Radio repair in dirty metal workshop, component cleaning

[Ttrees]

Hello folks, wondering if you can help me with this one..
This basic wee radio has seen me through quite a few metalworking projects, and is now just emitting a buzz when plugged in...
I haven't used it in a good while, actually doing some woodworking if you can believe it :shock:
and presumed the problem was just a damaged cable, which I realised today is not the problem.

After taking it apart and giving it an inspection/clean I am left presuming that the problem is in the input, (not pictured)
as it sounds like an arc is happening when plugged in, happening in all modes...empty tape deck, CD, FM/AM.
Another clue was I was finding the channels were so hard to tune in to...like a drop of a feather to fine tune it,
and on some channels it was picking up two at a time...giving some funky remixes (hammer)
Now the radio doesn't work, and I doubt the other unused settings work either.

I took it apart expecting the speakers to be caked in metal dust, and cleaned the small amount off with a magnetic screwdriver,
I could only get at the back of the speakers at the actual magnet though...
Anyway assembled it again and the problem still the exact same.

This leaves me to presume it is at the input where it looks to be a transformer or something... a wrapping around a box shape.
I am not a bright spark in this field whatsoever, and have no knowledge of this sort of thing.
I dared not to touch anything that looked dangerous, as I learned my lesson when disassembling a disposable camera
when I was little....dang thing stuck to me and wouldn't come off my finger when vigorously shaken =D>
It would probably make a useful device, now come to think of it

Whats the advice from this point ?
Do I have to drain the power or wait till the charge dissipates?
Is it the dangerous bit atall, or if that's elsewhere?
Am I on the right track even?
The only other place to check in more detail I suppose, would be the tuning and volume entry points.

Here is a useless piccy which was just intended for reassembly, so I suppose I might have to go through this again
It may help you save me from another sticky situation :lol:


Thanks
Tom

 

[Tasky]

If you think being full of metal dust (or any cack in general) is the issue, I'd suggest nipping up your local Euro Car Parts or similar and getting a big can of contact cleaner.... then hose the radio out with it. It comes with a brush nozzle, so get into all the corners and gaps, give it a good scrubbing. One final flush down and then leave it for a few minutes for the cleaner to evaporate off.

 

[sunnybob]

Honestly, dump it. music centres are ten a penny at any junk store.
Local council tips have piles of them.
If you have to buy one component it will be more than the thing is worth.

Transformers dont store electric. only capacitors do that.

Do the lights come on? if so its not the transformer. If the radio AND the other media players dont work, as a beginner you will never find the problem.

 

[Ttrees]

Thanks folks
I wouldn't buy another one though, as I believe it hasn't let the magic smoke out yet.
As I rather like trying to find out the problems in these things...there's no other way I will learn.
This brings to mind a Winston Churchill quote, which I live by...
"A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty"

I will have to check for the lights...I believe there's a screen to display CD tracks
And I have a multimeter in the house, but know little about it, trying to learn things like continuity tests on other things.

I'm looking to fix a clothes iron too, but thats for another day...
If it doesn't work I may have to make a hot pipe bending iron out of it.

Tom

 

[Racers]

Sounds like an amplifier problem its the chip under the silver heat sink bottom right, it you can unsolder it from the board and find out the type you might be able to replace it.
I wouldn't bother as it might be a very difficult part to source and its just not worth the time and effort.

Pete

 

[sunnybob]

The problem with fault finding on circuit boards, is that you cant. you can use the "inspired guess" principle but the only sure way to check every single component is to unsolder it, check it, and then resolder it so you can unsolder the next piece.
Because a normal multitester (on, say ohms) will give you a circuit by going all around the board and coming back at you from the other side of the broken piece. And you have no concept of diodes (one way valves) transistors (which will multiply your tester results) let alone potentiometers which can also change the strength of any signal you may be looking for.

Honestly, this is NOT a thing to learn fault finding on. Bin it, save a week of your life, and move on.

Now a clothes iron.. thats the thing to learn from. A fuse, a thermostat and an element. All easily explained and tested on their own.

 

[Ttrees]

I still think its to do with the input box lump, I will save you the time and take a piccy later to
explain this.
And the irons not so simple from the looks of things, maybe the old ones are more basic, but the newish ones vary wildly
from a laymans perspective.
Thanks
Tom

 

[sunnybob]

You are first person I have EVER known who thinks an iron is more complicated than a radio.
=D> =D> =D> =D> =D> =D> =D> =D> =D> =D> =D> =D>
Nothing further to add :roll:

 

[Ttrees]

I do hope cleaning the radio will be easier and simpler than having to figure out, source parts and install parts for a clothes iron.
Tom