stt1
Professional
Symptoms:
Music partially missing, also all "speech" parts missing. Only R-VOL potentiometer changes the volume, on both channels. L-VOL potentiometer has no effect at all.
An example from Youtube: https://www.youtube.com/watch?v=nLwB1ZdZN_0&feature=youtu.be&t=167
Missing compared to the youtube-video:
"The Great Ragtime Show" -speech (when the brown picture of airplane and pilot scrolls to screen) and all the applauses (during the pilot running animation is shown)
What I can hear from the PCB:
Short propeller/copter sound (~1-2 sec)
One short shooting effect
When the game runs, I can hear sound effects, or at least most of them, musical parts are missing a lot - they sound mostly "flat" and bass-oriented.
Done so far:
Measured the potentiometers, they seem to be ok.
Audio amplifier (Toshiba TA8205AH) changed, did not help.
I have found information that this PCB has YM2151 for the sounds - didn't find any such chip, just one (has markings 3569 9221S C13680R on it) which I suspect being one, next to the audio amp. See the attachment, please.
This PCB has also another audio-chip (PSG sounds?) - Hudson HuC6280A
Does someone have an educated guess which one of these would most likely cause the problem?
Would the oddball (3569...) chip be YM2151?
Any other ideas to check around?
Music partially missing, also all "speech" parts missing. Only R-VOL potentiometer changes the volume, on both channels. L-VOL potentiometer has no effect at all.
An example from Youtube: https://www.youtube.com/watch?v=nLwB1ZdZN_0&feature=youtu.be&t=167
Missing compared to the youtube-video:
"The Great Ragtime Show" -speech (when the brown picture of airplane and pilot scrolls to screen) and all the applauses (during the pilot running animation is shown)
What I can hear from the PCB:
Short propeller/copter sound (~1-2 sec)
One short shooting effect
When the game runs, I can hear sound effects, or at least most of them, musical parts are missing a lot - they sound mostly "flat" and bass-oriented.
Done so far:
Measured the potentiometers, they seem to be ok.
Audio amplifier (Toshiba TA8205AH) changed, did not help.
I have found information that this PCB has YM2151 for the sounds - didn't find any such chip, just one (has markings 3569 9221S C13680R on it) which I suspect being one, next to the audio amp. See the attachment, please.
This PCB has also another audio-chip (PSG sounds?) - Hudson HuC6280A
Does someone have an educated guess which one of these would most likely cause the problem?
Would the oddball (3569...) chip be YM2151?
Any other ideas to check around?
