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CC Clarke

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About CC Clarke

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    Hartford, CT
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    Beer, Astrophotography, Astronomy, Electronics, Hiking, Unobtainable Women, Robotics, Cooking
  1. Extra console room between the case plastic and RF shield was provided for air circulation. CCC
  2. Always check power and timing first. You can use a logic probe to verify the clock signals, but an oscope with a freq counter is ideal. Before you get too far, pull the 2156, 2157, and sound chip out if socketed. (The home screen is contained in the 2155 GROM.) If a GROM or sound chip is bad, they can hold the bus down. After verifying the power and timing, (3 Mhz CPU clocks can be quickly checked on the clock chip, then four pins on the 9900 CPU) verify GROM select is on the GROM sockets, followed by READY on the CPU. Loss of READY will prevent power up, resulting in a "Dead", described above by the OP. If READY is missing or wrong, (Like GROM Select, it has a very noticeable signature on a scope.) First piggy-back then power up both ROMs, and if that doesn't work, replace them one at a time, followed by the 6810 scratchpad RAMs. CCC
  3. Hakko makes a good product, (I use their fume extractors) but I have yet to find a better soldering workstation than those produced by Metcal (later bought out by OK Industries.) If you know of a better one, I'd love to test one out. Working in the aerospace industry, this is all I see used at all the contractors sites I've visited when high-reliability, ESD-safe soldering is required. Note there are only two controls, a power switch on top and a selector switch between two outputs (for a solder hand piece and a solder extractor) on the front. No temperature controls are needed. The tip senses how much heat is required and the unit provides the power instantly. I've never burned a board, lifted an etch, or even measeled the laminate with one of these. I use one at home too. There's nothing cheap about these, but if you can find one in your budget, by all means grab one! Tips aren't cheap either, but last a long time. Metcals are the gold standard for professional solder stations. Pictured is a Metcal 500 series. CCC
  4. If memory serves me correctly, this problem came to light very early in the year (1983) when the transformers failed high pot testing (this is an extreme test where the secondary is intentionally shorted out and the primary (120vac) is left powered up. After about 45 minutes, (the exterior case would start to deform from the internal heat) the transformer would fry. I used to spend many nights doing this test, and they were very repeatable. US Underwriter's Laboratories had approved the transformer, but the Canadian (CSA I think it was called) Product Safety group flagged it as a potential problem if it wasn't grounded. The factory had to grind off the CSA stamp on the bottom of the transformers. (You can look at the bottom of one to see if it was affected by looking for the circular grinding marks.) I never heard of anyone getting zapped by their 99/4A, though I have repaired TI computers where you could feel a slight tingle when your wrist lightly brushed against the aluminum trim. Anyway, this was just another major public relations headache at a time when TI was reeling financially by trying to price-cut their 99/4A to compete with the lesser capable VIC 20 -instead of the comparable C-64, which coast more. I don't remember what it cost the company to recall all the outstanding transformers, but it wasn't cheap. Did it kill the 99/4A? No. But it did cast it in more of a negative light when it was under intense scrutiny to be profitable. J. Fred Bucey was a Lubbock native and CEO of the company then. He made the decision to pull the plug and left a lot of people unemployed in Lubbock during the fall of '83. I was lucky, and got out about six months before the axe fell. CC
  5. This basic tutorial should help with the pots: http://www.instructables.com/id/How-to-measure-resistance-of-a-Potentiometer/ The headphone jack pinouts are described here: http://www.electro-tech-online.com/attachments/stereo-headphones-plug-and-jack-png.30117/ CC
  6. As I dig through old posts, I found this one that asked about the differences in the QI and thought I might be able to shed a little light on it: As most readers know, the final version of the QI was TI's effort to reduce the cost as much as possible, both in materials, and labor. The 4A is an exceptionally-well built (from a manufacturing standpoint) machine, and cost more to produce than it's rivals, some of which were built overseas. With price reductions occurring and more looming during the summer of '82, every effort was made to economize the design to try to "tough out the market" and determine which competitors would fall during what were later dubbed, "The Home Computer Wars." From a historical perspective, it was very interesting to work as a grunt in the trenches, wondering how this would all play out. TI had done very well with their consumer products, (calculators, Speak and Spell, etc.) but got their butts handed to them with watches, --once they were produced by overseas competitors. I'm sure corporate pride came into play, but we all know the forces that converged to make the company throw in the towel later on. I have a very late model QI, produced in Oct '83, when TI exited the market. The plastics module next door to the production line module was downsizing, (they hired hundreds of low-paid summer interns, eager to get experience learning about plastics manufacturing before they returned to school) so that worked in the company's favor if they could reduce costs there as well. "The Beige" --as we called it, was not well-received (cosmetically) compared to the venerable, aluminum-clad 4A, which was called "The Classic" by us. QI Changes Include: 1. Elimination of the red power LED and two-piece black slider in favor of a colored (blue on mine) slider at the foot of the GROM port enclosure to toggle the power supply switch. ​2. Reduced parts count on the motherboard. The majority of the timing and control logic chips were consolidated in a single, custom 40-pin chip. This made troubleshooting a lot easier, since dead computers having timing-related faults required more labor to isolate. Of all the bad chips, the 26 & 27 ROMS were by far, responsible for most failures, but were easy to fix - usually by piggy-backing them with known good ROMS. 3. Elimination of bus bars, which varied in build quality. Some were paper-covered and others were laminated and more robust. Instead, power was distributed via blue bus wires. 4. Elimination of sockets (except for the VDP.) This was good for the bottom line, but made troubleshooting a little harder since the first step with a dead board (after verifying power and clocks) was to pull the GROMS and sound chip to free up the bus if it was being held down by one of them. Sockets, GROMS, the 9901, 9900, and VDP and connectors were hand-stuffed, which increased the chances for human error (bent pins, and chips inserted backwards.) Everyone got a kick out of finding a 64-pin 9900 installed the wrong way (rare, but it happened.) The laughing subsided when the time came to de-solder and put one back in. 5. Crap-tastic, cheap keyboards. By this time, Mitsumi was the most prevalent keyboard vendor (yeah, low bidder) and the reliability then was nearly as bad as now. The best keyboards always came from Alps. 6. A re-designed power supply with fewer components and increased heat-sinks for more efficient cooling. Heat is the sworn enemy of electronics, and this power supply ran cooler, plus it was easier to install without having an LED to position in the case. I'm sure the metal cladding contributed to the retained heat too. 7. One-piece shielding, which was hand-soldered to the board after it had passed power-up and diagnostics. This eliminated the two clips and dual-shell shield, along with the different-sized fasteners with retaining nuts to keep everything intact, saving labor. 8. Elimination of the I/O port door. The newer power supply with two pins (vice four) eliminated the ground wire. The fourth (cosmetic) pin was mainly for alignment. When you're building 10,000 machines per shift, all of these changes saved a lot of money! I hope this thirty-five year-old recollection answers the (new) question! CC
  7. I'm on vacation and the wife's at work, so I have time to burn on stuff like this. This isn't all-inclusive, but it's close. It took me years to buy all of these tools, but the savings in time and results I get when using them are worth it. Electronic Workbench Tools The majority of these items are sourced from Techni-Tool, but it pays (or saves) to shop around. Many of these tools cost more than what you’ll find at hobby stores, but as a craftsman, I don’t mind paying more for a set of tools that will last forever (or years under heavy use.) Your mileage may vary. At work, cost is irrelevant, but at home, I tend to buy the highest quality for the best value. The first tool to invest in is the most important one on your bench -a good quality of comfortable safety glasses. The rest of these tools are of little use if you’re blind. http://www.techni-tool.com/147SF142 If you’ve ever seen what solder splatter does to an eyeball, (or the flying cut end of a wire or component) believe me, it isn’t pretty. I cannot emphasize the use of safety glasses strongly enough. Sermon over. Wire Strippers: Mechanical (Good) For 22-10 gauge: http://www.techni-tool.com/618PL1117 These should satisfy most needs. You might want to go a little smaller -depending on your projects, to #28. Thermal (Best) These are the preferred method to avoid nicking or marring conductors when wire stripping. Pricey, but after using all manner of thermal strippers, I prefer these from Teledyne: http://www.techni-tool.com/768ST026 These (American Beauty) strippers are really good too, and have the added benefit of compatibility with tips for resistance soldering tweezers, which are the best tool to work on solder cup connectors: https://americanbeautytools.com/Thermal-Strippers/164 Much too expensive for home use, but like I said, really nice and prevent damage to connector body inserts. Acid Brush: Buy in bulk and save. These are used to remove flux (and pretty much anything else) from PCBs and wire joints- http://www.techni-tool.com/872SO014EA Old Pro tip: Use scissors to cut them at a 45 degree angle 1/4 “ from the metal handle for best results. You get the handy combination of hard and soft bristles in one brush! Menda Pump Dispenser: This is the industry standard for IPA (isopropyl alcohol for you normal people following along) storage on your bench - http://www.techni-tool.com/548CH7353 Handy! Obligatory Memorable Bad Story: At TI, I observed the 99/4 repair tech at the bench next to me dipping his soldering iron tip in his Menda dispenser to clean it off, rather than the wet sponge on his solder station. I casually mentioned that IPA was kind of flammable and he pretty much blew me off. Okay . . . A few nights later, I heard a commotion and glanced over at his bench which was pretty much totally on fire. Not only had he ignited the IPA on the top of dispenser, but he panicked and knocked it over (the top wasn't on tight) and spilled IPA all over the place. A couple hundred of my fellow employees got a (real) fire drill out of it. He was later fired for stalking women in the (confined) burn-in racks with his pants around his ankles. Just another never-a-dull moment @ TI night! Hand Tools: Diagonal Cutters: There are lots of types of cutters, but the diagonals are good for general purpose use. Wiha, Sandvic, and Lindstrom hand Tools are hard to beat. If you spend $$$ for any one hand tool, buy decent cutters. These last a long time (but aren’t meant for large gauge wire!) http://www.techni-tool.com/844PL164http://www.techni-tool.com/844PL164 Tweezers: Fine and coarse, you always need tweezers. This is a Swiss-made set that works great and is cheaper than other same-quality sets: http://www.techni-tool.com/758TW546 Be warned: If you drop them on the floor, their most likely ruined! In this case, Swiss=precision. Wire Forming Pliers: Anytime you work with wire or discrete components, you’ll need to bend leads. Avoid any tools with serrated edges which leave tooling marks on the components or deformation in conductor insulation. These are the right tools to do it properly: Duckbill (or Flat-nosed) Pliers: This is a good quality, less expensive set: http://www.techni-tool.com/352PL2842 Round-nosed Pliers: These get more use than duckbill pliers, but can get expensive; this set is relatively inexpensive: http://www.techni-tool.com/352PL2843 These Lindstom’s are pricey, but I love them: http://www.techni-tool.com/844PL759 Other Tools: Multi-Meter: This is an indispensable tool I use constantly, so I will pay more for the best. Almost any meter is better than none at all. I’ve relied on the Fluke 77 series for more than twenty-five years and can say without reservation, these things can take a beating. The battery seems to last forever. http://www.techni-tool.com/374ME774 Optivisor: Another tool I use constantly around the house or at my bench. There are lots of similar magnifiers out there, but after trying most of them, this is my favorite: http://www.techni-tool.com/298IN072 Great for removing splinters (see Swiss tweezers above) and things of that nature. Let there be light: No Optivisor is complete without the Quasar LED attachment: https://www.amazon.com/Quasar-Led-Lighting-System-Optivisors/dp/B0058ECQ46/ref=as_li_ss_tl?ie=UTF8&linkCode=ll1&tag=atariage&linkId=71c498ca5213318381e42a2d88e4c18f Solder Stations: The self-adjusting (no temp controls!) Metcal solder stations are expensive and worth every penny. Tips are expensive too, so I recommend buy both used. Here’s one of their least expensive: http://www.techni-tool.com/551SO1195 You'll sneer with self-righteousness at lesser stations for the rest of your life if you get one of these. Le crème of le crop. My favorite (for a single outlet control) is the MX-500. Small, mighty, perfect. Kester is the goto name in solder: .062” http://www.techni-tool.com/488SO061 .025” http://www.techni-tool.com/488SO144 Heat Gun: If you use heat shrink tubing, (and who doesn't?!) you need a heat gun to shrink it properly (never a match or lighter!) Weller’s heat gun is light and compact, and actually a pretty good buy. http://www.techni-tool.com/812PR010 I’ve used this model for 25 years. Old Pro Tip: The switch has three settings, OFF, Heat, and just air. Always set it to air after using the heat setting to gently cool the heating coils, which prolongs the life of the tool. As long as you’re interested in a heat gun, you’ll need . . . heat shrink! Here’s the best: (polyolefin from 3M; my preferred color is clear so I can spot broken joints) http://www.techni-tool.com/105PR577 Anything 3M makes always does what it says it will. This heat shrink is no exception. Solder Wick: http://www.techni-tool.com/237SO225 This has rosin flux (and multiple sizes) to quickly remove flux. I know some people use the old-style one-handed vacuum pumps, but they can be more trouble than they’re worth. If you do a lot of component removal, (especially ICs) invest in a real de-soldering station. Metcal is one vendor. Static Safety. If you work with IC’s and many PCBs, ESD is a concern, especially in low humidity environments. You’ll need a mat: http://www.techni-tool.com/105ST6427 A wrist strap: http://www.techni-tool.com/WWG22C690 and of course, you’ll need to connect the mat to a suitable ground. Here’s an affordable kit with everything: http://www.techni-tool.com/758ST017 ​These are my preferred tool to lap splice or attach wires to pots, etc. The tool can be taken apart and laid into a wire bundle when needed: http://www.techni-tool.com/711IE015 I always wrap tape around the serrated edge of the roach clips to prevent deforming wire insulation. Optional Tools: Chemtronics Flux-Off: This does a great job (better than IPA) but costs more. The result is a PCB that’s hospital-grade clean with little scrubbing: http://www.techni-tool.com/237CH5301 Solder Fume Extractor: You can hold your breath while solder fumes are rising towards your nostrils or use one of these instead: http://www.techni-tool.com/606PR8115 Prices are all over the map on fume extractors, so this is a good-quality alternative to those costing over $1000. ​Solder Holder: I have one for each different diameter roll of solder on my bench: http://www.techni-tool.com/812SO001 Stereo Microscope: When you want to do the best job possible, nothing beats this for close-up work. Even your smallest movement is magnified, so one of these makes you extra careful. I finally found one I could afford (a Bausch and Lomb on eBay) after two years of searching. Here's what they look like: http://www.techni-tool.com/516IN714 Fiber-Optic Light: In the old days, we had to walk through two feet of snow (backwards!) to get to work. When we arrived, we were forced to toil under a pair of incandescent lamps that cooked the tops of your hands after a few hours. Now, there are fiber lights on flexible stalks, and all the heat is contained in a separate housing.http://www.techni-tool.com/560IN301 Bulbs are expensive! Super-pointy test leads: Standard test leads are usually too big for ICs and hard-to reach areas. These probe tips are replaceable, and sharp enough to pierce insulation (I hate doing that, but sometimes you've gotta do what you gotta do.) http://www.techni-tool.com/458TE6275 Electronic Surplus Stores: Many large towns have one of these places. You can save a fortune if you know what you're looking for. (Especially with good quality, Teflon insulated wire.) Here's one I like to haunt when I'm in the Orlando area: http://www.skycraftsurplus.com/ Okay, I'm out of things for you to buy. Start small and work your way up. The hand tools and a good solder station should be your first priority. And oh yeah, please don't forget the safety glasses!! Happy soldering, CC
  8. Before I forget what you mentioned in your post regarding flux. . . The purpose of flux when soldering (not time travel, ie: flux capacitors) is to remove contaminants and promote proper wetting (coverage) of the solder joint, yielding a smooth, shiny surface. Contaminants (from the operator's hands, on the solder, and components being joined) are supposed to join in suspension with the flux and rise to the top of the joint when heated, allowing easy removal after the joint cools. The longer you wait to remove flux, the harder it is to do so. Inspection of the joint requires being able to see the joint, so all flux residue needs to be removed for thorough visual inspection. This is another reason you don't want solder "blobs" for joints; you can't tell what is actually joined, if the through hole is properly filled, (voids can form) or components are physically damaged. The (newer) IPC standards which I certify and teach to are a combination of the multiple workmanship standards that have existed for decades within DoD, NASA, and private industry. Each can specify any exceptions in-house, but the IPC standards are becoming more and more prevalent. Once you're certified, the cert stays with you - not the company or organization you work for a period of two years. Trainers and students alike have to re-certify to remain current. Personally, the IPC standards are much more relaxed than the standards to which I was originally trained, but that's not necessarily a bad thing. It required expending a lot of time to get the joints "perfect" and by perfect I mean they had to stand up to many requirements that aren't always realistic. The good thing is the requirements are more standardized, so most companies are singing to the same sheet of music. Written testing (as opposed to practical performance testing which I grade) is conducted via computer with IPC regional centers because . . . The Chinese (who are required to exhibit the same workmanship standards in their exported products as specified in contractual requirements) began copying IPC docs (and tests) to prove organizational certification, rather than comply with regional training center --like we have to do in the US. (Presently, the Chinese don't innovate - they imitate.) IPC is a money-making organization, so to protect their turf, so to speak, IPC went to online testing, minimizing fraudulent credentials. This has the bonus of legitimizing the Chinese training market for them. Smart, eh? You can purchase their training guides on their website, along with lots of other useful documents. (But none are cheap.) http://www.ipc.org/ContentPage.aspx?pageid=Standards---for those who may be curious. While I'm on my soapbox . . . I'll put together a list of good tools that will make any electronics bench useful and post back. CC
  9. I also added some tips in your other post in the 99/4 HW/SW Development section a few min ago that may be of help to anyone looking to increase their solder skills. As for color-blindness, some QA departments require testing for this to certify solderers. Bad story: I worked on a job with a guy who mixed some critical chemicals (in color-coded containers) into some very expensive flight-level hardware. During subsequent operation, we had a catastrophic failure. A team was called (independent of us) in to investigate and compile a report. It turned out the wrong chemicals were loaded into the wrong tanks, resulting in the "problem." The guy who load them turned out to be color-blind and had been hiding it from us. That little (preventable) mistake cost a couple of million bucks and of course, he was removed from his position. When you're working on (the really) expensive hardware, mistakes are bound to happen, no matter how many checks are made. As long as you own up to it, nobody gets pissed if it's caught early, before damage occurs. No one is immune, including yours truly. I always tell this story to new people who have never worked on high-rel hardware before: Once, I found a tiny (.08") screw on the floor that looked like it came from one of my devices that had been installed in a higher level assembly and passed testing. (This was a billion dollar piece of hardware when assembled.) When I brought it to the attention of the boss, he shrugged it off and said (and I quote) . . . "Ain't nothing in this pig held together by one fastener!" To which I replied, "Yes there is, and it's located in the hardware I installed. If I'm wrong, we lose time. If I'm right, and we don't verify it, we could lose everything, and kick ourselves in the ass for eternity for not checking." After a moment, he let out a long exhale and said to everyone assembled, "Open it up!" I felt about one inch tall because a lot of people had to undo a lot of work to check this. Hours later, they accessed the space and sure enough, there was no fastener installed. We called a quick meeting and I was definitely in the limelight. I felt horrible. The Lead Engineer said, "Sometimes doing the right thing is the hardest. This tiny screw could have meant the difference between success or failure. Never hesitate to call attention to detail, even if it means making yourself look bad in the process. I will never get upset for preventing failure. Knowingly hide something and if I find out, you're gone. Credibility is what makes everything work, and without it, we can't put faith or trust in what we build." Everybody who stayed up all night to discover my error, shook my hand and congratulated me - this was the opposite reaction I expected. Nobody was mad. That experience drove home an important lesson about never taking anything for granted where workmanship is concerned, that I apply to every project I work on, big or small, cheap or expensive. Credibility that takes years to acquire can be destroyed in a second. You can bet that verification of my mistake was added to the procedure. In the High-Rel world, many changes to procedures exist because of lessons learned - sometimes the hard way. So if you're soldering and suspect a problem, check it up-front, before you proceed. The extra time to verify any questionable workmanship is always worth it. CC
  10. I ran across this thread and thought I'd toss in my .02 since it's a subject I'm familiar with. Choosing a soldering iron is probably the most important issue when building a soldering toolkit. In my soldering career, I've used most just about everything out there, with mixed results. At the low end, are consumer-grade soldering stations that include variable temperature irons with replaceable tips. For most people, this is more than adequate. Apply heat (called dwell time) for too long and you run the chance of lifting pads, damaging the PCB laminate, (small voids, called blisters appear in the substrate, or in extreme cases, the board is charred) or melting the insulation when soldering wires. Too little heat, and you can end up with a non-shiny, cold solder joint, which will plague your work with continuity problems. On the high end of the scale are irons that self-adjust their tip temperature to the application. The first time I used one, I couldn't believe the results. These are hands-down the best thing to improve the soldering world and are the standard in aerospace companies doing high-reliability soldering. There's no guesswork involved. Place the clean tip at the joint, and simply paint the solder, allowing the heat to do the work. Adequate (liquid) flux allows proper solder wetting, giving a smooth, shiny appearance, with no voids, or wavy lines (caused by removing the heat too soon as the solder flows.) The MetCal MX-500 is my goto iron. (The MFR-1110 is fine too.) Info here: http://www.okinternational.com/metcal/english/globalnavigation/products/hand-soldering-systems OK-Industries bought out MetCal awhile back, but retained the name since it's an industry standard. OKI is a good company. I have an old and very reliable OK Industries solder extractor that makes quick work of safely removing ICs from multi-layered boards. I bought it after using a squeeze bulb-type and many yards of Solder Wick to remove solder. The difference was like night and day. For the hard-core hobbyist, or someone who wants a truly great soldering station, I highly recommend buying a (used) MetCal from eBay or amazon, as well as the required tips, which can easily run $25-$40 each. I have about ten different types, from super-small needle points, to curved standard points, and broad points when more heat is required. Note there is only an ON/OFF switch on the MetCals. Everything else is automatic. This is as simple as it gets. Buying used is the way to go. A little info to reduce common confusion regarding solder: I've used them all, lead-free, (big in the EU) No-Clean, and rosin-activated solder. Stay away from lead-free solder if at all possible. The joints look dull and it requires more flux (and subsequent cleaning) to get a good joint filet (slope/angle of the solder flow.) No-Clean solder is more trouble than it's worth. The point is to use it with No-Clean flux which is supposed to reduce clean-up and speed production as well as minimize fumes that can be deposited on optical surfaces. You end up spending more time trying to get a decent-looking joint (which means continued application of heat) and sometimes, it still looks bad. Wetting (solder flow) action is almost non-existent, requiring more solder. This is useful for throughput in wave soldering applications where you're cranking out 1000 boards an hour. For hand-soldering and touch-up work, it's less than fun. Liquid rosin flux is preferred. A great trick a wise man once taught me is to pour a little in a small tin or plastic tray and let it evaporate overnight. (There's alcohol in the flux.) The result is an amber-colored sludge that will harden over time. I put just enough alcohol (IPA) in it just to make it gooey to the point where it sticks to an applicator, then place it on the joint. This is especially useful when lap-splicing two (or more) wires together. The flux stays in place, rather then run down the insulation as with liquid flux. When I'm done, I place the tin into a re-sealable plastic bag until the next time. A tiny bit of liquid flux (a table-spoon) lasts a year, and I solder frequently. There are many different brands of eutectic solder. Kester 44 is preferred, (SN60Pb40) along with their liquid flux. I keep two diameters on hand, .031" and for the fine stuff, .015" Info here: http://www.kester.com/products/product/44-flux-cored-wire You can buy solder and flux from Digi-Key. This is just a quick and dirty overview. The industry standards for solder and flux I cite come from J-STD 001. The 001 standard has a separate addendum for solder and flux, which goes into mind-numbing detail covering each. If you have any questions, please don't hesitate to ask. CC
  11. First off, I mean this as a constructive critique, no ego, or anything like that. You're fighting two issues here. The first is inadequate documentation. The second is your workmanship, and by that I mean you can easily create more problems than you solve if you don't get a handle on your soldering, you can damage components or worse. . . Few things in life are as satisfying as building something that not only works but is assembled properly. Sexy soldering falls into that category. If you destroy boards and components, you'll end up frustrated and miss out on a skill that is very easy to master once you know how to do it. Practice is a big part of learning (as well as failing, and avoiding making the same mistake twice.) I certify solder operators, and see these types of problems with most every student who's never performed high-reliability soldering before. This board doesn't need to survive a moonshot, but the basics still apply. A couple of observations that if you follow, will yield better results and eliminate bad habits: 1. Put the board away and practice some of the basics for an afternoon; like tinning wires, (do fifty wires on each end) splicing, (I'll address that separately) and through-hole soldering on a scrap PCB. When tinning, only tin the wire up to the point where the solder flows one to two wire diameters from the insulation. (A common theme I'll repeat.) 2. Use the right tools. That means the proper flux, acid brushes to clean the flux with and good-quality wire. The old adage, "Good tools do a good job" is a fundamental requirement for decent soldering. You needn't spend big bucks either. I recommend spending the bucks for an Opti-visor. http://www.techni-tool.com/298IN072They're worth it, and you'll use them for lots of things. The lighting kit is a must-have: http://www.micromark.com/quasar-lighting-system-for-optivisor,8608.html. Check Amazon.com for good deals on these too. I showed up at work with a set of these one day, (I used them daily in my previous job) and within two weeks, a dozen people had ordered them. For hand tools, solder wick, (please tell me you're using this stuff!) and nearly anything else you could ever need, this is a great source: http://www.techni-tool.com/ 3. Learn the basics of what makes a good (wire) solder joint. In a nutshell, the filet should be smooth on the pad and tapered onto the wire conductor. Example 1 shows your best joint. Note how it's mini-volcano-shaped. That's what you want on EVERYTHING. The end of the wire insulation should be one to two wire diameters from the solder. Never embedded into the joint and never charred. Watch someone who knows what they're doing on You Tube. (Get second opinions, because there are an awful lot of hobbyists trying to impress people with their new Xmas cameras, reinforcing bad habits online.) 4. Use good quality wire. And by that I mean Teflon-insulated, stranded wire, in the proper gauge. Teflon insulation resists melting and drawing back from the heat. The single-strand, cheap stuff you've got is a PITA to work with. Not impossible, but you need to be skilled in soldering to pull it off. I avoid it entirely. 5. Don't wrap wires for splicing - that's called a Western Union or lineman's splice for a reason - electricians do it - not electronics techs. Twist it all up and where will it always break? On the ends of the wires, right by the insulation - wrapping is convenient, but mechanically stressful on copper wire. Rather, do a lap splice. With properly stripped and tinned wires, line them up end to end with the tip of the conductor one to two wire diameters from the edge of the insulation. Apply flux, (liquid- not paste!) heat, then "paint" the two wires to flow the solder. Not too much solder - you should be able to discern the outline of the conductors in the joint. 99% of your joints have WAY too much solder on them. Again, you should be able to see the wire outline, not a blob on the pad. Heat and "paint" the solder - the flux will do the rest. Clean the remaining flux completely. Apply polyolefin heat shrink (a kit of various gauges is cheap and lasts a long time. You'll be surprised how often you reach for it. NEVER use electrician's tape to insulate a splice. That's for . . . electricians. Over time, it gets warm, and gummy, and can slide or roll off, exposing the joint. 6. Immediately remove flux after each solder joint is complete with IPA and a proper acid brush. Nearly all of your joints exhibit flux debris. Sticky boards attract contaminants and obscure solder defects. And they're . . . sticky. . . nasty. 7. Use the shortest lengths of wire to do the job on the PCB. That means forming them into L shapes or whatever, placing the leads through the holes and taping them down before applying solder. Your board will look professional and be easier to troubleshoot if required. Fighting a rat's nest or worm orgy is no fun. I've attached one pic w/examples. More if you need them. Practice and you'll be a pro in no time! CC
  12. For DC applications, Polystyrene has been largely eliminated by polyester (Mylar) film capacitors. One bonus is the Mylar caps are a lot easier to find. CC
  13. I've used Visio professionally for fifteen years to create schematics. There are lots of programs to create them, as well as simultaneously building PCBs or logic testing circuits as they're designed, but for all-around ease of use and interchange between Word and PowerPoint, Visio is hard to beat when all that's required is a schematic. I once worked in a place as a consultant where the principle engineers were delivering schematics in different formats. It looked like multiple companies were designing the electronics on the same floor. As the end user, I sat everyone down and told them we weren't leaving the room until we standardized the documentation. Every drawing had a different look and it was driving me nuts. Based on my recommendation, (I wasn't a Visio user then) Viso beat AutoCAD -which was used by one guy who had been around forever and wasn't about to change "his way". AutoCAD was total overkill for a 2D environment - trying to get revisions out of him was like pulling teeth. The AutoCAD designer went ape$h!t and walked out the door that day. He was as hooked on complexity as I was on simplicity. After that, all of our docs had a common "look" to them and once I subsequently learned Visio, was able to make changes on the spot. TI has a common look to their documentation, which make learning the circuity and troubleshooting much easier. Most large companies have a standardized format designers and tech writers are required to adhere to. Visio can't do everything, but there are circumstances where it works very well and is affordable for the average home user. Best of all, it's very easy to learn with a workflow that has commonality with other Microsoft apps. CC
  14. Is the picture of the board w/components supposed to represent the schematic above it? If so, it doesn't (without seeing the reverse side.) If not, never mind. Posting a pic of your board would be easier to find any wiring error(s). As for the determining the pinouts of the pots, (without a data sheet) use your multimeter (set to Resistance) across the two outer contacts. You should get a single resistance that doesn't very when the trimmer is rotated. Then measure from one end across the middle. When turned, the output resistance should vary. CC
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