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

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Old 12th Dec 2019, 12:00 am   #1
19Seventy7
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Default Dynatron HFC51 volume change

Hi,

I have a Dynatron HFC 51, which I've had for a couple of years now, but recently I've started having issues with audio.

The audio level can suddenly change, it usually gets louder, then stay at it's louder level for a few minutes, then drop again, to a quiet level.

The left channel is also unusable as it gives a very loud distorted noise, this happens through both headphones, and the loud speakers.

I have had the distortion issue for a while now, but it was very quiet, and only noticeable with no music, but it now overpowers the music.

I did search for a diagram and found one online, but it's too much for what I can afford.

The player uses a Dynatron SA29 "chassis" (I don't know if that's the term for record players)

I guess it's something in the amplifier section?

Thanks
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Old 12th Dec 2019, 8:17 am   #2
qualityten
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Default Re: Dynatron HFC51 volume change

Hi, this thread may help you somewhat https://www.vintage-radio.net/forum/...d.php?p=485094
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Old 12th Dec 2019, 11:38 pm   #3
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Default Re: Dynatron HFC51 volume change

Hi,

Thank you, for linking that, i'll get to reading it now

Thanks
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Old 13th Dec 2019, 12:52 pm   #4
Edward Huggins
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Default Re: Dynatron HFC51 volume change

Failure of one Channel in these is a very common problem. What is your skill level in fault finding/voltage measuring on old equipment such as this?
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Old 14th Dec 2019, 12:48 am   #5
19Seventy7
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Default Re: Dynatron HFC51 volume change

Hi,

I'm so-so with fault finding, I have some limited experience and know-how, with some guidance I can do it

I'm not too great at following schematics and diagrams, although.

Thanks
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Old 14th Dec 2019, 2:26 pm   #6
Dodgy Geezer
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Default Re: Dynatron HFC51 volume change

I'm going to go right out on a limb here, since I am unskilled and incompetent at electronics - but I have a Sony HMK-80B which has a similar problem, and I believe it to be caused by a failing volume pot together with poor contacts at the headphone socket...
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Old 14th Dec 2019, 4:34 pm   #7
Edward Huggins
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Default Re: Dynatron HFC51 volume change

A Volume Pot does not actually "fail" enough to impair volume - but the track does get worn so that over time, the volume may become intermittent, but not necessarily reduced in amplitude.
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Old 15th Dec 2019, 5:50 pm   #8
19Seventy7
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Default Re: Dynatron HFC51 volume change

Hi,

the volume changes on both channels, but the heavy distortion is from the left channel only, so it could possibly be the volume control, it's a slider and I think these had their problems, but I think the volume drops, and then raises to its normal level, so i'm not sure

Thanks
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