What does a bad transistor sound like. A bad transistor will read otherwise.

What does a bad transistor sound like tube – sound differences. Alan0354 Super Member. 2v for junction losses. What does a bad u-joint sound like? A u-joint that’s dry (from a lack of grease) or worn out will usually make a cyclical squeaking or clicking sound. solid state power amplifiers of either silicon transistor or MOSFET based that can rival the sound quality of single ended zero feed back triode audio power amplifiers based on either the 300B or the If it turns out not to be the diffamp, it still sounds like front-end. You'd think if it was just Mr. Changing the temperature is a better way. In other words we call it a It seems that my next step is to re solder all transistor points and see if that's the case. Nikko newbie Active Member. Bad caps cause a lot of electronics to fail long before they should today. Here are a few sounds that can indicate a bad It's usually caused by bad transistors in the differential stage of the power amp. Many who are not actually familiar think quality comes from inspection. First. So, stay with The Drive’s crack informational team as we walk you The output transistors are getting hot because they are conducting too much current. The truth is that if you are relying on inspection, you have already lost Attached is a image of what the board looked like when the 2 resisters blew (R100 brown black brown gold) and the second image is what the amp board looks like. It is better to look for the causes of poor sound transistor amplifiers in their schemes. Again, I recapped the entire unit, replacing all elctros. can also be smoothing capacitors in the power supply or rectifiers . It is a bit tedious to replace this transistor so before I begin, I wanted to ask if periodic low frequency "thumping" could typically be caused by a bad Anyway, I would like to have an idea this early so I can plan on what transistor to use for best audio amplification. I actually like op-amps better than transistors or tubes, but I use transformers to color the sound to simulate what I believe to be the prevailing characteristics of acoustic space but a lot of that comes down to the associations I make of music being something that occurs in an acoustic space, and also what I consider the salient Sub has power, but no inputted sound will come out. Sometimes the starter may fail suddenly, and other times the failure is intermittent as the unit slowly Alternator sounds can sound similar to other problems, so you should usually take these sounds and combine them with other signs of a bad alternator before diagnosing it However, after about 30 minutes of play it suddenly goes into am amazingly bad sound – massive distortion, crackling, . The primary (but by no means only) form of Transistor vs. There should be continuity there, assuming the amp It really did sound like Royce's voice, it's quite distinct. As the What Does A Bad Engine Mount Sound Like? A bad engine mount often produces clunking, banging, or rattling noises, especially during acceleration, deceleration, or when driving over bumps. It is traditional that transistor amps have negative feedback - usually lots of it. thanks again, i have had a hard time You are right, transistors don't really "amplify" anything, it's more like "replicate on a larger scale. But, in this circuit, negative feedback is not present. Same They do have a sound, but no small part of that sound is the noise they tend to make. Lots of distortions can also sound like fuzzes, especially if they are transistor based and have a bias control. , would it still sound 100% the same as before with the triad? If the reception is poor, look at the antenna’s length (about 2m) and placement. Capacitors can become "staticy" and I bet resistors can also. Bias is an issue that is a bit foggy to me and can certainly cause trouble for the outputs. Freeze spray and wait (give it time to work) or heating with My guess is that a leaky transistor sounds like an un-biased ge transistor, one that goes in and out of bias. I also thought you had determined from measurements that the power transistor unit was actually bad. A triode is the simplest amplifying valve there is, and a twin A bipolar transistor - properly known as a bipolar junction transistor or BJT - is a versatile discrete semiconductor device. Even in clean arrangements, adding distortion to a bass track can make it pop in a mix, tightening up the low end and contributing tasty upper harmonics that help the bass stand out whether you’re listening back on high-end studio monitors or a smartphone speaker. funny noise could be bad solder, bad transistor, or bad resistor. The various transistors listed here probably have a broad range of sounds beyond this. Sounds like it's time to start replacing transistors. No visibly damaged components. Germanium Transistors Tube Distortion for Juicy Bass. Active Speaker Powers on but No Sound Things have come a long way since then, and although it's still possible to make a really bad transistor amp, no-one seems to want them. It compares the output to the input and corrects it. Connect the negative probe to the “N” or the emitt If you suspect that your circuit board has a bad transistor, you can test for a failure by using a multimeter. The middle section is covered with a layer of insulator (glass) and a conductive layer on top is the gate. Transistors have diodes made of either silicon or germanium. The sound does not change with volume, it stays exactly the same. The output was basically rail voltage, minus maybe 1. In this video I discuss the common symptoms of a failing connecting rod bearings. You see, this method quickly identifies a bad resistor in no time. Because I wondering how much that interstage is influencing the sound. These sounds act as warning signs, helping you detect an issue early before it escalates into costly engine repairs or even a breakdown. Then check all diodes and low-ohm resistors in the same way. 1 - How a Transistor Causes Distortion. Yes there is. Replace all with KSC1815YTA from Mouser or Digikey. Harsher tones What Sound Does a Bad Starter Make? A bad starter’s tell-tale noise is loud clicking. I wonder if it sounds more euphonic in tube mode with the increased 2nd harmonic distortion and if it's jarring in transistor mode compared between them and between normal mode; assuming no distortion is the best; The reinforcing properties of a field effect transistor (like lamps) can be characterized by a slope (ie, the current flow ratio of increment to the increment of voltage “gate – source”). You should check all the components directly connected to a failed semiconductor I think -- usually a shorted one, be it a diode or transistor, also subjects connected components to excessive voltage or current as well. Generally, depending upon the design of the output stage, a failed transistor would probably cause a dead channel, either by applying DC rail voltage to the speaker or no signal What Does a Bad Starter Sound Like? A starter can fail in a number of ways. If its not affected by volume it'll be downstream of the volume control, otherwise its upstream. In very small amounts, and with some programme material, some listeners may like the sound of IMD, as it imparts a 'wall of sound' effect. he's just commenting that the ultimate output power limitation is constrained by the power source, not the transistors. It’s my favorite Wampler pedal because it gets the job done; those cascading transistors sound like a really nice Marshall without the price tag or noise level. So it is critical to choose a power In this #Shorts video I show what a failed transfer case (PTU) sounds like and what the failure of that part looked like. I recently bought a TP-Link Nano USB400 for Bluetooth connectivity in my desktop. It "sounds" like you may have frosted a ground trace. One of the output transistors sees a voltage above it's breakdown voltage, and shorts. They are the biggest cause of noise and bad sound in a power amp, and modern parts are better/working properly. I paired it with my existing Realme Wireless earphones. Hello everyone, For the past couple of years I have been having a weird sensitivity issue with my left ear. They don't sound any different, in principle. Ge While better gas mileage may sound like a good deal, it can damage your engine and may cause even more expensive repairs. If your signal that you want to amplify is what you use to control how much in between the transistor is on and you make on and off much bigger than the original signal, then you have amplified the signal coming out of the on and off port. The output transistors act somewhat like a variable resistor whose resistance changes with the input signal. All of the transistors check out except the four in the RF chain. I *think A Digital-to-Analog Converter (DAC) is a critical component in any audio setup, responsible for converting digital audio signals into analog sound waves. A bad turbo on a diesel engine sounds just like a bad turbo on a petrol engine. Strangely, really bad valve amps are popular in some quarters. 6 ohms. Adding a Fuzz control knob at the Emitter is a great touch, as well. How did you determine that the transistor unit was "bad"?? From your current description, it sounds like you may have two good transistor units and the problem is with the ECU. To see this, imagine that, for some reason (noise or some other disturbance), the voltage at the output of The transistor configuration does not appear to be an effective contant current generator. You are measuring the current in four places and then summing the result. In terms of how bad the distortion is, its on a level wher ethe song can barely be heard , its not a buzz , its crackling in the sound. MOSFET's don't sound like good tube amps But, like all things the final decision rests with you - we can only express opinions. Current is the Effect. I had three driver transistors bad and some over heated emitter resistors on the drivers. Due to improper combustion of the fuel It was an option for the 1956 Chrysler and Imperial cars. Discrete semiconductors vary from diodes and rectifiers to BJTs, and this particular device is designed My list so far (for reference, my board is AW 115-1071 REV. This amp also sounds really good. Author: I agree. Negative feedback is a strong tool for noise reduction in analog circuits. It will sound somewhat different depending on the Does the transistor need more juice? less resistance on the 9v input? also this circuit seems to work fine: TBH it doesnt sound like radio intereference more like an electrical problem. Its not about better or worse, its about a difference. A lot of ideas about tube amps come from the sound of designs more than 60 years old. I didn't notice the voltage difference and replaced the chip. Otherwise means a value that is MOSFETs (the most common type of transistor in modern ICs) are laid like this: there is a giant "bed" of one semiconductor type (let's say, p-type), and it has two pockets of another type (n) - those are source and drain. Sometimes external causes may damage or even destroy transistors. Replace all bad components with like parts. (Image credit: Future) “The rectifier is a diode, meaning it’s got two parts (‘di’) and a triode has three parts (‘tri’). Tube amps sound different from solid state amps. All is OK until you try to run with a larger output voltage swing. 0/USB 3. These can include the car lurching forward or I have just had a frustrating experience with an NPN transistor that came from a pack of 15 "switching transistors" from Radio Shack. 1 Why do Transistors Fail? All semiconductor devices are extremely reliable. There are several reasons for this, although some are not obvious. it looks like s1 s2 sensitivity switch might need cleaning . My favorite was this one, with a BC108 What is a transistor is and how it works, explained quickly and easily Think of it like this, when you hear the sound if someone else's recorded voice it sounds as much like them as your recording sounds like you. I'd try spraying the diff transistors in isolation (Through a drinking straw, etc) and let them come back to temp, checking if they get noisy with the temperature transistion. Gain sounds depend a lot on context, and the same effect can sound like many different things depending on the song. Cracked solder connections can do this also. I thought my usb port was bad, so I tried switching to every USB 3. The AC system in your car is designed to function unobtrusively and quietly without making any grinding noises. I have a Luxman L-430 that works great, but somehow the sound doesn't quite do it for me. Replacin I will say that it sounds very very good now. I'm not super familiar with the Fuzz Mister, but this sounds exactly like a misbiased transistor. It’s not the usual jack issue that can be motion related, and tends to not be as subtle a sound - like a distorted hiss that is envelope related - it tracks with the sound of the note. Because a typical Bad resistors in circuits. Why does an Ekasi oscillator oscillate? From my research, I learned that when this is first plugged in, the capacitor is charging, so the LED doesn't shine. Let's look at a common bipolar transistor as an example. Of course then the output swings to that transistors rail voltage, causing over Repairing a Sansui Receiver with a hissing sound coming from both channels, one louder than the other. Both silicon and germanium are both on the Periodic Table of Elements, in the same group (14). I have been reading about the I want to know it is sound in theory. Manufacturing Faults Manufacturing faults do (very occasionally) occur, usually in new equipment. A. 1. Try using trimmers for I've got this periodic low-freq thump in one channel of a preamp, and I've traced the source to right around the area of a transistor. Sometimes this will result in a transistor (or a circuit board) not working A one-time problem I had that caused me to misdiagnose a bad STK. Jacks, cables, solder joints, tubes, capacitors (a bad electrolytic Transistor Faults Module 7. The first transistor was invented in 1947 by a team of scientists at Bell An FET compressor is a type of audio compressor that uses a field effect transistor as the gain control element in the signal path. MOSFET's don't sound like good tube amps But, like all things the final decision rests with you - we can only express What Does a Bad Wheel Bearing Sound Like? With a damaged or broken wheel bearing, it may sound like you’re driving over a rumble strip on the shoulder of a The 6BQ5 screen shouldn't be connected to the same power supply node as the 12AX7s - it draws more current than they do, so variation in screen current makes the supply voltage change, which makes the plate voltage on the first stage change, which gets amplified by the following two stages. maybe current source for the diffs, etc. " The amount of energy that the base current lets through is directly proportional to the larger Collector-Emitter current. The specs on the packaging say "Typical hfe: 200" but when I measure and calculate the Connect the negative probe to the “N” or the emitter. This rig in question is a Zenith Trans-Oceanic Royal 1000 made in October of 1958. This is a An nMOS transistor works like this: When a voltage higher than the transistor’s threshold voltage (V TH) is applied between the gate and the source, a current can flow from the A one-time problem I had that caused me to misdiagnose a bad STK. i don't know why people keep recommending them. As temperature rises, the junction voltage falls, and gain There's plenty of threads about known bad transistors, you'll just have to download the SM's and see if they are in the receivers you have. Certainly the 'hiss' that I get from FET's can drive me to distraction. These sounds occur because the Occasionally I have found that an emitter resistor associated with the bad transistor has also faulted but I believe that is a result of the transistor malfunction, not a cause. Like I said before, I do not believe it is the amp because it gets loud. A bipolar junction transistor (BJT) has a negative temperature coefficient. Please correct me if this is not the case. I checked the fuse for the left channel. This helps stop them from getting too hot and causing Transistor Noise. With some online searching i found others having problems with the 2SA798 transistor so I ordered a couple. So what happens it the highs especially sound like a butterfly is flapping it's What you got to do is, temporarily cut the Vcc+ and Vcc- to the amplifier and insert a 22 ohms, 2Watts resistor in each of those power lines. all i see is resistors that get selected . It is pretty simple, so I am just going through and checking every component. Always check the voltages at the transistor terminals after replacement to make sure there are no abnormal readings. 0 Transistor Limitations. Okay, that makes sense, but I didn't hear it the first time. So "holding back current" is a really bad way to think of it. But its limitations are visible symptoms. That's how you would like an output stage of an amplifier to behave: deliver power from the power source Because the electrical signal passes through a glass valve rather than a transistor, certain dynamic and colorful qualities are imparted to the source signal. These should always be replaced in all old amps, even without symptoms. This video from audioholics is a The History of Transistors. The TK-140 gives extra long-life to output transistors. A transistor radio uses a transistor-based circuit to boost sound. Transistors, like MOSFETs and BJTs, can have flicker and shot noise. Whenever it is exposed to loud enough sounds it basically sounds like a vibrating blown out speaker inside my head. My favorite thing about them was variety of sounds you could get by trying different transistors, diodes, input caps, etc. Reactions: KentTeffeteller and Vasil Penev. If the transistor had the same resistance as the source, half of the voltage would be gone, this effect is called "loading". Does not sound like a good idea. To me, MOSFET amps sound like a poor transistor attempt at creating tube ambiencewhy not just use tubes and get it right to start?? Aside from maintenance issues of tube amps, they sound like tubes because they ARE tubes. Taking all 4 faulty Transistors out and replacing with To me, MOSFET amps sound like a poor transistor attempt at creating tube ambiencewhy not just use tubes and get it right to start?? Aside from maintenance issues of tube amps, they sound like tubes because they ARE tubes. Quote from: WEEZ. What does a bad stylus sound like on vinyl records? The needle of your turntable is a sensitive piece of equipment. It’s like making sure the battery stays 77°F (25°C) or lower. All of the transistors check out except the Tapping a transistor that is "cracking" normally will not show a problem. When a DAC is of high quality, it reproduces audio faithfully, capturing A faulty fuel injector can lead to various problems for your vehicle, often accompanied by distinct and unusual sounds. Click to expand 2SC458LG are known noisy transistors. Be careful when testing JFET front end's. One of those assumption is that negative feedback is present. It just sounds like a Steps for Troubleshooting a Bad AC Compressor. If there is a fault in a new It's not a serious amp power wise, it's just the only transistor amp I've ever heard that sounds like a single ended tube amp. That transistor had shorted, sending rail voltage to the input. Transistors sometimes fail producing "popcorn" noise which is exactly what it sounds like. High levels of IMD just sound dreadful with any recorded or reinforced music source. Now, a resistor may be through hole or SMDs. Get a DMM and set it to diode mode 2. The transistor gets a percentage of the signal voltage equal to its percentage of the total resistance. Mar 23, 2016 #7 Ok, sorry I am so ignorant A previous attempt at repair with high voltages at speaker relay I found at Q301 a 2SA798 transistor high voltages. There should be continuity there, assuming the amp But to the person listening, it may sound like a distortion, or an overdrive, or some other gainy sound. Make sure the headphones’ impedance matches the circuit’s needs (2k to 3k). But that comes at an additional cost. It serves to "catch" the pulse of reverse-polarity voltage that comes back out of Re: What does it sound like when an output transformer is going bad? There are a lot of things more likely to "go bad" long before your output transformer. Meaning, these resistors will limit any dangerous (transistor killing current) if As mentioned by u/eastoe you have a noisy transistor on your PHONO board (I have a 2230 on the bench as I type), Either the 2Sc1000 or 2Sc458. Voltage is the Cause. I checked the woofer, 7. i have opened up the amp, The potentiometer looks like your typical unit much like the one you pictured, except the marantz seems to have a small metal box attached to the back of the meter. In most cars, The overall result is that the amplifier sounds louder (because of the additional distortion), but usually does not sound anywhere near as bad as the figures might suggest. A bad transistor will read otherwise. The various transistors in the If the transistor is known to be an NPN type, below are the troubleshooting steps on how to know if a transistor defective. The worst part is that my own voice can trigger it and once it gets going it is triggered more easily for a while. Jun 16 power transistor that has high Cob is like the cap loading the driver transistor in the power amp. My issue my be just a Troubleshooting Common Transistor Amplifier Issues: Comprehensive guide for diagnosing and resolving biasing, distortion, thermal, and noise issues in BJT and MOSFET Unwanted signals at the output of an electronics system are termed noise. For Keeping transistors cool is vital to avoid overheating. Below is an example of what popcorn noise from a bad transistor looks like on an oscilloscope. Fixed the channel. 7V. If its got any significant DC it should not come out of protect, but if it does because of some funky problem it will make a noticeable pop noise. Bad handling of FETs can lead to damage by electrostatic discharge. Bass and distortion go together like peas and carrots. Sony led the way in making their own transistors, raising the bar for quality. If the transistor has very high resistance, it will get the vast majority of the signal voltage and measure accurately. i will check into getting a replacement. and the screen current changes some more. I moved around the room and it Transistor vs. Now onto the next part of your question. I suspect that SETs have more of that "tube sound", at least based on what little exposure I've had with SETs. i often find that 1 in 10 works as noise generator and 1 in 30 works properly (good noise level/sound). Does theTriad HS 29 interstage, have an equal share of the pultec sound? Like, What if you took it out and put something else (substitute) like a Jensen Interstage just an example. This is my true concern. There shaped like little "outhouses and sound like shit" Reactions: merlynski, jberger, Ds2000 and 1 other person. What Is a Transistor Radio. External Causes. It is responsible for picking up dust and "Your TK-140 is equipped with a newly developed protection circuit which guards against widespread transistor damage due to a short circuit which could otherwise occur at the ouput jack. Connect the positive probe of the DMM to the base or the “P” or the base of the above figure for the NPN type. They’re both metalloid materials (containing metal and non-metal materials, like any well-rounded musician ;) and both have atomic numbers (14 and 32 respectively). HOWEVER, different brands of the same numbered transistor, and even different batches of the same numbered transistor from the same manufacturer (brand) CAN result in a different sound in the same circuit, simply because they have different specs, such as hfe. When under 2 watts it just sounds so clear, it kind of baffles me how such cheap components, weird "or poor" design choices can come together and sound really good. Each relay has a rectifier diode in parallel with the two coil pins. . No point in the dispute between transistor fans and valve enthusiasts is defended more passionately than the sound of their respective systems. While better gas mileage may sound like a good deal, it can damage your engine and From plus to minus the voltage is 60 volts. Turn off amp, measure (ohms) from the input RCA shell to the output ground "-". Transistors should be selected in pairs . dly66 Super Member. As I mentioned earlier, the Bad Monkey is a Tube Screamer–style Buffered signals have low impedance compared to passive pickups, which interferes with the desired operating characteristics of the input stage transistor in the fuzz face circuit. So, a transistor using this resistor will draw 12 mA at most and always slightly less. Negative Feedback for Noise Reduction. I have read some threads how the other transistor (BJT/FET) is better, but other forums say that the Jack Gull wrote:i don't like to use 04s for noise generators. The common tie point of the transistors is the amplifier output. Where is this 100ohm bias resistor you mentioned earlier? Putting the switching transistor (Q5 ??) at that place in the circuit looks a bad idea. Nobody then why not do it the first time. What does a noisy transistor sound like? The "sound of transistors gone noisy" has been described often as "snap, crackle, pop" "bacon frying" "wind blowing" or "leaves rustling". I've done a couple of amps in a box, like the Twin Twelve (which sounds like a Silvertone 1484) and the Charlie Brown (which sounds like the classic JTM45 Marshall). Because electronic circuits can cease to function if any one of their Sounds like it's time to start replacing transistors. The very old AC128 germanium transistor had a different base-emitter voltage requirement compared to a silicon transistor and had a poor high frequency response so it will sound different to a silicon transistor. I just posted it to see of the topology of the amp Like a junction transistor, a FET (field effect transistor) has three different terminals—but they have the names source (analogous to the emitter), drain (analogous to the Thanks for your quick response. The fact of the matter is that there is no point trying to make a transistor amp sound like a valve amp, since those who like valve amplifiers will still want to see the So you too could suffer from early infant mortality of your expensive electronic devices, just like I did. The noise amplitude may be large enough to severely distort, or completely swamp, the wanted signals. i was uncertian if this was part of the potentiometer. Then do the same for the driver transistors (the ones that drive the power transistors). It just makes a constant, even, pulsing sound (like a motor boat). key the defective radio and talk, whistle, fart, whatever. But not the simplest scheme . The drawback is that you will experience greater cross-over distortion, the point where one transistor turns off while the other takes over. This article explores in detail what a bad fuel injector sounds like, why these noises occur, and how Yeah so just to clarify, it’s not happening with turning the pots. Saturation occurs when the device ( like an NPN transistor) draws as much current as possible through the collector load. "snap, crackle, pop" "bacon frying" "wind blowing" or "leaves rustling". Bad rod bearing will make a knocking, striking and rattling noise. Even power supplies and the design of the circuit board can add to the noise. In other words we call it a Any “unmistakable” guitar sound isn’t just the product of a gifted musician, nor is it just the result of cultural context; it’s contingent on the combined work of transistors, speakers Resistors make thermal noise. Could be something simple like a loose or corroded screw. Ie, it makes it sound like shit. The FET works by applying a voltage to the gate of the FET, which in turn controls the flow of An important place to start explaining why the Bad Monkey can sound like some of our favorite Tube Screamer–style overdrives lies in its EQ section. They sounded like serious shit, with regular voice drops/artifacts every 5 seconds. in other words, everything will 'seem' to be working up to the This mode puts the transistor into DIAC like mode but only a poor version . First, the circuit as you present it is a bit too simple -- the resistor in series with the battery as shown on this page is necessary, and must be about the right value. When the capacitor reaches 12v, then the current switches to Remove all the power transistors one at a time and check across the pins with a meter for low resistance/shorts. The 2230 on my bench is getting the full meal deal, new caps on everything but the tuner boards, all of the known noisy transistors replaced, trimmers, diodes and new Micas and General discussion about music electronics. I know that cable and jack issues often masquerade as electronics. this indicates audio for modulation is reaching the driver, and the driver is using that audio to modulate the rf it is amplifying. The base current just controls the C-E current, it's not amplified into it. :yes: I know that there are true low noise FET's around, but transistors like the old BC549C's that have been around since the mid 1960's are superbly quiet and are commonly available. For amplification issues, try different transistors like the 2N2222 or the Germanium transistor AC187. N. Three times higher gain sounds like you are using the wrong sub of transistor. It 's better than Le Pacific . Could be the main filter caps C1,2 (6800uf), if these are original then they are long overdue, suggest replace with quality Steps for Troubleshooting a Bad AC Compressor. I'm no good at guitar but that should give an idea of what it sounds like. Provided they are operated correctly there is no reason for them to fail at all; but of course they do fail and this can be for a variety of reasons. Some of the sounds that we associate with bad bearings can also be indicators of problems with other parts of the vehicle, but there are a few tricks to test whether the noise is a bearing issue. Gain ranges can be all over the place with germanium, and temperature variance makes it worse. The history of transistors dates back to the early 20th century. To It doesn't sound like a transistor issue to me. looks like the unit should have jumpers to jumper ext adapt . A good transistor will read a voltage around 0. This circuit gives a good sound . The input on that particular amp comes off a small signal transistor. For those who thought that they sound same as solid state amps, well, I have to say they are all wrong. Jun 10, 2018 #13 Nobody in mass production does 100% QC unless specifically asked for by the customer. V. Steps: 1. Jun 15, 2017 #4 I want to add I knew what I wanted to post, but I choose a bad example. Compare the traditional and well proven G'day mate, that's interesting. In most cars, 3. The scheme from the publication Elektor ( 2004 , No. The "sound of transistors gone noisy" has been described very well above. similar to impedance switch . I changed the original circuit - I would suspect modern amps would close the gap, but older tube designs had a sound quite different from transistor designs. It is a Vthreshold triggered negative incremental resistance until the hold current threshold reverts back to high impedance. Adds static too though. Author: Leonard Krugman The minimum signal that can be applied to a transistor is limited by the internal noise generated by the transistor. I have an old germanium reel to reel, and looping that through the tape monitor does add some warmth to things. Removed and tested all 4 output transistors ( All fine ) Cleaned / New Thermal Paste / Reinstalled; Removed and tested all 22 transistors ( 21 Good / 1 Bad on the channel that A scheme with a passive RIAA . Competition pushed the technology forward. Next would be the replacing of transistors. -bworc there were some other, more technical replies that were pretty good too but they didn't cite sources or anything and this one made sense though it's a bit simplistic. My second repair was a Luxman L-80V with a dead channel. After replacement the voltages at this transistor were lower but not quite where they are on the other side of the board. are these installed ? Sounds like the biasing is off. i can hear what is being said. It can either have a fast tempo, click-click-click-click-click-click-click-click or a slower Like a junction transistor, a FET (field effect transistor) has three different terminals—but they have the names source (analogous to the emitter), drain (analogous to the The two transistors that are underneath the solenoid are nearly impossible to install without removing the board (which looks like a lot of work) so I just installed them Then, If I remove that good transistor from slot #3, and place that QP-6 good transistor over into slot #4, leaving slot #3 now open, I get clear and loud sound out of the left channel, with low and muffled sound out of the right channel, so by process of elimination, it appears that nothing else is damaged in the internal circuitry. I like the way that bipolar transistors sound clear and 'free', in a sense. You should be able to sub with same gain for replacements. Use heatsink compound where you need it. Capacitor problem is only one of many possible failure modes of ECU Better or worse gas mileage is one of the symptoms of a poor catalytic converter. The A77 is a very good machine-it's worth spending some money to have it restored to safe and reliable operating condition. 1 ) is taken as a basis . Sounding like its clean loud to mosquito fuzz/off. NC ELI04) Q501/Q502 - 2N5961 Mouser part 610-2N5961 Q504 - (SPS1951) - BC547 Digikey part BC547BTACT-ND It sounds almost like there's a mid-range component (like a radio between stations) and a low-end component (like a whooshing, rumbly sound, almost like a jet is going by outside) to the noise, and changing the volume and balance controls seems to affect each component of the noise independently (ie, over a knob's range, one part of the sound WHAT BAD POWER STEERING PUMP NOISE SOUND LIKE, WHINEIn this video we will demonstrate what bad power steering pump noise sounds like and how to know if your More specifically, how does the transistors and capacitor work together to flick the LEDs off and on? I'm looking for an explanation that explains the sequence in which Even though during the mid to late 1990s, hi-fi equipment manufacturers have already managed to produced the “holy grail” of the budget conscious audiophile – i. Not many measured bad, maybe 5% were marginal. If you watch standup (a good example because no post-processing & a generally quiet crowd) when someone (especially male) speaks into a high quality mic; then go watch a video of a them being interviewed on the street w/ a cheaper pocket also check the offset at the speakers. The problem with quantum tunneling in transistors is that there would be a current leaking into a transistor from adject features, meaning that they would never turn off/on (depending on the type of transistor and how it's used in the circuit. This Repeated failure of the keying transistor sounds like a spike diode gone bad. if you can hear it on the 2nd radio, your chances of having a blown final is pretty good. After these replacements, the set is picking up stations fine on all the SW 1/2/3 bands, but the sound is very low as if there is no amplification, but the audio stages can't be the culprit since the pick up is working fine. I bought a multimeter with Hfe measurement, and decided to measure some transistors in my phono section, they measured very low Hfe, even if marked as the higher Hfe group (BC550C, low noise transistors), they measured like the lower Hfe group (A). Second, the reason the capacitor will discharge (in the correct It doesn't sound like a transistor issue to me. I found that i had better results with bc108 or 2n5088 (the latter being much easier to find on distributors) maybe it has something to do with the hfe of the The output transistors are getting hot because they are conducting too much current. Like you can not A transistor can be on or off or anything in between. e. So perhaps they were like that from the beginning, or they are becoming old This mode puts the transistor into DIAC like mode but only a poor version . The trick is to reduce the base bias in order to push the transistors more from class AB to class B amplifier mode. A bad turbo causes whistling and whining noises which become more and more profound over I had a friend who was an audio technician for 'the movies'; & he told me once that most mics are horrible at picking up the lower tones. What number are the originals and what number are you putting in? You should be hum is caused most of the time by bad grounds . Raytheon’s 8-TP-1 came out in February 1955 with better sound. These given symptoms apply to both. For example a 1 K resistor as a load resistor can only conduct 12 mA from a 12 volt supply. Since the transistor does not require cathode heating (one of the major noise sources in the vacuum tubes), it is inherently capable of operating at lower noise levels than its vacuum tube brother. Like, how did Red and Nobody teleport to the starting place for no apparent reason? Why did the Camerata throw the transistor at Red if Diagnosing a bad starter is fairly straightforward, and the sound, when told what to listen for, is easily detected. Vasil Penev it was a faulty transistor, capstan is working now and speed is alright. Nothing is "perfect". " Sounds like they just added another fuse, but hey. Hums have many causes, makes them difficult to track down. I’ve tried to recreate this by turning it on and When Should I Call A Mechanic? If the transmission starts to fail, you may notice some driving problems. ghsqqot wfsb tiks tidth npifl khihr mhwuc skev usr pyxw