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."
+++
I like tinkering with electronics and one awesome way of doing that is
by [repairing things that are broken](/tags/audiorepair/). 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
1. Isolate and/or reproduce the problem
1. Find a service manual, datasheet, and other documentation
1. Theorize a solution to the problem
1. Find and order replacement parts
1. Perform the actual repair
1. Test the repair
1. Reassemble the device
Sometimes a problem is obvious. Like the [repair of the HP 34401A](/projects/repair-hp-34401a-bench-multimeter/),
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](/projects/repair-philips-42pfl6057h-12/).
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