ASSEMBLY NOTES FOR DSP-10 Rev B and C by Bob Larkin, W7PUA Rev 0, 27 Nov 1998 Rev 2, Aug 1999 Rev 3, 24 Aug 1999 Rev 4, 20 Sept 1999 Rev 4.1 1 Oct 1999 Rev 4.2 21 Oct 1999 Rev 4.3 27 Oct 1999 Rev 4.4 10 Nov 1999 Rev 4.5 4 Dec 1999 Rev 4.6 12 June 2000 NOTE: Revs 4.x are addendums to Rev 4, placed at the bottom of these notes. These notes are, hopefully, an assistance in the assembly of the PC Board for the DSP10 project, and the box enclosures. This is not a "Heathkit!" These are not step-by-step instructions and you will need to lay the whole project out before you, and think about what is involved and how to do it. Use these notes as an aid once you have the big picture in mind. The order of these notes is clearly not from beginning to end. Read through the notes completely. 1 - The main pc board uses mostly surface mount parts. This can be the subject of some worry at first, but most people find that the assembly is easier than using through-hole parts, once the techniques are learned. The following tools are a must: * A quality soldering iron with a 1/16 inch tip * Stainless steel tweezers with a bend near the tip * Solder flux in either a squeeze bottle or felt tip pen * 1/32 inch flux core 60% tin (Sn) solder * Cleaning solvent for the flux being used * Reading glasses or magnifiers, if they seem to help * Solder Wick or equivalent, 1/16 inch wide * Wet sponge for cleaning your soldering iron * Stainless steel pick with a right angle bend near the tip. To attach a component, first place some flux on all the pads being used on the board. Pick up the component with the tweezers and solder one end or pin down without adding any solder. Make sure that the component is in position and down against the PC board. Next solder the remaining end or pins using the smallest possible amount of solder. Now go back and add a very small amount of solder to the first end or pin. After the board or some portion is complete, go back and clean the flux away and carefully inspect the connections. The solder should not bulge up on the component ends and ideally will form a concave fillet. If you spent too much time making a connection it will not be shiny. If so, add more flux and re-flow the connection. If the solder bulges excessively, remove some with the Solder Wick. If you must remove a component, first use Solder Wick to remove as much solder as possible. For two- ended components such as resistors, move the soldering iron between the two ends (or use two soldering irons if you have them) until the component comes up. Shake it free from the surface tension of the solder onto a newspaper. In the case of multi-pin components such as integrated circuits, it is very important that the solder is first removed completely. It will then be possible to lift the component starting from one corner with a sharp pick while applying heat along the one side with the soldering iron. It is important that the iron be clean and have a shiny coating of solder. A good quality plated soldering-iron tip is most helpful. Relative to through-hole components there are the advantages that all work is done from one side and that no component leads need to be trimmed. The biggest disadvantage of the surface mount is that not all components, particularly ceramic capacitors, have their values marked and so greater care is needed to avoid mistakes. 2 - The PC board has a lot of parts on it. If you are not sure about soldering on the surface mount boards, start with a scrap piece of practice board and some extra low cost parts. Look at N4UAU's articles in April, May, June and July 1999 QST on surface mount construction. Start out slowly and you will be pleasantly surprised how well it will turn out! 3 - WIRES: In order to not require a multi-layer PC board, there are wires on the back of the board. These are marked on the back with a silk-screen legend (rev C only) with designators W1, W2, etc. Three wires are 50 Ohm coax cable. These should be installed first. Next is a wire that is best kept against the ground plane with a dab of RTV or the like. The remaining 25 are hookup wire and any wire will do; 22 AWG or 24 AWG is probably the easiest to work with. The following list can be used to check off the wires, and also may be useful for trouble shooting: W13 C78 to U15-1 Coax 19.68 MHz LO to mixer W24 C127 to U3 Coax 126 MHz LO to mixer W29 R150 to U7-1 Coax 10 MHz ref sig to 126 MHz PLL W12 U7-4 to R60 Wire 19.68MHz to PLL IC. Glue to ground plane W1 P101-1 to Fuse Wire +13.6VDC W2 P108-8 to L107 Wire +5 to external control W3 U110-8 to F111 Wire PLL Lock Out W4 U108-1 to R130 Wire Transmit Control W5 U108-2 to R133 Wire Receive Control W6 F1 to D107,D108 Wire R_ATT1 Pin diode current W7 F2 to D109,D110 Wire R_ATT2 Pin Diode Current W8 F5 to Q106-1 Wire +10 Receive W9 U12 to Q106-1 Wire +10 Receive W10 R102 to Q105-1 Wire +10 Transmit to Red LED W11 R50 to L29 Wire +10 Transmit to U6 W14 U11-1 to Q5E Wire 15 kHz transmit i-f W15 C40 to P5-4 Wire DAC1 for transmit i-f W16 L17 to R4 Wire +10 Transmit to Diode T/R W17 L17 to R12 Wire +10 Transmit to Diode Ant T/R W18 L17 to Q105-1 Wire +10 Transmit W19 L108 to +5 Dist Wire +5 feed to distribution point W20 D112 to U102 Wire +5 W21 D111 to U102 Wire +5 W22 U11-3 to C85 Wire Left Audio W23 R57 to F109 Wire SER_CLK to U7, MC145170 W25 U11-4 to P5-4 Wire DAC_1 Left Audio W26 F108 to R55 Wire SER_DAT to MC145170 W27 F114 to R56 Wire SER_EN2 to MC145170 W28 P5-6 to C86 Wire Right Audio 4 - Do NOT have a fuse in the holder clips when you solder them! 5 - The two TO-220 voltage regulators, U10 and U102, mount under the board. They can be mounted to the box with a 6-32 screw, #6 washer, lock washer and nut. Bend the leads right where they change size. 6 - There are a few toroidal coils. Estimate the amount of wire needed and cut off a little extra. Feed the wire through the center the same number of times as there are turns. The turns can be in either direction. Line the turns up reasonably close together. If you have the polyurethane covering it is easy to remove with a soldering iron (an example is Belden's Beldsol wire. Otherwise, carefully remove the enamel with a sharp knife. 7 - The 19.665 MHz crystals are soldered to the surface mount pads. Their case is soldered to the ground strip towards the edge of the board, as shown in the part layout. The symbols on the part layout make it appear that there is a chip resistor across the leads of the crystals. This, of course, is not the case. 8 - The pads for the surface mount capacitors will take 1206 size parts. They are closely enough spaced to also take 0805 size parts. So, wherever you see either a 1206 or a 0805 cap listed, either size can be used based on what you have, or can find. In the case of resistors, be sure to use 1206 size, as the dissipation may not be adequate for the 0805 size. [See rev 4.2 below for correction] 9 - The two TUF-1 mixers are mounted through the board by their pins. There is a dot in the silk screen (Rev C) showing pin 1 (blue glass.) As an additional check, the grounded pin of the mixer (no glass at all) goes to the ground plane on the back of the board. Check the pins carefully, as the mixer is tough to get out of the board if it is backwards. The mixers should sit a few thousanths of an inch above the board to be fully safe from shorts. A tiny piece of Scotch tape at each end may help. 10 - There are two type of slug tuned coils with nominal inductances of 0.1uH and 2.2uH. Be careful to not get these mixed up. These 10K series Toko parts do not have their values on them, but they are marked: L1, L2, L8, L9, L10, L11, L102 0.1uH (100nH) TOKO TKENS-T1044 L12, L13 2.2uH TOKO TKANS-9447HM 11 - The input lead on the MSA or MAR RF IC's is pin 1 and is marked by a 45 degree cut. Mount these against the PC board with the leads bent down fairly close to the case. 12 - The required capacitors for C108 and C109 on the 10 MHz oscillator may vary some depending on the crystal. There is some room in the area of these caps if more are needed in parallel. Also, be sure that a plug in jumper connects pins 1 and 2 of P106 for the crystal oscillator option. If an external reference is used it should go to P106, pin 2, with the ground to pin 3. 11 - CORRECTIONS: A - In Sept 99 QST, p38, has Digi-Key part numbers corresponding to an earlier loop filter than that shown in the schematic. All part values are correct. The proper Digi-Key numbers are: C111 0.005-uF Film Capacitor - Use 0.0047-uF (DK PS1472J) C112 0.068 uF Film Capacitor - (DK P4723) B - In Oct 99 QST, the two LED's, D102 and D103 are specified as size T1-3/4, from Radio Shack. These will fit very tightly in the board holes. A better part is size T1 such as the LiteOn brand available from Digi-Key (and other sources.) The part numbers are: D102 Amber (DK 160-1079) D103 Red (DK 160-1078) 14 - Gerry Edson, WA0KNW, of Mini-Circuits has offered the following improvement: "In the article you indicate that various of the MAR series of monolithic amplifiers can be used by trimming and bending the leads. This trimming and bending is not necessary, as we do that for you if you add "SM" to the part numbers - examples - MAR-6SM, MAR-3SM, etc. We do charge an additional $0.05 for doing this, but the result is improved coplanarity of the leads, and it eliminates the possibility of separating the leads from the die when hand bending the leads." 15 - As shown on both the part layout and the QST schematic, C61 is a film type capacitor. There are also ceramic chips of the same .01 uF value, but they are not interchangeable. 16 - The MAR/MSA amplifier IC’s are sometimes shown on the part layout without the cut lead. In all cases, though, the dot on the layout drawing is at the input, or slant-cut lead side. 17 - Watch the polarity of the electrolytic caps. I think there is a plus sign on the silk screen for each of these. 18 - Some additional data follows. This is a single part list for the entire PC board. It does not have the details of the parts or their source for purchasing. So it needs to be used in conjunction with the QST article (Sept, Oct and Nov 1999.) But, it is handy for buying parts. The parts off the board are not listed here---see QST. DSP 10 TRANSCEIVER Quantity Type Value Ref Designators ======================================================================== 1 74HC14 U110 2 74HC595 U107,U108 2 4066B U11,U12 2 CAP .001 C62,C113 1 CAP .005 (or 0.0047) C111 23 CAP .01 C7,C8,C10,C12,C13,C34,C40, C42,C44,C46,C47,C48,C49, C57,C79,C81,C85,C86, C120,C123,C137,C138,C142 1 CAP .01 FILM C61 1 CAP .015 C95 1 CAP .033 C60 1 CAP .04PF C24 1 CAP .068 C112 2 CAP .1 C30,C31 21 CAP .22 C32,C33,C36,C38,C56,C58, C67,C76,C77,C83,C87,C88, C91,C92,C94,C107,C121, C122,C126,C134,C140 3 CAP 0.5PF C16,C19,C21 2 CAP 1 C3,C18 4 CAP 2.2UF C35,C39,C59,C139 2 CAP 2.7 C14,C23 1 CAP 3.3 C119 2 CAP 6.8 C125,C146 3 CAP 8.2 C15,C22,C52 6 CAP 10 C26,C28,C68,C109,C117,C141 1 CAP 10UF C133 5 CAP 12 C2,C4,C17,C20,C27 8 CAP 15 C25,C29,C50,C51,C53,C96, C97,C98 4 CAP 22 C72,C108,C143,C144 1 CAP 33 C6 10 CAP 47 C1,C5,C63,C64,C65,C75, C114,C115,C116,C118 16 CAP 47UF C37,C54,C55,C66,C82,C84, C89,C90,C101,C103,C104, C105,C106,C131,C132,C145 1 CAP 100 C70 1 CAP 220 C71 14 CAP 470 C9,C11,C41,C43,C45,C73, C74,C78,C80,C93,C124,C127, C135,C136 1 CAP 470UF 25V C102 1 CAP_TUNING 1.8-6 C69 1 CAP_TUNING 2.8-12.5 C110 1 CRYSTAL 10MHZ X101 4 CRYSTAL 19.66MHZ X1,X2,X3,X4 1 DIODE 1N5401 D101 6 DIODE BAR74 D4,D5,D6,D105,D111,D112 4 DIODE_AKA BAV74 D107,D108,D109,D110 2 DIODE_AKA HSMP-3804 D1,D2 4 DIODE_VARICAP FMMV2101 D104,D113,D114,D115 1 DIODE_VARICAP23 FMMV2103 D3 1 D_OPAMP1_SO8 LM358M U109 12 FB FB L16,L17,L26,L27,L28,L29, L30,L31,L106,L107,L108, L109 18 FILTER_T 470 F1,F2,F3,F4,F5,F101,F102, F103,F105,F106,F108,F109, F110,F111,F112,F113,F114, F115 1 FUSE 1A FS1 6 HDR_2PIN P1,P2,P3,P6,P7,P103 2 HDR_3PIN P105,P106 1 HDR_4PIN P4 1 HDR_5PIN P102 2 HDR_8PIN P5,P108 1 HDR_12PIN P101 2 IND 39NH L3,L19 6 INDI .33UH L4,L5,L6,L7,L14,L15 4 INDI .36UH L23,L24,L25,L103 1 INDI .50UH L21 1 INDI 2.2UH L22 1 INDI 10UH L20 1 INDI 39NH L104 1 INDI 47UH L101 1 INDI 100NH L18 1 INDI 330UH L32 2 IND_VARIABLE 2.2UH L12,L13 7 IND_VARIABLE 100NH L1,L2,L8,L9,L10,L11,L102 2 JFETN J310 Q4,Q101 1 LED AMBER T-1 D102 1 LED RED T-1 D103 1 SOPAMP_8PIN OP27 U6 2 LM78L05ACZA LM78L05 U13,U103 1 LM833 U10 1 LM1877N-9 U14 1 LM2937ET-10 U101 1 LM7805CTB U102 1 LMX1501A U104 1 MC145170 U7 2 MIXER_TUF-1 U3,U15 2 AMP_MSA MSA0386 U2,U9 2 AMP_MSA MSA0486 U5,U106 4 AMP_MSA MSA0686 U1,U4,U8,U105 1 NPN 2N5109 Q2 4 NPN FMMT3904 Q1,Q5,Q103,Q104 3 PNP FMMT3906 Q3,Q6,Q102 2 P-CHAN MOSFET ZVP2106A Q105,Q106 1 RES 1MEG R135 1 RES 2.2 R10 2 RES 2.7 R42,R43 1 RES 6.8K R15 25 RES 10K R13,R16,R26,R27,R30,R31, R33,R34,R37,R38,R104,R122, R125,R126,R127,R128,R129, R130,R131,R132,R133,R134, R139,R147,R151,(+R21 Rev4.5) 3 RES 22 R11,R111,R112 1 RES 22K R143 4 RES 33K R46,R105,R138,R145 2 RES 47 R60,R121 4 RES 47K R35,R36,R48,R54,(+R49 Rev4.5) 1 RES 68 R62 2 RES 75K R137,R142 9 RES 100 R20,R22,R44,R45,R50,R59, R67,R110,R150 12 RES 100K R23,R24,R39,R40,R41, R47,R53,R66,R106,R146,R152 (-R21 Rev4.5) 1 RES 180K R141 1 RES 220 R123 10 RES 330 R1,R2,R3,R5,R6,R7,R61,R64, R113,R114 12 RES 470 R28,R58,R63,R68,R107, R109,R136,R140,R144,R148, R149 (-R108 Rev4.5) 3 RES 680 R4,R12,R65 6 RES 1000 R9,R19,R25,R101,R102,R103 3 RES 1800 R51,R52 (-R49, Rev4.5) 3 RES 2200 R55,R56,R57 1 RES 2700 R14 3 RES 3300 R8,R17,R29 2 RES 4700 R119,R120,R108 (+R108 Rev4.5) 1 RES 5600 R18 1 RES_VAR 10K R124 REV 4: 20 SEPT 99 - Added notes 15, 16, 17 and moved 15 to 18. Revised notes 7 & 8. RSL REV 4.1: 1 OCT 99 - Added addendum, corrected L32 core, added info on assembly. RSL REV 4.2: 21 OCT 99- Added info on DSP box and board mounting, 0805 chip caps and the part installation order. RSL REV 4.3: 27 OCT 99- In part list, just above, made C61 separate line, moved U6 and combined F2 with other filters; added notes on 78L05 silk screen; added notes on EZ-Kit heat sink. REV 4.4: 10 NOV 99- Microphone connection correction, assembly hints. RSL REV 4.5: 4 DEC 99 - Corrected R49, R21, R108. Added notes on DSP Grounding, silk-screen markings and L/R conventions. Corrected pin 31 and 32 of EZ-Kit P3. RSL ******************************************************************************* ADDENDUM FOR REV 4.1 - 1 Oct 99. RSL Correction: The core listed for L32, Fig 4 Sept 99 QST, should be Amidon FT23-43. Correction: Not listed is that C30 and C31 are FILM caps, such as Digi-Key P4725 (0.1 uF, as listed,) and C95 is a FILM cap, such as Digi-Key P4715 (0.015 uF, as listed.) Apparently, Digi-Key no longer carries the 470 uF electrolytic, C102. Mouser 140-XAL25V470 should work in place of the DK part. L32 is wound with #32 wire and the core is about 1/4 inch in diameter. In order that this core not behave as an antenna at 15 kHz it needs to be small and the magnetic field needs to be concentrated in the core (no air gaps.) This is achieved with this coil design, but it does take a few minutes to wind. Try to keep the turns in line around the toroid. But, don't worry if the turns sometimes overlap or get looped under the prior turn. It will not affect the functionality. The instructions for soldering the coax cables to the bottom of the PC board assume that there is no solder mask on that side. In their enthusiasm to do a good job, the board maker for the boards sold by W7SLB added a bottom mask. This is not a problem, but, it may be necessary to scrape some mask away where the braid of the coax is soldered to the ground plane. This can be done with the blade of a knife. In Fig 2 (Sept QST) it is pointed out that unless otherwise noted, the capacitors are ceramic chips. For instance, the .01 uF can be Mouser 140-CC502B103K [No, See Rev 4.2 below] and the 0.22 uF can be Mouser 140-CC502Z224M. The toroidal powdered iron cores, T37-6 and T25-17 are made by Micrometals and available in small quantities from several sources, including Amidon. The Pi filters, FIL1, FIL2, etc., have three leads coming out the bottom. The center lead is ground. The pads on the PC board have a through-hole for the center lead. The two side leads should be bent at right angles and cut short to fit the square "SMT" pads. When you look at the board you will see the arrangement. The 10K Toko coils, like L1, are really hard to get out from the PC board, if they are in the wrong place. Check twice, then solder. UNSOLDERING: Oops, it is not the right part!! What to do: Put liquid flux on the surface-mount parts before working on them. Then remove the extra solder with Solder-Wick or similar braid. Next heat both ends of the part at the same time, which can be done with one iron, but is easier with two, if you have them. The surface tension of the solder will cause the part to cling to the soldering iron, when it is ready to come free. Knock it free into a paper towel. Apply more solder flux, whenever it seems like the heat is not transferring to the pads and the part. NEVER PRY THE PARTS UP. Prying is how the pads on the PC board disappear! REUSE: SMT resistors and inductors tend to be OK after being carefully removed. Ceramic caps are questionable. They can develop microscopic cracks that are very difficult or impossible to see. The best practice is to use new ceramic caps. Likewise these cracks are the reason to NEVER PUSH on the chip caps during installation. All of this is not to suggest that these parts are particularly delicate, but rather that some precautions are needed! ******************************************************************************* ADDENDUM FOR REV 4.2 - 21 Oct 99. RSL BOX FOR DSP: The box size in the drawing furnished with the PC Board from Mashell Electric is snug around the DSP board. This can be problematic when taking the board in and out. If you keep to the 3.6 inch inside dimension shown on the drawing, you must use nuts no bigger than 3/16 across. Alternatively, the ground contact to the cover can come from finger stock, as shown on the cover of Nov 1999 QST. Otherwise, to use the hardware store type of 1/4 inch brass nuts, you should increase the box width by 0.1 to 0.2 inches. This extra size should be arranged to not cause the box to overhang the main board any extra. Doing so, would put P5 and P108 under the box. There is some extra room on the other side, overhanging the voltage regulators, U101 and U102. Thanks to W7LHL for pointing this out. Also, do not mount any nuts on the ends of the box, but only as shown in the drawing. Four or five ground points will keep things quiet at 2-meters. For reference purposes, the mounting centers on the EZ-KIT Lite are 5.20x3.20 inches. Before mounting the EZ-Kit board, you must, of course, remove the rubber "Bumpon" feet. If you are careful, these can be reused on the bottom of the main die-cast box. SPACERS: A sketch of the board mounting, that I used, is included with the PC Board. This uses 8 round, metal spacers, 0.187 inches long, Such as (Johnson Component) Digi-Key J166, and four threaded metal round spacers, 1.000 inches long, such as (Johnson Components) Digi-Key J243. These are all 0.25 inches in diameter. It is tricky to get the EZ-Kit board in, unless one glues the spacers to either the bottom of the board, or to the bottom of the inner enclosure. RTV works fine for this. Alternatively, "male/female" spacers can be used under the EZ-Kit board, if they can be found. NOTE 8 ABOVE: It incorrectly states that ALL chip caps can be 0805 or 1206 size. Two values, 470 pF and 0.01 uF should be only 0805. This makes the 0.01 part from Mouser, listed in rev 4.1 above incorrect. Examples of 0805 parts for these two values are: 470 pF Digi-Key PCC471BNCT Mouser 140-CC501B471K 0.01 uF Digi-Key PCC103BNCT Mouser 140-CC501Z103M P6 and P7: These are not used at present (marked ALC and VLF.) They go to the Right (Q), unused ADC input for transmit and receive. PART INSTALLATION ORDER: Get the little low chip parts in, and inspected, before placing the bigger ones. This gives you the maximum working room. There are two pages of color copies that come with the PCB from W7SLB that show the location of all the common parts (like 0.01 uF chip caps, or 10K chip resistors.) Do all of these "in-color" parts first and then recheck that they are in the right spots. This helps to prevent mistakes with the chip caps that are not marked. When you put down the common chip caps, you will notice that, most likely, each value has a "different" look. After they are on the board is a really good time to check things carefully, as the situation is still pretty much observable. When you get to putting the caps like 10pf NPO and 15pf NPO, they will look very much alike. So go carefully through those values. ******************************************************************************* ADDENDUM FOR REV 4.3 - 27 Oct 99, RSL IMPORTANT!! 78L05 SILK SCREEN MARKINGS: The silk-screen legend is backwards for the 78L05 regulators, U13 and U103. The flat sides of both TO-92 packages should be towards the top of the board. There is no problem in installing the parts, of course. The sketch of the package included with the board is correct. Thanks to KD7TS for catching this. EZ-KIT HEAT: The way the EZ-Kit comes, the 7805 voltage regulator runs a little warmer than you like to touch, but not burning hot. This is probably within specs, but it is pretty toasty. When you put the board in a sealed box, the regulator gets warmer yet. I have not heard of any failures due to this heat. To be safe though, I took a piece of copper, 0.25x2 inches, drilled a 0.140 hole in it and fastened it to the regulator with 6-32 hardware. This cools the regulator quite a bit. Be careful that you do not end up with the heat sink strip too high, or the box cover will hit it. The tab is grounded, so it is not an electrical hazard. ******************************************************************************* ADDENDUM FOR REV 4.4 - 10 Nov 99, RSL MICROPHONE CONNECTIONS: I must have put the microphone connections for J202 onto paper late at night. If you want to use the Radio Shack 21-1172 microphone, the correct connections are: J202, Pin 1 Ground to J102-2 & Box J202, Pin 2 NC J202, Pin 3 PTT to J102-4 J202, Pin 4 Mike audio to J102-1 J202, Pin 5 NC The Radio Shack microphone does not need power, so the +5 is unused. Thanks to KD7TS for catching this. Also, be sure to notice the non-sequential numbering system of the Circular DIN connectors. STANDOFFS: Hunting around in my junk box, I came across some of the little 4-40 male/female standoffs that are used to mount 'D Connectors' to a panel. These are 0.187 inches on the spacer and quite ideal for mounting the EZ-Kit box down to the 1 inch standoffs. This avoids any gluing or soldering of the spacers to keep them from moving around. SOLDERING IRONS: W7LHL bought a Xytronic JS1258 (Jameco 116572) soldering iron and reports good success with it. He says the cord is stiffer than he would prefer, but the iron works well on the small surface-mount parts. He uses a XY1, Semi-Chisel 1/32-inch tip (Jameco 35078). The big feature of the iron is that it costs about $20 and the tips are $4. EZ-KIT BOX: I drilled two 1/4-inch holes in the cover for the EZ-Kit box to line up with the Red LED and the Reset Switch. This is not required for operation of the transceiver, but it is handy when getting things working. You need to reset the DSP board before reloading the DSP program. And if it doesn't work, you always wonder if the DSP was really reset. The Red LED blinks when the board is reset, waiting for a program download. These two holes allow these items to be dealt with. EZ-KIT: Your DSP may come with R28 missing. If so, you need not remove it!! ******************************************************************************* ADDENDUM FOR REV 4.5 - 4 Dec 99, RSL CORRECTIONS: R49 should be 47K not 1.8K and R21 should be 10K, not 100K, R108 should be 4.7K not 470. BOX GROUND: The grounding of the EZ-Kit is not shown on the schematics. You do not get automatic grounds from the mounting posts with this board. It is a multilayer board and so has good low-inductnce ground paths once the path is on the board. Between the DSP box and the EZ-Kit it is desireable to have at least one good short ground. One way to accomplish this is with a short lead from either (or both) P3-1 or P3-50 to the adjacent box wall. I used #20 wire for this and have had no problems. SILK-SCREEN MARKINGS: In addition to the two silk-screen errors for U13 and U103 listed in rev 4.3 above, there are a few other areas that need clarification. Q105 and Q106 from Zetex do not have the same shape as the outline shown, which is a conventional TO-92. The flat side of the TO-92 has the markings, and the marked side of the Zetex package goes the same direction. In other words, if you look from the edge of the board, you should be able to read the markings on Q105 and Q106. C69 and C110 are small ceramic variables. The markings show a flat side. As they are shown, the screwdriver will be on the "hot" side of the capacitor. This works, but is annoying when adjusting. If you install them the reverse of the markings the screwdriver will be grounded when they are being adjusted. Hint: If you look at the back side of the capacitor, the grounded side is clear. On the back side of the board, one end of W27 is not marked on the silk-screen. It is shown on the drawing of the wires, so I doubt that anyone has missed installing the wire. The missing marking is the ungrounded pad, half way between W26 and W23, in the U7 area. CORRECTION: It is listed elsewhere, but a reminder here that the wire from J101-11 goes to EZ-Kit P2-32 and J101-12 goes to P3-31. LEFT/RIGHT: I think I have it correct now. For the 1/8-inch stereo plugs, the convention seems to be that the ring is "Left" and the tip is "Right". If your speakers seem to be wrong (I don't know how you can tell) switch their positions (or the wires). If someone thinks this is wrong, please let me (W7PUA) know! INTERFERENCE: The corner of P106 may need to share space with C109. Just let P106 sit high enough to clear the capacitor, which needs to be installed first. SMALL PADS: C140 and C150 are 1206 parts on 0805 pads. This is tight. The part covers almost all of the pad, leaving little room for inspection. The solder connection is still practical, with care. Afterwards, use a magnifying glass to carefully inspect the connections to be sure that you see solder flow on the ends of the capacitors. C101 is a surface mount electrolytic with pads that are too small. Scrape the solder mask off of the ground trace, clear back to the ground via, (removing the letter 'C' in C101) and there is enough room to mount the part. R124 PATTERN: R124 may not line up with the pads and the silk-screen marking, depending on which version of the 3329 pot you have. If so, bend the center wire so that it lines up better, and push the part away from C131. There is plenty of room and it all works out fine if you don't try to push the pot down too far. Short leads help to make the pot mechanically stable, but are of no concern electrically. MISC: L101 has no preferred direction for insertion. The 18 filters, like F1, F2,... should have their outside leads bent at right angles and the leads cut short. They will then fit the pads. It is important that the center grounded lead be down against the board for low inductance. It takes a bit of soldering iron heat to solder the 6 grounds in the middle of U14. These are the heat-sink pins for the IC. The leads of the two JFET's Q4 and Q101 should be reasonably short. The bottom of the package should sit about 1/8-inch (3 mm) above the board. C112 leads may be too narrow for their mounting holes. Just bend them to suit. These do not need to be extremely short. The MOSFET's Q105, Q106 and the regulators, U13 and U103 do not require particularly short leads and should be pushed down until the bottom of the packages are about 3/16-inch (5 mm) above the board. SCHEMATIC: Sheet 2 of the schematic that comes with the board says that the U104 synthesizer has 2 kHz steps. It has 5 kHz steps. No wiring change is involved. TEST PADS: There are several places on the board where test points have been brought to small square pads. In one case, next to pin 15 of U104, it looks like there should be a surface mount part. Note that there are no lines on the silk screen pattern and no part goes there! Those pads are used to probe the phase detector inputs on U104. ******************************************************************************* ADDENDUM FOR REV 4.6 - 12 June 2000, RSL CORRECTION: The symbols for the 2 power MOSFETS (Q105, Q106, p36 Oct 99 QST) should be for the enhancement mode (2 breaks in the main line). They are P-Channel and the source is connected to the +10V bus (as shown).