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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment. |
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11th Feb 2024, 6:52 pm | #1 |
Heptode
Join Date: Mar 2014
Location: Leeds, West Yorkshire, UK.
Posts: 899
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Pioneer LX 550
Hi all
while listening to Jonny Walker this after noon the pioneer just went silent .It had been on for about an hour when i went to the kitchen to check on the oven .When i came back it had stopped working. I turned it off and on and then turned up the volume and i could hear radio 2 but very faint . Usually when switching on there's a couple of seconds delay before anything happens then you hear what sounds like a relay click in could it be that ?any suggestions very welcome. thanks K |
11th Feb 2024, 6:55 pm | #2 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
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Re: Pioneer LX 550
Are both channels affected?
It's possible you have a protection relay fault, but that wouldn't normally affect both channels equally. |
11th Feb 2024, 7:36 pm | #3 |
Heptode
Join Date: Mar 2014
Location: Leeds, West Yorkshire, UK.
Posts: 899
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Re: Pioneer LX 550
Hi Paul
yes both channels are affected .I switched it on about ten mins ago and it came on for a few seconds and then went off again |
11th Feb 2024, 8:38 pm | #4 |
Moderator
Join Date: Mar 2012
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Re: Pioneer LX 550
Could still be the protection relay driver circuit, or even a genuine DC offset fault and therefore a valid cause of protection. Offset on any one channel disables both outputs but doesn't easily fit the very quiet sound.
Lids off, check all power supply rails, check output voltages of both power amps before the protection relay. There isn't much else common to both channels. Do CD/Tape/Gram work both channels? David
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11th Feb 2024, 8:42 pm | #5 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
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Re: Pioneer LX 550
Obviously the first thing to do is check for dry joints around the protection relay.
You may have a more serious fault which is tripping it though. |
11th Feb 2024, 9:39 pm | #6 |
Dekatron
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,809
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Re: Pioneer LX 550
I acquired a vintage Aiwa receiver recently and the sound was dodgy and intermittent on both channels. I removed the start up relay, cleaned the contacts with a slither of card laced with switch cleaner, now all is fine.
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11th Feb 2024, 10:10 pm | #7 |
Heptode
Join Date: Mar 2014
Location: Leeds, West Yorkshire, UK.
Posts: 899
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Re: Pioneer LX 550
Will have a look at it tomorrow [it's a major operation just disconnecting everything and getting it down off its shelf].
Thanks guys.Will let you know how I get on |
11th Feb 2024, 10:13 pm | #8 | |
Heptode
Join Date: Mar 2014
Location: Leeds, West Yorkshire, UK.
Posts: 899
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Re: Pioneer LX 550
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13th Feb 2024, 3:34 pm | #9 |
Heptode
Join Date: Mar 2014
Location: Leeds, West Yorkshire, UK.
Posts: 899
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Re: Pioneer LX 550
I have decided not to mess with this myself and have someone who knows what their doing put it right . Its now some 45 years old so i could just buy something new but my friends in the know tell me not to bother as the Pioneer is well worth fixing and better quality than new stuff [ it does sound nice when its working] so if there's anyone willing to take it on please contact me
Regards K |
13th Feb 2024, 6:35 pm | #10 |
Dekatron
Join Date: Sep 2015
Location: Southwold, Suffolk, UK.
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Re: Pioneer LX 550
What classic styling this has. It looks so solid and well made. I hope this will sound as good as it looks.
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14th Feb 2024, 11:09 am | #11 |
Triode
Join Date: Jun 2016
Location: Grantham, Lincolnshire, UK.
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Re: Pioneer LX 550
Do the dial lights work?
I think this is similar to an SX550 that I have and it does not have a protection relay as such but just a muting circuit. It uses the dial light power supply to initiate the power on delay. Mine had a failed bulb and fuse for this line giving the same problem. I guess the bulb went 'short' before dying and blew the fuse. |
14th Feb 2024, 8:44 pm | #12 | |
Heptode
Join Date: Mar 2014
Location: Leeds, West Yorkshire, UK.
Posts: 899
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Re: Pioneer LX 550
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14th Feb 2024, 8:48 pm | #13 |
Heptode
Join Date: Mar 2014
Location: Leeds, West Yorkshire, UK.
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Re: Pioneer LX 550
it is very heavy and as for its performance its far better than you think it would be .Only 25 watts per channel but with a good pair of speakers it sounds very good and the added bonus is its pre digital so no fancy gismos to get in the way
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14th Feb 2024, 8:49 pm | #14 | ||
Heptode
Join Date: Mar 2014
Location: Leeds, West Yorkshire, UK.
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Re: Pioneer LX 550
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14th Feb 2024, 9:02 pm | #15 | |||
Dekatron
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,809
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Re: Pioneer LX 550
Quote:
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14th Feb 2024, 9:08 pm | #16 |
Pentode
Join Date: Jul 2010
Location: London, UK.
Posts: 222
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Re: Pioneer LX 550
The more common SX-550 has a MW/FM tuner. The LX-550 has LW too, so not material to the fault. Actually not material at all in a few weeks when Droitwich closes down.
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14th Feb 2024, 9:22 pm | #17 | ||
Heptode
Join Date: Mar 2014
Location: Leeds, West Yorkshire, UK.
Posts: 899
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Re: Pioneer LX 550
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15th Feb 2024, 11:27 am | #18 |
Triode
Join Date: Jun 2016
Location: Grantham, Lincolnshire, UK.
Posts: 27
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Re: Pioneer LX 550
I bought the SX550 new in 1977 (I think from Laskys) and at the time did not know of the LX550.
It has been a good 'workhorse' and when last tried still worked. Did the dial lights go out when the problem occured, and is the power indicator also out(everything on the 8V AC line not working)? Is there the 8V A/C supply present on both pins of fuse FU 5. If there is not then it is worrying that the 8V winding of the transformer could be faulty. Looking more closely at the schematic (snippit from SX550 attached), the A/C for the dial lights being removed initiates an immediate mute of the audio, so I think it is acting as a power off mute (to eliminate spurious effects on shutdown). So with this not present it is always in the power off mute mode. |