First jukebox!

[woodmedic]

Hello everyone.  I just picked up my first jukebox which is a Rockola 480.  I love projects and this should be a fun one.  It has 1 major problem so far.  When you first plug it in, it makes a god awful loud buzz sound.  Sounds like what I would imagine someone getting electrocuted would sound like.    Anyway if you leave it plugged in with the buzz happening, the overload light will eventually turn on.  If you unplug the speakers at the amp, and keep messing with it, it will eventually stay on and the buzz is gone.  At that point it plays and sounds pretty good.  I have ordered a manual and am waiting for that to begin with the diagnosis.  In the meantime I was wondering if maybe this was a common problem with these that someone would be able to tell me about.  Thanks for looking and I can't wait to dig into this thing!

[Ron Rich]

Hi Chris,
You'd best wait ! Allowing that "buzz to continue to happen, may result in an expensive repair bill ! If you have the electronic skills to work on transistorized audio equipment, wait till you have the schematic ( I hope you asked the supplier of the manual you ordered if it contained the schematic ?). If not, check our FAQ's section above and find someone who can repair the amp for you. Ron Rich

[woodmedic]

Thanks Ron! Yes the manual I ordered is supposed to contain the fold outs as well as parts and service. I have not been messing with it anymore since the initial test run. I will wait for my manual and see what I can figure out. Just wanted to see if someone pointed out that this model always has XXXX problem and this is the fix. Thanks for the reply and I will update after I dig into it.

[jukenorman]

Hi Chris, These Rock-Ola amplifiers can be quite susceptible to bad solder joints ("cold" as you guys say, "dry" as us lot say!). So if you are looking for something simple and straightforward to start with, remove the circuit boards from the amp. and re-do the solder joints on the plugs/sockets on these boards.
Norman.

[woodmedic]

I think that is a great idea!  Plus it will give me something to do while I wait for my manual to arrive.  Thanks for the input!

[Ron Rich]

Hi Chris, and Norman
"--dry--" If a solder joint is "wet", I can gar-un-tee it won't conduct-- like the old saying goes (My Grandmother taught me this, and she was born/raised in England)---") why can't the English learn to speak
On the other hand Chris--want "something to do-"?-READ the stickies posted here--(You'll note that this hint was posted !) Ron Rich

[woodmedic]

I actually have been reading the stickies. I missed the one about cold solder joints I guess.

[woodmedic]

Well they are multiplying! I picked up a Rock-Ola 477 yesterday. Amazing how similar these two models are despite how different they look on the outside.

[Ron Rich]

Chris,
Not too amazing, at all ! Juke, makers changed very little from model to model--changes COST money-- ALL manufacturing companies make every attempt to get the most out of "jigs" and "castings". Many times you may see something that was not used for years, re-used, as it much less expensive to re-use than to design a new casting. One of Seeburgs cabinet design engineers, once "bragged" to me that a certain model cabinet (when new), was designed solely out of used jigs and dies. To look at this cabinet, I wooda never knowed ~!~ LOL Ron Rich

[woodmedic]

As mentioned above, I now have a Rockola 477 and also a 480. Both use the 52280-a amplifier. I received the manual and started checking into the issues. One had a horrible loud buzz upon turning on and the other was missing the right channel. I found multiple cold solder joints in both amps which I addressed. I also found a shorted 2n3055 in the one with the missing channel. I replaced the transistor and put both units back together. I checked all of the fuses and corrected the values in a few positions that were not correct from someone else replacing them. The amp that was buzzing very loud was the one with the bad transistor. It now works but has a fairly quiet buzz in the side that had the bad transistor. The other amp that was missing a channel now sounds pretty darn good. I spoke with a man at jukebox Friday night that does all sorts of amp repair and he was telling me that the are parts on the driver boards that will certainly go out in the near future and are irreplaceable. I did not have the amp in front of me when he was telling me this and he was not specific on what the part was. The P.E.C. 8 part number 52357 is the only thing I could think of on the driver board that looked like a proprietary part. These also look to have been replaced on one of the amps so I could see that they failed from time to time. Does anyone have a source for these 52357's in a stash somewhere? I would like to get my hands on some for future use to keep these jukeboxes I have running.

[jukenorman]

Hi Chris,
I was going to say that you could probably manufacture your own 52357 PEC if you set your mind to it, but Jukebox Revival in the Netherlands has already done that - see here
www.jukebox-revival.eu/index.php/rockola-p-e-c-52357-protection-circuit.html

Norman.

[woodmedic]

Holy cow Norman that is great! I didn't find those in my search. Thanks for sharing!

[Ron Rich]

Hi All,
What does the "PEC" Stand for ? I know what they are, just don't know what that term could stand for ??
Thanks, Ron Rich

[woodmedic]

I think it may be Packaged Electrical Component. Not positive though.

[Ron Rich]

Thanks, Chris--Much better then the blank space my mind (?) generated !
Ron Rich