No volume with arcing at solenoid?

[daddypine]

Hi, I have a uk Bal AMI model I 200 Manual. I have managed to solve and repair several electrical issues with my limited electrical knowledge but a mechanical engineer is where my trade was.

The problem I am having, and it did start slowly over time, is everything works ok to the point just after the machine places the needle on the record, then, a clicking/ chattering sound starts and there is no volume from the amp.
Originally, this would only happen for 2 to 6 seconds, then the noise would stop and the volume would fade up but now, the sound continues, and if you let it, sometimes throughout the whole record. I have pinned the sound down 
to the box which has the carousel jog button on along with an on and off switch. On looking under the box while in situ and making the noise, I can see what looks to be electrical arcing across the contacts of the switches on the side of a solenoid (tried to upload photo but site would not let me). The solenoid/ electro magnet seems to operate ok, thus throwing the switch to make the upper and lower switch contacts come together, but the arcing is then between the remaining open switch contacts.

I assume this is just a solenoid that brings the volume circuit into play once the record starts to play then disconnects it as it ends playing of the record. I have removed the box and tried to clean the contacts first with a fine embryo
paper then a piece of card. having replaced the unit the clicking sound is still there, any suggestion please?

The amplifier was professionally rebuilt two years ago.

Thanks in advance, Paul. 

[Ron Rich]

Hi Paul,
I am having a problem finding an English, to American-lEnglish translator, on the web, so I will need to make some assumptions-- I am ASSUMING the "jog button" is the scan start button -- and I am ASSuming the on/off switch is for the 24 v motor control circuits-- And I am ASSUMING the "solenoid" is what we would call a "relay"-- I also need to ASSUME the manual you have contains schematics/parts lists. If so, please use the terms in the manual, so we can all understand, and possibly come to some conclusions, that will help you-- You might start with the FAQ's section on cleaning contacts, and see what happens-- Ron Rich

[daddypine]

Hi Ron,
I am a complete novice and may have the terminology wrong, apologies for that. I have tried to post pictures but just get the message "This forum has exceeded its attachment space limit. Your file cannot be uploaded."

As far as I can break it down, there is a box to the right of the turntable (below the facia) with a button with the words "Manual rotate" next to it, which when pressed, rotates the drum containing all the records. I'm not 100% sure what the switch next to it does as I have never had cause to use these. Inside this box is a circular electro magnet which actuates a series of three contacts on the side of it, I assume this is the relay. When relaxed, only one switch of three makes contact. When energised, the first switch opens and the the remaining two then make contact. The one that has just opened is where the sparks are jumping and seems to be where the noise is coming from..

That's probably not much more help but, as a novice, is the best I can do I'm afraid.

Paul.

[jukenorman]

Hi Paul,
I have tried to understand your problem. The box you are referring to is known as the control box and what you have inside it is the reversing relay. As far as I can see (from AMi I diagrams), the reversing relay has two contacts, one a changeover contact and the other a normally open. It is possible though that BAL-AMi used two normally open and one normally closed contact.

A normally open contact is in parallel with the cam switch that operates the mute relay on the amplifier - so if that contact is poorly adjusted and just touching, it might be pulling in the mute relay (no sound). If that is the case, it should also be pulling in the reversing relay and replacing the record but if the RR NO (reversing relay normally open) contact is only just touching, it might not be able to pass enough current to operate both relays and probably also might explain why it is arcing.

Although reading over your message again, it looks like you are suggesting that the contact which is arcing is the normally closed which wrecks the above theory unless something is shorting? I do feel that the mute relay must be involved somehow.

Norman.

[daddypine]

Hi Norman,

I have tried to upload a photo of the said box several times but it won't let me, could I email you the picture by any chance, so you can take a quick look and at least know that we are both on the same page?

I have a reproduction manual which came with the jukebox and does have several wiring diagrams in, the one I am looking at is the "Record changer pictorial wiring diagram" which I assume the item you refer to is 
the record changer control box. It gives details of the colours of the wires but looking inside the box, they are all yellow so that could be fun.

Is the reversing relay there to reverse the motor controlling the arm that puts the record on and off? if so what controls the volume up and down to the amp?

Thanks for taking the time to reply, I am very keen to learn. Although my time served trade was a toolmaker at Rolls Royce, at 67, I am trying to learn basic electronics as this area fascinates me. 
Hope I can repay the help if ever you have an issue with a jet engine.  :-)

Many thanks, Paul.

[jukenorman]

Hi Paul,
There is a "sticky" post on how a jukebox works - that would be a really good place for you to start.

The diagrams that I am looking at are the record changer schem-a-grams. I only have the AMi I (not BAL-AMi) manuals although I don't believe there is much difference - the amplifier is UK made and the turntable motor is 230V AC for example.

The reversing relay does indeed reverse the transfer motor. There is a volume control for the amplifier but there is also a muting relay which mutes the amplifier when the jukebox is not playing a record to suppress interference from the scan and transfer motors. A contact on the reversing relay holds the mute relay energised in certain parts of the transfer. That's the only interface I can see between the control box and the amplifier so I suspect your problem is there somewhere.

Posting pictures to the forum is no longer possible. Our Belgian friend Cedric has a really good solution using casimages.com but the website is only in French! You can post images to a third party website and post links - that way you would get more feedback because more people would have the opportunity to see them. I have a Dropbox account which allows more than pictures to be shared but there are others like imgbb.com.

Norman.

[Ron Rich]

Guyz,
READ our FAQ's -- you can post photo's here ! As stated above--Cedric has done a beautiful job of doing so ! Ron Rich

[jukenorman]

Hi Ron,
I was examining Cedric's photos, they are actually posted via a 3rd party French website, casimages.com - all the details on the website are in French though. It's a while since I attempted to post an attachment here but the last time I tried, the site had reached its file storage allocation which is probably why Paul can't post a picture.

Norman.

Edit - I have tried imgbox which is free.  Image below hopefully!  Image not embedded though?

imgbox.com/0M4hhg6B.jpg