Rock-Ola CD8 Bubbler - No sound

[simonguk]

Hi Guys

I recently bought a 2nd user Rock-Ola CD8 Bubbler jukebox that was manufactured in 2004 and I'm having some issues with it.
It has yellow internals

After setting up the unit all worked fine for about 3 hours but then CD's started skipping which got worse until the CD got slower and slower until it eventually stopped. After this any CD loaded would not spin, but you could see the player trying to do so.

The seller arranged for the CD-Pro drive unit to be collected and he tested it on his own unit with no problems, so serviced it and shipped it back and I re-installed it today.

The CD now spins fine and everything seems to be working normally but I now have no sound coming from the jukebox - Nothing at all from the speakers !
I've checked that everything is plugged in OK and it seems to be and I've also tried playing music via the Bluetooth connection but still nothing, so that seems to rule out anything to do with the CD

Looking at the amp, all LED's are lit normally so I don't think it's a fuse and I've got into set-up and done a factory re-set on the internal amp but no difference.

I'm at a bit of a loss to work out why the sound has suddenly stopped working, so wondering if it's something silly like if I've somehow muted something !?

The seller is being really helpful but he's around 2hrs drive from us so not easy for him to diagnose remotely.
He's even offered to collect it an provide a refund, but my wife's fallen in love with the unit and reluctant to return it if it's something silly or can be repaired

Any advice would be greatly appreciated

Thanks in advance

Simon G

[Ron Rich]

Hi Simon,
More info needed--please read the "Hi Newbies" post in our FAQ's section. Ron Rich

[simonguk]

Apologies Ron

It’s a model CD8C-CE with serial number 105301 manufactured 24th Sept 2004.

so far ive tried the following ....

1. Removed the CD, checked cable connections and refitted
2. Checked all connections and plugs for anything loose
3. Checked the jukebox isn’t in mute mode by muting ‘ unmuting using both remote and button on back and checking the display shows mute / unmute
4. Factory re-set the internal amp settings
5. Carried out a complete factory reset of all machine settings
6. Tried playing music over Bluetooth
7. Run full diagnostic mode which passed without errors

I’ve checked the amp trouble shooting section in the service manual, but it refers to disconnecting Comm’s from the amp and pressing a test button under the LED’s, but there doesn’t seem to be a test button or cable labelled comms on the amp

cheers

Simon

[simonguk]

I’ve an update on the issue ...

After doing all of the above ive noticed that both the internal an external amp overload LED’s are now lit
Does this sound like a faulty amp or can it be caused by an external issue ?

Many thanks

Simon

[Ron Rich]

Hi Simon,
Have you checked the speaker connections-- are they correct ? Is there any old wiring that went to "remote" speakers left on or near the amp ? I would guess the overload LED's are lit, as the amp is "overloaded" ? Ron Rich

[simonguk]

Hi Ron

Sorry, red herring re the overload LED’s- I hadn’t realised it’s normal for these to be lit when no cd is playing as the jukebox goes into mute mode.
When playing a cd the LED’s go out, but unfortunately still no audio.

I’ve checked all speaker connections and they all look good - the jukebox is in perfect condition with no modified or additional speaker wiring.

It’s a really strange issue as everything looks to be working perfectly, but just no sound

[simonguk]

A further update ....

I've connected some external speakers to the ext speaker connections on the amp and these work fine.

[Ron Rich]

What "kind" of speakers ? Ron Rich

[simonguk]

Apr 22, 2021 12:55:23 GMT Ron Rich said:

What "kind" of speakers ? Ron Rich

Hi Ron

Just a simple speaker from our TV surround sound system as it's the only speaker I have available.
I tried connecting to both left & right speaker outputs and the audio was fine and the volume adjusted using the remote control as normal.

The seller has suggested that there could be a problem with the output transistor board on the amp as these are apparently prone to failing on the yellow amps.
He's been told that these can potentially be swapped, which would disable to ability to use external speakers but I'm not concerned about that.

Unless anyone can point me to anything else that could cause the issue I'm probably going to remove the amp and post it to him to see if he can get it repaired.

[Ron Rich]

Hi Simon,
Beyond me-- I don't think RockOla would use "separate" output transistors, for speakers ? My GUESS, would be, that there is something in "programming" that controls the internal speakers-- Let us know when you find it ! Ron Rich

[jukenorman]

Yes, these have two amplifiers - a main amp for the internal loudspeakers and an external amp for remote loudspeakers.

Norman.

[Ron Rich]

OK Guyz,
That being the case, there MUST be separate "volume controls" ?? Once again GUESSING, the VC for the main output JB speakers, is turned off/down ?? (programming ) Ron Rich

[jukenorman]

I think you just set up the conditions for the two amps via the programming. I'm fairly certain that I have come across a previous query on one of the forums (maybe the departed UK Yahoo one?) where the main amp had failed on a Rock-Ola Bubbler and the internal speakers were then connected to the external amp.

Norman.

[simonguk]

Thanks guys

@ Norman - you are correct 👍

It turns out that the amp board driving the internal speakers had failed - I confirmed this by swapping the two amp boards around and using the external one to drive the internal speakers.
I discovered after doing this that I could have just plugged the internal speaker plug into the external socket 😊

This fixed the issue but when playing music I noticed a significant hum that appeared to come from the amp (not through speakers) and I assumed this may be due to the faulty board still being connected. I’ve now removed the offending board and the hum has gone and after a 2 hour continuous test all seems well.

Even though we don’t plan to use external speakers I’m going to see if some can fix the faulty board

[Ron Rich]

Simon,
Are these two boards exactly the same ? Ron Rich