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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment. |
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Thread Tools |
6th Dec 2017, 8:43 pm | #1 |
Heptode
Join Date: Mar 2014
Location: Leeds, West Yorkshire, UK.
Posts: 902
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Fidelity HF?
Hi all
this machine has developed a fault. It will play well for about five minutes and then the sound distorts. Switching off and on cures the fault for a few minutes and then it happens again. When i got this machine it was a complete wreck but it did have a working amplifier so apart from replacing the cut off flex i have done nothing to the amp. Tested the cartridge in another machine and its fine. Any ideas guys? Not sure what model it is because the label was missing along with some of the Rexine. In one of the photos i am pointing at a capacitor that's looking a little rough. |
6th Dec 2017, 8:49 pm | #2 |
Nonode
Join Date: Jun 2014
Location: Bristol, UK.
Posts: 2,074
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Re: Fidelity HF?
Smoothing capacitor on the way out? Did you hear any 'ripple' as part of the distortion? Not suggesting you switch it on again if that is the problem.
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'....don't go mistaking Paradise for that home across the road!' (Bob Dylan) |
6th Dec 2017, 8:58 pm | #3 |
Heptode
Join Date: Mar 2014
Location: Leeds, West Yorkshire, UK.
Posts: 902
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Re: Fidelity HF?
No .the sound just starts to degrade about half way through the record 2 or 3 minutes
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6th Dec 2017, 8:59 pm | #4 |
Dekatron
Join Date: Nov 2009
Location: Lincolnshire, UK.
Posts: 5,000
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Re: Fidelity HF?
Spray some freezer spray on that chip when it does it
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6th Dec 2017, 9:42 pm | #5 |
Dekatron
Join Date: Jan 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 8,194
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Re: Fidelity HF?
Resistors used in these amps were also not of the best quality and end caps could have bad connections.
Ed |
6th Dec 2017, 9:59 pm | #6 |
Heptode
Join Date: Mar 2014
Location: Leeds, West Yorkshire, UK.
Posts: 902
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Re: Fidelity HF?
Well it seems like it was the smoothing cap after all .I replaced it [temporarily] with another and its been happily playing 45s for the last half hour .however this is the first time i have seen a capacitor rated this way [25 volts /1mO ] as apposed to MFDS .Can you explain please
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6th Dec 2017, 10:48 pm | #7 |
Heptode
Join Date: Jul 2006
Location: North Herts. UK.
Posts: 549
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Re: Fidelity HF?
I think it's just that the unit (in this case millifarads) is used in place of the decimal point, as is often done with resistance values, so that the rating of the component can be expressed in only three characters.
So 1m0 is 1.0 mF, or 1000 uF. 4700 uF, or 4.7 mF would be 4m7, etc. |
6th Dec 2017, 10:55 pm | #8 |
Heptode
Join Date: Mar 2014
Location: Leeds, West Yorkshire, UK.
Posts: 902
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Re: Fidelity HF?
Thanks Tom. The one I put in is 1500 mfds. Will it be OK or shall I change it?
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6th Dec 2017, 11:38 pm | #9 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,535
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Re: Fidelity HF?
It'll be fine. The original 1000uF will simply have been the smallest value (cheapest part) that the designer could get away with.
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7th Dec 2017, 12:49 am | #10 |
Nonode
Join Date: Jun 2014
Location: Bristol, UK.
Posts: 2,074
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Re: Fidelity HF?
Good news! Possibly just in time! You have done a lovely job of restoration - it looks very good.
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'....don't go mistaking Paradise for that home across the road!' (Bob Dylan) |
7th Dec 2017, 11:58 am | #11 |
Dekatron
Join Date: Sep 2015
Location: Southwold, Suffolk, UK.
Posts: 8,327
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Re: Fidelity HF?
Fidelity HF?? - I'm 99% sure this is a Fidelity HF45. The single chip amplifier version came in about 1967-68.
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Edward. |
7th Dec 2017, 10:58 pm | #12 |
Heptode
Join Date: Mar 2014
Location: Leeds, West Yorkshire, UK.
Posts: 902
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Re: Fidelity HF?
Thanks Edward. I was thinking early 70's the deck being only a three speed. It was a total wreck when I got it. Part of the rexine was torn off. The knobs were missing along with its flex and the arm had been snapped off. It was originally a grey colour. I have to say it sounds rather good especially for a Fidelity. My grandson wanted one of those Crosley crapophones for Xmas. Well let me tell you he isn't getting one he is getting this instead.
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7th Dec 2017, 10:59 pm | #13 |
Dekatron
Join Date: Aug 2013
Location: Wigan, Greater Manchester, UK.
Posts: 9,433
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Re: Fidelity HF?
It does look good, like new.
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Frank |