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Author Topic: Most common cause of no ADPCM on the Duo?  (Read 642 times)

ApolloBoy

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Most common cause of no ADPCM on the Duo?
« on: April 27, 2012, 01:31:35 PM »
I'm in the process of fixing/modding a PCE Duo for a customer and when I tested it, it worked fine except that the PCM audio was totally dead. I'm not sure where to start, so I'm wondering what the most common cause of this problem is.
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Quote from: Arkhan
it makes me laugh because people are like I REMEMBER PLAYIN THAT BACK IN THE DAY, MAN THAT WAS FUN.

and then I go "yeah I remember playing that 2 days ago because I still have my SNES, retard"

Duo_R

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Re: Most common cause of no ADPCM on the Duo?
« Reply #1 on: April 27, 2012, 01:45:35 PM »
Did this unit have a full cap replacement? I tried a jumper method thanks to TheSteve that helped me narrow the problem to the source.
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grahf

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Re: Most common cause of no ADPCM on the Duo?
« Reply #2 on: April 27, 2012, 01:59:12 PM »
I guess it goes without saying to consider the capacitors? I also seem to remember someone having to replace the ADPCM memory, but i'm not positive.
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thesteve

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Re: Most common cause of no ADPCM on the Duo?
« Reply #3 on: April 27, 2012, 06:17:18 PM »
adpcm probs could be mixer or data
see if the chip outputs sound
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ApolloBoy

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Re: Most common cause of no ADPCM on the Duo?
« Reply #4 on: April 27, 2012, 06:25:58 PM »
Quote from: Duo_R on April 27, 2012, 01:45:35 PM
Did this unit have a full cap replacement? I tried a jumper method thanks to TheSteve that helped me narrow the problem to the source.

I recently did a total recap of this Duo and both Redbook and HuC6280 audio work perfectly. What's the possibility of a bad op-amp being the cause?
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Quote from: Arkhan
it makes me laugh because people are like I REMEMBER PLAYIN THAT BACK IN THE DAY, MAN THAT WAS FUN.

and then I go "yeah I remember playing that 2 days ago because I still have my SNES, retard"

Keith Courage

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Re: Most common cause of no ADPCM on the Duo?
« Reply #5 on: April 27, 2012, 06:53:02 PM »
Sometimes a bad trace can be the issue. I have followed the trace off of pin 10 on the 5205 chip and found that a few of the small resistors there were either not working or a trace was not going from one to the other. Check to see if there is any sound coming from the chip at all by running pin 10 all the way to one of the audio out pins on the AV port. This way you can at least determine if the chip is working or not.
« Last Edit: April 27, 2012, 07:23:20 PM by Keith Courage »
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Duo_R

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Re: Most common cause of no ADPCM on the Duo?
« Reply #6 on: April 27, 2012, 06:57:16 PM »
mine was a bad trace
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ApolloBoy

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Re: Most common cause of no ADPCM on the Duo?
« Reply #7 on: May 25, 2012, 06:01:46 PM »
Just did the pin 10 jumper wire and the PCM chip is not putting out any audio whatsoever. :(  How much do M5205s usually go for?
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Quote from: Arkhan
it makes me laugh because people are like I REMEMBER PLAYIN THAT BACK IN THE DAY, MAN THAT WAS FUN.

and then I go "yeah I remember playing that 2 days ago because I still have my SNES, retard"

thesteve

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Re: Most common cause of no ADPCM on the Duo?
« Reply #8 on: May 25, 2012, 06:23:10 PM »
slow down, NLA but likely not failed.
use a logic probe to check it for data, clock, power ect.
best bet is still a bad trace/via
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ApolloBoy

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Re: Most common cause of no ADPCM on the Duo?
« Reply #9 on: May 25, 2012, 06:42:01 PM »
Quote from: thesteve on May 25, 2012, 06:23:10 PM
use a logic probe to check it for data, clock, power ect.
best bet is still a bad trace/via
Double checked and I didn't see any bad traces or vias. Luckily I found a logic probe so I can check out the chip in further detail. What pins should I test for and what should their states be?
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Quote from: Arkhan
it makes me laugh because people are like I REMEMBER PLAYIN THAT BACK IN THE DAY, MAN THAT WAS FUN.

and then I go "yeah I remember playing that 2 days ago because I still have my SNES, retard"

thesteve

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Re: Most common cause of no ADPCM on the Duo?
« Reply #10 on: May 25, 2012, 07:11:20 PM »
IDK i dont have a pinout for it.
i know someone else had a data issue, that was a bad trace
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snow Crash

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Re: Most common cause of no ADPCM on the Duo?
« Reply #11 on: May 25, 2012, 11:19:11 PM »
Quote from: ApolloBoy on May 25, 2012, 06:42:01 PM
Quote from: thesteve on May 25, 2012, 06:23:10 PM
use a logic probe to check it for data, clock, power ect.
best bet is still a bad trace/via

Double checked and I didn't see any bad traces or vias. Luckily I found a logic probe so I can check out the chip in further detail. What pins should I test for and what should their states be?


http://www.jammarcade.net/oki-m5205-datasheet/
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Duo_R

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Re: Most common cause of no ADPCM on the Duo?
« Reply #12 on: May 26, 2012, 05:25:45 AM »
I had some members here send me parts from a bad duo, and if that wasn't the issue I sent the part back. Maybe you can have some luck there because some of the parts don't have easily obtainable replacements.

Steve is right though, my issue was just a bad trace.
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thesteve

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Re: Most common cause of no ADPCM on the Duo?
« Reply #13 on: May 26, 2012, 07:31:42 AM »
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ApolloBoy

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Re: Most common cause of no ADPCM on the Duo?
« Reply #14 on: May 27, 2012, 07:10:13 AM »
Triple checked the board this morning and still no signs of bad traces or vias. I'll whip out my logic probe in a bit and see what I get.

EDIT: Just checked the voltage pin on the M5205 and it's reading as 3.93V instead of 5, hm...
« Last Edit: May 27, 2012, 07:51:49 AM by ApolloBoy »
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Quote from: Arkhan
it makes me laugh because people are like I REMEMBER PLAYIN THAT BACK IN THE DAY, MAN THAT WAS FUN.

and then I go "yeah I remember playing that 2 days ago because I still have my SNES, retard"
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