Rowe/AMi CD-RN Buzz

I have a frustrating fault on a Rowe/AMi CD-RN. I know, all faults are frustrating, but this one takes the biscuit.

Switch-on, make selection, song plays, OK
Select to play whole album:
one track is played in full
disc is returned to carousel
jukebox develops an almighty buzz

After jukebox has been left switched-off for a while everything is okay again.

I have switched-out the amp - no change
I have switched-out the output transformer assembly - no change
I have switched-out the cross-over assembly - no change

I am suspecting either the Central Control Computer, or the Mech. Computer, but neither are showing an error.

Any ideas would be welcome.

Hi Keith,
MUCH more info needed--
1. Which CCC is installed--which version chip, and is it programmed for a album play--and is it programmed for free play, and if so, for free album play ? What happens if you play two "singles" ?
2. Which MCC is installed--which version chip ?
3. When it "buzzes", have you removed the amp input RCA plugs--if so, does that stop the buzz ?
4. When it is buzzing, what is the com link doing ?
Ron Rich

Hi Ron,

The CCC is the 40832220
The chip is v3.2
Album Play, Free Play and Free Album Play are all programmed, but I think this is irrelevant now, as the buzzing has also started just randomly in the middle of playing a single track.
The MCC is the 61086201
The chip on the MCC I'm not sure at the moment.
When the buzzing starts and I unplug the RCA leads from the Amp, the buzzing does stop. However, after a short time a much quieter buzz starts.
When the jukebox is buzzing the com link light is flashing, about once per second and the jukebox seems to be paralyzed, as it won't cancel or do anything else.

Hi Keith,
OK--You have the "latest" CCC, but, an early chip--it should be updated to at least a 4.1. You can also use a 4.3, but NOT, a 4.2, which was a "bad version". The only difference between a 4.1 and a 4.3 is factory default pricing.
The MCC is an early type, however, other then "added features, it is the same as the last type--but, why don't you know the version of the chip--it's "readable" on the display- ??
As for the buzz, when you remove the input plugs from the am, I think this proves that the problem is prior to the amp--I think the "softer buzz" you hear is the AVC trying to adjust to the non-input situation.
Do you have another MCC ? I would change that and see what happens--could be that the DAC is bad--or if that does the same thing with the new MCC, it's the player itself ( which one is in it--a -4 , or later) ?
One other "thought"--There could be a problem somewhere in one of the "plugs"--I would suspect a power ground plug somewhere, either not making good contact, or a poorly soldered "header"--might try "wiggling" them around when it's "making that buzzzzzz---"
Ron Rich

The player is a 12.
I forgot to get the MCC chip version last time the machine was on.
Interesting what you said about the power ground. Did you mean any plug in-particular, because the mains power cord has a bent/straightened ground pin?

Hi Keith,
I don't think the mains plug will have any bearing on this--but the"commons" all through the system, starting inside the power supply ( which version is being used here ?), to the plug on the CCC-MCC's sure can "raise hell"--
Ron Rich

I have another MCC (61086202) on the way. I will try replacing that first, then take it from there. I will update this thread in a week or two when I have some news.

Keith,
Before changing anything, I would "go thru" -ALL- of the ground and common pins/headers on the phono--Clean/reform the pins, check the solder job on the headers--Ron Rich

So, I resoldered all the headers - no change (unless I missed one).
I got another MCC and player - no change.

Then I noticed something odd. The buzz goes away completely if I unplug the 120v lighting cable from the power supply.

The fault isn't in the power supply because I have checked it with another one.

I now have a new fault, in that the display has stopped working, even though the LED is still lit on the back of the PCB. I am going to remove the display and reflow all the solder points. I don't know if this fault is related to the buzzing, but I want to get the display sorted before continuing.

Okay I'm stumped!!!

I got another box in today (a working one).
I swapped the entire mech. (basket, player, MCC, the lot). I also swapped the CCC.
Switched-on, still the same fault (after a short while, buzzing which stops the CCC talking to the MCC).

I can't think where else to look. I have swapped-out practically ever part. Only parts not swapped are the harness, volume control, keyboard, speakers and lights (but the lights and keyboard have been disconnected).

Main error is: 05-63 mech to CCC comm lost.
At one point I got a System Error showing on the CCC and the juke went into Out Of Order mode. I think that was just because it had tried to establish a link between the MCC and CCC over and over and couldn't.

As the wiring loom is one of the only things I haven't changed I am beginning to suspect that, but the juke works fine when it has been switched off for a while, and then goes faulty after an indiscriminate amount of time. So, I can't see how this can be the wiring.

I do know that whatever is causing the buzz is cause the MCC to CCC comm error.

Oh, I got the display fixed. That had nothing to do with the buzzing problem.

Keith,
I believe you are having "typical, Rowe (A-MP) plug problems". Check ALL plugs starting INSIDE the power supply. Remove EACH pin, clean reform, or replace any that do not "shine up". It sounds as if it is a "ground", or "common" pin, causing your problems. Also, at the same time, check the mating, "header pins", for "burned spots"--Ron Rich

FIX IT WHIP-PEEEEEEEE!!!!!!!!!

Thanks for all your help Ron, you certainly pointed me in the right direction.

As it turned out, the fault was being caused by one of the wires going to the heaters on the bubble tubes. The plastic cover on the connector had gone brittle and broken off and the connector was touching the metal mounting bracket above which is grounded.

Easy fix, hours and hours to find.

Thanks again Ron. Did Steve have what you wanted?

Keith,
Glad you "found-it" !! I just "found one ( I HOPE) that has been "driving me nuts" ( or "nuttier") for at least two years--feels good, although I am not 100 % sure it's fixed, as it was an "intermittent" problem--
Yes--Steve had it--thanks--Ron Rich