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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment.

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Old 4th Aug 2020, 1:37 pm   #1
John_Arbon
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Default 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
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Old 4th Aug 2020, 2:45 pm   #2
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Default 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.
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Old 4th Aug 2020, 3:20 pm   #3
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Default 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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Old 6th Aug 2020, 5:59 pm   #4
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Default 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
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Old 10th Aug 2020, 7:37 am   #5
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Default 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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Old 10th Aug 2020, 12:30 pm   #6
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Default Re: Fidelity HF35 Valve version

You may have to post them one at a time from an ipad.
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Old 10th Aug 2020, 3:27 pm   #7
Edward Huggins
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Default Re: Fidelity HF35 Valve version

Quote:
Originally Posted by John_Arbon View Post
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
Just make sure that these old unconnected wires do not cause a short aross the OP transformer's secondary.
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Old 10th Aug 2020, 8:17 pm   #8
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Default 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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Old 10th Aug 2020, 8:23 pm   #9
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Default 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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Old 10th Aug 2020, 8:33 pm   #10
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Default 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.

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Old 10th Aug 2020, 8:36 pm   #11
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Default 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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Old 11th Aug 2020, 1:24 pm   #12
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Default

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?
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Old 11th Aug 2020, 2:21 pm   #13
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Default 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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Old 11th Aug 2020, 2:26 pm   #14
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Default 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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Old 11th Aug 2020, 8:02 pm   #15
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Default 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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Old 15th Aug 2020, 12:33 pm   #16
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Default 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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