When posting the image, orient the camera so that the amp is displayed lengthwise through the longest axis of the frame of the camera. If you're in a forum where there is nothing but slang, then it's appropriate for you to reply that way. This includes punctuation, capitalization and proper spelling. BEFORE entering all of the values, make sure that you can produce the screen capture. Many times, a distorted or intermittent channel is due to nothing more than a dirty contact in a potentiometer or a switch. When posting on the forum, post a single, good quality photo of the entire board. Previously, we looked a scenario where the amp would try to power up but would go into protect or blow a fuse. If you have no interest in repairing your own amp, you should look for a local repair shop before shipping the amp to be repaired. It's not important that the face of the scope be well lit when all that's needed is a photo of the displayed waveform. When you're done viewing the photo, close the window. This section was added because I get so many requests for help with these amps for one very specific problem. Many times, when you copy a link from the address bar (especially for something found via the search function on a site), the link will only work from the browser that was used for the search. When an amplifier will not power up, you have to confirm that you have ~12v across the B+ and ground terminals. KEC_2SD1047 The input op-amp is generally very near the RCA jacks like THIS. Olympus C-740: In the following images, you can see that one meter reading is approximately 3.3k ohms. 47 - Inductor It's not safe to charge a battery in a confined space and most chargers produce a lot of electrical noise/hum (not something you want when troubleshooting an amplifier). It's a general purpose resistor used to drop voltage in the circuit. There will be times when a mistake (slipped probes, overheating components that fail) will cause components to burn. If you can get a good deal on a 15MHz or 20MHz scope, don't pass it up because you don't think it's up to the task. That's because it's being asked to dissipate too much power (in the form of heat). When buying semiconductors, you should only buy from reputable distributors. Power Amplifier Section: If you can take a good photo (again, take several and send the best) that's better than the ones you find on the internet, post that photo. Time is fleeting. When checking power transistors in the power supply or the audio section of an amplifier, you look for shorts between the legs. In the first two photos, you can see the diffuser I used on this camera. You can download the following test tones. Take the time to look at several pages to find the one that shows the front panel the best (all text legible). This means the the 'on' time won't always be 100% (50% per output). More detailed photos will follow. This removes everything that's not in the selected rectangle. IR_IRFZ48N Inserting a dropping resistor reduces the voltage drop across the transistor (some is dropped across the resistor before transistor). If you're interested in doing repair work and you have to constantly wait for someone to provide every minute detail, you probably won't make it in this business. IR_IRFZ44N The negative rail voltage would be the same distance below the reference line as this is above the reference line. IR_IRFZ44_NoSuffix - If you send us an amplifier, and there turns out to be nothing wrong with it, there will be a $35 testing fee for the amplifier, if the amplifier does need repair, there is no testing fee applied. The screw was tightened (by hand) until it bottomed out in the socket and then the nut was drawn down on the ring terminal. Hitachi_2SK135 The second photo is the same signal displayed on a Tektronix 5110 oscilloscope rated for 2MHz (not a misprint, 2MHz). In these two images, you see that the forward voltage drop is 0.6v. Are you using a test speaker appropriate for the amp that you're repairing? List of Test Equipment: Ignorant means that you don't know. The 'brains' of this error correction circuit is the 'differential amplifier'. When measuring the voltage, the amplifier's main ground terminal is generally (but not always) a good reference point (for placement of the black meter probe). In most amplifiers, the value of the gate resistors is between 27 and 100 ohms. Intelligent, ignorant people ask questions to learn. The service manual voltages are wrong because they have the wrong pin configuration. Pin 12:  Shop products from small business brands sold in Amazons store. To check them, you need to understand their basic construction (as it applies here). You would have the black probe on the amplifier's main ground terminal for that measurement. If there is no short between the center and outer legs of the rectifier, it's likely OK.

IR_IRFP360LC I may have more than 100 emails and forum posts in the matter of a few days. Series-pass transistors (BJTs) are used to increase the output current capacity of the regulator. If you're trying to make measurements and you're coming up with readings that don't appear (to yourself or to someone helping you) to be correct, post a link to the owner's manual to your meter so that the person helping you can try to determine why you are getting unusual readings. Then read the following chapters (some of these are links previously seen in the text above): 23 - Amplifiers As an example, if you're measuring the voltage on the power supply driver IC (TL494, TL594, SG3525), you'd place the black probe on the amplifier's ground terminal and touch the probe alternately to each of the pins of the driver IC. Many people use the terms hiss, hum, buzz. Many times, a schematic diagram or photos from an amp 'similar' to the one you have will be used for a reference. The problem is virtually always the same. If you have a thread or email chain that you've started for one amp, don't ask questions about another amp in that chain/thread. List EVERYTHING, no matter how insignificant it seems. Turn around time is dependent on how many amplifiers we have before yours, and we will not put anyone ahead of anyone else on the list. If you post a really large image, it will be displayed as a smaller thumbnail. This is a bias compensating transistor. The cathode is directly connected to the base of Q4901 (3rd leg). Others could simply be manufactured with very low standards. Without voltage on pin 12, the IC won't power up. In most cases, it's best to use the exact replacement part when repairing an amplifier. Photos, especially good quality photos, allow me to see the amp in question and will often make it possible to help the owner get it repaired. IC# << insert IC circuit board designation here Lower voltage (15v) will be produced for the preamp section of the amp but the power amplifier section doesn't use a negative power supply. The same is true for the output transistors. Noise: R147 is the pink resistor. Professional Computer Repair Tool Precision Laptop Screwdriver Kit, XOOL 140 in 1 Electronics Repair Tool with 120 Magnetic Bits, Compatible for Macbook, iPhone, Game Console, Tablet, Skar Audio Dual 10" Complete 2,400 Watt SDR Series Subwoofer Bass Package - Includes Loaded Enclosure with Amplifier, Sony STRDH190 2-ch Home Stereo Receiver with Phono Inputs & Bluetooth Black, Hautton Precision Screwdriver Set, 126 in 1 Magnetic Screwdriver Kit, Multi-function Professional Repair Tool Kit with Portable Oxford Bag for Phone Laptop PC Watch Electronics and More -Black, 328 PCS Sleeving Wrap Wire Car Electrical Cable Tube Kits Heat Shrink Tube Tubing Polyolefin 8 Sizes Mixed Color Connector Repair Durable and Deft, Anti aging neck firming and tightening cream, All customers get FREE Shipping on orders over $25 shipped by Amazon.

The first shows the scope with DC coupling (read the 'Oscilloscope' page of this site if you don't understand 'coupling'). The only time (that I can think of) that you would place the red probe on the B+ terminal is when you were measuring the voltage on the B+ terminal. In THIS photo, the drivers are the small rectangular components with the circuit board designations Q903, Q909, Q904 and Q910.

The Zener should have 12v (10%) when the voltage is measured directly across it. If you're using Firefox, open IE or Chrome. You can send the parts to the manufacturer and they will be able to determine if the components are genuine or counterfeit. The green links are photos. The language/terms used in parts of it (the work 'lazy' keeps creeping in) may not be pleasant but it seems that too many people require stronger language to motivate them. This does several things. This makes the matching of the components that much more critical. If you don't have favorite software, something like Irfanview can be used. In these instances, you can see a direct short between the first and second terminals. You need to read EVERYTHING on that page but pay special attention to the section labeled Best Initial Settings. If the person corresponding with you is taking the time to use proper grammar, punctuation, capitalization and paragraph breaks, you should do the same. If you'd like more information on the capabilities of Irfan-View, you can find it on my computer site. Each time you start a different repair, start a new chain/thread. It may seem a bit strange that there is photographic information on an amplifier repair page but there are thousands of amplifiers on the market that I've never seen and will never have in my shop. Click HERE to go directly to the relevant section. Sometimes it's near the top, sometimes it's buried in the body of the datasheet. If your transistors look like the die has been glued to the tab or the die is significantly smaller than the ones in the photos below (for the same part/manufacturer), you may have counterfeit parts. The tab of the transistors here are completely insulated. When this happens, the drivers have to work against the internal short of the FET to try to pull the gate voltage down. The transistor fails because it runs too hot. Discover more about the small businesses partnering with Amazon and Amazons commitment to empowering them. Note: A simple guide for getting your amplifier repaired. If you're new to repair work and you're attempting to repair an amplifier, you're not expected to know everything. If the power supply is blown, it's generally not possible for the audio circuit to trip the protection circuit and therefore the protection LED will not light. If I find images that are significantly better than what you took with your camera, it's unlikely that you will get a response. If you don't have both positive and negative regulated voltage on the power supply pins of the audio op-amps, you need to trace back the circuit to the regulators to see why you don't have the proper regulated voltage (generally 15v). ELEGOO Mega R3 Project The Most Complete Ultimate Starter Kit w/ TUTORIAL Compatible with Arduino IDE, Sunbuck Wireless Bluetooth Audio Amplifiers, 200W Power Home Stereo Amplifier Receiver, with USB, SD Card, FM Radio, Remote Control, Dual Channel Sound, for Theater Entertainment Studio Use(AS-35BU), J-B Weld 2130 Vinyl and Leather Repair Kit, Precision Screwdriver Kit, XOOL 200 in 1 Electronics Repair Tool Magnetic Driver Kit with 164 Bits, Flexible Shaft, Extension Rod for Computer, Mobile Phone, Smartphone, Game Console, PC, Tablet, Echo Link Amp - Stream and amplify hi-fi music to your speakers. Meter Make/Model: For example, if someone states that the datasheet for an IRFZ44 provides specific information for that component and you ask the person helping you what a datasheet is, you are not well suited for this type of work. If you clicked the links, you should have noticed that the power supply FETs were in a smaller case/package than the output transistors (look at the screw head for scale). Pin 2:  Spanish language page with lots of examples. Does the noise go away when no signal source is connected? The signal is a 160kHz square wave. Don't Forget the Units! If you've made it this far, and you're still interested in doing this type of work, read the first 12 chapters of the site until you understand them completely. Surface mount components make a repair slightly more difficult. For those who don't have a camera that can take good quality photos (only have cell phone or web cam), you can use a lower quality image and mark up the photo in Irfanview, Microsoft Paint (free with Windows) or your favorite photo editing software. Refer to the page for more information on reading resistor values. This is actually a, Pins 1, 2, 15, and 16 are the error amps and drive pin 3 internally (see datasheet for internal schematic). It will at least show me that you're trying. If you did know everything, you wouldn't need the help. Pin 1:  If you have a part that you'd like to use as a substitute, post the datasheet (or a link to the datasheet) for both the original and the substitute part. Many times, the (only) fault is due to a mistake made during the previous repair attempt. Scroll down to the section labeled "Checking Field Effect Transistors". We will never try to save money/time by using an inferior, or non-direct replacement parts. SK_2SC4467 Voltage 'Across' or Voltage 'On' a Component Terminal: Note: If the fuse protecting the amp is too large, if the protection circuit doesn't respond quickly enough or if the power supply is poorly designed, the power supply transistors may fail. In a day's time, I probably won't remember much of the repair and after a week, it's unlikely that I'll remember any of it without skimming over the unbroken chain of messages. Below, you can see two different scopes. If you get a reading of near zero ohms with any combination of the meter probes across the legs of any individual transistor, the transistor is likely shorted (or is in parallel with a shorted component). At the end of this page, I've posted a couple of photos and more information that may help you in your search for a usable scope. For example, an FET could be used in the power supply or in the output stage of the audio power amplifier. Over and under-voltage protection is employed in some amplifiers. Foreword: When viewing the oscillation on the output transistors, you may not have the scope's timebase and/or trigger level set correctly and may see something like the waveform displayed in the following image. We include fedex insurance on every amplifier, but no one wants to have to fill out insurance paperwork, so package it well! BJTs are often referred to simply as bipolar transistors. If you've never read this page, continue reading below and you'll come to the section I've referred to here. Others have electrical connections to ground the heatsink. It gets very confusing, especially if the original poster has additional questions about their amp. If your amp only distorts as the output increases (but well before you think it should), you need to confirm that the DC voltage across the B+ and ground terminals of the amp (multimeter probes placed directly on the metal part of the B+ and ground terminals on the amp) is remaining at or above 12v. Although the 2230 has slightly better resolution, the 5110 has good enough resolution for virtually any problem that you'll encounter. Rectification and Filtering: Here the wire didn't need to be stripped because there was no electrical connection. Without a schematic (many manufacturers won't provide schematics), it can be much tougher. As with any type of work, it's easier to do a job with good quality tools. The tutorial will help fill in large gaps that won't be filled by college courses. Most cameras have a zoom function. The following photos are for those who don't understand R-R oscillation. If you believe that something doesn't seem quite the same on your amp, ask questions or ask for clarification. When it's suggested that you operate all controls through their entire range, that is in reference to the controls accessible from the outside of the amp. This will help those helping you to ask for tests that you can perform with the tools that you have. Is only one channel distorted or are multiple channels distorted? Some people will argue that a 2MHz scope will not be able to resolve tiny high frequency glitches. This camera cost only about $20 (plus shipping) on eBay. You should read approximately 11.5v between pin 15 (black probe) and pin 3 (red probe) on the IR2010S ICs. If you're familiar with the manual modes and know how to use them, you're likely just bored if you're reading this. There are a couple of ways to confirm that the link works universally. Please don't submit cell phone images. The information and suggestions on this page alone could help a lot of people make a lot of money if they take the time to read it (a good tech can make between $60 and $90/hour) but time after time, they state that they've read all of it and then ask questions that tend to indicate that they have barely skimmed over it -- at best. The power LED is not a good indicator of the condition of an amplifier. - We try to keep turn around times low by always prioritizing customer repairs before amplifiers for us to sell. To be able to do any troubleshooting, you need to know what your meter is telling you. You can see that there is rail to rail activity but you cannot see the individual pulses. For some reason, people think that they should place the red probe on the positive terminal of the amp when measuring voltage. THIS is a plain text file (open with Windows Notepad) that has no formatting and retains the spaces as they should be. Pin 5:  In virtually all commercially available, solid state amplifiers, there is an error correction circuit. 2SC3855 Noise and distortion should be treated differently when asking for help with a repair. In this amplifier, Zener diodes are used to set the regulated voltage. SK_2SA1694 Putting forth a bit of extra effort could mean the difference between getting the desired answer in a few minutes or having it take a few days (or longer). Zoom Range: Except for a very tiny fraction of the population, that's getting them nowhere. In the driver transistor photo, you can see a small transistor between the output transistors on the heatsink. For more detailed information, follow the links provided. If it's via email, simply fill in the voltages after each pin number. The resistor or headlamp will go in series with the B+ power supply wire. Don't Try to Seem like You Know what You're Talking About if You Don't: If you don't understand precisely what a scope does and how they function, read the Oscilloscope page of this site (page #73). The information on this page is for those who are interested in trying to repair their own amplifiers. The op-amps in this package are being used in the filter (low pass crossover) circuit. If you're asking for help and I need these voltages, I'll generally give a list for you to fill in the blanks. You should be aware that they have a problem with keeping the memory (internal backup battery is dead in most of them) but they'll work OK on full auto. After downloading the program, you open the image in Irfan-View, drag a rectangle around the area you want to keep and hit ctrl-y. Remember, when posting questions on forums or repairing via email, it can take 24 hours or more between the question and answer. While I have a lot of photos and schematic diagrams (been collecting them for quite a long time), I don't have information on every amp. If you've ever seen a damaged amp that pushed or pulled the speaker cone to its limits when the amp powered up (common on some Rockford amplifiers), that was almost certainly due to a shorted output transistor. This product is certified by Amazon to work with Alexa. You want the least angle possible without having the flash reflect off of the board and back into the lens. THIS page shows a slightly different way to check transistors and has applets to allow you to send me or post screen caps of the readings from transistors (click the black bar at the right of the applet for instructions). Basically, the only difference was the angle at which the photo was taken. They are typically smaller and the pads can be damaged easily if you're not careful. The tripod sockets are typically relatively fragile plastic so you have to be very careful to avoid breaking them. If a smaller transistor is driving a larger transistor (or a group of larger transistors), you generally refer to them as driver transistors. Sometimes it's simply caused by having the switch between positions. Q21 and Q9 are transistors. is a link to this site's home page. These are almost always BJTs so it's not necessary to refer to them as driver BJTs. It is designed to shut the amp down if it gets too hot. The non-bridging speaker terminals (the speaker terminals that are NOT used when the amp is bridged) are often the reference point (black probe placed there) for the secondary ground. If you look closely at the first value, you can see that there is a 'k' in front of the symbol for ohms. This would save the time between the posts or emails from the person helping you with the repair (or whatever you're doing) and shows that you're thinking and willing to put forth a bit of effort. I try to push and prod them to get motivated but it's difficult (I'm referring to those who 'claim' they want to learn). This can be done with your favorite software. When you're dealing with people who are MUCH more knowledgeable than you are about a subject and you do the same thing, you just seem like an idiot. The following shelving unit is one that I built to for my shop. Is it distorted at all output levels or only at higher output levels? Troubleshooting a dead amplifier is different. Depending on how busy the person helping you is, that could mean a day or even a week wasted. Posting Links: You can also see that the leads have become discolored due to heat. If the B+ supply voltage is too high or too low, the amp will shut down. In many cases, it's simply an indication that the amp has B+ and remote voltage.



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