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Super Monaco GP Airdrive

man. that schematic in intense!
monacosndr.jpg

So double amps: one for front and one for the rear. + another (board) for the sub?

I would disconnect one connector at a the time to try and isolate the issue, starting probably with the yellow.

Again, after the trace search you've done, this is macro !
 
OK, thanks. The noise comes out of all speakers including the sub which made me think it can't be an amp (not all with the same fault!). I'll give this a go tomorrow. Cheers
 
Thanks. I'll pull it out and make a list, unless anyone knows of a list already done?! Just all the electrolytic caps?
 
Electrolytic caps, yes. I wouldn't bother replacing the filter cap though.

There's possibly a list, but lists can be wrong. Better just to make your own IMO.
 
Ok. I don't think I need to remove the board from the tube to do this so easier to take the whole unit out?
 
OK, back to the sound fault! I unplugged one of the amps (rear sound) as soon as I plug in the connector arrowed (even with the actual sound plug for that amp disconnected-I tried that AFTER taking this picture!) I get noise on ALL channels. So, I guess something bad on this amp but what?

20221216_121046.jpg


I know NOTHING about amps! Obviously I could start swapping components between the two but that could take ages....

Any amp experts on here? Rectifier or smoothing cap perhaps?
 
Hi,

ok, there's a interfering signal coming from somewhere.
Since some peripherals are installed here, we now have to find out where the interference signal is coming from.

Do you have any PC speakers, like this one, or an audio power amplifier with an external input?

A.jpg



B.png


Here you can see a section of the game board. I have drawn the pinout for you on connector E.
This connection has the audio output for front L+R and a mixed output for bass.
Unplug the 6-pin plug and connect to the PC speakers or an alternative audio power amplifier, always GND and an Audio Out connection (L / R / Bass)

Here is the assignment of such a 3.5 jack plug of the PC speakers
C.jpg


I am curious whether you can hear the interference signal on all three audio outputs or not...
 
If you unplug connector e, the AMP for front and bass will not receive an audio signal.
I would like to know if the interference signal is coming from the gameboard, hence the test with the PC speakers.

You can also test the following:
Only disconnect connector E, but leave all AMPs connected, can you still hear the interference signal on the speakers?
 
I see, I did it the other way around. With the 1 amp connected (along with the sub amp) I get all sounds from all connectors on the game board with no noise. As soon as I connect (the power) connector to the other amp (with all other connectors to that amp disconnected) I get the noise back. N.B, the 1 amp works fine in connector E or the connector on the sound daughter board, the sub works fine too. If you plug power to the 2nd amp the noise is present at all connections on the game board. So at present I can have the sub working and either the front speakers or rear speakers but not both. Something on that 2nd amp is causing noise on the other amps as soon as power is applied to it...
 
Ah interesting
What happens if you only have the AMP for the rear speakers in operation and disconnect the AMP for the front and sub from the power supply?
 
OK, this is weird! Doing as you suggested, dead, no sound at all, so it appears an amp must be connected on the left hand side for the other one to work. So, I swapped over the amps. No noise until....I plug that connector (arrowed in my pic above) in on the second amp!! The amps work individually OK on the left hand side but as soon as that connector is plugged in the noise starts!
 
The 6pin Connector (arrowed) is the Power connector.
Pin 6+7 is for 18V AC Power Input (Power for the AMP)
Pin 1+2+3+4 is 12VDC OUT (Power Out from AMP)

one of the 12VDC OUT ist for Sentinel Door and the other 12VDC OUT is for the Safety Sensor

Maby on the 12VDC circuit is a Problem and make trouble in the AMP

it is possible to unplug the wires red / red / white / white and connect only blu and orange ?
 
Perhaps there is an overload on one of the two 12VDC outputs and the internal rectifier circuitry is overloaded.
You can also try to measure the two 12VDC connections with a multimeter, maybe that will give you some insight
 
With those unplugged both amps work fine :) Sentinel door = coin mech? Look what I found in there!! I don't need the coin mech as it's on free play and ancient anyway!

20221216_152852.jpg


20221216_152843.jpg
 
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