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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment. |
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22nd Oct 2021, 11:14 am | #1 |
Triode
Join Date: Sep 2020
Location: Telford, Shropshire, UK.
Posts: 42
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Help with smoothing capacitor on record player
Hi All
I’ve seen a couple of threads relating to smoothing capacitors. I am restoring a Portadyne 60s record player and have serviced all the mechanicals, I noticed a stain on the inside of the box under the smoothing cap, and was careful on applying volts, when I did there is a really loud hum, I assume the smoothing capacitor has gone and wondered if somebody would be prepared to repair the can or could help me repair (I’m in Telford, UK), photos attached. Label for type has PS1053/34 L1 J100 Thanks Dave |
22nd Oct 2021, 11:36 am | #2 |
Dekatron
Join Date: Aug 2013
Location: Wigan, Greater Manchester, UK.
Posts: 9,433
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Re: Help with smoothing capacitor on record player
Some suggestions on re stuffing the electrolytic capacitor.
https://vintage-radio.net/forum/showthread.php?t=161784
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Frank |
22nd Oct 2021, 11:58 am | #3 |
Triode
Join Date: Sep 2020
Location: Telford, Shropshire, UK.
Posts: 42
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Re: Help with smoothing capacitor on record player
Thanks Frank, think this might be beyond me skills to repair so if someone is prepared to look at the amp and repair for me that would be the best option thanks Dave
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22nd Oct 2021, 3:15 pm | #4 | |
Heptode
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Location: Sunderland, Tyne and Wear, UK.
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Re: Help with smoothing capacitor on record player
Quote:
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22nd Oct 2021, 5:57 pm | #5 |
Triode
Join Date: Sep 2020
Location: Telford, Shropshire, UK.
Posts: 42
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Re: Help with smoothing capacitor on record player
Thanks Bob do you know where I can get one of these? I did wonder about that, if this is shot would it cause the loud hum?
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22nd Oct 2021, 9:26 pm | #6 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,536
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Re: Help with smoothing capacitor on record player
Depends where it is in the circuit. If it's a grid coupling cap to the output valve, it could cause excessive current in that valve which might result in more hum but it's more likely that dried up electroytics in the can are to blame.
Dual 32uF caps are still fairly easy to find, the low voltage 25uF one can be fitted separately (as indeed could all three). You're about an hour (40miles) away, fancy bringing it to Leominster?
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23rd Oct 2021, 8:02 am | #7 |
Dekatron
Join Date: Sep 2015
Location: Southwold, Suffolk, UK.
Posts: 8,338
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Re: Help with smoothing capacitor on record player
It's a single-stage amp so there's no grid-coupling cap, it's the variable tone control cap. I would have thought that re-stuffing the big cap can is a step too far? Yes, a dual 32F 350V (or 2 sperate ones) and a separate 25uF 25V cathode cap are readily available and will replace all those that were in the single can. If the OP can solder, he might find it easier to do that than he thinks.
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Edward. |
23rd Oct 2021, 9:06 am | #8 |
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Re: Help with smoothing capacitor on record player
If the OP does that he should make sure that all the PCB lands to which the can's mounting tags are soldered are linked together as the connection between them is via the can.
If I were the OP I'd take up Herald's offer.
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Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |
23rd Oct 2021, 9:48 am | #9 |
Triode
Join Date: Sep 2020
Location: Telford, Shropshire, UK.
Posts: 42
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Re: Help with smoothing capacitor on record player
Hi all.
Bit the bullet and started to desolder, yes the can is the negative so going to make sure all the connections that went to the can side are connected together with the neg ends of the capacitors. That then leaves the three pos ends of the caps to go the red, yellow and green connected wires. Having fun |
23rd Oct 2021, 10:09 am | #10 |
Dekatron
Join Date: Sep 2015
Location: Southwold, Suffolk, UK.
Posts: 8,338
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Re: Help with smoothing capacitor on record player
Start with the cathode cap (25uF 25V) that goes to pin 3 of the UL84 when viewed from underneath,
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Edward. |
23rd Oct 2021, 10:58 am | #11 |
Triode
Join Date: Sep 2020
Location: Telford, Shropshire, UK.
Posts: 42
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Re: Help with smoothing capacitor on record player
Hi Edward nearest one I can find for the cathode cap is 33uf 25V unless you/anyone else can point me in the direction of one of the 25uf ones thanks Dave
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23rd Oct 2021, 11:36 am | #12 |
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Re: Help with smoothing capacitor on record player
22uF or 33UF 25V both will be fine in this role.
Cheers Mike T
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23rd Oct 2021, 11:57 am | #13 |
Triode
Join Date: Sep 2020
Location: Telford, Shropshire, UK.
Posts: 42
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Re: Help with smoothing capacitor on record player
Thanks Mike I’ll post on completion and let you all know if it’s a success - worried look lol
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23rd Oct 2021, 3:32 pm | #14 |
Triode
Join Date: Sep 2020
Location: Telford, Shropshire, UK.
Posts: 42
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Re: Help with smoothing capacitor on record player
Whilst de-soldering the components I noticed that the wire going from terminal 4 on the valve to the negative on the can passes through the earth point connection and is not actually soldered but loose, I’m thinking this could actually be the cause of the loud hum as the can would floating. I’m going to continue to replace components but wondered if I was thinking correctly. Thanks Dave
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23rd Oct 2021, 5:27 pm | #15 |
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Re: Help with smoothing capacitor on record player
UL84 pin 4 is one side of the heater. If it wasn't connected to ground then, depending on the routing of the wiring and PCB tracks, it's possible the valve wouldn't light up.
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Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |
23rd Oct 2021, 6:01 pm | #16 |
Triode
Join Date: Sep 2020
Location: Telford, Shropshire, UK.
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Re: Help with smoothing capacitor on record player
Hi Graham think that is what happened when I powered it up originally only one valve glowed, the one that didn’t I think was the one with this loose connection so that aligns with your comment. Just one question when I replace the capacitors s it OK to use circuit board or are the voltages too high? Thanks Dave
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23rd Oct 2021, 6:45 pm | #17 | |
Moderator
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Re: Help with smoothing capacitor on record player
Quote:
Sorry, but I don't understand that question.
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Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |
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23rd Oct 2021, 7:12 pm | #18 |
Hexode
Join Date: Oct 2019
Location: Weymouth, Dorset, UK.
Posts: 476
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Re: Help with smoothing capacitor on record player
I will be pleased to re stuff the can with modern day electrolytics and check the amplifier for you at cost plus postage back.
I have refurbished many with great success. Please PM me if you would like to have it done. Best regards.
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Valve equipment repairs since 1968 https://jonsnell.co.uk |
23rd Oct 2021, 8:17 pm | #19 | ||
Triode
Join Date: Sep 2020
Location: Telford, Shropshire, UK.
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Re: Help with smoothing capacitor on record player
Quote:
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23rd Oct 2021, 8:23 pm | #20 |
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Location: Ipswich, Suffolk, IP4, UK.
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Re: Help with smoothing capacitor on record player
Sorry, but I mistakenly thought the player used a Printed Circuit Board which it doesn't?
It's usual to mount replacement caps on tag strip. You can use circuit board, but make sure the tracks are wide and here's good separation between them.
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Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |