led 2 is out

[Joe Thomas]

so i picked up a rockola 477 and it's acting very strange. my led #2 is out. I'm wondering what could be causing this? thanks!

[Ed Inman]

Disconnect the low voltage power plug, reset the yellow button breaker, see if it comes back on.

If so turn the machine off, reconnect the low voltage power plug, & report back on what happens. --Ed

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[Joe Thomas]

ok, so the yellow button was stuck in. so i pulled it out and plugged low voltage plug back in. all leds came on and now the amp is making this really loud humming sound when i plug it in. my sister was saying the guy before put in a new power supply so i don't know what kind or if it's the correct one. thanks!

On Monday, July 22, 2019 at 8:38:34 AM UTC-4, Ed wrote:

Disconnect the low voltage power plug, reset the yellow button breaker, see if it comes back on.

If so turn the machine off, reconnect the low voltage power plug, & report back on what happens. --Ed

-----Original Message-----
From: Joe Thomas
Sent: Jul 21, 2019 10:28 PM
To: rockola477
Subject: led 2 is out

so i picked up a rockola 477 and it's acting very strange. my led #2 is out. I'm wondering what could be causing this? thanks!

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[Ed Inman]

On page 63 of your manual you will see a page called sound system adjustments which explains a relatively simple way to test and reset the proper voltages on both driver boards in the amp. If you don't have a manual for the 477 you can read it here: https://web.archive.org/web/20100824055405/http://thearcadeboneyard.com/RockolaJukeboxManuals.html

Before resetting the driver board voltages check all six fuses for continuity and replace as required with fuses of the same amperage.  If either driver board refuses to reset voltage exactly as explained there is likely a short or bad connection somewhere. This may require cleaning terminals or re-flowing solder at any given spot where continuity is shown to be weak or has failed It is also common in amps of this age that capacitors--in particular the two mail filter caps in front need replacement.

None of this is particularly difficult for a skilled person in electronics but if you do not have that background don't just go taking the amp apart--you will likely just do more damage than good.

For amplifier repair you may wish to inquire with Ross Bloomgren: https://www.facebook.com/pg/RJBElectronicServices/about/

hope this helps some--good luck! -- Ed

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[Joe Thomas]

wow, thanks for the info, i do have the manual and will check this out when i get a chance. i am pretty handy with a solder iron so hopefully i can fix it!

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[jeanmi chel]

hi

sometimes my 477 make a really loud  hummm...i need to disconnect and clean the connectors and it works,you can try to make it work without the amp connected

[Joe Thomas]

ah, good idea! I was reading somewhere the 54510 amp might work in place of the 52280 amp that the 477 uses. anybody know if this is true?

[Joe Thomas]

ok, so heres an update. i ordered a working amp from ebay and put it in. worked like a dream for 2 weeks! was so happy and then BAM, machine gun sounds are back! The "LIGHT ON SPEAKER OVERLOAD" light comes on now (i assume it was always on i just didn't notice). Why the heck would it work perfect for 2 weeks like that and then crap out?

thanks

On Monday, July 22, 2019 at 12:12:14 PM UTC-4, Ed wrote:

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[Ed Inman]

Maybe just be a bad connection somewhere.

Check fuses. Clean terminals. Check for proper continuity throughout. Reflow or add a little solder wherever continuity may be weak. (A little fresh solder at virtually all terminal pins usually doesn't hurt.) Reset the driver board voltages per the manual instructions. If either refuses to set properly it's usually a sign of a bad connection somewhere in the driver board itself--at least that's my experience).

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[Joe Thomas]

you mean the speaker terminals?

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[Joe Thomas]

oh and why does it say 5 amp fuses on the front of the amp but inside it says to use 3amp? thanks!

[Ed Inman]

Cleaning speaker terminals can't hurt but I was mainly talking about the internal PC board terminals. 

The two 5 amp fuses go up top where the arrow points. Four 3 amp fuses go on the internal fuse board 52275-A.

You might want to join some of the facebook jukebox pages to ask questions.

This googlegroups listserv is very old and not widely read anymore. --Ed

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