Hum noise from my Rock-Ola 459

[Ron Rich]

Hi Paul,
Yep, the three of me often have "discussions among ourselves". We have discussed this and decided that it makes no difference where we start, as it will come down to whatever happens to be, the last thing we dis-connect. Ron & friends

[jukenorman]

Paul,
I'm losing the thread here, do you have hum when you turn the jukebox on or only when you make a selection? Maybe one of Ron's friends remembers?
Norman.

[Ron Rich]

Hi Norman,
No, unfortunately, all of ussins, have the problem of a great, but, not too long memory ! The thread can be picked up on the top left of any page-in the "prev---next" boxes Ron Rich

[Paul]

Hi Norman.

The hum from the speakers behaviour is:

Immediate from turning the jukebox on and remains on until jukebox is switch off.
Can be heard when record is playing.
Is not volume dependant.

Thank you

Paul

[Paul]

Hi Ron.

Thank you to all three.

Will take a look.

Many thanks

Paul.

[Paul]

Hi Folks.

Thoughts/brainstorming on:

Hum noise issue from my Rockola 459 cont...

Using a multimeter, I took voltage readings from the power supplying cables to my speakers and noted the following

One set of speaker cables had a voltage reading of 4(approx) while the other had a voltage reading of 6(approx), a differential of approx 2. Although I noted these readings, I don't know what it means!

Any ideas?

Many thanks

Paul

[Ron Rich]

Paul,
What, are you reading ? AC or DC? If AC you have internal amplifier problems, which should be fixed ! Ron Rich

[Paul]

Hi Ron.

Thank you Ron for your constructive advice regarding my Amp situation.

I'm reading AC.

Problem I'm having Ron is that I cant get anyone, at the moment, to look at it. Also, I am unsure how to remove the Pre-Amp/Amp! It does look complicated.

I did contact the the main electronic shop in Belfast. I then tried another electronic repair shop in Belfast. Both repair shops declined to look at it.

I have advertised for someone, with the know-how, to look at it. No response.

I have recently been given a contact name of a electronic engineer, but I have been unsuccessful in all my attempts in contacting him. I have been told he is extremely busy and working very long hours. This situation of demand on his time, I would have to respect.

I've noted that when connected to smaller, good Pioneer speakers, outside the jukebox,the intensity of the hum seems reduced and a lot easier to listen to.

Yet the advice from yourself and Mike is of paramount importance to the jukebox health and with certainty, the PreAmp/Amp situation will need to be addressed.

Thank you Ron for your continued support and help.

Paul

[Ron Rich]

Paul,Do you have the service manual --that should tell you how to remove it-- or the parts manual- Ron Rich

[jukenorman]

It shouldn't be overly difficult to remove the amplifier - disconnect the electrical plugs and earthing, remove two screws at the top, the amplifier base sits in a slot so lift and tilt. What might be more of an issue, you need the large fold out schematic for the circuit diagram and low voltage electric power is supplied from the adjacent power supply.
Norman.

[Paul]

Hi Folks.

Thank you for your helpful feedback.

Ron:

I do have a service manual, Phonographs. Its not like the user manual type that I'm used to reading. For me, it is a very complicated, intimidating and, a very of-putting manual.
It mostly consist of schematics and descriptions of how the various systems work and their adjustments.
I believe the manual has been pitched for guys like yourself with have a high level experience/knowledge/skill of the workings of the jukebox.
The manual certainly isn't for me, but I wont give up on it.
I have been looking for a user manual for some time. I did post a request earlier for such a manual and was told Rockola did not write a user manual.
Very unfortunate indeed as I feel there would be a large audience for such a manual.
However, indeed Ron, I will keep looking.

Many thanks
Paul

Norman:

Thank you Norman for your procedure on how to remove the Amp.
The steps you describe make it sound straight forward for its removal. Thank you.
I have located the two screws referenced and I think I can also see the slots too.
There is a pre-amp there too Norman. Does it stay in-situ or, can I expect the pre-amp and amp to come out together?
I do have a service manual with schematics too.
If I get to the removal stage of the Amp successfully, I will be one happy chap indeed. Then I can seek someone to look at it!

Thanks Norman.

Paul

[jukenorman]

Paul, you remove the complete amplifier chassis - everything!

[jukeboxgeek]

Paul
For what it’s worth, I suggest that you might consider eliminating one potential noise source......disconnect (unplug ) all the wires and plugs going to/from your external wall box unit and the stepper unit in the jukebox. .......this will Isolate your jukebox completely from the outside world .....physically remove the Stepper Unit from inside the jukebox. However, please note.......without the remote Wallbox and stepper unit hooked up to your jukebox.......you MUST have and install a jumper plug into the “Receiver” socket that will be now “open “ after you unplugged the cable to isolate the Wall box. Without the jumper plug you won’t be able to make any record selection at all. If we’re lucky you will find the necessary plug detailed on your schematics. Good luck.

And another “for what it’s worth”....it seems someone has attempted to replace the individual ballast that was mounted in - between the two large speakers once upon a time......with a “dual” element ballast . Seems it also did not/doesn’t work, ......so my suggestion is that you disconnect and physically remove this “dual ballast” that is mounted between your two large speakers . My money says your “hum” problem just might go away.....
Good luck.
Mike

[Paul]

Hi Folks.

Thank you for your feedback. Very constructive indeed.

Hi Norman:
I'm still bouncing the Amp removal situation in my head. At the moment, I still cant find anyone who will look it, after its removal. This is a huge problem for me, however, I will continue to seek out someone to look at it for me. Thank you.

Hi Mike:
Will take a closer look at the plugs and wires from the regions mentioned above. This will give me some insight to the various components you mention. Thank you.
Regarding the ballast point, I did, from an earlier suggestion, disconnect the power to both the upper and lower ballast. Unfortunately, the hum was still present. I think you are correct in that the lower ballast is defective. It supplies the lower fluorescent tube, which I haven't been able to engage it to light. Yes Mike, think I will physically remove it.
I am, considering, from an early suggestion, fitting LED lighting.

Massive thank you folks.

Take care

Paul