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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment. |
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4th Aug 2020, 1:37 pm | #1 |
Diode
Join Date: Aug 2020
Location: South Molton, Devon, UK.
Posts: 6
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Fidelity HF35 Valve version
Hello,
I have acquired an old HF35 Fidelity record player which a friend would like repaired. It appears someone has connected an external speaker off the original speaker, now removed, and I presume blown the circuit. There is a burnt out capacitor, but without testing the the other components look intact. I would like to repair the player but I can’t find a circuit diagram for the player. Can anyone help? Would ideally like a circuit diagram or someone who can identify the components and suitable replacements. I can post a pic! Cheers John |
4th Aug 2020, 2:45 pm | #2 |
Dekatron
Join Date: Nov 2009
Location: Lincolnshire, UK.
Posts: 4,985
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Re: Fidelity HF35 Valve version
Hello, and welcome.
These are a simple record player that uses a 'live chassis', so care is needed when working on one. You'll need a multimeter (DVM) to make tests. There's a few variations on these old players, so forum members will need to see pictures (or a picture) of the electrical innards of your player (instructions on posting pictures directly to the forum I think are somewhere in the FAQ section if you don't know how). It could be that what you think is a capacitor burnt out is in fact a resistor, so picture/s are definitely needed. A circuit diagram won't be needed to fix this player, so no need to worry about finding one. |
4th Aug 2020, 3:20 pm | #3 |
Dekatron
Join Date: Sep 2015
Location: Southwold, Suffolk, UK.
Posts: 8,302
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Re: Fidelity HF35 Valve version
Do you mean that the original internal speaker is still in-situ and the external speaker has been disconnected - or - that the internal speaker has been removed and the player has been run with no speaker connected at all? The amplifier is a very simple and you are unlikely to need a circuit diagram for this. Check for continuity of the primary and secondary of the OP transformer, measure the large surge resistor and the top cut tone control cap.
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Edward. |
6th Aug 2020, 5:59 pm | #4 |
Diode
Join Date: Aug 2020
Location: South Molton, Devon, UK.
Posts: 6
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Re: Fidelity HF35 Valve version
Many thanks, I will post a picture. Yep having a closer look it is a fried resistor.
The original speaker is still there, but the add on has gone just left the old wires behind! Seems like it will be a fairly simple fix. John |
10th Aug 2020, 7:37 am | #5 |
Diode
Join Date: Aug 2020
Location: South Molton, Devon, UK.
Posts: 6
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Re: Fidelity HF35 Valve version
Trying to post pics from an iPad, but without any joy. I will try another way. Ta John
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10th Aug 2020, 12:30 pm | #6 |
Dekatron
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 9,637
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Re: Fidelity HF35 Valve version
You may have to post them one at a time from an ipad.
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10th Aug 2020, 3:27 pm | #7 |
Dekatron
Join Date: Sep 2015
Location: Southwold, Suffolk, UK.
Posts: 8,302
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Re: Fidelity HF35 Valve version
Just make sure that these old unconnected wires do not cause a short aross the OP transformer's secondary.
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Edward. |
10th Aug 2020, 8:17 pm | #8 |
Diode
Join Date: Aug 2020
Location: South Molton, Devon, UK.
Posts: 6
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Re: Fidelity HF35 Valve version
Rightio, looks like I have found a way round it, so attached are the pics of the circuit including the fried resistor. Any help with identify the value of the fried resistor would be good. John
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10th Aug 2020, 8:23 pm | #9 |
Dekatron
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 9,637
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Re: Fidelity HF35 Valve version
It's your UL84 that's cooked, not the resistor. The white deposit means that it's lost it's vacuum. Probably a cracked pin.
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10th Aug 2020, 8:33 pm | #10 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Re: Fidelity HF35 Valve version
The charred looking resistor (the rectifiers surge limiter) would be 130 Ohm as fitted:
https://www.vintage-radio.net/forum/...5&d=1341001528 Lawrence. Last edited by ms660; 10th Aug 2020 at 8:41 pm. Reason: link added |
10th Aug 2020, 8:36 pm | #11 |
Dekatron
Join Date: Oct 2003
Location: Croydon, Surrey, UK.
Posts: 7,548
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Re: Fidelity HF35 Valve version
The resistor may look cooked but is probably perfectly OK. Replace the UL84 first as (stated above) it has lost its vacuum and is useless. Valves of this type will normally have a silvery deposit at the top, indicating a good vacuum. It goes white when air enters.
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There are lots of brilliant keyboard players and then there is Rick Wakeman..... |
11th Aug 2020, 1:24 pm | #12 |
Diode
Join Date: Aug 2020
Location: South Molton, Devon, UK.
Posts: 6
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Yep, on inspection it is cracked. Apart from the rather fried looking resistor what else do you think is worth replacing, thought I would replace the other valve as well for good measure. Cheers for all the help thus far. John
Many thanks, any suggestions for best on place for components in the UK? |
11th Aug 2020, 2:21 pm | #13 |
Moderator
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 21,192
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Re: Fidelity HF35 Valve version
There's no point in replacing components unless they're faulty. There's a chance you'll introduce new faults.
The most unreliable part is the cartridge.
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Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |
11th Aug 2020, 2:26 pm | #14 |
Dekatron
Join Date: Oct 2003
Location: Croydon, Surrey, UK.
Posts: 7,548
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Re: Fidelity HF35 Valve version
No need to replace the other valve unless it is faulty. Contrary to what you may have heard, valves are not as unreliable as they were made out to be! They are also a diminishing resource so replacing them just for the sake of it, depletes what is available when they really are needed. For the moment, just replace the UL84. Don't even worry about the resistor at this stage....in fact measure the value of it and post the result here. Very often those old carbon stick resistors could lose all their paint and others would even look 'bubbled' but still be perfectly serviceable.
These amplifiers are incredibly simple and there is not much to go wrong.
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There are lots of brilliant keyboard players and then there is Rick Wakeman..... |
11th Aug 2020, 8:02 pm | #15 |
Dekatron
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 9,637
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Re: Fidelity HF35 Valve version
Apart from the fact that those big old resistors are tough as old boots, the value isn't critical. It was probably 20% tolerance when new. Likely only marginally adrift now.
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15th Aug 2020, 12:33 pm | #16 |
Diode
Join Date: Aug 2020
Location: South Molton, Devon, UK.
Posts: 6
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Re: Fidelity HF35 Valve version
Thanks for all your help, it’s on the road to recovery. Hopefully I will be able to post a pic of the restored article. Got to be honest it’s a pretty ropey old thing, not a patch on my lovely old Monarch!
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