuit operation of the DSP Musicolour. In this instalment, we guide you through the construction. The operation of the firmware and troubleshooting tips will be described next month. In this issue there are also notes and errata for the schematic published last month. B efore we start any construction, let’s make a couple of things perfectly clear about the complexity and skill levels needed to build the DSP Musicolour. (1) This project is not suitable for beginners. In fact, you should not attempt to construct this project without considerable experience, particularly with mains devices. (2) This project controls mains (230/240V or 110/120V) voltages. Mains voltage can be lethal. Hence it is especially important to double check and be certain that mains power is not applied whenever working with the PC boards. NEVER apply mains power to the main PC board unless it is fully enclosed in a plastic case with the case screws done up. Construction: Display Board The DSP Musicolour is built on two separate PC boards. The main board consists of the Triac output section at 230/240VAC mains potential and the low voltage section containing the op amps and the dsPIC30F4011 microcontroller. The two sections of the main board are isolated by optocouplers and the mains transformer. The vertical display 24  Silicon Chip board is all low voltage circuitry and its supply rail is +5V. We’ll begin the construction with the display board, which is coded 10107082 and measures 247mm x 76mm. Note: our prototype DSP Musicolour used single-side boards with many links, however kitset suppliers are likely to provide the boards in double-sided form with plated-through holes, in which case only a few links will be necessary. First, you should check the PC board for hairline cracks in the tracks and any visible shorts between tracks. Fix any defects. The component overlay is shown in Fig.1. The first components to go in are the resistors, 31 in total. As you install them, check the colour code of each resistor against the colour code table. Better still, check the values with a digital multimeter before soldering each one onto the PC board. The seven signal diodes can be soldered in next. It is vital that they are oriented correctly and you should refer to the component overlay and check carefully against it. The diode’s cathode (K) is indicated by a line at one end of the body. Next, solder in the four 16-pin IC sockets. Make sure these siliconchip.com.au The main and display boards assembled in the case, before the rear panel (and rear panel wiring) is fitted. This prototype photo has single-sided PC boards – production boards should be double sided to eliminate most links. However, if you etch your own PC board it will probably be as per the prototype and require links as shown above. are oriented correctly as per the component overlay. Although the sockets are optional, we do recommend them. They make replacing the ICs much easier, if needed. The sockets for the three Kingbright dot matrix LED modules can now be installed. Cut three 14-pin IC sockets in half with pliers to get six 7-pin sockets and solder them in as shown on the component overlay. The sockets are used to raise the dot matrix modules to make them sit close to the acrylic front panel. They also make replacing the modules much easier if they should ever fail. Once this is done, you can solder in the 22 BC327 transistors. These are all PNP types and should be pushed down so that they sit quite close the board in order to clear the front panel. However, be careful not to push them too close, as this may damage the leads. About 2mm proud of the board surface is ideal. Next, you can solder in the three 10kW potentiometers and the capacitors. The three 100nF monolithic types are placed near the IC sockets for the 74HC595 shift registers (IC3, IC4 & IC5). The two electrolytics are placed near VR3 and must be installed the right way around. Their negative terminals are indicated on their bodies and you should refer to the component overlay before you solder them to ensure they are correctly in place. The 26-pin IDC (insulation displacement connector) header (CON7) can be soldered in next and you should refer to the component overlay to get the correct orientasiliconchip.com.au tion. Note that there is a key-way on one side of the socket. Pin 1 of the header should be indicated by an arrow in the plastic socket. Finally, solder in the seven vertical tactile switches which have LEDs inside. There are three red and four blue switches. These switches have six leads arranged in two rows of three. The middle leads in each of the two rows are used to connect Warning! All the parts in the red shaded area on the Main Board component layout diagram (Fig .3) operate at mains potential (ie, 240VAC) and contact with any of these parts could be FATAL. These parts include the PC trac ks, the opto-couplers (OPTO1-4), the Triacs, the 100 mH inductors, the 680W resistors, the 100nF 250VAC capa citors, screw terminal blocks CON4-CON6, the transformer primary and the wiring to the mains input and output sock ets. DO NOT TOUCH any of these parts unless the power cord is unplugged from the mains supply. DO NOT CONNECT this device to the mains unless it is fully enclosed in the specified case. This project is not for the inexperi enced. Do not build it unless you know exactly wha t you are doing and are completely familiar with mains wiring practices and construction techniques. July 2008  25 100nF Q4 LED ARRAY 3 Q1 LED ARRAY 2 Q6 470Ω Q9 Q10 470Ω Q12 470Ω Q13 470Ω Q11 Q15 470Ω Q14 470Ω 470Ω 470Ω 470Ω 470Ω 100nF 100nF 470Ω IC1 74HC595 IC2 74HC595 1k S1 S2 S3 VR2 10k LIN YALPSID RUOLOCISUM 28070101 CS Q21 S6 1k 47 ∝F D7 470Ω D6 Q16 D5 S5 Q20 4148 470Ω S7 VR1 10k LIN 470Ω + 1k 1k 4148 D1 4148 4148 VR3 10k LIN 470Ω S4 Q19 1k 470Ω + 1 ∝F D4 1k Q17 D3 4148 470Ω D2 4148 1k 4148 8002/30 GM Q18 Q22 Links LK1, LK2 & LK3 need to be installed, depending on whether you will be powering the DSP Musicolour from 110-120VAC or 230240VAC. If you are in Australia, New Zealand and most parts of Europe, you will be using 230V-240V while 110V-120VAC is used in America and Japan, for example. For 230-240V operation, you should install link LK2 and leave out LK1 and LK3, under the transformer. For 110-120V operation, you should install links LK1 and LK3 and leave out LK2. LED ARRAY 1 Q8 Links for 230/240VAC or 110/120VAC operation TA12-11EWA Q7 470Ω Assembling the main board The main board is coded 10107081 and measures 221mm x 165mm. The component overlay is shown in Fig.3. Again, begin the construction by checking the copper pattern for defects such as track breaks or shorts. Fix any defects that may be apparent. 74HC595 TA12-11EWA 470Ω Attaching the front panel The final task is to attach the acrylic front panel. The four mounting holes are used to attach the front panel to the display board using four M3 Nylon screws (25mm). You will need to cut off 2mm from four 15mm tapped Nylon spacers to make them measure 13mm. This is the correct spacing between the display board and the front panel that fits with the grooves in the plastic case (Altronics H0482). Finally cut the remaining four 15mm tapped Nylon spacers to 4mm and use these as the nuts to attach the front panel. Then simply attach the three knobs to the potentiometers and that should complete the assembly of the display board. IC3 TA12-11EWA 470Ω Q5 This completes the construction of the display board. The last thing to do is to make up the ribbon (IDC) cable used to connect the display board to the main board. To do this, you will need a vise. Cut 15cm of 26-way ribbon cable and slide it into position into each 26-pin IDC line socket. Conductor 1 of the ribbon cable is indicated by a different colour – usually the ribbon cable is grey and conductor 1 is red. This should match pin 1 of the line sockets, indicated by arrows. You should slide the ribbon cable into place and then use a vise to attach the cable. Finally attach the clip to only one line socket leaving the other one without one. The line socket for the display must not have a clip attached, in order to clear the front panel. Once you are satisfied that everything is in order, you can insert the ICs into their sockets, making sure that they are correctly aligned. Then insert the three Kingbright dot matrix LED modules into their sockets. Make sure that pin 1 of the Kingbright modules is facing down as indicated on the component overlay. The modules should show a digit ‘1’ indicating pin 1. 470Ω Q3 Ribbon cable assembly IC4 ULN2003 Q2 the internal LED and you should make sure that they are oriented correctly, otherwise the LED will not light up. For each switch, the cathode is indicated by a dab of coloured paint on the lead with the colour matching the colour of the LED inside the switch. The switch should be soldered with the cathode facing up in the normal orientation. Switches S1-S3 should be red while switches S4-S7 should be blue. Note that this differs from the prototype photos shown here and in last month’s article. 1k 1k 470Ω Fig.1: component overlay for the display PC board with a matching photo opposite. Start assembly with the display PC board as detailed in the text. The top layer of the PC board is shown in green – if you etch your own (single-sided) board, the green tracks will need to be replaced with wire links, with holes drilled in appropriate places. 26  Silicon Chip 25 26 1 2 CON7 (CONNECTS TO CON1 ON MAIN BOARD) siliconchip.com.au You must never install all three links LK1, LK2 and LK3 at the same time. This will short the mains supply and blow the fuse and possibly trip the circuit breakers in your home! Make sure you have installed LK2 (for 230-240V) or LK1 and LK3 (for 110-120V) correctly before proceeding. There is an optional link near the two 270W 1W resistors and CON2. This is shown as LK4 on the main circuit (Fig.2) in last month’s issue and this will normally be omitted. Its operation will be explained in next month’s article. Next, you can move on to installing the resistors. Again, check each value against the component overlay diagram of Fig.3 , the colour code table and with your digital multimeter. There are seven diodes on the board and it is vital that they are oriented correctly. Diodes D11-D14 are 1N4004 while D8-D10 are 1N4148. Notice that diodes D11-D14 (the bridge rectifier) are not all oriented the same way (their orientation alternates). Once the diodes are in, you can solder in the two IC sockets; the 40-pin socket for IC1and the 16-pin socket for the LM324 quad op amp (IC2). Make sure these are oriented correctly as per the component overlay. Next, solder in the four optocouplers (MOC3021). These are 6-pin devices and it is vital that they be oriented correctly, with their pin 1 on the low voltage side of the board. The capacitors go in next. The MKT and monolithic capacitors are not polarised but the electrolytic capacitors are and you should refer to the component overlay to install them correctly. The four 100nF X2-type 250VAC capacitors on the mains side of the board should be soldered in so they are sitting flush, ie, without any of their leads being exposed. Next, to install the LM317T regulator REG1, bend the leads by 90° before threading them through the holes on the board. Then fasten the tabs to the TO-220 mini heatsink and to the main board using one M3 10mm screw and one M3 nut. Do this before soldering the leads, as the stress of tightening the tab could cause cracks in the solder joints if the regulator is soldered in first. The 3mm red LED (LED8) can be installed next. This must be oriented correctly with its flat side as shown on the(HEATSINK) component overlay. LOCK The two 2-pin jumpers labelled M3 LK5 and LK6 on the component SCREW WASHER 10mm terminal strip and soldered overlay can be made from the 28-pin header LONG in. They will accept optional jumper shunts. You should also take two single pins from the 28-pin header terM3 NUT minal strip and solder these in for the two test points TP0 and TP1, near regulator REG1. The test pointsBTA41-600B will be used to measure the input BTA41-600B TRIAC and output of the regulator, as will be TRIAC explained below. After that you can install the electret microphone insert, again making sure that it is oriented correctly. Next, install the 26-way IDC header, as shown on the component PC BOARD (HEATSINK) M3 SCREW 10mm LONG BTA41-600B TRIAC HEATSINK LOCK WASHER M3 NUT BTA41-600B TRIAC BTA41-600B TRIAC M3 SCREW 10mm LONG LOCK WASHER M3 NUT BTA41-600B TRIAC PC BOARD HEATSINK Fig.2: elevation (left) and plan (right) views of the way the Triacs are mounted to the double-sided heatsinks (two Triacs to each heatsink). Use an M3 metal screw (10mm) and an M3 nut. siliconchip.com.au BTA41-600B TRIAC M3 SCREW 10mm LOCK WASHER M3 NUT July 2008  27 OPTIONAL LINK D10 TNORF 1 8 0 7 0 1 0 1 CS LK2 240V JP1 LK1 120V + + CABLE TIES L4 100 µH TRIAC1 TRIAC3 TRIAC2 TRIAC4 100nF 100nF 250VAC 250VAC X2 X2 RE G NAD E GATL OV S NIA M CON4 CABLE TIES 100nF 250VAC X2 L1 100 µH 100nF 250VAC X2 L2 100 µH CON6 N MAINS 110V-240V N A A V 0 5 2-V 0 2 1 S NIA M CON5 K CA B BACK Fig.3: component overlay for the main board, which includes all the mainspotential circuitry (apart from the input/output IEC sockets). The top (component) side of the PC board is shown with green tracks; the bottom side in the usual copper colour. The dotted area above shows the section of the PC board which has components and tracks at mains potential. Never operate the DSP Musicolour unless it is inside its case with the lid screwed on. siliconchip.com.au WARNING: All parts in this section operate at 230/240V. WARNING! DO NOT FIT ALL THREE LINKS AT THE SAME TIME 680Ω 680Ω 680Ω 680Ω JP3 LK3 120V JP2 PRIMARY PRIMARY L3 100 µH 8 0 0 2/ 4 0 G M RU OL O CISU M OPTO1 240V: FIT LK2 ONLY 120V: FIT LK1 & LK3 ONLY OPTO 1–4: MOC3021 TRANSFORMER T1 30VA 7.5V + MIC 220Ω OPTO2 REG1 LM317T 100Ω TPI TP0 100Ω 100Ω 100nF 4.7k 220Ω 220Ω 220Ω OPTO3 FRONT + 470 µF D11 D12 D13 D14 1 µF D9 47 µF SECONDARY SECONDARY L O SI E NIL N OITALINE ISOLATION OPTO4 CON1 470Ω 4700 µF 16V 4148 5.6nF 10k 10k 47 µF 100Ω 1 2 10k 100k 100nF D8 LED8 100nF 270 Ω 1W 1k 4148 dsPIC 30F4011 LK5 LK6 9 10 + 1k CON2 270 Ω 1W 33k 3.3k 68nF 28  Silicon Chip + IC2 LM324 68nF At this stage it is prudent to go back over your work and make sure everything looks in order by comparing your populated board with the component overlay. If you are absolutely satisfied that you have installed or omitted LK1, LK2 and LK3 as per the instructions (depending on the mains voltage in your area), you can solder in the mains transformer. This should only fit one way and its primary and secondary sides should be 10k 33k 68nF Final main board construction IC1 1k 68nF Once that is done you are ready to solder in the four Triacs. It is most important that these be insulated tab types, which is why BTA41-600B are specified. You should use a multimeter and measure the resistance from pin 2 (the middle lead) of each of the four Triacs to their metal tabs. This should indicate a very high resistance or open circuit. On the other hand, if it indicates a low resistance or short circuit you probably do not have the correct Triac and you should not proceed. Once you have verified that the Triacs have insulated tabs, attach two to each double-sided heatsink using an M3 10mm screw and M3 nut as shown in Fig.2. Notice that the tabs of the Triacs are in direct contact with the heatsink. It is then a matter of sliding the heatsink with the two attached Triacs onto the PC board. The heatsink has two mounting pins to locate them on the PC board. You can then solder the two Triacs in place. Repeat this for the other pair of Triacs. The construction of the main board is now complete as regards to soldering in components. The only component missing is the potted transformer. 1k 4148 CON3 Installing the Triacs 270 Ω 1W overlay. This has a keyway on its side which should face the microcontroller. CON2 consists of a 2-way and a 3-way mini terminal block slotted into each other to make a 5-way terminal block. Two 2-way terminal blocks CON4 and CON5 and the 3-way terminal block CON6 should be soldered in next. Their screw terminal inputs should be facing the BACK edge of the main board. You can also solder in the four 100mH chokes (these must be rated at 5A) which sit vertically on the main board. As these are wound with enamelled copper wire, you should ensure that the terminals have been properly stripped and tinned before you attempt to solder them in place. clearly marked. The secondary side should point towards the low voltage side of the circuit while its primary side should point towards the two heatsinks holding the four Triacs. You should attach the transformer to the main board using an M4 screw before soldering the leads. The screw will need to be threaded from the copper side (bottom side) of the board and holds the heavy transformer in place (the screw hole is the one in the middle of the transformer just to the left of LK3 on the component overlay). Now solder the transformer in place. Installation instructions >1mm ENAMELLED COPPER WIRE LINKS (FOR S/S PC BOARD ONLY) This prototype photograph matches the overlay at left, with the exception of most of the wire links which have now been replaced by tracks on a double sided board. Again, if you etch your own single-sided board, the links will be required. In the case of the two heavy enamelled copper wire links in the mains section of the board (arrowed above), make sure you use similar heavy enamelled copper wire – for safety’s sake! siliconchip.com.au If you have followed these instructions, you should now have an assembled display board with its four ICs in their sockets and a 26-way ribbon cable plugged into it with its other end as yet unconnected. You should also have an assembled main board with all components soldered and with IC1 and IC2 out of their sockets for now. Notice that the case is not symmetrical and so the main board has indicators “FRONT” and “BACK” on the component overlay, indicating the back and front panels. Attach the main board to the case using the four mounting holes and M3 10mm screws. The two lower screws attach directly to the case (Altronics H0482) while the top two screws should be attached using two 3mm x 15mm Nylon spacers, cut to 8mm long and with longer M3 Nylon 25mm screws. The spacers are used to provide support to the main board when it is in the case. You will need to drill two 3mm holes in the bottom of the plastic case to thread these through as shown in Fig.7. You can then attach them to the PC board using M3 nuts (also shown in Fig.7). Once the main board has been attached to the case, continue by installing the appropriate fuse inside the male IEC socket – 10A (for 230-240V operation) or 15A (for 110-120V operation). You will now need to make up some connections for the back panel, using the individual cables from the 1m length of three-core mains flex cable, spade lugs and a crimping tool. (The three-core mains cable is used to ensure sufficient voltage rating for these mains-carrying connectors). First remove the outer insulation from the three-core mains flex and use the brown, blue and green/yellow wires, following Fig.4, which details the lengths of the wires you need to make. These are labelled W1 to W9 in Fig.4 and these numbers will be referred to below. July 2008  29 The rear panel of the DSP Musicolour sports the IEC power input socket with integral fuse and mains switch (far right), the four IEC controlled output sockets (centre), 6.5mm audio input socket and stereo audio (speaker level) input sockets (far left). If the speaker level input sockets are used, they’re designed to go in parallel with existing speakers. 50mm All these crimps need to be done carefully to ensure the connections are tight between the spade lugs and the wire. Don’t be tempted to use an automotive-type crimper – they’re not strong enough to produce a quality crimp and your wires could come out of the spade lugs. You need a good quality ratchet-type crimper and good quality spade lugs. W1: 40mm W2: 80mm 80mm 80mm 80mm Back panel installation and wiring 90mm MATES WITH 'N' TERMINAL OF CON6 W3: (IECF4) (IECF3) (IECF2) (IECF1) MATES WITH 'A' TERMINAL OF CON6 (IECM1) 90mm W4: (IECM1) W5: 80mm TO SPADE CONNECTOR UNDER EARTH SCREW ON BACK PANEL 80mm (IECM1) 80mm (IECF1) 80mm (IECF2) 80mm (IECF3) 120mm (IECF4) MATES WITH TERMINAL 5 OF CON2 120mm W6: OC1 (CON5) (IECF1) 120mm W7: OC2 (CON5) (IECF2) 150mm W8: OC3 (CON4) (IECF3) 200mm W9: (IECF4) OC4 (CON4) Fig.4: you will need to make up several crimped connector cables for the DSP Musicolour. This diagram shows the various types, colours and lengths. 30  Silicon Chip The back panel is made of steel and kits should be supplied with all holes punched and drilled. Snap in the male IEC socket (with the fuse installed as explained previously) and the four female IEC sockets as well as the optional microphone jack and audio speaker terminal block. The audio speaker terminal block is attached using two Nylon M3 12mm screws with two 3mm x 6.3mm nylon spacers used as nuts. Next, install the “earth” spade lug on the back panel using an M3 x 10mm screw, shakeproof washer and two nuts (see Fig.5). These will be used to earth the back panel later on. Check with a DMM that the screw is electrically connected to the back panel (ie, 0W or very close). You may have to scrape some paint away under the nuts to ensure intimate contact. Install the back panel in the case and use the display board with its attached plastic front panel as the front panel (but without yet connecting the display board to the main board using the 26-way ribbon cable). Install W1-W9 as shown in the wiring diagram for the back panel (see Fig.6). The insulated spade lugs are colour coded so that the brown should indicate live (Active) while blue indicates the Neutral mains connection. A green/yellow cable is used for the Earth connection. Follow the wiring diagram carefully to complete the wiring of the back panel. You should be left with seven loose wires from W1-W9. One green and yellow end of W5 connects to pin 5 of CON2 as explained below in the section on Earthing. The other 6 loose ends of W3-W9 connect to CON4, CON5 and CON6 terminal blocks as shown in the wiring diagram Fig.6. Make all these connections, paying particular attention to the earthing instructions below. Also, use the holes on the main board for attaching these wires solidly to the main board using cable ties. Also use cable ties around each of the three wires connecting to each female IEC socket. This is particularly important to hold the wires in place, especially since two of the female IEC sockets sit above the low voltage part of the main board. Should the live connection to one of these come off, the cable ties should ensure that they do not fall onto the siliconchip.com.au DSP Musicolour Parts List Main Board and hardware 1 PC board, coded 10107081, 221mm x 165mm 1 Case (Altronics H0482) with steel panel punched for IEC sockets 1 transparent red acrylic front panel, 254 x 75 x 3mm with silk-screen labelling and drilled to suit 1 30VA 120V-240V 7.5+7.5V Potted Toroidal transformer (Altronics M4615) 1 Chassis Male IEC socket with switch and fuse (Jaycar PP4003) 1 IEC female power lead 240VAC (Jaycar PS4106) 4 IEC male to 3-pin (GPO) socket (Jaycar PS4100) (optional) 4 Chassis Female IEC sockets (Jaycar PS4002, Altronics P8327) 1 3AG 10A fast blow fuse (Jaycar SF2204) 1 26-way IDC header 1 10-way right-angled IDC header (optional) 1 0.15m x IDC ribbon cable 16-way (Jaycar WM4502) (optional) 2 IDC line sockets 10-way (Jaycar PS0984) (optional) 3 2-way Mini PCB Terminal Block –5mm spacing (Jaycar HM3173, Altronics P2032A) 2 3-way Mini PCB Terminal Block – 5mm spacing (Jaycar HM3172, Altronics P2033A) 7 6.4mm blue insulated spade lugs (Jaycar PT4625) 7 6.8mm red insulated spade lugs (Jaycar PT4525) 5 6.8mm yellow spade lugs (Jaycar PT4707) 1 1m 3-core mains flex 10A (Jaycar WB1562) Wire for connecting audio socket 1 6.5mm audio mono chassis socket (Jaycar PS0162) 1 4-way audio speaker terminal block (Jaycar PT3002) 1 40-pin IC socket 1 16-pin IC socket 6 M3 screws 10mm long 1 M4 screw 10mm long 7 M3 nuts 2 Nylon M3 screws 12mm long (Jaycar HP0140) 2 Nylon M3 screws 25mm long (Jaycar HP0142) 4 Tapped Nylon spacers 3mm x 6.3mm (Jaycar HP0920) 2 Heavy Duty TOP-3 (ML97 type) heatsinks (Jaycar HH8526) 1 TO220 Mini (6073B type) heatsink (Jaycar HH8502) 2 Jumper shunts (Jaycar HM3240) 1 28-pin header terminal strips (Jaycar HM3211) 1 1m Tinned copper wire (Jaycar WW4032) 1 0.15m Enamel copper wire (1mm thick) (Jaycar WW4022) 1 electret microphone insert (Jaycar AM4011) 4 100uH 5A toroid suppression chokes (Jaycar LF1270) (L1-L4) 3 push-on 18T spline knobs to suit (Jaycar HK7730/31/32; Altronics H6510) 1 dsPIC30F4011 microcontroller IC (IC1), programmed with 1010708A.HEX 1 LM324 quad op amp (IC2) 4 BTA41-600B insulated tab Triacs 4 MOC3021 optocouplers 3 1N4148 diodes (D8-D10) 4 1N4004 diodes (D11-D14) 1 3mm red LED (LED8) Semiconductors 1 LM317T 3-pin adjustable voltage regulator (REG1) Resistors (0.25W, 1%) 22 470W 9 1kW siliconchip.com.au siliconchip.com.au Capacitors 1 4700mF 16V electrolytic 1 470mF 16V electrolytic 2 47mF 16V electrolytic 1 1mF 16V electrolytic 4 100nF 250VAC X2 style 15mm pitch metallised polypropylene (Jaycar RG5236) 3 100nF monolithic 4 68nF MKT 1 5.6nF MKT Resistors (0.25W, 1%, unless specified) 4 100W 4 220W 3 270W 1W 1 470W 4 680W 4 1kW 1 3.3kW 1 4.7kW 4 10kW 2 33kW 1 100kW Display Board 1 PC board, coded 10107082, 247 mm x 76 mm 3 Kingbright TA12-11EWA red 5x7 dot matrix LED modules (Tenrod TA12-11EWA) 3 9mm 18T Spline Shaft Single Rotary Pots 10kW Linear (Altronics R1946) 3 SPST Vertical PC mount tactile switch with LED (red) (Jaycar SP0612, Altronics SS1174) 4 SPST Vertical PC mount tactile switch with LED (blue) (Jaycar SP0614, Altronics SS1177) 1 26-way IDC header 4 16-pin IC socket 3 14-pin IC socket (cut in half) 4 Nylon screws M3 25mm (Jaycar HP0142) 8 tapped Nylon spacers 3mm x 15mm (Jaycar HP0926) 1 0.15m x IDC ribbon cable 26-way (Jaycar WM4504) 2 IDC line sockets 26-way (Jaycar PS0987) 1 2m tinned copper (Jaycar WW4032) Semiconductors 3 74HC595 shift registers (IC3-IC5) 1 ULN2003 line driver (IC6) 7 1N4148 diodes (D1-D7) 22 BC327 PNP transistors (Q1-Q22) Capacitors 1 47mF 16V electrolytic 1 1mF 16V electrolytic 3 100nF monolithic July 2008  31 K CA B (W1) RE G NAD (W5) (W6) E GATL OV S NIA M IECM1 (W3) CABLE TIES CABLE TIES (W4) IECF1 (W7) (W8) IECF2 + (W9) IECF3 + + 1 2 + IECF4 9 10 CON3 Preliminary power supply check 1 SIG GND (W5) 4 (W3) 3 R IN MIC IN L IN MIC IN CON2 2 5 RIGHT LEFT STEREO SPEAKER INPUT Once you have done that it is time to check the power supply rails before final assembly. To do this solder two wires to the two test-point stakes (TP0 and TP1) near REG1 and use pin 1 of CON2 as the GND reference. The wires should be long enough to leave the case and be accessed from outside the case. You can thread them through the hole used to mount the microphone jack on the back panel. Now close the case – attach the top half and screw in the two screws to seal it. (W2) (W3) CRIMPED QUICK Connect the CONNECTOR TO SPADE LUG green/yellow earth wire (W5) M3 X 10mm TO IEC as shown in the SCREW AND MAINS TWO NUTS wiring diagram INPUT SOCKET in Fig.6 so that the earth of the male IEC socket M3 STAR WASHER connects to the earths of all the Fig.5: the green/yellow female IEC sockets earth wire must be and the crimped securely connected to connector which the back panel via a is fastened to the crimped spade connearthing screw on ector and an M3 screw the back panel, with two nuts and a star washer. as shown at right (Fig.5). The remaining end of W5 should connect to pin 5 of CON2 (the 5-way terminal block) as shown in Fig.6. Do not proceed unless you are satisfied that W5 connects all these points to the male IEC socket’s earth terminal (the middle terminal). Again, you should use a multimeter or continuity tester to make sure that all these points (including chassis earth) are electrically connected (0W or very close). V 0 5 2-V 0 2 1 S NIA M EARTH (MAIN PC BOARD) CON4 OC3 OC4 MUSICOLOUR BACK PANEL CON5 Earthing OC2 OC1 low voltage section of the main board. Once you have attached the cable ties as shown in Fig.6 and the photographs you should proceed to the earthing section below. A mF Code IEC Code EIA Code 0.1mF 100n 104 0.068mF 68n 683 0.0056mF 5n6 562 CON6 Value 100nF 68nF 5.6nF N Capacitor Codes Fig.6: here’s the other side of the back panel, showing the wiring between the IEC mains input socket/fuse/switch (top in this diagram), the four IEC female output sockets (IECF1-4) and the PC board. Note carefully the position of the earth wire. Not shown here are the cable ties around all the cables coming from the IEC sockets (male and female). These are important safety items and should not be overlooked (see photo above right). 32  Silicon Chip siliconchip.com.au Looking from front to rear, the mains wiring can clearly be seen. All wiring here is mains-rated – the easiest way to ensure this is to use lengths of cable stripped from a scrap of mains-rated flexible lead. Don’t forget the cable ties: they’re just in case! You should only proceed if the case is closed, the back and front panels have been installed, the back panel has been wired correctly as shown in Fig.6 and the back panel has been properly earthed as explained above. Notice that the display board is not yet connected to the main board using the 26-way ribbon cable and that IC1 and IC2 on the main board are out of their sockets still. Also the audio terminal block and the microphone jack on the back panel are not yet connected. You can then apply power using an IEC power cable and flicking the switch on the male IEC socket to the ON position. You should measure the voltages at TP0 and TP1 relative to the GND wire using a multimeter. Normal levels should give around +10V DC on TP1 and +5V DC on TP0. If the level on TP1 is not close to +10V you should disconnect power immediately and recheck your work. If the voltage at TP0 is close to +5V it indicates that you are on the right track. If the voltage at TP0 is much different from +5V (note that anything from +4.8 to +5.2V is actually OK) then there is something wrong and you should recheck your work. Check the diodes D11-D14 are oriented correctly. Check that REG1 is correct and the resistors associated with REG1 are indeed 100W. Check that the large 4700mF electrolytic is correctly installed and that all the other electrolytics are correctly oriented according to the component overlay. Final Assembly If (and only if) the voltages at TP0 and TP1 are OK, then proceed. First switch off mains power and disconnect the mains cord. Once you are absolutely certain there is no mains power being supplied, open the case. Unsolder the two wires attached to TP0 and TP1 and also remove the GND connection at pin 1 of CON2. These are no longer needed. Install IC1 and IC2 on the main board IC sockets. Make sure they are oriented correctly. IC1 should be programmed with the latest version of the firmware. If you are building the DSP Musicolour from a kit, IC1 will be pre-programmed. If you are not, CON3, the optional10-way IDC header can be used to program IC1 using an external connection. More on this next month. Now connect the audio speaker terminal block by soldering Resistor Colour Codes o o o o o o o o o o o siliconchip.com.au No. 1 2 4 1 1 13 4 23 3 4 4 Value 100kW 33kW 10kW 4.7kW 3.3kW 1kW 680W 470W 270W (1W) 220W 100W 4-Band Code (1%) brown black yellow brown yellow yellow orange brown brown black orange brown yellow violet red brown yellow yellow red brown brown black red brown blue grey brown brown yellow violet brown brown red violet brown brown red red brown brown brown black brown brown 5-Band Code (1%) brown black black orange brown yellow yellow black red brown brown black black red brown yellow violet black brown brown yellow yellow black brown brown brown black black brown brown blue grey black black brown yellow violet black black brown red violet black black brown red red black black brown brown black black black brown July 2008  33 four wires onto the audio speaker terminals and connecting them to the terminal block CON2. Also solder wires to the microphone jack and connect these to CON2. Fig.6 shows this connection (among others). Connect the 26-way ribbon cable from the display board to the main board (CON1 on the main board). The photo overleaf shows the completed assembly (showing an early but similar prototype) just before closing the case. Close the case of the lid and screw it shut. Your DSP Musicolour is now fully assembled. In next month’s article we will explain the user menus and the operating instructions for the DSP Musicolour as well as calibration instructions. Stay tuned. SC 77.5mm 75mm 94mm (FRONT) (REAR) LOWER HALF OF CASE (VIEWED FROM BELOW) 78.5mm (REAR SMALL SELF-TAPPERS PANEL) SCREWING INTO MOULDED STANDOFFS M3 NYLON SPACERS CUT TO 8mm LONG M3 NUTS (METAL) (FRONT PANEL) MAIN PC BOARD (BOTTOM OF CASE) 25mm M3 NYLON SCREWS Fig.7: this scaled drawing shows how the main board is secured in the case (note the use of Nylon spacers and screws for safety). DSP Musicolour Notes and Errata In the Main Board schematic on pages 34-35 of the May 2008 issue, there are a number of minor errors. The labels P6C and P6D on pins 26 and 25 of IC1 should read PGC and PGD. The labels TRIAC2 and TRIAC3 should be swapped and pin 18 (OC2)‑ of IC1 actually connects to OPTO3 while pin 22 (OC3) connects to pin 1 of OPTO2. In the Display Board schematic published on page 37, there is an extra 470W resistor shown immediately to the right of pin 7 (Q7) of IC4. This resistor is not required – the component overlays and parts list in this issue reflect this. 34  Silicon Chip siliconchip.com.au