Spot the Fault
As I write this, my surround sound receiver is playing up. The front left channel is distorted. It wasn’t always that way; originally it was crackling when first turned on, then it went away. I had the main board resoldered as I thought it may have been a dry joint, but alas it made no difference. The fault steadily changed from an intermittent crackle to an always-there distortion. So now I am contemplating what to do, pull the whole system apart and repair it and hope it stays good, or go and get myself a new receiver. The later is a likely choice as mine does not have any of the new features available such as Dolby Digital / DTS processing, nor even anything better than S-Video switching. Many problems can be fixed or at least the technician’s work can be made easier by some simply detective work you can carry out yourself.
Most faults with hifi and video products are usually one of two things. Something doesn’t sound / look right or something wont play. Of course there are more but these are the most common. We’ll start with the sound first. The most obvious one is one of the channels has no sound, crackles, cuts-out or is distorted. First see if it happens on all modes, that is on CD, DVD, radio etc. If it is only on one mode, then likely that piece of equipment or cabling has an issue. Check to make sure the cables are connected. The next step is to try them in another input, for example connect the cables from the CD to the VCR inputs and see if it now works. If it does, then that input on the amp / pre-amp is faulty. If it is still there, then try another set of RCA cables. This will show if there is a fault. (RCA cables often have problems where the internal wires are soldered onto the plugs.)
Now you have isolated the sources, next is the amp and speakers. Check the speaker of the channel in question, following the cabling from the actual speaker back. Make sure the equipment is turned off; if a speaker lead has come undone, you do not want to accidentally make a short circuit as you may end up with an expensive repair bill! If the speaker leads seem okay, swap the channel for another one to test it. If the fault stays on the same speaker, then that speaker is likely to be faulty. If the fault happens to “move” to another speaker, then the fault is with the amp. These simple steps allow you to isolate each part of the system in turn. It is often a good idea to reverse what you have done and see if the fault goes back to how it was. This will give some more credibility to what you have found. Once you have determine what part of the system is at fault, you can then have it repaired armed with the knowledge that you have picked the right part and wont be wasting time and money having repairs only to find out it is fine! This advice is also valid for video, simply do the tests on the video cables, video equipment and TV monitor instead.
Other faults such as CD / DVD not playing the disc, tape not working, radio not tuning etc, are all in most cases a fault with the unit in question. There are still some things you should check. Inspect the material first, is the CD / DVD scratched or dirty? Did you put it in upside down? Are the tapes (cassette or VCR) gummed up or warped? Is that record warped? Sometimes it is the simplest thing that can cause a playback problem. If there is nothing obvious, then try some other music or movies. If everything you try is resulting in the same issues, then you can be certain which equipment is at fault. With tuners, make sure the aerial is okay, even going as far as connecting a length of wire to test it. Tape cleaners and laser lens cleaners are available, these can be a good investment, make sure the instructions supplied are followed! These cleaners often will not remove built-up dirt, in that case they are regarding as being useful for ongoing maintenance. It is best to avoid opening units and doing your own repairs. Unless you have the technical background, this can be dangerous and often results in great damage hence more expense. Spray lubricants virtually never fix electronic equipment!
Some faults are not there all the time; they are regarded as intermittent and are a technician’s worst enemy. Of course once the tech has it on their bench, the unit will invariably work fine. They wont have all day to sit and stare at it waiting for something to happen but you can offer some help. Keep notes of when the fault is occurring. When first switched on when it is cold or after it has warmed up? Only when you do certain things, or at certain times of the day? How long does the fault last for? Make a detailed description; sometimes even the smallest detail can give the technician a clue as to what is wrong. Take any offending material along, for example if it skips only on certain CD’s, take them with you and offer them up for testing. Ultimately a solution will come up!
Written by Leon Gross, originally published in Audio & Video Lifestyle magazine.
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