124 lines
5.7 KiB
Markdown
124 lines
5.7 KiB
Markdown
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date = 2020-03-29
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title = "Why I will not repair your amplifier"
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tags = ["audiorepair", "rant"]
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description = "I get about ten emails a month on average from people who want me to remotely repair their amplifier or TV. Here's why I won't do that."
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I like tinkering with electronics and one awesome way of doing that is
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by [repairing things that are broken](/tags/audiorepair/). I get about ten or more requests
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every month from random people from the internet to help them repair there device. My
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reaction is always the same: no, I will not. This posts tries to explain why
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I say no and what alternative I can offer them.
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When I repair something (or anybody else for that matter), it will cost
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something. There's a lot of things that go into a successful repair,
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especially of hardware you're not intimately familar with. These are
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the steps I normally take:
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1. Disassemble the device
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1. Isolate and/or reproduce the problem
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1. Find a service manual, datasheet, and other documentation
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1. Theorize a solution to the problem
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1. Find and order replacement parts
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1. Perform the actual repair
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1. Test the repair
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1. Reassemble the device
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Sometimes a problem is obvious. Like the [repair of the HP 34401A](/projects/repair-hp-34401a-bench-multimeter/),
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which turned out to be blown fuse. Sometimes the problem is more subtle and difficult to find, like with the
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[repair of my Philips 3D LED TV](/projects/repair-philips-42pfl6057h-12/).
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When I'm looking for a repair project, I always do some research first - I'm not blindly buying things
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marked 'with defect'. TV's often have a broken screen - which I can't fix. Some amplifiers have issues
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with HDMI ports, which I know will require me to purchase a rather expensive replacement circuit board. The
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repair will be expensive and not very interesting. If I'm looking to resell a device, those costs add up and
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may not make it worth the effort.
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Now imagine some guy, let's call him John, emails you out of the blue:
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> Hello,
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>
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> I have a problem with my Denon some model or other. There is no sound at all.
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> Can you help me repair this. I have no experience with electronics, but I
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> do have a screwdriver.
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>
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> Thanks!
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There are quite a few problems with answering these kinds of messages.
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Let's take a look at some legitimate reasons why your amplifier might not
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produce and sound:
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* Did you turn the amplifier on?
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* Did you connect speakers?
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* To the right outputs?
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* That are not blown or shorted?
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* With enough power?
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* With the correct impedance for your amplifier?
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* Is your amp muted or is the volume set to its lowest setting?
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* Does the source contain audio?
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* Did you select the correct source?
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* Did you connect the source correctly?
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* Is the source using a digitial format your amp can decode?
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* Did you mess with assignable inputs and does the input use the correct audio connector?
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* If your source is phono, do you need a pre-amplifier?
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* Did you leave your headphones connected?
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* If using HDMI or optical, maybe you try a different cable first?
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These are all legit reasons why an amplifier could not produce sound. And this is
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just the part to make sure there's actually something broken in the first place.
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Next, the person has little to no experience with electronics. At the very least you
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need to understand the dangers of opening an amplifier and what precautions to take
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to work with it safely.
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Next, you will need at least a multimeter and maybe even an oscilloscope to find the
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exact problem. You will need to look for shorts, high resistances, check diodes and
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transistors.
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After that you will need a soldering iron or SMD rework station. You will need solder,
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flux, solder wick or solder sucker. Do you know how to use these tools?
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When finished, you need to verify your work - did you put everything back together
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correctly? Did you now make any shorts by accident?
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It's not feasible for me to personally to take someone by the hand and guide them
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through this process.
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Some people will the reply to me:
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> Can I just ship it to you, then?
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Well, no.
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I don't have time for it. I don't want to risk damaging your stuff beyond repair -
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or in transit. And most of all, I'm not interested. This is not my day job, so
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I get to be picky.
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So, what _can_ I offer people who ask for my help.
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First of all, if you device is under warranty, take that route. Just go back
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to the place you bought it or to the manufacturer and get them to repair it under
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warranty. You paid for that service, use it.
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If your device is out of warranty, there are two options. Which you choose depends
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on your confidence level for repairing electronics.
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If you don't have any tools available and this is your first time, you're probably
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better off finding a local technician to perform the repair. This will cost you
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money, and there's a chance the repair cannot be carried out because parts are
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no longer available or the cost of the repair is higher than purchasing a new
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comparable product.
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If you do have some tools, basic electronics knowledge, and a willingness to
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learn more, you should hop over to [/r/AskElectronics](https://www.reddit.com/r/AskElectronics/)
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and [/r/audiorepair](https://www.reddit.com/r/audiorepair/). There are over 80,000 people
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there who can help you out. Most of them will have more experience than me. Some
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might even know your particular device or the problem you're having.
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An added benefit is that your quest will be documented online for others to read.
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Repairing can be great fun. Most people can do it, given you have the right
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tools and an eagerness to learn. There's a great bunch of people out there who're
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ready to help you out - for your benefit and that of the entire community. |