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Old 14th Oct 2018, 5:48 pm   #1
Electronpusher0
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Default Dual 505-2 Capacitors bulging

This has probably been covered before but I have just repaired my 4th Dual 505 deck and in EVERY case the RIFA capacitors were either bulging or actually smoking.
I now keep a stock of replacement capacitors specifically for Duals and when I get one in they are the first thing changed, before even powering up.

The capacitors are used as mains dropper and phase capacitor for the motor and for switch suppression.
There are 3 capacitors on the pcb, values are 0.33uf, 68nF and either 10nF or 22nF for the switch suppression, all X rated of course.
I attach a couple of photos of the 68nF from the latest deck.

Peter
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Old 14th Oct 2018, 10:36 pm   #2
'LIVEWIRE?'
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Default Re: Dual 505-2 Capacitors bulging

I tend to regard RIFA Capacitors of that type (in any piece of equipment) as 'replace on sight'.
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Old 15th Oct 2018, 8:01 am   #3
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Default Re: Dual 505-2 Capacitors bulging

It's worth noting that modern RIFA capacitors are as good as Vishay or any other brand.
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Old 15th Oct 2018, 11:06 am   #4
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Default Re: Dual 505-2 Capacitors bulging

And the old ones are well past their expected end of life dates anyway- just like old wax/paper capacitors.

Unlike the latter, they're normally connected somewhere that significant energy is available to make their failure more dramatic, though wax/paper ones in similar locations (DAC90A anyone?) can behave similarly but perhaps with less olfactory effects!
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Old 15th Oct 2018, 11:07 am   #5
Nickthedentist
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Default Re: Dual 505-2 Capacitors bulging

It's a shame that these caps failing must have sent many a nice Dual deck to landfill. OTOH, it means that those in the know can often pick up a really decent turntable for peanuts.
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Old 15th Oct 2018, 12:57 pm   #6
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Default Re: Dual 505-2 Capacitors bulging

How does one determine the capacitance of the cap in the picture? Markings? or look at the circuit diagram.
Gaz
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Old 15th Oct 2018, 1:07 pm   #7
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Default Re: Dual 505-2 Capacitors bulging

The markings if they haven't been obliterated.

Lawrence.
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Old 15th Oct 2018, 2:00 pm   #8
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Default Re: Dual 505-2 Capacitors bulging

The value must be marked on the other side that is not shown in the photos.
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