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Old 11th Dec 2019, 3:58 pm   #1
WalterGibbons
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Default Pioneer SX-424 only playing one channel

Hi, I've just dug an old SX-424 out of a cupboard and spent half the morning rearranging my living room to accommodate it! Just switched it on and I'm only getting sound from one speaker. It worked a couple of years ago when it went in the cupboard. The only thing I can imagine I've done is turn it upside down today to re-attach the feet I'd previously removed. But I did it carefully and seriously doubt that would cause this issue.

It's definitely the amp - I've tried headphones, tried swapping speakers, different carts, the radio. Nothing gives me left and right. The weird balance/voume knob really doesn't help matters!

I've opened it up but have no idea what I'm looking at. Any suggestions on what may be a simple fix before I look for someone?
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Old 11th Dec 2019, 4:08 pm   #2
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Default Re: Pioneer SX-424 only playing one channel

Clean all the switch contacts with Servisol.
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Old 11th Dec 2019, 4:08 pm   #3
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Default Re: Pioneer SX-424 only playing one channel

There are 3 fuses on the rear on some models?
One is mains, leave that alone.
The other 2 are marked 'Protection Fuse' Left and Right? Check one has not blown.
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Old 11th Dec 2019, 4:29 pm   #4
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Default Re: Pioneer SX-424 only playing one channel

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Originally Posted by snowman_al View Post
There are 3 fuses on the rear on some models?
One is mains, leave that alone.
The other 2 are marked 'Protection Fuse' Left and Right? Check one has not blown.
Bingo! Thank you!!
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Old 11th Dec 2019, 5:03 pm   #5
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Default Re: Pioneer SX-424 only playing one channel

Another quick question - I can't find 1.2A fuses in the UK - I assume it's OK to go for a higher ampage?

Last edited by WalterGibbons; 11th Dec 2019 at 5:09 pm.
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Old 11th Dec 2019, 5:18 pm   #6
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Default Re: Pioneer SX-424 only playing one channel

I'd advise against going higher.

In order to recommend a fuse we'd need to know its physical size and speed. The latter is generally indicated by the lettering on the end caps.
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Old 11th Dec 2019, 5:22 pm   #7
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Default Re: Pioneer SX-424 only playing one channel

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I'd advise against going higher.

In order to recommend a fuse we'd need to know its physical size and speed. The latter is generally indicated by the lettering on the end caps.
Ah. The lettering says "SOC 1.2A"
I don't have a way to measure 100% accurately, but to my eye it's 30mm x approximately 6mm.

Thank you - I was actually tying my laces there to go to Halfords
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Old 11th Dec 2019, 5:28 pm   #8
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Default Re: Pioneer SX-424 only playing one channel

SOC is the manufacturer. There should be other markings as described here:-

https://www.swe-check.com.au/pages/l...e_markings.php
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Old 11th Dec 2019, 5:37 pm   #9
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Default Re: Pioneer SX-424 only playing one channel

The only other thing is a symbol - Kind of Letter T with two top bars, in a triangle.
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Old 11th Dec 2019, 5:42 pm   #10
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Default Re: Pioneer SX-424 only playing one channel

That's the approval marking. In this case MITI (Japan) - now know as METI.
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Old 11th Dec 2019, 5:42 pm   #11
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Default Re: Pioneer SX-424 only playing one channel

BTW. Have you swopped the good fuse to the other channel to check that it works?
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Old 11th Dec 2019, 5:44 pm   #12
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Default Re: Pioneer SX-424 only playing one channel

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BTW. Have you swopped the good fuse to the other channel to check that it works?
I did! And yes, it worked
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Old 11th Dec 2019, 5:46 pm   #13
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Default Re: Pioneer SX-424 only playing one channel

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That's the approval marking. In this case MITI (Japan) - now know as METI.
That's everything that's on there.
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Old 11th Dec 2019, 5:48 pm   #14
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Default Re: Pioneer SX-424 only playing one channel

These should do the job. Other suppliers are available.

https://uk.rs-online.com/web/p/cartridge-fuses/0412649/
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Old 11th Dec 2019, 5:57 pm   #15
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Default Re: Pioneer SX-424 only playing one channel

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These should do the job. Other suppliers are available.

https://uk.rs-online.com/web/p/cartridge-fuses/0412649/
I've been on that site for an hour and didn't see these!

Would I do damage if I used this..?

https://www.halfords.com/workshop-to...s-2-amp-hfs117

(Halfords is 2 mins walk from me!)
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Old 11th Dec 2019, 6:01 pm   #16
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Default Re: Pioneer SX-424 only playing one channel

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Originally Posted by WalterGibbons View Post
Another quick question - I can't find 1.2A fuses in the UK - I assume it's OK to go for a higher ampage?
The ''current'' standard is 1.25A and that will be fine. I would not be tempted to go higher...
You will find 1.25A, 6 x 30mm (= 6.3 x 32mm = 1/4 x 1 1/4 inch) cartridge fuses on line. CPC, Farnell and ebay. Buy a few.
Once you have them, swap the good side one for the blown one. If it works all is good. If it 'pops' there is a fault on the amplifier or that speaker / cable.
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Old 11th Dec 2019, 6:10 pm   #17
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Default Re: Pioneer SX-424 only playing one channel

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Originally Posted by WalterGibbons View Post

Would I do damage if I used this..?

https://www.halfords.com/workshop-to...s-2-amp-hfs117

(Halfords is 2 mins walk from me!)
You need to prove the fuse failed from old age and not because of a fault on the amp / speaker.
If you swap the good fuse to the faulty side and it works, then they would be ok for a temporary fix. Order some proper rating ones and fit them ASAP.
If it fails you have 2 dead fuses and a faulty channel...
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Old 11th Dec 2019, 6:16 pm   #18
WalterGibbons
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Default Re: Pioneer SX-424 only playing one channel

Quote:
Originally Posted by snowman_al View Post

You need to prove the fuse failed from old age and not because of a fault on the amp / speaker.
If you swap the good fuse to the faulty side and it works, then they would be ok for a temporary fix. Order some proper rating ones and fit them ASAP.
If it fails you have 2 dead fuses and a faulty channel...
OK thanks. The good fuse works on the faulty side, so I'm fairly confident.

Just saw RS do free next day delivery on some 14 pence fuses! So I guess I can contain myself till tomorrow. It's too wet to walk to Halfords anyway.
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