Vintage Synth Explorer Forums

Hi, just had desk repaired. Was working fine for the first couple of hours, then she died. There was a strong burning smell so i opened her up and there was a strong smell from around the internal power supply. Transformer was roasting hot, i'm not technician so don't know if that is normal...
The bridge rectifier had been replaced on the PS.
Any opinions?

leonidspaul wrote:Hi, just had desk repaired. Was working fine for the first couple of hours, then she died. There was a strong burning smell so i opened her up and there was a strong smell from around the internal power supply. Transformer was roasting hot, i'm not technician so don't know if that is normal...

I can assure you that there is no mixer on the market which burns up internal components as a part of its normal operation. Either the power supply has a shorted filter cap, or there's a short somewhere in the board that's overloading the power supply. Try disconnecting everything from the supply, then plug it in for a minute and see if it gets hot or smells. If so, the problem is in the supply itself. If not, you've got a bit of detective work to do.

Take it back to whoever repaired it and tell them to do it properly this time.

Stab Frenzy wrote:Take it back to whoever repaired it and tell them to do it properly this time.

At No Charge

Yeah i'll be returning it alright. After i disconnected everything and put in a new fuse it went again but this time also tripping the house electricity. So i'm not going near the PS, i'll leave it to the experts. Thanks for the replies!

Esus wrote:

Stab Frenzy wrote:Take it back to whoever repaired it and tell them to do it properly this time.

At No Charge

No, assuming they only charged to replace the rectifier the first time it's fair enough that they charge to replace the rest of the power supply as well. Usually when something goes on a power supply it puts strain on the rest of the components, so if you replace one thing usually another will go pretty soon after.

It's best to replace all power supply components at once, that's what I meant by doing it properly.

So is that an expensive job to replace the PS?

Unfortunately, your "tech" botched something in a major way by what you are describing since a power supply causing a mains breaker to trip (not to mention the burning and fuse blowing) means that the device is pulling WAY more current than intended. Depending on where it is actually failing it may have damaged other components up to the point of whatever burned up so when they get the PSU sorted out, make sure you go over the devices functionality carefully and make sure everything is still working. Hopefully, the short was in the PSU somewhere and replacing all the components there be the extent of the damage. Generally, linear power supplies are not that expensive to fix but finding a perfect replacement will probably be tricky since a lot of the time, the transformer itself is a custom made for that device. The large value caps will probably be the most expensive but if the device is more the 15 years old, they all should be replaced since electrolytic capacitors do have a finite lifetime

Altitude wrote:Unfortunately, your "tech" botched something in a major way by what you are describing since a power supply causing a mains breaker to trip (not to mention the burning and fuse blowing) means that the device is pulling WAY more current than intended.

Forget I said At No Charge---you might want to get your money back and find a tech that knows what he's doing.