I get no sound output on my STE, not thru Monitor output or on the RCA L+R outputs. even tried RF, no luck, all give expected video tho..
I have tried to reseat the YM2149 chip and i have checked that it does indeed get the 5v its supposed to on pin 40.
No chips is getting remarkably hot after some time running (except cpu), and i see no caps looking suspicios.
Im out of ideas, what do i check next? what can i do?
Im new here but really hope to get some help =/
STE No sound - some troubleshooting done!
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RetroBrain
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siriushardware
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Re: STE No sound - some troubleshooting done!
What sort of tools do you have access to? A Multimeter? A Scope? (Edit: Obviously you do have a meter otherwise you would not be able to say that the YM has 5V supply)
Have you established if it is only YM sound which is missing, or DMA sound as well? That will narrow down the area of your fault.
Try running a demo which you know uses STe sound output, or alternatively use the DMA sound test program linked to in this thread:
http://www.atari-forum.com/viewtopic.ph ... st#p277598
If you get DMA sound output but no YM sound output the fault is more likely to be around the YM chip itself or the path from it to the audio output mixer IC.
If you have no sound at all including no DMA sound output then your problem is more likely to be around the output mixer IC, the LMC1992.
Checking for power to that LMC1992 chip would be a good start. It comes from a little three leg regulator IC (which looks very much like a transistor) but has a 'U' number next to it on the mainboard. It should be identifiable from the number '78L82' on its face. One of the legs of that chip should have 8.2 volts on it, and that is the supply for the LMC1992 IC. On the LMC1992 itself, you should be able to find that voltage on pin 28.
Have you established if it is only YM sound which is missing, or DMA sound as well? That will narrow down the area of your fault.
Try running a demo which you know uses STe sound output, or alternatively use the DMA sound test program linked to in this thread:
http://www.atari-forum.com/viewtopic.ph ... st#p277598
If you get DMA sound output but no YM sound output the fault is more likely to be around the YM chip itself or the path from it to the audio output mixer IC.
If you have no sound at all including no DMA sound output then your problem is more likely to be around the output mixer IC, the LMC1992.
Checking for power to that LMC1992 chip would be a good start. It comes from a little three leg regulator IC (which looks very much like a transistor) but has a 'U' number next to it on the mainboard. It should be identifiable from the number '78L82' on its face. One of the legs of that chip should have 8.2 volts on it, and that is the supply for the LMC1992 IC. On the LMC1992 itself, you should be able to find that voltage on pin 28.