Hobbyist electronics and amateur radio related videos and comments. Typically, videos are posted to reflect what I am doing or thinking about at that time.
@DB7BPB, I don't have access to a copy of it any more. The article I used at the time was published in the ARRL's QST magazine: APR 2010 - QST (PG. 65) Adapting Aviation Headsets to Ham Radios (Hints and Kinks) Author: Raydo, John, K0IZConvert an Aviation Headset for Amateur Radio Use (Feature) Author: Russo, Richard, KB3VZL Unfortunately, one needs an active ARRL subscription to access their QST archive, where this article can be read. If you can find an ARRL member (my membership lapsed a few years ago), it is available to review, and it works. I hope this helps you track it down (and reminds me to restart my QST subscription - it's a great magazine).Good luck and 73 de Matt, M0NJX
Great video, this might explain why my TX5 is in the tank. I set the radio aside several months back during a move and thought I'd pick it up again. Will certainly be inspecting these FETs and surrounding circuitry. What did you use to replace the 2SK2973? Seems that they're no longer available at DigiKey or Mouser?
@BurressEd, I hope the video helps in some small way. I sourced four original FETs (new old stock) on Ebay. There are a lot of smaller independent electronics component sellers that offer genuine NOS items: I am based in the UK, with personal good experience of Cricklewood Electronics and Silicon Ark Electronics, which have had hard to find parts at a fair price. The video is my genuine experience of troubleshooting and effecting a fix. Best of luck in your own adventure!
@theheathkitshop2424, I measured it higher at 4.2V. The TX5 line is perhaps not an ideal 5V in itself, as it only enables bias circuits as required, so perhaps the difference from 5V and my measurement is still sufficient to operate. My investigation through TX5 did resolve the issues (bad pre-amp FET), but I could not resolve that 4.2-5V difference.
@@robgooderham7344 Thank you for watching and your feedback. I made the video initially to record what I was doing, to share with the owner the progress I was making and ultimately morphed into the video presented here. I am not trained in electronics, so this really is just a bloke having a go and actually solving the problem (check out Part 2 for the fix)
There's a 6.4V drop from the top of the circuit to the bottom of the zener. At the "input" to the wilson mirror, that is is also taken up by two diode junctions, say ~1.3V, leaving 5.1V. The resistors down the input line to that point are (10k + 2.5k + 91k). Following ohm's law, we can divide 5.1 by that to arrive at around 49uA of current coming down that line, which is mirrored on the output. For "normal" zeners, they usually hold a 0 tempco closer to 5.1V or 5.6V. BTW for the ...next time you are building such a current mirror, I suggest to weld the BJTs right next to each other so you can bend them to literally touch their bodies together. Even dab a tiny bit of thermal compound between and then superglue to hold it in place if you wanna go ham. The diodes themselves aren't temperature stable but their shared temperature keeps the mirrored current stable.
@ivolol, great analysis 👍🏻. Thanks for watching! I appreciate your good observations. I had thought of physically fixing the transistors together, but thought the ambient air would be essentially uniform enough… but perhaps I could do better.
Use 425 degrees and 25%. Preload the pads with a little leaded solder if you have an issue. Always better to use higher heat and less working time around surface mount components. Karl
@karlfell3768, thanks for the guidance! Glad to see I was not too far off the mark - and a few others have recommended adding leaded solder to pads to help soften/lower the melting point 👍🏻
I never solder without removing the board from the device. It is very dangerous. The easiest way to desolder a part that is soldered with lead-free solder is to add a little regular solder and then desolder a part. Congratulations on the successful repair!
@ukrainehamradio, yes, I did debate to remove the board first, but as the FET was “right there” at the edge and seemed accessible, I did it in situ. Thanks for the tip about ‘presoldering’ to remove soldered items, as adding lead solder would ease the solder mix to aid removal 👍🏻. I am pleased personally to have achieved this repair, as I continue to learn about electronics and repair. I am equally pleased the owner can enjoy his rig (20+ years so far; taken all around the world; keen SOTA activator) once again.
@richardsage3139, just looking at the schematics, you will notice that tx and rx on all bands pass through the same filter network section of the rig. If it has stopped working on 2m and 70cm, but works (rx and tx) on HF/50m, then I'd look at the switching relays: on tx, there is relay RL3017 that switches HF&50 / VHF&UHF, and transistor Q3021 that signals to this relay to tx in VHF or UHF - if either failed, it might operate only in one (HF&50) and not VHF/UHF. But I cannot explain rx VHF and rx UHF failures by relays alone, since these bands have different signal paths through low pass filters (VHF) and specific UHF high pass filters.... I do see however, in the block diagram, a diodes D3003, D3005 that control rx/tx of VHF and D3004, D3035, D3006 that control tx/rx on UHF. If a pair has blown, this would kill UHF/VHF in tx and rx, but leave HF/50 working. Get the service manual (google it), look at the Block Diagram (p. 5) and work from there... good luck!
Thanks for this very helpful description how to mount the pulser. Before the video, I was hesitant to buy it since I was unsure about the installation. It perfectly worked with your description.
Just got my Quick 861DW just over a week ago. Didn't quite realize how much of an upgrade these higher end stations were - how much I was being held back. My first subject was the southbridge of an Xbox 360. Flowed it right off in no time; no ripped pads. Was well aware how much heat travels, but didn't expect the furthest corners of the board nearly too hot to touch. That 861 put a lot of energy into that board. Gonna get myself a large preheater and make a return to BGA and larger ICs. Oddly enough, I'm finding it difficult to find compatible large BGA nozzles.
@nuckenfutz9983, this has been my first experience of hot air stations and equally impressed with how effective these tools are for the modern era of QFNs and SOIC SMD packages. I’ve tried soldering iron bits and pieces in the past, but for anything complicated or which has contacts underneath the device, hot air stations are essential. Suddenly, everything seems repairable!
@stevenmobile1, thank you! Part 2 can now be attempted as I was waiting to obtain a hot air station for the soldering work. Hot Air Soldering and portable HDD repair: Hot Air Soldering and HDD repair ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-H2R2tQW4BRE.html
Your ESD connection. You were not measuring resistance, you were testing continuity. ESD lines usually have upwards of 10 Megaohm's of resistance in line. You don't want low resistance on a ESD protection line. If you did and it came in contact with mains voltage POW!!!! Also, if there was charge on something and you grounded it you stand a chance of damaging it. The high resistance path to ground slowly bleeds off charge while also protecting the device and you should contact with mains voltage happen.
@mikesradiorepair, you are absolutely right: I checked the ESD path and it reads 1MOhm from the crocodile clip to the mains earth terminal. I was in auto-moron mode when I checked it originally in the video, confused by the Ohm in the Fluke display. Thanks for calling it out!
I also have a commodore calc looking identical to yours but mine have a lot more functions. Every buttom has two functions. A lot of them is quick functions like miles to km, fshrenheit to celsius, pund to kilo and so on. Also more different collours on the buttons. But the brown plastic case and the wi dows with red diggit is the same. Unfortnately the label under the calc is gone. Commodore proberly made some different versions of it.
Sounds like you might have an SR1800 model? They made a lot of models in the 1970s, as calculator-on-chip advances made more and more functions possible. It was a tremendous period of innovation, matched only by the commercial success and explosion of calculators in every household, engineer's desk or accountant's office. These old things are a time capsule of a period when the act of calculation was visible to a person, and admired and valued for its speed and accuracy. Nowadays, we are totally ignorant of the immense calculation speeds in a little black chip in a smartwatch or smartphone - once the processor speeds reach millions or billions of calcs per second, things stop being a perceivable event and become a background thing to be accepted as just *there*, like sunshine or air :-)
@@queueriousso true! Somehow I kind of pity young people because nothing can be special for them. I still remember when unpacking my first computer, a commodore 64. That event was very special but today no electronic hardware can make me curious anymore. By the way, I also had to change the battery in my commodore calc but now it works great. As a matter of fact, I still use a fysical calculator almost every day, I prefer them compared to the app calc in the phone. This commodore 4190 is going to be my new to go one.
I had no idea this mod was available. I never installed my Telrad because it deployed double stick 3M tape and I intended to make a 'scope mounting rings attachment bar for it. I had never thought about how I wouldn't be able to see the target object behind the glowing rings. I'll give this a go too. 73 es cheers.
Hi Steve, yes do have a go. The ability to control brightness and duration of pulses has helped me enormously when star-hopping and tracking down galaxies and nebulae. It’s a straightforward official mod. Also, to prevent dewing of the glass Telrad screen, I use a 100ohm high current resistor, TO-220 style, soldered to a scrap of single sided PCB board, and wedged into the base of the glass/body. Runoff 12V battery, it heats up nicely and dew evaporates easily. 73 de Matt M0NJX
@DavidHodgson-rm5gw, I dont recall the values unfortunately. I certainly didn’t use special values, and would have used a capacitor that was at hand. Start with a larger value of C (say 1nF or 1uF) and try some random wire coiled up, and see what happens. The frequency should be 1/2pi(sqrt(LC)). Good luck and thanks for watching.
For me with basic understanding of electronics but knowledge of resistance paths I totally understand your way of thinking. Only de soldering can give you the right measurements but that’s not desirable with those small parts. The FET seems to be the suspect.
@prillewitz, Yes, the comments I make about the resistance values I measured are observations that support the hypothesis that the FET(s) is/are dead in the pre-driver circuit. The logic is consistent with a bad FET fault. I am saving up to get a hot air solder station soon and to start the repair. I have another small repair that needs this tool too (a dead portable HDD that I need to get working again). I shall post the repair outcome in a few weeks I hope. Thanks for watching!
@carl-gunnarhillefors7612, Part 2 is in the works: I need to get paid, get a hot air station, get some practice, do the repair, and test the result… I hope to release Part 2 in the coming few weeks!
@terencekaye9948, my printer is an old Samsung M2020 laser printer. They stopped making printers and sold the business to HP. But it still works well, using toner (incredibly fine plastic powder)…
@nandhakumara4082, I dont recall the capacitor value - it really is not that important. Try something you have at hand and experiment. The inductor was literally a coil of some wire I had on my desk: again, not a critical value. With any L and C values, this circuit will work. What will change is the frequency of dates oscillation. Good luck and thanks for watching.
@chrisj0, "Will our hero get a decent hot air solder station? will a new FET bring the radio back to life? Stay tuned for the next dramatic installment of Queuerious Guy: Trapped in Electrospace...!"
I've recently bought a Torque T-100 3 to use my bass though occasionally... But...the reverb appears non-functional. Do you think this amp needs a dedicated footswitch for the reverb to work? Also...I can't hear any springs "doinging" about inside when I move it about...so is it another type of reverb...rather than a spring reverb? Any help would be greatly appreciated 😊
@christoguichard4311, from what I understand, the 'spring reverb' works by taking the electric instrument signal from the amp circuits, to a transducer (something to convert electric signals to sound (motion) waves - piezo perhaps?). These sound waves travel down the springs - which takes time - and at the other end of the spring, there is another transducer that converts the motion to electrical signals once more. This creates a delay heard in the speaker. I think the more reverb added, the more sensitive the transducer setting, until you can hear the reflections of the waves along the springs, which creates some echo too. To check if it is a spring reverb unit, look for the spring unit inside the cabinet, near the speaker. It is a large thing, so would fit only inside the large speaker box. There could be a lot of reasons for the lack of reverb in the speaker - broken springs? bad transducers? no electric signal getting into/out of the reverb unit.... If you try to check the electric signal path into the reverb circuit and try to debug it. good luck, and I wish I could help more.
@americanteeek It is from John Raydo, K0IZ, published in the ARRL’s magazine called QST in April 2010, p.65 entitled “adapting aviation headsets to ham radios”, part of the Hints and Kinks column series. My URL link does not work any longer. If you can find a ARRL member, they will have access to the QST archive and this article. Unfortunately, at this time my membership has lapsed. If I find it online, I will repost it here. 73 de Matt M0NJX aka Queuerious Guy
Oh my oh my! This is just great. The spirit that drove viejo NASA (prior to congress shoving its oar in.) What can I say? "Thanks" would be a start but would never do this video justice. I like the way you have taken a logic based approach rather than the analogue one that I dimly recall but cannot remember. This has usurped all others in the To-Do list. Respect Sir!
@KL3NCH, I am glad you like it and hope you get good use out of it. I had no idea how to achieve the modification at the outset, and the video documents my approach, thought process and analysis. I’m as pleased with the outcome as you are 😅.
@fluke196c, it is “curious” spelt differently “queue-rious”. I am curious about how things work in science, astronomy, electronics, radio, etc. I usually have a list of things I want to know - a queue of ideas … so I decided upon the name.
First class! I came here after a search looking details for a mod. that I know exists to vary the group lengths randomly instead of five characters per group. I cannot locate that resource any longer. I know it involved an additional switch on the rear panel, and an RC network, but it could have been as simple as a single resistor. This introduction of randomness would really improve the utility of the device. I kind of hoped I'd derive some clue from your circuit exploration, but for me the search continues! Cheers anyway for a great video.
@KL3NCH, many thanks for watching and your comments. I’ve not heard of this hack: rather than 5 character groups, how many might be sent randomly, 1 to 5? Or a larger group potentially? Let me think about how this might be done and see if I can work something out. I am not very experienced in electronics, but I love a challenge! 73 de M0NJX aka Queuerious Guy :-)
I uploaded a new video of doing this modification. This might be what you wanted to do: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-DJ3cfwxYvLI.htmlsi=7Y7Lj8bVI3-QDh4k
As has been stated, do not over analyze the obvious. Also, nothing beats a very good visual inspection of a faulty item FIRST! I have found many faults JUST visually. Sounds like a high current was injected into the supply at some point. This type of fault can occur when charging a battery and connecting it to the power supply set to a lower voltage. It then becomes an unhappy current sink, likely why the trace blew open. And... yes... practice makes perfect! 👍
Excellent video! You definitely are a very analytically minded person, which will help you learn a lot of the troubleshooting shorth cuts as you go along. A little advice, try not to over think things. For instance, when you found that the 10 volts on the output, was not jiving with the 11.2 volts on the rail, I could tell from the tone of your voice that you was thinking, "that's not possible". Yet you went on to try and analyze what the issue could be. Go with your logic instead! You knew it was not possible. Therefore a broken wire, trace, or bad solder joint HAD to be the issue. Also, I would suggest, when you feel more comfortable, and have the safety precautions down to a T, try an old All American Five tube radio from the 50's. Troubleshooting a tube radio with point to point wiring (no PCB), will help you see things from a totally different perspective than you are use too. Just remember, they are extremely high voltage (350+DC) and low current vs. what you are doing here which is low voltage and higher current. However, safety first! 400+ volts DC can put you in a 6 foot hole in short order (pun intended). Anyway, it would help you to see circuits from a totally different perspective. That would dampen you over analytical side (cautious fear of missing something) while increasing your logical side (confidence in what you know to be true). It will also help you to evaluate current flow from the correct orientation of electron flow from negative to positive. Doing these logic-strengthening experiments will help take you from an electronic technician perspective, closer to an electronic engineering perspective (EE). Practice utmost safety, thinking outside the analytical box, and following your logic intuition, which I see as exemplary! Sorry for rattling on. My excuse is my old age, and a desire to see you be the best at electronics. Because you have what it takes! Best Regard, Paul
@ElectroRestore, thank you for your thoughtful and impassioned comments! I have to agree with your observations: I have a PhD in mathematics that attests to my analytic and logical mind 🙂 I am trying to raise my game in electronics and repair, as I love the investigation, problem-solving and analysis, and hands-on creativity of fixing things. I just need more experience and core electronics knowledge - this is why I challenge myself to 'have a go' and the sense of achievement in repairing these things is immense! I have considered valve/tube gear, and am starting to grow most comfortable and safety-conscious with mains-powered things - I live in the UK with 240V mains gear. Perhaps in the a future video, you'll see my first faltering steps with tube radios or amplifiers...again, many thanks for your valued comments!
You repeated yourself quite a bit in this one explaining the same things several times but you gave yourself the answer pretty early, I figure there was a break somewhere in the circuit the second you said you had different voltages on a supposed common trace, it is actually pretty wild how much you can find by making a good visual inspection of stuff when troubleshooting. you also could had measured the voltage drop across the trace at the positive output using one probe to your multimeter on that terminal and then pointing in different locations with the second probe in the common trace, the spot you read a voltage across the line you have your break in the circuit. there have likely been a short on that circuit at some point making too much current go from the output into the circuit board burning the trace, likely that replaced capacitor or something been shorted. I would had checked and replaced old soggy capacitors while having the device apart to if I would have it in use often to make less chance of breaking rare parts just because the caps are in poor condition. it´s a nice power supply
Thank you for your considered comment. I appreciate your feedback! I like the idea you suggested (if I have understood it well) to test voltage drops across what should be electrically connected traces/components (there should be zero drop, and when there is, it is a location to investigate). And yes, sorry for the repetition as I digest what I am seeing in the circuit, trying to make sense. I am learning slowly about electronics and value your feedback.
@@queuerious no problem :) I been doing repairs and even design of electronic devices for a very long time now so I probably think in a different spectrum now than compared to when I began to work with it myself too. I am sure you will learn a lot if you keep repairing stuff and it can actually be pretty fun too as you can get stuff cheaper when broken and then fix it yourself. I am too broke to buy stuff new so it kind of been my only way to get stuff broken and then learn how to fix it. But you understood it correctly, when measuring this broken trace a good connection should essentially show zero volts across it. In your case when you would measure voltage across the broken part you would see the differential voltage across your multimeter or 1,2 volts or so. As the voltage potential at the break will have the sum of the different potentials across it. For example if you have 10,0 volts on the output terminal and 11,2 on the common rail to it the difference will be 1,2 volts even if both voltages are positive you will still measure a voltage with the higher voltage marked as positive and the lower as negative on the multimeter. This way you also can know which side of the break has the higher voltage to it at the same time without even using a grounded reference. Electricity is a weird thing right
Linear supplies are much nicer than switch mode but they don't deliver the current you get from a switching supply, at least in a reasonable size. I have both linear and switched depending on the application I'm working on. That's a nice supply
@uvx508, it was instructive to me on how these devices work and I’m glad I did it, building up confidence and some repair/troubleshooting skills along the way. Thanks for watching!
@victorb22622, you are right - an iron can work well and is pretty straightforward. My experience with an iron was that it was too variable to continue using. I found the laminator much more consistent and predictable.
@prickassen742, You will find the link to the circuit diagram in the description - it takes you to the Television May 1989 magazine pdf. I copy it here for completeness: www.worldradiohistory.com/UK/Practical-Television/80s/Television-Servicing-UK-1989-05.pdf Thanks for watching and your opinions are as valid as anyone else.
Why would you put it in a plastic or wooden case!? Why does it say put it in a plastic box and not a metal box!? I don't get it? You want the pcb to be RF isolated right!? Put the whole thing in a faraday cage!? Except for the probe tip! That is why you also also use coax cable right!? Whay would you want that 60/50Hertz hum All the time!?🤷🏻♂️🤷🏻♂️ You only want to pick up a signal at the near vicinity of the probe tip right!?
I know, that was my first reaction too. All the valve gear tracers with magic eye tubes (eg Heathkits) were in metal cases.... I built it following the article's instructions...🤔
@stevehead365, do try to keep it going. The battery pack would be NiMH or other early rechargeable pack - and they do like to rupture and ooze inside and make a mess.
Shielded signal cables have left the chat 😂 Considering that the whole idea of signal tracing is to determine the quality along the signal path, why are you using all those antennas to introduce massive amounts of random noise into the circuit, defeating the purpose of the test equipment? . Copy/Paste from the article *_"use good quality flexible screened audio leads for both probes"_* 😉
Thanks johncoops6897 for the comment. Yes, the probes use screened two-conductor cabling, each with a single grounded wire external to each probe. This is as the design describes. The remainder hook up wires were a quick test of the circuit, which works well even with the low level of care in the testing. In the final build (currently underway), I will be focusing on how to minimise stray noise.
No, this is a standard A4 laminator. The PCB boards are at most 1.6mm thick, and while the laminator does 'groan' with some noise, it works well to evenly press and heat the copper and toner printing. Thanks for watching and good luck!
