Tron channels 1-3 missing

z0ner

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So pissed. I put in an untested Satan's Hollow boardset to test for a friend, and after it booted successfully I swapped it out for my 100% working Tron.

Now I have lost channels 1-3. Put in the SH and it's the same. I checked voltage to the left speaker and it seems it's working, no loose connections.

I can't be certain it's the SH's fault - maybe the sound board decided to coincidentally fail?

What should I try next?
 
Are you saying that the Satan's Hollow is missing channels 1-3 as well, or just your Tron? Am I remembering correctly that CH1-3 come out the left speaker, CH4-6 come out the right speaker?

If SH is missing it too, then I'd look at your dual amplifier board. If it's just Tron, then it could be lots of things on the board, but I find that the 8910s tend to fail often.

DogP
 
I've tested two Trons and a SH, and they are all missing channels 1-3 (left). The Trons were all working previously.

I've ordered a Dual Amp rebuild kit, but how do I diagnose it to make sure?
 
The amp is really simple. You could undo the input pins from the connector and swap L and R... if CH1-3 is now audible (out the right side), and CH4-6 are now missing, then you know it's the amp.

You could also touch the bottom of the pins of each amp. If you hear a buzz from one and not the other, then you know there's a problem with the circuitry (or wiring) for that amp/speaker.

IIRC, there's a common problem where one of the tantalum caps gets shorted. I'd measure the resistance across the tantalum caps... if one of them is low, then you probably need to replace it.

DogP
 
Thanks for the advice!

I'm still pretty new at this but does that mean based on the schematic below that I want to take a molex pin extractor and undo pins J2-P4 and J1-P3 (for left), and swap with J2-P1 and J1-P7 (right)? Did I get those correct? EDIT: After a closer look I think it's J1-P2, J1-P3, (Left Audio/Left Shield) to J1-P6, J1-P7 (Right Audio/Right Shield)?

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I think the easier route would be like you said, and just touch the bottom of the amps. Are you referring to the 3730's?
 
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J2 is the output so you don't need to do anything to that. I think he's suggesting swapping pins 2 and 6 on J1. You're basically just swapping the left and right channels coming into the amp board to see if the problem remains on the same side. If the same speaker is still out after the swap (the left one) then it's either the amp board or the speaker itself.

You don't need to swap the shield pins I don't think. Those are both connected to the ground so I believe they are interchangeable. Someone correct me if I'm wrong. My connector didn't even have the R shield.
 
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J2 is the output so you don't need to do anything to that. I think he's suggesting swapping pins 2 and 6 on J1. You're basically just swapping the left and right channels coming into the amp board to see if the problem remains on the same side. If the same speaker is still out after the swap (the left one) then it's either the amp board or the speaker itself.

You don't need to swap the shield pins I don't think. Those are both connected to the ground so I believe they are interchangeable. Someone correct me if I'm wrong. My connector didn't even have the R shield.
Yep... that's exactly what I'm suggesting.

And yes, touch the pins of the 3730s... you should hear a buzz.

DogP
 
Update:

I first swapped the speaker connectors to rule out a blown speaker, and got 4-6 on the LEFT side. Speakers = good.

I then put my greasy mitts under the 3730's one at a time, and they both buzzed out.

Tomorrow I'll swap the pins but I think they will prove the amp is working.

I'm still using the legacy power supply, and I'm stressing it by having to turn it on and off 2-3 times before I get a stable boot. It's had that issue since I got it in March. I've got the ArcadeShop switcher + adapter. I may decide to hook that up. I know the boards were working, unless of course the legacy supply is ruining them.
 
Update:

I first swapped the speaker connectors to rule out a blown speaker, and got 4-6 on the LEFT side. Speakers = good.

I then put my greasy mitts under the 3730's one at a time, and they both buzzed out.

Tomorrow I'll swap the pins but I think they will prove the amp is working.

I'm still using the legacy power supply, and I'm stressing it by having to turn it on and off 2-3 times before I get a stable boot. It's had that issue since I got it in March. I've got the ArcadeShop switcher + adapter. I may decide to hook that up. I know the boards were working, unless of course the legacy supply is ruining them.

Well, speakers are good.

I'm not sold on the buzz test. It proves there's continuity from the board to the speaker but not that the components are working properly.

Power supply seems unlikely since all the boards in the stack get power from one supply. I doubt 3 different board sets would all lose the same components on the same PCB in the stack causing the same channels (1-3) to drop out because of a power problem. The amp still seems more likely.

You can swap pins on J1 to test it or just go ahead and replace the caps and the amp for the left channel. That will either fix the problem or do no harm.

If I had my Tron I'd say just bring a board set down and test it on mine to rule out a board problem for certain. I hope to have it back by this weekend.
 
I'm not sold on the buzz test. It proves there's continuity from the board to the speaker but not that the components are working properly.
Actually, the buzz test is proving that the amp is ampliying, and that the wiring/speaker is good (putting your fingers just on the speaker wires wouldn't cause a buzz, but putting it on the input to the amp causes the amp to amplify the interference caused by your finger).

But yes, I agree that it doesn't mean everything is good. It's more of a simple test to find a bad amp than a check to prove the amp is good. I would still swap the wires to see if anything changes, and suspect the tantalum caps if there is a problem with the amp board.

I agree that the power supply is unlikely the culprit, since both sets of channels come from the same supply.

DogP
 
Swapped 2 and 6 on J1 and still only had 4-6, now playing from the left speaker.

I'm starting to question the universe now, knowing I couldn't have blown the SSIO on three boards. In addition, I now have a low freq hum.

Fear leads to anger :)

With the game on, I started moving connectors and bumped J3. I heard a bunch of static. Apparently with all the board swaps I must've gotten heavy handed with the J3 connector. I'll be re-crimping them soon, but all 6 channels are now working fine.

Thanks for your input, guys.
 
Swapped 2 and 6 on J1 and still only had 4-6, now playing from the left speaker.

I'm starting to question the universe now, knowing I couldn't have blown the SSIO on three boards. In addition, I now have a low freq hum.

Fear leads to anger :)

With the game on, I started moving connectors and bumped J3. I heard a bunch of static. Apparently with all the board swaps I must've gotten heavy handed with the J3 connector. I'll be re-crimping them soon, but all 6 channels are now working fine.

Thanks for your input, guys.

Good news! Glad it's working.
 
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