Why I will not repair your amplifier

Posted:
~1000wrds (~5min)

Tagged audiorepair rant

I like tinkering with electronics and one awesome way of doing that is by repairing things that are broken. I get about ten or more requests every month from random people from the internet to help them repair there device. My reaction is always the same: no, I will not. This posts tries to explain why I say no and what alternative I can offer them.

When I repair something (or anybody else for that matter), it will cost something. There’s a lot of things that go into a successful repair, especially of hardware you’re not intimately familar with. These are the steps I normally take:

  1. Disassemble the device
  2. Isolate and/or reproduce the problem
  3. Find a service manual, datasheet, and other documentation
  4. Theorize a solution to the problem
  5. Find and order replacement parts
  6. Perform the actual repair
  7. Test the repair
  8. Reassemble the device

Sometimes a problem is obvious. Like the repair of the HP 34401A, which turned out to be blown fuse. Sometimes the problem is more subtle and difficult to find, like with the repair of my Philips 3D LED TV.

When I’m looking for a repair project, I always do some research first - I’m not blindly buying things marked ‘with defect’. TV’s often have a broken screen - which I can’t fix. Some amplifiers have issues with HDMI ports, which I know will require me to purchase a rather expensive replacement circuit board. The repair will be expensive and not very interesting. If I’m looking to resell a device, those costs add up and may not make it worth the effort.

Now imagine some guy, let’s call him John, emails you out of the blue:

Hello,

I have a problem with my Denon some model or other. There is no sound at all. Can you help me repair this. I have no experience with electronics, but I do have a screwdriver.

Thanks!

There are quite a few problems with answering these kinds of messages.

Let’s take a look at some legitimate reasons why your amplifier might not produce and sound:

  • Did you turn the amplifier on?
  • Did you connect speakers?
    • To the right outputs?
    • That are not blown or shorted?
    • With enough power?
    • With the correct impedance for your amplifier?
  • Is your amp muted or is the volume set to its lowest setting?
  • Does the source contain audio?
  • Did you select the correct source?
  • Did you connect the source correctly?
  • Is the source using a digitial format your amp can decode?
  • Did you mess with assignable inputs and does the input use the correct audio connector?
  • If your source is phono, do you need a pre-amplifier?
  • Did you leave your headphones connected?
  • If using HDMI or optical, maybe you try a different cable first?

These are all legit reasons why an amplifier could not produce sound. And this is just the part to make sure there’s actually something broken in the first place.

Next, the person has little to no experience with electronics. At the very least you need to understand the dangers of opening an amplifier and what precautions to take to work with it safely.

Next, you will need at least a multimeter and maybe even an oscilloscope to find the exact problem. You will need to look for shorts, high resistances, check diodes and transistors.

After that you will need a soldering iron or SMD rework station. You will need solder, flux, solder wick or solder sucker. Do you know how to use these tools?

When finished, you need to verify your work - did you put everything back together correctly? Did you now make any shorts by accident?

It’s not feasible for me to personally to take someone by the hand and guide them through this process.

Some people will the reply to me:

Can I just ship it to you, then?

Well, no.

I don’t have time for it. I don’t want to risk damaging your stuff beyond repair - or in transit. And most of all, I’m not interested. This is not my day job, so I get to be picky.

So, what can I offer people who ask for my help.

First of all, if you device is under warranty, take that route. Just go back to the place you bought it or to the manufacturer and get them to repair it under warranty. You paid for that service, use it.

If your device is out of warranty, there are two options. Which you choose depends on your confidence level for repairing electronics.

If you don’t have any tools available and this is your first time, you’re probably better off finding a local technician to perform the repair. This will cost you money, and there’s a chance the repair cannot be carried out because parts are no longer available or the cost of the repair is higher than purchasing a new comparable product.

If you do have some tools, basic electronics knowledge, and a willingness to learn more, you should hop over to /r/AskElectronics and /r/audiorepair. There are over 80,000 people there who can help you out. Most of them will have more experience than me. Some might even know your particular device or the problem you’re having.

An added benefit is that your quest will be documented online for others to read.

Repairing can be great fun. Most people can do it, given you have the right tools and an eagerness to learn. There’s a great bunch of people out there who’re ready to help you out - for your benefit and that of the entire community.

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