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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment. |
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14th Oct 2018, 5:48 pm | #1 |
Nonode
Join Date: Jun 2016
Location: Bognor Regis, West Sussex, UK.
Posts: 2,288
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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 |
14th Oct 2018, 10:36 pm | #2 |
Rest in Peace
Join Date: Mar 2006
Location: N.W. Oxfordshire(Chipping Norton)
Posts: 7,306
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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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15th Oct 2018, 8:01 am | #3 |
Dekatron
Join Date: Oct 2003
Location: Croydon, Surrey, UK.
Posts: 7,549
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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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15th Oct 2018, 11:06 am | #4 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,528
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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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15th Oct 2018, 11:07 am | #5 |
Dekatron
Join Date: Jan 2005
Location: Oxford, UK.
Posts: 17,820
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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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15th Oct 2018, 12:57 pm | #6 |
Octode
Join Date: Aug 2010
Location: Beeston, Leeds, West Yorkshire, UK.
Posts: 1,234
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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 |
15th Oct 2018, 1:07 pm | #7 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Re: Dual 505-2 Capacitors bulging
The markings if they haven't been obliterated.
Lawrence. |
15th Oct 2018, 2:00 pm | #8 |
Dekatron
Join Date: Apr 2012
Location: Worksop, Nottinghamshire, UK.
Posts: 5,549
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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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