Hum noise from my Rock-Ola 459

[Paul]

Hi Ron.

Hope you are well.

Did as suggested.

Firstly, disconnected the power cable from the lower ballast.

Hum is still there.

Secondly, removed the top lamp from the other ballast.

Hum still there!

Very challenging indeed. Jeepers!

The part that I find very confusing is, if I disconnect one of the large speakers and remove the other large speaker, from in-situ, then reconnect it outside the jukebox, by way of extended cable, to the external speaker, the hum goes away! When all is returned to their original location, hum returns!

What would suggest next move?

Thanks and greatly appreciated.

Paul

[Ron Rich]

Hi Paul,

I dono ?? If you can, disconnect AC power from everything, except the amp-- then "add back" power, till the hum appears--??

P. S.-- Is the whole phono "earthed" ?  Is the earth connection, at the wall plug good ?   Ron Rich

[jukenorman]

Paul,
Clearly that transformer is a modification / repair of some sort. It's quite difficult for us to second guess its purpose and how it's affecting the operation of the jukebox re hum. But whatever, if you can isolate the power to that transformer, then it cannot possibly be the source of the hum problem. Removing the front door and moving it away from this transformer, as you have done, would probably suggest that it's not the problem whether power is there or not.
Norman.

[Paul]

Hi Folks.

Thank you for your feedback

Sorry for the delay as I was, again, away from home for a few days.

Re: hum noise from speakers, I have done the following;

Regarding earthing, I plugged the jukebox into several sockets throughout the house with the same end result -- hum.

I cant remember if the hum was present at point of purchasing, however, it was present when first engaged at home.

A new plug serving the jukebox has been fitted and the earthing wire within is well secured.

I removed the lower ballast completely and the hum was still present.

Intrigued, I once again removed one of the large speakers, from in-situ and, reconnected it outside the jukebox, no hum. The second speaker remained in place and was disconnected. Played a record and the sound from the external speaker was very good. Returned it to its original position, reconnected everything, switched on, and hum returned! Torture or what!

I am considering replacing the cables to the speakers with a much better, quality material, although I have been informed that use of coaxial cable(TV areal cable) would be a suitable shielding cable to use.

Folks, where do you think I should go from here?

Thanks and with appreciation.

Paul

[jukenorman]

I would be surprised if it was the cables unless they are damaged. When you are returning the good sounding speaker to the cabinet and reconnecting it, is there a possibilty you have some sort of hum loop through the second speaker that previously was disconnected?
Norman.

[Paul]

Hi Norman.

Both speakers are working well when connected separately or as a pair when outside the jukebox.

When both were connected, in-situ, the hum was present.

Then I disconnected one of them. Hum was still in other speaker. I reversed the connection situation and the second speaker had the hum.

In summary, both speakers hum when connected in-situ, both at the individual level and together.

However, the hum, when the speakers are connected outside the jukebox, seems to have gone. I can hear a very faint hum, but I'm told that usually normal.

This morning I replaced the wires with good quality speaker wires and jeepers, as you mentioned, made no change.

I'm now considering removing the large speakers completely and inserting another, much smaller set and with the same OHMS. These speakers have a robust plastic casing and can actually sit in the cabinet.

Or, connect the speaker system (with different speakers) externally. Although, do think those arrangements defeat the purpose of the Jukebox?

Whats your thoughts Norman?

Thanks and much appreciated.

Paul

[jukenorman]

Replacing the speakers will upset the balance of the sound and would be an absolute last resort for me. There has to be a reason and I would suspect that it's something like a ground loop. It's a bit of a shot in the dark but you could try insulating washers and insulating sleeves on the loudspeker fixing screws when fitted in the jukebox?
Norman.

[Ron Rich]

Gentz,
Something we have not considered-- Are the speakers yo found in that cabinet the correct ones for that jukebox ? Did you try twisting the wires leading to the speakers? Coax is usually not recommended as "speaker wire" ! Since a "new plug was fitted", was it done, PROPERLY ? Does this phono have provisions for any remote equipment" requiring a transformer power supply ? Ron Rich

[Paul]

Hi folks.

Thank you for your feedback.

Norman:

I could try, as per suggestion, use of insulating washers and insulating sleeves on the loud speaker fixing screws. Will feedback my findings.

Ron:

Yes, Ron they are the correct speakers for this model. I checked the spec from literature and they are in agreement.

Yes Ron. Twisted the wires going to both speakers. Hum still present.

New plug was fitted by myself. All wires completely seated and secured with no bare wires showing.

I don't know Ron how to answer your last question. I don't know what to look for.

Folks. I did rig up a Coax cable to the speakers and also ran in a earth. Same result: hum!

Folks, can I please continue to challenge your knowledge, skill and experience on the painful, annoying and challenging hum problem, PLEASE.

Best Regards and thank you.

Paul

[Paul]

Hi Folks.

Hope all is well.

Norman----Hoping to get insulating sleeves and washers. Also, considering plastic nuts too.

Ron----Having looked closer into the jukebox, I can see the following:

A wall box receiver---Remote control socket.

There is a plastic, block plug, with approx 8 wires inserted into the plug, that is plugged into the wall box receiver.

I've also noticed a earthing wire with a clean cut at its end and not connected to anything.

I can only assume that it was at one point, inserted into the block, which has, at one point, been purposely cut---I don't know.

I did check the loose earthing with a multimeter and sounds good.


Do I tape up the end of the disconnected earth wire to avoid a short or,

Do I connect it to another earthing or,

Do I pull the plug out?

Regards and thank you.

Paul

[jukenorman]

Paul,
I wouldn't go to any trouble with the insulating sleeves, at least initially, just use some tape. I was figuring - speakers removed from cabinet, no hum and the only material difference is the fixings. So it's very much a bit of a long shot.

You don't actually need the stepper (wall box receiver) if you're not using a wallbox - but it won't be doing any harm if it's installed correctly. With regard to your disconnected earth, if it's there it should probably be connected to an earthing point and you should at least try it to see if it cures the hum (another long shot though).

Norman.

[Ron Rich]

Hi All,
IMHO, ANY, non-used equipment, should be dis-connected ! This goes for anything "electrical" ! Ron Rich

[Paul]

Hi Norman.

I have actioned as suggested---use of insulated washers and insulated threaded sectioned of bolt.

Connected the lone earth, to another established earth, tested it with a multi-meter, all seemed good.

Reconnected large speaker and hum still present.

The problem I am now facing is: not being able to differentiate between the intensities of hum, whether the speakers are connected in-situ or, outside the cabinet!

I think I'm beginning to hear the hum call me during sleep!

Hence, is it something else, such as the Amp, as previously hinted, and not the speakers giving rise to the hum. I really don't know. Is it North, South, East or West.

You all have went down so many avenues and, travelled so far in helping me source the problem in addition to gaining valuable experience. I am really grateful to you all for your massive input.

A colleague of mine suggested isolating the whole speaker when connected in-situ, by enclosure and use of a tin foil surface as a shield. For example, a cardboard box with a layer of tin foil. However, to take care not to cause a short! Mmmmm sounds a bit dodgy, I thought.

Any thoughts.

Thank you.

Paul

[Ron Rich]

Hi Paul,
I did not think your isolating the speakers would help in your eternal quest for that elusive hum, but,I sure did not wish to dis-courage you ! Me, myself and I, have done so much with so little for so long, that we are now qualified to do anything, with nothing ! Should you wish to pursue your "hummm" further, we suggest that you begin by eliminating power from components, one at a time, till the hum is gone ! Ron Rich

[Paul]

Hi Ron.

I like the "Me, myself and I" of self description, in your latest post. Love it.

I have been thinking of your point (systematic component power isolation) from your earlier suggestion.

Please excuse my ignorance in the world of jukebox challenges!

There seems to be a massive lack of your skills, experience and knowledge, in Northern Ireland.

Can I please ask, is there a sequence/order of isolating/reconnecting each component. For, example, start by disconnect/reconnecting the speakers, then, move on to the ballasts then, to the credit unit and so on?

Ron, what would be your order of component power isolation?

Many thanks and greatly appreciated.

Paul