hi-fi power supply fault?

[gboy]

Hi, I'm trying to fix my daughters hi-fi without breaking the bank. The live input to the transformer seems to have a small capacitor in series but although live up until the capacitor there is nothing after it. Am I right in thinking that the capacitor needs to be replaced and if so what value is it likely to be?

 

[breezer]

i doubt it and its value will / should be written on it.

capacitors in power supplies are often used to smooth the ac, so they are fitted across the supply

post a pic

 

[rssteve]

no need to break the bank, argos sell a hifi for under £20.

 

[electronicsuk]

If it's in series with the power supply then it's more likely to be an inductor. Unless there are some markings then I can't see how you're going to find the correct replacement part, assuming it even is causing the problem in the first place. Nontheless, I congratulate you on attempting to fix it rather than throwing away, but most products these days aren't designed to be fixed outside the factory.

 

[breezer]

aren't designed to be fixed outside the factory.

or even in the factory.

since most electronic stuff has surface mount technology, its easier for them to throw it away too

and stuff that hasnt got surface mount technology is expensive to repair due to the time it takes.

 

[tim west]

It may be a fuse device /thermal cutout rather than what looks like a small disc capacitor if you bypass the device just for test purposes you will be able to see if this is the problem or a fault further on thats if the transformer is still ok you should get a reading across both coils using a meter on resistance reading.

 

[gboy]

Thanks for the replies guys. It's a sony and I only repair rather than throw away for fun. Some time ago I replaced the lazer on this set and the part cost over half the unit's original purchase price. Shame to give up now on what could be a more trivial fault. I'll try and post a pic later on. Thanks again.

 

[gboy]

It may be a fuse device /thermal cutout rather than what looks like a small disc capacitor if you bypass the device just for test purposes you will be able to see if this is the problem or a fault further on thats if the transformer is still ok you should get a reading across both coils using a meter on resistance reading.

Thanks Tim I'll try your suggestions.

 

[mattylad]

Whats the model number of this unit?
A Schematic is usually available for most Sony gear.

 

[macmini]

no need to break the bank, argos sell a hifi for under £20.

They don't sell a hifi for £20 whatsoever, they sell a piece of plastic that makes noise for £20!

 

[gboy]

It may be a fuse device /thermal cutout rather than what looks like a small disc capacitor if you bypass the device just for test purposes you will be able to see if this is the problem or a fault further on thats if the transformer is still ok you should get a reading across both coils using a meter on resistance reading.

Hi, I've bypassed the small blue disc with a fuse and yes the unit now works although it doesn't seem to want to switch off. I'm tempted now to wire a switch (lamp on/off type) into the mains lead, however if I can find out the value of the capacitor or whatever I should be well placed to renew it which would be the proper way I know.

Whats the model number of this unit?
A Schematic is usually available for most Sony gear.

Hi it's a HCD-EP303. I thought the schematic would be mega-bucks. Do you know where I can obtain one. Thanks again for all the interest guys.

 

[rssteve]

It may be a fuse device /thermal cutout rather than what looks like a small disc capacitor if you bypass the device just for test purposes you will be able to see if this is the problem or a fault further on thats if the transformer is still ok you should get a reading across both coils using a meter on resistance reading.

Hi, I've bypassed the small blue disc with a fuse and yes the unit now works although it doesn't seem to want to switch off. I'm tempted now to wire a switch (lamp on/off type) into the mains lead, however if I can find out the value of the capacitor or whatever I should be well placed to renew it which would be the proper way I know.

Whats the model number of this unit?
A Schematic is usually available for most Sony gear.

Hi it's a HCD-EP303. I thought the schematic would be mega-bucks. Do you know where I can obtain one. Thanks again for all the interest guys.

ok just makesure your home insurance is up to date, incase you burn the place down.

 

[gboy]

It may be a fuse device /thermal cutout rather than what looks like a small disc capacitor if you bypass the device just for test purposes you will be able to see if this is the problem or a fault further on thats if the transformer is still ok you should get a reading across both coils using a meter on resistance reading.

Hi, I've bypassed the small blue disc with a fuse and yes the unit now works although it doesn't seem to want to switch off. I'm tempted now to wire a switch (lamp on/off type) into the mains lead, however if I can find out the value of the capacitor or whatever I should be well placed to renew it which would be the proper way I know.

Whats the model number of this unit?
A Schematic is usually available for most Sony gear.

Hi it's a HCD-EP303. I thought the schematic would be mega-bucks. Do you know where I can obtain one. Thanks again for all the interest guys.

ok just makesure your home insurance is up to date, incase you burn the place down.

You are advising against the on/off switch then?

 

[rssteve]

im advising against trying to fix electrical goods, especially for your children, when they are designed to be thrown away once out of service. You clearly are not sure what does what inside the unit so froma safety point of view i wouldn't say the risk of fixing it is worth the cost of a new unit.

You say the unit will now not turn off then obviously something inside the unit is not functioning right after shorting something out. This may cause overheating and fire risk.

 

[gboy]

im advising against trying to fix electrical goods, especially for your children, when they are designed to be thrown away once out of service. You clearly are not sure what does what inside the unit so froma safety point of view i wouldn't say the risk of fixing it is worth the cost of a new unit.

I'd say the unit is repairable, the defective component in this case probably a couple of pounds and ten minutes with a soldering iron. Several years ago the replacement of a component would be easily accomplished by a radio repair shop and for a fraction of the cost of a new unit. These days the only economical way is DIY and sorry to say it but that's what this site is about IMO. As I've already replaced the cd-read laser two years ago at a cost for the part alone in excess of 50% of the unit's initial purchase price of £100 then I think I am well able to replace a capacitor or whatever it turns out to be. I've been fixing electrical equipment since the late sixties when it was a profession and/or hobby for thousands of like-minded individuals.

You say the unit will now not turn off then obviously something inside the unit is not functioning right after shorting something out. This may cause overheating and fire risk.

I was following a previous poster's advice to bypass the component for test purposes. You're quite right though safety is always of paramount importance and the fire risk you have cautioned against is real.