Slow turntable!

[Hugh Jaleak]

Wondering if someone more knowlegeable can shed some light on this for me please. A friend has just purchased a secondhand Ariston 'Q' deck turntable for playing her vinyl collection. Power supply is via a 12v transformer, the plug in type, with a jack plugging into turntable. Tested here, output constant 12.16/12.17 V D.C. L.P.'s play ok. Take it to her flat round the corner, output 12.15/12.16 V but this can suddenly drop to 10-11 V, turntable slows down with corresponding change in sound. (Boy George sounds like Barry White im told!)

Would I be right in thinking the voltage fluctuations from the transformer are caused by fluctuations in the Mains voltage? Surely a 240-12 V transformer will give a 20x reduction in input voltage, if input drops then output drops correspondingly. Obviously with a turntable speed is critical, she dont want to buy another turntable for same to reoccur.

If its of any relevance she's also having a lot of lightbulbs blow, 3 in last week.

Any sensible thoughts welcome!

Cheers,

Nick and very stressed Kaz!

 

[bernardgreen]

Surely a 240-12 V transformer will give a 20x reduction in input voltage, if input drops then output drops correspondingly.

For a transformer that is correct but the output will be AC not DC.

The power supply is probably an electronic ""transformer"" with rectifier ( AC to DC ) and maybe some voltage regulation as well.

You say it is second hand, do you know if it is the power supply that was originally supplied when the deck was new or is it one that has replaced the original ?.

If the deck is trying to take more current than the power supply can provide then the voltage will drop.

Does the deck have a label giving current required as so many mA ( or in the instruction book ) ? This must be less than the figure on the power supply.

 

[slup]

Hi

The acceptable power supply range for the turntable is 12-15V according to the instruction manual.

I'm guessing the turntable has a voltage regulator in it rather than the power supply itself. Either this voltage regulator is faulty, or the PSU output voltage is dropping too low causing the internal regulator to drop out.

I'd just get a cheap, unregulated PSU - needs to be 12V at 350mA minimum.

Steve

Untitled

• slup
• 5 Mar 2009
• 1

 

[Hugh Jaleak]

Thanks Gents. It came with original power supply, problems started as mentioned so I tested supply. 17V+ with little variation here. Wires were also rather frayed, leading it to cut in and out so assumed bad connection, Kaz opted to purchase new power supply. New transformer is this:
http://www.argos.co.uk/static/Product/catalogId/1500001501/partNumber/9829701.htm
Which id have thought adequate? Please note the voltage drops I read on my digital meter were with no load on the supply.