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Fix radio field

[Music] [Applause] [Music] welcome back boys and girls we're in the lab today and this is what should probably have been my first electronics video but but was this the second anyway we're gonna get into it finally electronics and I've had several friends and colleagues fellow ham radio operators and the like who've been saying you really got a you really gotta get to the electronics well this is what I do machining and and fabrication is is a hobby it's a basis for you know gobbling things together and making stuff and doing prototypes but electronics is what I do it's what I'm trained for and it's how I made my living and I spent most of that living in laboratory environments doing a lot of laboratory and calibration and interfacing I've seen all kinds of I started in design electronic design which I really like and I still I still enjoy the technology has gotten away from me a little bit I haven't exactly kept up with all the all the changes but we you know we've gotten into the surface mount and that sort of thing so this is gonna be a little more serious in terms of what I'm presenting to you I'm this is not going to be a basic electronics stuff I'm going to make the assumption that you are if you're if you're getting your hands into modern solid-state radio you know transceivers that you you know enough about electronics to know whether or not you should have your hands in it and if you know that if you know that much that I can I can talk to you on that level I will go through some basic system training on you just how to think your way through a problem these these radios pull these electronic devices today that they're fairly complex electronic the electronics of radio hasn't really changed much some of the devices and techniques you know the integrated and balanced modulators and things of that nature had have changed things slightly but basically that's all the same the control systems have gotten a lot more complex though the proprietary chipsets digital controls phase lock loop you know multiple overlapping phase locked loops can quickly become confusing and an overwhelming if you're trying to troubleshoot you know which came first the chicken or the egg I mean we're dealing with a lot of a lot of feedback systems here and it's a loop and if the loops not working right you need to determine why sometimes that's that's difficult without breaking the loop so I'm gonna get into all of this sort of stuff and you know I know we'll we'll we'll try to simplify or whenever we can and then build on those those concepts but I'm gonna tell you first off a couple of things that need to be remembered and applied and I don't care whether you're you know you know playing around with a you know a simple little code key oscillator or you know the latest and greatest you know yaesu eft whatever they've got out there now with all the bells and whistles I'm not really into solid-state radio you know I'm sorry solid-state it the software-defined radio so we're not gonna be playing around with any of that so anyway the first rule of thumb is wanna know first or second maybe the first the first rule of thumb is it's been my experience that 95% or more of all electronic problems freaking connectors and I and I say that with that emphasis because they are just the Bugaboo connectors are then they never seem adequate you know if if you need a 10 amp connector you know you probably should be using a 30 I mean they're just awful the a good gold-plated connector with lots of surface contact area is you know obviously your best bet and that's really what you get to work with usually it's some sort of you know tin plate cat plate whatever and the contact surface area is you know if if you've if you've got 10 or 15% of true true metal to metal contact in a connector you're probably ahead of the game and the spring tension the actual contact pressure is usually not very much especially if you're dealing with a multi connector with lots of contacts if you had really adequate contact pressure on every contact you could you couldn't put the thing in and out you couldn't plug it in and out of just you know the forces would be so great so contacts are always a problem so they need to be clean and you know you can polish them up with a little a q-tip and a rubbing your some rubbing alcohol or something along those lines if you need something more abrasive maybe a brass or a metal but I don't like Mina steel brushes but little brass brushes you know anything to to get the surface corrosion off don't go spraying you know blue stuff or deoxy tore anything through your radio I mean I know a lot of people advocate that it's not a good idea if you want to use an electronics cleaner use a you know quick evaporating I got some here electronic cleaner something that evaporates it's clean doesn't leave a residue if you feel you absolutely need to put something on a set of contacts whether it's an edge card connector or what have you but you feel that it's in an environment where it's going to be subject to moisture and you just want to give it a little surface protection I like silicone grease you know a thin film with silicone grease is usually it works pretty well if it's a real high current connection like the the 20 amp power connection between your not not this end of it but you know you've all seen you've all seen these you know these these 20 amp for wire ribbons on the you know a CSI comes Kenwood's what-have-you at the terminal end where it's screwed to your fuse block or power supply or whatever I like something called Copperweld in Copperweld that's antenna wire copper shield kop are shield copper shields made by allen bradley it's a non acidifying very stable highly refined grease which is laden with copper finely ground copper you can also use never sees the real never sees is uses nickel the I think primer tech I don't know about promote I'm not sure about their their version of Nemesis but I believe the Permatex and some other brands use aluminum don't use that you don't want the aluminum but a metal bearing grease for high current connections silicon or a silicon dielectric grease for everything else including coax connectors I said in another video and I'll say it again the best way to keep moisture out of a connection is not to wrap it with all kinds of Voodoo tape and sealants and goop the best way to keep anything out of a connection is to fill that connection with something else preferably something that is that abhors moisture a good dielectric grease fill that connector up screw it together you're done that doesn't mean water migrate into the coax and and and contaminate the shield and the insult and the dielectric and all of that but when you take that connector apart it'll be clean and and that's important because that's the connection the problem with connections is when they do begin to fail even before they actually go open they start to become nonlinear they start to react like a diode and for for radio applications that's that's awful I mean you start to create you know tremendous amounts of harmonics you know the antenna connection is where the tubing slides together in aluminum radio antennas you start to get diodes in those after a few years of being up in the in the weather and you know also the neighbors are complaining about you know TVI whatever though nobody uses TV antennas anymore so it doesn't really matter but you you get my point your rectification not good not a good thing in repeater sight so I could tell you stories about rectification at repeater sites in every piece of metal in the environment including the building structure but we won't go there today okay so connections connections basically sock always be suspect of your connections wiggle things touch things poke things fried things while they're live active and receive transit whatever I like to use I have fiberglass fiberglass and bamboo chopsticks worked very well chopsticks by the way can be carved to make tuning tools and all kinds of things I'll go over equipment and tools and stuff in a moment I may never get to this radio I got a TS 440 here that we're gonna we're gonna go through we've got its got VCO issues I believe which is nice to know what the problem is but we'll still get into some trouble shooting technique okay so connections I could go on and on about connections I'll bring it up again as opportunities arise so yeah poke things prod things a lot of times you'll find the problem is simply a connection anything anything that's spring-loaded you know fuse connections contacts if they get hot the springs weaken even even the best beryllium copper will will lose its tensile strength if it gets annealed from current heating okay moving on rule number two and this is really important and I I see it all the time I have seen it in every system I have ever been involved with dealing with technicians who they whether they are factory trained in there their product or just hobbyist it doesn't matter it's a common it's a common floor fault of our novice technicians the uninitiated let have let's say don't guess at what the problem could be a lot of times somebody will sit in front of a piece of equipment it's not working and they go well may-maybe it's this and they'll start poking with something and say well maybe it's maybe it's that no sock poking with something and they do maybe maybe maybe maybe maybe and you can do maybes forever this is my rule call it you know marks rule or whatever the number of things in any given system the number of things that can be wrong are like a geometric it's like a geometric square you know you can multiply things by all of the factors that are required for the device to function properly and you can play maybe it's this maybe it's that for a long long time and never find the problem the quickest way to determine what's wrong with any system is to go down the list of what is required for that system to function it's a much shorter list by leaps and bounds it is a much much shorter list and yes it's kind of kind of boring and it's kind of simple and it may you know it may make you feel as if you're not the brilliance you know tactician that you'd like to think you are or technician or whatever but it is a very effective tactic you know start with is it plugged in you know if I have an external power supply is my power supply giving me the proper voltage is that voltage reaching the radio do I have a wiring problem you know just do are all the wires energized this this thing here that I showed you before this has four wires well what if one wire is open well let's let's say one positive leg is open and the two grounds are good it's two grounds two hots and that leg isn't quite carrying the current you need so Yuki the ready it works fine and receive and you put it in transmitting yeah it gets kind of squirrely and Wakko and she what the heck's about it you got this voltage drop across the one wire or maybe powers not being distributed evenly in the radio because you've got one wire bit so do you have power okay after that I like to go I like to find in any of these devices almost all of them have in it but I do do a V our board is the voltage regulator board one location whether it's part of the power supply or separate from the power supply often separate from the power supply there'll be one board that will contain a bank of regulators so you'll have maybe one or two regulators for eight volts which they tend to like to use for switching you'll have five volts obviously if there's logic in the radio this probably be five volts now the newest stuff is down to 3.3 volts you might have a 3.3 volt regulator and you'll have a number of voltages in the radio that will be labeled with the T or an R you know txb rxb which are switched so are those voltages there are they correct and they're easily they're easily found they're gonna be they're gonna be on the pins of some header on the board you know look at your schematics look for those if you have a service manual a lot of times they'll outline all of those lines in red which is very convenient okay so do we have power and so far what we're using is a voltmeter very simple if you have access to an oscilloscope an oscilloscope is fine I like an oscilloscope I've just become very accustomed to an oscilloscope I never trust meters especially digital meters I like analog meters I use digital meters for setting specific values where I need to see you know thirteen point eight zero zero zero zero there are you know is that where I need is real specific number accuracy yeah I'll use a digital meter but for just general troubleshooting I like to see is my voltage wavering on a meter and I've really an oscilloscope guy I like the oscilloscope I like the very high impedance you know ten to one probe and I just you know go poking around and you get to see all kinds of other things like it's the noise on the line you know some of these radios will simply not function right if an output capacitor on a regulator is bad usually on these little three terminal 3 terminal 4 terminal regulators you'll have like a 1 microfarad electrolytic on the output side I've seen them go bad and the output of the of the thing will be negative you put an analog meter on there or digital meter on there and you'll see an average of 5 volts it looks fine you put a scope on there and you see vive volts plus or minus some sort of oscillating signal that could be as much as 2 volts a lot of stuffs not gonna like that not gonna work with that you got a bad bad output cap on a regulator so simple stuff do you have power do you have power and is it correct both to the radio and inside the radio okay so go down the list of what do you need after that you have basically what is a radio it's it's oscillators and mixers oscillators mixes and amplifiers a'lamin that so do you have all your oscillators there are they operating at the right frequencies and the right levels do you have first local do you have second local if you have local oscillators and what frequency are they are moving on do we have mixer action is the mix of developing an output now here's where it gets to become a little Ricky if you don't have certain kinds of test equipment mixers are always going to well now I shouldn't say always balance mixers woman but anyway generally mixers will always display quite a bit of their fundamental inputs so meaning f1 and f2 will be very prevalent I mean you'll have lots of f1 and f2 at the output of the mixer the product that you desire which is f1 minus f2 + f2 minus f1 + f1 minus f2 you know is for whatever + and - all of those products are going to be selected for in following stages so if you go directly to the output of a mixer if you see anything anything at all usually one of the one of the inputs is going to be significant that's primarily what you're going to see you're going to see either f1 or f2 in predominantly so if you're if the output of your mixer is supposed to be 455 and the input is you know 8.33 and you know whatever you know 9 roughly don't expect to see 455 in the output but if you go one or two stages beyond that yes then you should definitely see 455 all right so do I have oscillator input to my mixers do I have output from my mixers and at that point if you're like troubleshooting a receiver obviously you probably want to bring up a signal generator and put a signal into the radio don't use the antenna for a signal source don't listen to you know noise on the air and try to get an idea of what's going on with the radio use something that's a little bit more stable and what I used to do I used to cheat before I had all of this these fun toys up here I used to cheat now you see I used to generate signals for tuning up VHF UHF stuff by using the local oscillator of his scanner and simply tuned the scanner to either 455 or 10.7 above or below the desired frequency depending on how it worked but usually you can program a scanner above or below its if' and localize you get enough leakage from the local oscillator in the scanner that you can plug it into the back of the radio and you have a pretty stable test signal may not be the level you want but it's stable and it's there and you can hear it and you can tune off it and head or dine it and all that that's kind of kind of nifty so yeah you need a test signal would would be preferable if you if you don't have a signal generator you can use the harmonic of just a dirty oscillator you know make yourself a little the single transistor crystal oscillator plug crystal in there and two into our harmonic of it it'll it'll be there you'll find some signal but symptom generators are nice to have even a cheesy one that floats around I I don't have any I don't have any cheesy ones anymore I sold them off or giving them away but I've had I've had some of the simpler I go and and what was his scent core and there's a whole bunch of them that I've had and they work I mean they generated signals they're not you know calibrated they're not stable but they work alright at war and market generators a lot of the radios have markers in them I mean just turn the marker on that's that's an excellent source of signal just you know troubleshooting receivers okay so my point is look for things that should be there so after that you get into more more detailed troubleshooting like looking at looking at voltages and when you look at voltages in circuitry a lot of times it's damn near impossible to gain access to a circuit point or to have a reference I'm even with the service manual they're not going to give you all the data that you might need so here's where you need to use some common sense you need to look at a circuit and you say well gee if I have a transistor and you know it's a it's a common common collector amplifier voltage amplifier you know and it's it's being fed with 12 volts through a resistor then I should probably see maybe I don't know six volts eight volts something like that at the collector and if you do then you can assume that that transistor is probably biased on and and functioning some RF circuits you won't see that because they'll they'll feed the collector through a very low impedance device I get like a choke like a little inductor so you will see you know B+ will be all the way up at like 12 volts so then you go to the emitter and usually there's a little feedback resistance on the emitter to ground you know maybe 100 ohms or a thousand ohms or whatever and you see a little voltage there okay that transistors biased move on don't worry about the specifics I have rarely rarely if ever found the voltages stated in the service manual or on a schematic are accurate they're close plus and minus 50% is not unusual you know if something specifies all we should have three volts here and you put a you put a probe on it and it's 2.1 or 4.2 or something it's around three volts really there's that much variation in in these circuits there shouldn't be ideally the engineers should design their bias circuits so that they are more self-stabilizing to accommodate for changes in a device gain but they're not and you know they could be all over the place some brands are worse than others I won't say which oh I will get all kinds of hate mail if I start telling people what I like what I don't like you might find out though it'll slip at some point let's see so look for what should be there it's boring it's tedious but you know what you'll get through it much quicker you will be able to go to lunch saying okay now I know what's wrong how am I gonna fix it what do I need to fix it as opposed to coming back from lunch and saying oh what the hell's wrong racing trust me look for what's wrong it's a much look for what's required not for what's wrong it's a much shorter list lastly static protection now if you live in the Everglades you can pretty much ignore what I'm gonna say you know maybe the Louisiana bayou somewhere you can get away with it but if you basically live anywhere else in the country static protection ground your equipment ground what you're working on before you open it up before you get your hands in it and what's going on here here we go and ground yourself this is a wrist strap it's much like a watch band actually I think does this a Speidel watch band is it's it's been resurrected several times in its life okay so it's a metal watch band after wearing this for a few hours you're gonna get a little you know body moisture underneath the band it's gonna make really really good contact and you don't want to electrocute yourself so it has to be resistive how much resistant anywhere from a hundred K to 10 megohm but certainly at least 100 K it takes only 5 milliamps of current across your chest to kill you what the average resistance of the body is varies greatly but I can tell you when it's salty sweat it's a lot lower so yeah this is I have a 1 mega ohm resistor in this lead C lead I have a 1 mega ohm resistor and a clipped lead and I have a little ground clip on my electrical stuff source and I test that regularly make sure I have good grounds here everywhere and make sure you're grounded I'll tell you a little story incidental incidentally good friend of mine brought me a Nikon nice 756 was it a pro I think was just 756 and brings me the radio and I'm going through it and I'm about to make some modifications radio was working fine nothing there wasn't a repair job I was about to make some modifications and I noticed on the back of the main board that there was a number of broken connectors not uncommon don't transport for here's another rule thunk don't transport your radios with things connected you got plugs and wires and cables and jacks take them out you're gonna carry it around you're gonna move it take them out take the wires out that's how you break break connectors on boards so I noticed that there's a number of connectors on the back of the board that are indeed broken the solder joints have broken boards not broken connectors are okay but they're not making contact they've the solder is broken away out of the boards all right let me let me just zip this board out and fix this up side of these connections up put it back together and it was in the summertime it's usually fairly humid down here I usually actually have the humidifier going dehumidifier I put the radio all back together and I've got no display hmm no display what the hell could be wrong so I make a long story short I go through the radio and it turns out to be this one tiny little 8 pin surface-mount chip little tiny flat pack is the eighth of an inch square if that much with 8 leads on it and it's a dual inverter it's a pair of digital inverters and it was being used solely as a crystal oscillator - you know the inverter was you know I had just had a crystal across it and that was the clock for the video processor I guess the GPU and okay well gee that's huh thank God it's not some proprietary chip that I can't get it's just a little too - gate oscillator - - gate inverter so I look it up and it's an obsoleted part nobody in the States has it not Mouser not allied not certainly not I come nobody has this little chip I can't find this stupid little chip it's a stupid little - gate inverter I can't find it it took me two years to find it I finally found a vendor from China that had glommed a stock of these things and was willing to sell me less than ten thousand pieces this is the problem we have with manufacturing United States but I'm not going on to that you know these these vendors want to deplete their inventory it's costing the money and government's taxing them on it they're not selling the parts nobody wants them get rid of him and they sell them off to China who's got lots of warehouse space and will eventually sell it back to us at ten times what they bought it for so I did find a vendor that was willing to sell me ten pieces so I now have ten of these little oscillator ships should I ever need them again but here's the kicker it took me two years and I would be like every couple of weeks I would be back online I had all kinds of feelers out Alibaba kept sending me messages for 10,000 pieces yes I got the chip I put it in the radios working two years later did I learn my lesson absolutely am i really careful about static 99.9 percent of the time was I careful enough this time obviously not and I learned my lesson so please don't fool around with static make sure you bring everything to the same potential touch the chest you touch the touch the board's before you take a tool and stick it in there make sure you're discharged beep oh where is it I don't see it here somewhere somewhere here I have a can maybe it's empty I might have used it all static guard I want to say clink free but that's a dryer sheet there's a product called static guard and we I think it came out in the 70s and the disco the disco girls used to spray it on their polyester skirts all the time so that their skirts wouldn't stick to their hose and ride up their backside which was kind of cute but you know anyway static guard it's in I think it's an ammonium salt it's an organic ammonium place sulfide salt anyway it works really well I spray it all over the place because I have carpet in my radio room here and yeah I can I can generate some static so there's lots of all this carpets so dirty and damp these days that maybe not so yeah grounding I'm not gonna get into talking about you know power sources obviously you should have you know properly fused power supply to your work area and don't cut the ground connections off your devices a lot of guys a lot of people will say oh don't use a grounded soldering iron because you can construct things out or that's a crock of horsepowers if you're using a soldering iron the device shouldn't be powered up there is no problem with using a grounded soldering right I don't know that there's any problem using an ungrounded soldering iron provided that it's you know static discharge I mean that's easy enough to do just touch it to the chassis bring everything to the same potential can you get everything to zero maybe not but if everything's at the same potential you know you shouldn't have a problem but it's those little charges it's those little things that will kill you something as simple as I'm sitting in there in a in a chair here and something as simple as spinning around to answer the phone and sliding my feet across the carpet and then spinning back I can pick up an incredible charge and you know I moved my feet ten inches but I was away from the bench whatever I did over here at the desk I was away from the bench I've built up a charge grounding static okay so I think that's enough of my BS for the moment maybe I can edit some of this crap out let's get into this radio [Music] [Applause] [Music] you