Bush SRP 31D not producing sound. - Page 4 - UK Vintage Radio Repair and Restoration Discussion Forum

AndiiT · 25th Jul 2012, 1:48 pm

Hi,
Is this player definitely an SRP31D and not a C?
I ask this because from what you say about the most recent tests (the buzz test) it sounds like the amplifier is working.

The D and C series players have their, STEREO and AMP co-axial sockets wired differently so if your player is wired as the C series model, for any reason, the flying coaxial lead must be inserted into the AMP socket in order to produce any sound from the cartridge.

Regards

Andrew

Station X · 25th Jul 2012, 2:32 pm

Given that in post #1 it's stated that the amplifier is fitted with ECL86's I'd say it's a D model.

Quote:

Originally Posted by Spencervs

the only thing that can go wrong is C2, right?

C2 is wired in parallel with R2, so even if it were faulty, which is unlikely, it won't stop the player working.

What you need to do now is trace the wire from R2 to the "AMP INPUT" socket. Touch this wire at each temination and check that you get a buzz. Only a disconnection of this wire will prevent the amplifier working.

Once you get a buzz from the centre connection of the amplifier socket, you'll need to check the plug which goes into the socket, the wires from there to the cartridge and the cartridge itself.

Spencervs · 25th Jul 2012, 2:33 pm

I'm led to believe it's a D as it has the BSR Monarch UA16 (I think its UA16 anyway) deck. As for the wiring, it is wired quite weirdly, it has the Co-ax set up at the back but it's wired inside in such a way that the stereo and mono are combined and there isn't really a need for the co-ax to be plugged in. I am unsure if this is factory soldering though or is some one else came along and did it. I have tried it both plugged in and out though when testing it on records.

I am though assuming it's D as I am led to believe the C series uses the Garrard Auto-slim whereas the D series uses Monarch UA16.

Station X · 25th Jul 2012, 2:35 pm

Unplug the coaxial plug. Do you get a buzz when you touch the centre contact of the socket?

Spencervs · 25th Jul 2012, 2:41 pm

I have some progress. R2 ends at the connector which leads to the co-axial plug, maybe it's the wire?

It doesn't make sense though because I tried another cartridge and it was still the same also, the sound faded out like the end of a song, just gradually phased out to nothing. Surely that's not the symptom of a broken wire?

Spencervs · 25th Jul 2012, 2:42 pm

I'm going to change the wire at the co-axial plug and try the buzz test on the socket, like you say.

Station X · 25th Jul 2012, 2:43 pm

Quote:

As for the wiring, it is wired quite weirdly, it has the Co-ax set up at the back but it's wired inside in such a way that the stereo and mono are combined and there isn't really a need for the co-ax to be plugged in. I am unsure if this is factory soldering though or is some one else came along and did it. I have tried it both plugged in and out though when testing it on records.

Can we have some good CLOSE UP pictures of the sockets and the wiring from them to the amplifier and cartridge please.

Spencervs · 25th Jul 2012, 4:04 pm

OK, can do, although since I replaced the wire, it now works! I played Blondie on it successfully but I am still concerned as when it was first working, I moved the mains wire into the slot (you know so you can close the lid?) and the sound went dead but the turntable was still spinning and there was power.

I then unplugged the co-ax and replugged it and there was sound again but then it fizzled down to very bitty sound. Then I turned it off and on again and the sound was fine and has been now for three singles. Does anyone else agree that this is seeming like a temporary fix? I don't understand why it suddenly decided to work!

Station X · 25th Jul 2012, 4:40 pm

Quote:

I moved the mains wire into the slot (you know so you can close the lid?) and the sound went dead but the turntable was still spinning and there was power.

Well it obviously isn't a problem with the mains lead then.

Quote:

I then unplugged the co-ax and replugged it and there was sound again but then it fizzled down to very bitty sound. Then I turned it off and on again and the sound was fine and has been now for three singles. Does anyone else agree that this is seeming like a temporary fix? I don't understand why it suddenly decided to work!

You obviously had or have a dodgy connection somewhere. It could be a soldered connection, or far more likely there's a problem with the coax plug or socket, or a problem with one of the connections on the back of the cartridge.

You could try using thin nosed pliers to squeze up slightly the various pluggable connectors so that they make better contact. Be careful though.

Spencervs · 25th Jul 2012, 7:41 pm

thanks guys for all your help, it still seems to work fine and I've had a few records on it now. Hopefully it will stay all right but there is definitely a silly lose connection somewhere so I know its nothing major!

I have noticed though that the spindle isn't dropping records properly, if there's more than two on it then it won't drop the middle ones... could this be due to the spindle wearing? if so where can I get a replacement?

Audio1950 · 25th Jul 2012, 8:11 pm

Are you saying that if four records are stacked, it will drop the first and last, but not the middle two?? That's not logical! The spindle definately won't be worn, they last forever. Make sure the records that won't drop are not fitted with those plastic "spiders", that replaced the original centres. They can occasionally cause problems. The other thing to check is that the sliding piece set into the top of the spindle is free to move, but if it is not dropping properly, this would cause two or more records to drop together.

Barry

Spencervs · 25th Jul 2012, 8:32 pm

The whole machine is just illogical to me. None of the records have the adaptors. The bit that pushes the records moves across but the records just don't move with it and sometimes they do and when they do they all fall! or one will fall and the rest won't. You have to poke the record so it goes down.

Station X · 25th Jul 2012, 10:37 pm

What diameter, approximately, are the holes in the records? Records were sold with a hole about 1/4" diameter, but for use with Juke Boxes the centre was cut out leaving a hole about 1 1/4" diameter. To play ex Juke Box records on a normal player you have to fit adaptors to reduce the hole down to 1/4" diameter again.

The "dropping" mechanism is perfectly logical. Try observing what happens if you rotate the turntable by hand.

Spencervs · 25th Jul 2012, 11:36 pm

No, I mean this machine can be a bit illogical sometimes, it only works when it wants to. It played a stack of Seekers singles fine but, this stack, I had to coax it to drop one this time (My Way by Frank Sinatra) but I've never had this problem before. All the records are the 1/4 inch hole, no adaptors.

Also the record player still makes that weird noise, the fwoooosshhhh when it's turned off sometimes.

Spencervs · 26th Jul 2012, 12:58 am

oh god! its done it again! the sound faded out... and there's no live buzz from the co-ax terminal. I am wondering if you think its the potentiometer (for volume) as I played with the volume knob and I did get some interesting sounds from the speakers... also sometimes it works then it doesn't... it just fluctuates and works when it wants to. when it phases out it sounds like someone gradually turning the volume down to nothing

Glowing Bits! · 26th Jul 2012, 1:53 am

Have the decoupling caps been changed?
If not, that could explain the strange fading thing.
As for the noise at switch-off, my Pioneer stereo unit does a similar thing when switching off, it's usually the output valves cooling and the electrolytic cans discharging, as far as I'm aware.

Spencervs · 26th Jul 2012, 1:08 pm

Are the decoupling caps the red and black electrolytic ones? It's very odd, it's having a spell of working at the moment but it's always temporary. Should I just replace them anyway to be sure? If so do you know where I can find them?

Glowing Bits! · 26th Jul 2012, 6:47 pm

If they're tubular, then yes, could you let me know what valve holder pin they're attached to?
If the decouplers have not been changed and the set works, it's by pure chance!
Most parts for valve sets are readily available, albeit in a slightly different rating but will still do the job.
Decouplers are usually 0.01UF or in some cases 0.1UF.

Glowing Bits! · 26th Jul 2012, 6:50 pm

Just had another look at the pic on page 1, there are some ceramic capacitors, I'm now thinking they might be the decouplers, me thinks a Trader sheet's in order!

Spencervs · 26th Jul 2012, 7:22 pm

I wouldn't use the photo from page 1 as its of an SRP31 that had spare (I couldn't get into the SRP31D at the time as the nuts had siezed) but the pics on post #36 are from the machine in question. There's a circuit diagram on this topic as linked by AC/HL https://www.vintage-radio.net/forum/...ad.php?t=86032 on post #4 if that's helpful. I take it you don't mean those Plessley 50uf 12v electrolytic capacitors in the circuit?

25th Jul 2012, 1:48 pm	#61
AndiiT Octode Join Date: Aug 2005 Location: Saltburn-East, Cleveland, UK. Posts: 1,786	Re: Bush SRP 31D not producing sound! Hi, Is this player definitely an SRP31D and not a C? I ask this because from what you say about the most recent tests (the buzz test) it sounds like the amplifier is working. The D and C series players have their, STEREO and AMP co-axial sockets wired differently so if your player is wired as the C series model, for any reason, the flying coaxial lead must be inserted into the AMP socket in order to produce any sound from the cartridge. Regards Andrew

25th Jul 2012, 2:33 pm	#63
Spencervs Hexode Join Date: Apr 2011 Location: Grove Park, SE London Posts: 382	Re: Bush SRP 31D not producing sound! I'm led to believe it's a D as it has the BSR Monarch UA16 (I think its UA16 anyway) deck. As for the wiring, it is wired quite weirdly, it has the Co-ax set up at the back but it's wired inside in such a way that the stereo and mono are combined and there isn't really a need for the co-ax to be plugged in. I am unsure if this is factory soldering though or is some one else came along and did it. I have tried it both plugged in and out though when testing it on records. I am though assuming it's D as I am led to believe the C series uses the Garrard Auto-slim whereas the D series uses Monarch UA16.

25th Jul 2012, 2:35 pm	#64
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,288	Re: Bush SRP 31D not producing sound! Unplug the coaxial plug. Do you get a buzz when you touch the centre contact of the socket? __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

25th Jul 2012, 2:41 pm	#65
Spencervs Hexode Join Date: Apr 2011 Location: Grove Park, SE London Posts: 382	Re: Bush SRP 31D not producing sound! I have some progress. R2 ends at the connector which leads to the co-axial plug, maybe it's the wire? It doesn't make sense though because I tried another cartridge and it was still the same also, the sound faded out like the end of a song, just gradually phased out to nothing. Surely that's not the symptom of a broken wire?

25th Jul 2012, 2:42 pm	#66
Spencervs Hexode Join Date: Apr 2011 Location: Grove Park, SE London Posts: 382	Re: Bush SRP 31D not producing sound! I'm going to change the wire at the co-axial plug and try the buzz test on the socket, like you say.

25th Jul 2012, 4:04 pm	#68
Spencervs Hexode Join Date: Apr 2011 Location: Grove Park, SE London Posts: 382	Re: Bush SRP 31D not producing sound! OK, can do, although since I replaced the wire, it now works! I played Blondie on it successfully but I am still concerned as when it was first working, I moved the mains wire into the slot (you know so you can close the lid?) and the sound went dead but the turntable was still spinning and there was power. I then unplugged the co-ax and replugged it and there was sound again but then it fizzled down to very bitty sound. Then I turned it off and on again and the sound was fine and has been now for three singles. Does anyone else agree that this is seeming like a temporary fix? I don't understand why it suddenly decided to work!

25th Jul 2012, 7:41 pm	#70
Spencervs Hexode Join Date: Apr 2011 Location: Grove Park, SE London Posts: 382	Re: Bush SRP 31D not producing sound! thanks guys for all your help, it still seems to work fine and I've had a few records on it now. Hopefully it will stay all right but there is definitely a silly lose connection somewhere so I know its nothing major! I have noticed though that the spindle isn't dropping records properly, if there's more than two on it then it won't drop the middle ones... could this be due to the spindle wearing? if so where can I get a replacement?

25th Jul 2012, 8:11 pm	#71
Audio1950 Dekatron Join Date: Nov 2008 Location: Whittlesey, near Peterborough, Cambridgeshire, UK. Posts: 3,761	Re: Bush SRP 31D not producing sound! Are you saying that if four records are stacked, it will drop the first and last, but not the middle two?? That's not logical! The spindle definately won't be worn, they last forever. Make sure the records that won't drop are not fitted with those plastic "spiders", that replaced the original centres. They can occasionally cause problems. The other thing to check is that the sliding piece set into the top of the spindle is free to move, but if it is not dropping properly, this would cause two or more records to drop together. Barry

25th Jul 2012, 8:32 pm	#72
Spencervs Hexode Join Date: Apr 2011 Location: Grove Park, SE London Posts: 382	Re: Bush SRP 31D not producing sound! The whole machine is just illogical to me. None of the records have the adaptors. The bit that pushes the records moves across but the records just don't move with it and sometimes they do and when they do they all fall! or one will fall and the rest won't. You have to poke the record so it goes down.

25th Jul 2012, 10:37 pm	#73
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,288	Re: Bush SRP 31D not producing sound! What diameter, approximately, are the holes in the records? Records were sold with a hole about 1/4" diameter, but for use with Juke Boxes the centre was cut out leaving a hole about 1 1/4" diameter. To play ex Juke Box records on a normal player you have to fit adaptors to reduce the hole down to 1/4" diameter again. The "dropping" mechanism is perfectly logical. Try observing what happens if you rotate the turntable by hand. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

25th Jul 2012, 11:36 pm	#74
Spencervs Hexode Join Date: Apr 2011 Location: Grove Park, SE London Posts: 382	Re: Bush SRP 31D not producing sound! No, I mean this machine can be a bit illogical sometimes, it only works when it wants to. It played a stack of Seekers singles fine but, this stack, I had to coax it to drop one this time (My Way by Frank Sinatra) but I've never had this problem before. All the records are the 1/4 inch hole, no adaptors. Also the record player still makes that weird noise, the fwoooosshhhh when it's turned off sometimes.

26th Jul 2012, 12:58 am	#75
Spencervs Hexode Join Date: Apr 2011 Location: Grove Park, SE London Posts: 382	Re: Bush SRP 31D not producing sound! oh god! its done it again! the sound faded out... and there's no live buzz from the co-ax terminal. I am wondering if you think its the potentiometer (for volume) as I played with the volume knob and I did get some interesting sounds from the speakers... also sometimes it works then it doesn't... it just fluctuates and works when it wants to. when it phases out it sounds like someone gradually turning the volume down to nothing

26th Jul 2012, 1:53 am	#76
Glowing Bits! Octode Join Date: Oct 2011 Location: Wrexham, North Wales, UK. Posts: 1,457	Re: Bush SRP 31D not producing sound! Have the decoupling caps been changed? If not, that could explain the strange fading thing. As for the noise at switch-off, my Pioneer stereo unit does a similar thing when switching off, it's usually the output valves cooling and the electrolytic cans discharging, as far as I'm aware.

26th Jul 2012, 1:08 pm	#77
Spencervs Hexode Join Date: Apr 2011 Location: Grove Park, SE London Posts: 382	Re: Bush SRP 31D not producing sound! Are the decoupling caps the red and black electrolytic ones? It's very odd, it's having a spell of working at the moment but it's always temporary. Should I just replace them anyway to be sure? If so do you know where I can find them?

26th Jul 2012, 6:47 pm	#78
Glowing Bits! Octode Join Date: Oct 2011 Location: Wrexham, North Wales, UK. Posts: 1,457	Re: Bush SRP 31D not producing sound! If they're tubular, then yes, could you let me know what valve holder pin they're attached to? If the decouplers have not been changed and the set works, it's by pure chance! Most parts for valve sets are readily available, albeit in a slightly different rating but will still do the job. Decouplers are usually 0.01UF or in some cases 0.1UF.

26th Jul 2012, 6:50 pm	#79
Glowing Bits! Octode Join Date: Oct 2011 Location: Wrexham, North Wales, UK. Posts: 1,457	Re: Bush SRP 31D not producing sound! Just had another look at the pic on page 1, there are some ceramic capacitors, I'm now thinking they might be the decouplers, me thinks a Trader sheet's in order!

26th Jul 2012, 7:22 pm	#80
Spencervs Hexode Join Date: Apr 2011 Location: Grove Park, SE London Posts: 382	Re: Bush SRP 31D not producing sound! I wouldn't use the photo from page 1 as its of an SRP31 that had spare (I couldn't get into the SRP31D at the time as the nuts had siezed) but the pics on post #36 are from the machine in question. There's a circuit diagram on this topic as linked by AC/HL https://www.vintage-radio.net/forum/...ad.php?t=86032 on post #4 if that's helpful. I take it you don't mean those Plessley 50uf 12v electrolytic capacitors in the circuit?