OK, so I bought my first (well, maybe not my first, as I had a few back in the 90's - but this is my first proper 80's model!) boom box recently, a Sharp GF9090, I had been looking around at various models and really liked the Sharp GF 9x9x series - saw one going on ebay that looked decent in the pics and was described as in good working order & condition - made a bid, it was mine!
I was quite excited about it, the seller was a bit slow to send which didn't help, but then last week it finally arrived. I opened the box, initially hit with that old musty smoke smell that electronic items take on after being in a smokers house for years on end - but then I started looking closer and it all felt like a bit of an anti climax - the good working box I was expecting was not quite so.
It looked OK (well, not too bad) from afar...
But up close it struck me as something that had been used on a building site!
Some corrosion inside from leaking batteries. The inner batter terminal is very corroded, I'll see if I can revive it, but may have to fit a new one.
Generally though, the internals 'looked' OK
I decided that even though I was disappointed, it was all fixable, so I may as well just plug it in and see what it sounded like. After a bit of fiddling with the power lead I had it switched on! Radio worked OK, switches & sliders scratchy and the tape player was chewing up tapes!!
After a quick clean up of the sliders though, the radio was at least usable. So I cracked on with what I was doing in the garden and left it playing. Over the hours it seemed to improve, initally the RH meter didn't really work, but after a while it started to come to life!
The sound was not quite right though, one channel was weaker than the other. You could see it on the VU meter and also by switching the balance over. It wasn't just that it was quieter, it sounded really flat. On the good channel the bass & treble sliders make a noticable difference as expected, but on the weak channel the bass has no effect and the treble only a small change. I swapped the speakers over, and fault stayed with the amp channel.
I have now stripped her down and have started looking for any failed components. I had a quick look on Saturday, checked the caps & resisitors around the pre & output amp stages but couldn't find anything obvious. Of course, it could be a signal problem at the tuner stage - hopefully tonight I will get more time to take a look.
I've got an HND in Electronics Engineering, but I'm very rusty as for just over 10 years now I have been working with machine tool/CNC/automation control systems and rarely have to get involved at an electronics level.
Any suggestions welcome
I was quite excited about it, the seller was a bit slow to send which didn't help, but then last week it finally arrived. I opened the box, initially hit with that old musty smoke smell that electronic items take on after being in a smokers house for years on end - but then I started looking closer and it all felt like a bit of an anti climax - the good working box I was expecting was not quite so.
It looked OK (well, not too bad) from afar...
But up close it struck me as something that had been used on a building site!
Some corrosion inside from leaking batteries. The inner batter terminal is very corroded, I'll see if I can revive it, but may have to fit a new one.
Generally though, the internals 'looked' OK
I decided that even though I was disappointed, it was all fixable, so I may as well just plug it in and see what it sounded like. After a bit of fiddling with the power lead I had it switched on! Radio worked OK, switches & sliders scratchy and the tape player was chewing up tapes!!
After a quick clean up of the sliders though, the radio was at least usable. So I cracked on with what I was doing in the garden and left it playing. Over the hours it seemed to improve, initally the RH meter didn't really work, but after a while it started to come to life!
The sound was not quite right though, one channel was weaker than the other. You could see it on the VU meter and also by switching the balance over. It wasn't just that it was quieter, it sounded really flat. On the good channel the bass & treble sliders make a noticable difference as expected, but on the weak channel the bass has no effect and the treble only a small change. I swapped the speakers over, and fault stayed with the amp channel.
I have now stripped her down and have started looking for any failed components. I had a quick look on Saturday, checked the caps & resisitors around the pre & output amp stages but couldn't find anything obvious. Of course, it could be a signal problem at the tuner stage - hopefully tonight I will get more time to take a look.
I've got an HND in Electronics Engineering, but I'm very rusty as for just over 10 years now I have been working with machine tool/CNC/automation control systems and rarely have to get involved at an electronics level.
Any suggestions welcome