No Cabinet Audio - 3.X

Questions about the RaspberryJAMMA adapter.

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Leonardite
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No Cabinet Audio - 3.X

Post by Leonardite » Fri Aug 06, 2021 2:08 am

Hey guys,

I've read several threads dealing with similar problems which have given me some clues as to my issue, but I finally broke down to register for the forum to ask for specific advice. I'm very much a novice, so any ideas you have would be a great help.

I am running 3.X on an old NBA Jam cabinet, and all is working smoothly, except I can't get any audio out of the cabinet speakers through the JAMMA connector. I have tried versions 3.9 and 3.8 as well, and no sound with those versions either. If I hook the JAMMA connector back into the NBA Jam circuit board, the audio works fine, so it's not the cabinet hardware. If I plug a pair of headphones into the DAC on the RaspberryJAMMA, I also get audio. Same thing with an old set of computer speakers (though with a strong buzz - probably external power interference?)

I'm curious if you have any ideas what the issue might be. I have tried two different 3.5mm cables, and neither send sound to the cabinet out of the DAC. The AN7511 chip doesn't show any observable sign of damage, but a hardware problem of some sort on the RaspberryJamma unfortunately seems possible, if not likely. Any ideas or tips you guys have would be greatly appreciated!

dee2eR
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Re: No Cabinet Audio - 3.X

Post by dee2eR » Fri Aug 06, 2021 2:56 am

Just in case, as it's the easiest place to start, you have turned the volume knob on the RaspberryJAMMA up, right?

How is your 12v to the JAMMA edge? The audio section of the RaspberryJAMMA runs off 12v so if it's out you won't have audio. (I can't remember offhand if NBAJam used 12v for audio, it may have - in which case your 12v is probably fine)

It's also worth checking the diode as it failing would stop the 12v getting to the AN7511, I'm yet to see a diode on a RaspberryJAMMA fail so it's probably not the diode.

Assuming your 12v is fine it does sound like the AN7511 chip could be damaged. Or possibly track damage on the RaspberryJAMMA PCB between the 3.5mm jack and the capacitor next to the volume knob.

The buzz when you tried the PC speakers could be power interference or a ground loop or something, hard to say for sure without knowing how it was all hooked up.

The good news is if it is broken in some way it is repairable. We just have to figure out whats gone/going wrong.

Leonardite
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Re: No Cabinet Audio - 3.X

Post by Leonardite » Mon Aug 09, 2021 3:31 am

Unfortunately, I'm going backwards. I have little doubt that it's operator error causing my problems, but I wanted to at least give an update since you have been so gracious to help me troubleshoot.

From your previous suggestions, I wish the problem was the volume knob, but unfortunately that's not it. The knob doesn't seem to do much of anything, even when the headphones are plugged in. The 12v doesn't seem to be the problem either. There is good voltage at the internal cabinet power supply switch, at the JAMMA edge, and at the amp chip itself. I removed the Pi and the RaspberryJAMMA from the cabinet to look at them more closely, and there are no visible signs of damage to the tracks or the chip. The only thing I see with my untrained eye is discoloration on the Pi audio jack, but I'm not using that. I am attaching pics if you see anything I'm missing.

When I reattached the Pi/RaspberryJAMMA to the cabinet, a new problem emerged: No power. I tested the fuse on the RaspberryJAMMA, and it appears to be blown. I don't know why that would have happened from removal/reinstall, as the only changes I made in the interim were to minimally adjust the voltage knob to get closer to 12v and 5v at the switch and edge. Power and sound work when I hook the JAMMA back to the original NBA Jam circuit board.

I should have mentioned in the original post that the entire configuration did originally work with 3.7 as purchased. However, when I messed up the CONFIG controls, I decided to reinstall as I (stupidly) didn't have a backup file. When I did so, I got the low voltage warning, so tried to manually increase the voltage at the switch. I'm thinking I may have fried the amp chip, or some other component, when I did so. When I installed the later Arpicade versions, everything worked fine, except for having no sound.

I'm guessing at this point I probably need a new amp chip, and now a fuse as well. I'm half-tempted just to get a new RaspberryJAMMA, as I don't know the root of the component problems, and have limited technical expertise to remedy them. If you have other ideas, I am definitely all ears. Otherwise, thanks a lot for taking your free time to help me mess around with this. While frustrating, the trial and error has been strangely fun to try and play with.
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dee2eR
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Re: No Cabinet Audio - 3.X

Post by dee2eR » Mon Aug 09, 2021 4:00 am

I'm guessing the audio isn't plugged in right in the photos due to your testing and that wasn't the source of your issue(? the DAC output isn't plugged in). Nothing else seems out of the ordinairy in the photos.

It's expected with headphones plugged into the DAC the volume knob wouldn't do anything. The volume knob will only work for the JAMMA edge mono sound, which won't have anything on it if you have the DAC audio hooked up to something else...

I'd be very happy to fix the board for you if you are happy to send it to me in Australia (not sure where in the world you are). The fuse is a simple fix (if you decide to DIY it use a 2A or 2.5A fuse not the 1A specified on the PCB silk screen) but getting the amp chip out to replace it can be tricky without the right tools and a little experience (assuming it's the amp chip at fault, can't see any signs of damage on it - but if the amp chip is getting power and the audio signal is getting to the chip I don't see what else it could be...).

I'd be happy to help guide you through a DIY repair too, if you want to give it a go. As I said already the hardest part is getting the amp chip out. As long as you don't really overheat the solder pads you shouldn't damage the PCB replacing a part.

Leonardite
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Re: No Cabinet Audio - 3.X

Post by Leonardite » Tue Aug 10, 2021 3:21 am

Thanks again for such a fast and helpful response. Good eye on the audio cable being disconnected from the DAC, but unfortunately that was leftover from me using the headphones to test the DAC. I did previously test with the cables connected many times, but no luck.

I tested the fuse again tonight, and it is definitely blown so I think that issue is straightforward.

I forgot to mention previously, but I tested the diode, it is working fine as you figured it would be. I also tested the voltage on the AN7511 amp chip again. 12 volts are getting to the supply pin (9v at the output pins...I'm not sure if that gives any additional clues or not.) Your explanation below makes sense. Power is getting to the chip, and (when the fuse isn't blown) sound is coming through the DAC when a speaker/headphones are hooked directly to it. It seems like replacing the chip is the logical spot to look.

It is incredibly gracious of you to offer to fix the board. I am in the United States, so I expect postage is probably going to be awfully steep to Australia. Add in the fact that I would expect to pay you fairly to make it worth your while, I'm probably not that far off from simply buying a new RaspberryJAMMA, which I had essentially resigned myself to anyway.

If you have some DIY advice on replacing the components, I'd be willing to give it a go. I don't feel like I have anything to lose, and I actually think it would be fun to try. If it looks like I'm in way over my head, and the cost makes sense, I can PM you for delivery details if you would want to work your repair magic. Either way, I'm incredibly grateful for your help so far in walking me through this. To be able to get this one-on-one support from the product inventor is truly amazing.

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Re: No Cabinet Audio - 3.X

Post by dee2eR » Tue Aug 10, 2021 5:12 am

I like your attitude, have a go at fixing it yourself - worse comes and it doesn't work after your attempted repair you can always send it to me to fix or buy another at that point. The total cost of the replacement parts will probably be less than $5, the satisfaction of fixing it yourself will hopefully be worth more than that...

The easiest way to remove and replace through holes parts (if you're not hoping to reuse them) is to cut them off from the parts side and then remove each leg of the (now cut off) component individually - one leg at a time is much easier than removing the whole chip at once. Then to remove the legs remove as much of the solder holding them in as possible with your favoured desoldering method, if you're lucky the legs will just fall out, if not you can use pliers/tweezers to pull gently from the parts side while heating from the other with your solding iron (you don't want to pull hard, your not forcing them out - more guiding it out while any remaining solder is liquified - try not to burn your fingers by heating for too long if your grabby tool of choice isn't insulated).

Once the component is off and the legs out remove any remaining solder in the through holes (at least enough to fit the new components in), if you find some solder is being stubborn you may want to add some extra fresh solder to it - sometimes that helps.

At this point you should be ready to put the new parts in. For the fuse there's no right or wrong way to put it in, the AN7511 needs to be orientated correctly (the half circle shaped identifying section of the chip is marked on the PCB). Try not to overheat the new components when installing them. Before soldering the AN7511 double check you have the orientation right, also make sure all 8 legs are going through the through holes (trust me, it sucks to solder in some of the legs only to then realise one has bent under the chip rather than going through the hole). Optionally, you could fix a chip socket to the board so you don't have to solder to the amp chip directly and if you ever had to replace it again it would be very quick and easy.

Finally, check you haven't got any shorts from your soldering (could be solder or even possibly flux residue) and then you can test the board.

Tools required are: desoldering tool*, soldering iron and side cutters fine enough to cut each leg of the AN7511, optionally you may want some needle nose pliers or tweezers too. *For the desoldering tool you have 3 options: solder wick + regular soldering iron, solder sucker + regular soldering iron, or a desoldering iron. If you have no desoldering tool the wick or a solder sucker will be much cheaper than getting a dedicated desolderer, I slightly prefer a solder sucker to using wick (either works but I generally do my desoldering with a dedicated desolderer) - your milage may vary.

Leonardite
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Re: No Cabinet Audio - 3.X

Post by Leonardite » Wed Aug 11, 2021 2:13 am

Thank you! I'll give this a shot and let you know the result, good bad or ugly. :lol:

Leonardite
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Re: No Cabinet Audio - 3.X

Post by Leonardite » Fri Jan 28, 2022 3:52 am

Life got in the way for a few months, but I finally was able to dive back into this project this week.

SUCCESS! As we surmised, the problems were the fuse and the AN7511 chip. I'd never soldered in my life before, but I borrowed what I needed from a friend, and replaced those components. I'm almost embarrassed at how proud I am haha. It's working like a charm now. Thanks for all your help troubleshooting, and for the great product. I can't wait to start customizing the cabinet again!

dee2eR
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Re: No Cabinet Audio - 3.X

Post by dee2eR » Sun Jan 30, 2022 1:13 am

Good work. Enjoy the pride in your repair, you earned it.

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