REPAIR GUIDE - TurboDuo: Sound Fix

[BlueBMW]

As far as I know 4558 is a standard code for that particular chip (its an op amp of some variation right?)  the other numbers are probably just batch numbers or serial numbers or mfg numbers.

[Duo_R]

update - I replaced the 4558 on the right, and the BU4053BF....and still no ADPCM. I also swapped another cap just in case it was bad (replacement). I gotta say I am not seeing any hope on this one. How about the 4558 near the audio circuit. maybe that one could have gone bad with all the leaking caps? Would that be related to ADPCM somehow?

OK Charlie or anyone else that knows, I am going to replace out the 4558's found here:



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Now my question, are all the 4558's on the Duo boards the same? There are other 4558's on the top of the Duo boards, but they have different codes printed on them. I don't see any reason they should be any different but wanted to see what you guys think.

So far I swapped out the 4558 on the left, but still no ADPCM!

[BlueBMW]

I'll just assume you've done all the caps near the audio circuit yes?

[Duo_R]

I kid you not...100% cap replacement. EVERY damn cap!!!

I'll just assume you've done all the caps near the audio circuit yes?

[BlueBMW]

Haha, i can see how that could get VERY frustrating then!  hmmm... well if there are any donor chips you need that a US Turbo CD mobo might have, let me know I've got a bad TGCD mobo laying around.

[Duo_R]

Ok I was talking to Chop last night and he gave me the idea that there might be a bad trace. I took some time and checked the adpcm circuit and discovered that one of the 4558 chips was not grounded....because if a bad trace. After booting up Gates if Thunder....i heard Bonk speak for the first time in a couple years! Now a side effect, for some reason the sound volume is now extremely low. It previously was running low about 40% of normal levels, now it is about 20%. Same if using the headphone Jack. Any theories here? Perhaps the 4558 in the sound circuit has failed? I feel like I am very close to full revival of my Duo that I have had since 1992!!!

[Charlie]

Hey,
Shouldn't this topic:
"No sound on right sound channel (ADPCM fixed)"
be made a part of this thread?  It seems to be a continuation, or at least a closely related subject. 

Or, I could just post the schematic here??

Charlie

[Duo_R]

It could but how exactly do you sticky two threads together?

Hey,
Shouldn't this topic:
"No sound on right sound channel (ADPCM fixed)"
be made a part of this thread?  It seems to be a continuation, or at least a closely related subject. 

Or, I could just post the schematic here??

Charlie

[Charlie]

Don't know, but...
I have occasionally seen a post in one thread move to another thread.  Can't that same thing be done on in this case?  (although it may mean a lot of one-at-a-time message moving).  Or just make the second thread a second sticky, and reference one to the other?

But I think that, given the prevalence of audio problems on Duo's, we should make sure that the info, the schematic, and the success here is readily "findable".

Just a thought.
Charlie

[Duo_R]

The trouble is when these threads get 20 pages deep, who is going to take the time to go through all this?

[Charlie]

The same  people, myself included, that go through 2+ years worth of threads to find that one single bit of elusive data they need.  That's how I got started here.  But I agree that moving 20 pages of posts is a lot of work.  Too bad there is not a way to link the two threads.  Guess it just means a lot of exercise for the Search Engine.

Charlie

[BlueBMW]

The same  people, myself included, that go through 2+ years worth of threads to find that one single bit of elusive data they need.  That's how I got started here.  But I agree that moving 20 pages of posts is a lot of work.  Too bad there is not a way to link the two threads.  Guess it just means a lot of exercise for the Search Engine.
Charlie

Cant you link directly to a post number?  Maybe the original poster (if they're still around) could add links to the first post that go directly to the golden nugget posts deeper in the thread.

[nat]

I can merge that thread into this one, but the result won't be pretty. The messages are merged chronologically, so, the posts from the other thread will get inserted in between messages from this thread, resulting in total fragmentation of each individual conversation.... If you catch my drift.

[Duo_R]

yeah that wouldn't be great. Maybe a reference to the other thread in the first post somehow?

[Charlie]

Definitely don't want the chronological screw-up, it would defeat the purpose of making important info readily available.

What if we made this thread itself a sticky, and just referenced each one to the other one?

Charlie