A4000 audio fix - pictures (pr0n for Zetr0)

chiark · 18 July 2008, 21:34

Well, I tried to repair my 4000s audio last week, and took some pics to keep the Beardy One excited...

First off, this is what it looked like before treatment

To remove surface mount caps, you can simply twist the cap off, then clean up

Clean up with solder wick etc..

And add the new caps!

Paul_s · 18 July 2008, 21:53

Blimey they really make a mess when they leak

. The CD32 uses similar caps if I'm not mistaken... hmm should check those out sometime

Good work tho chap

keropi · 18 July 2008, 22:02

nice work!

rkauer · 18 July 2008, 22:55

Like I always sustain, caps 433 and 443 must be swapped for non-polarized types!

They leak because the alternate current over 'em. That's not a fast-to-appear problem, but they will surface at some point (like those caps on A3640).

Zetr0 · 19 July 2008, 12:09

@chiark

AWESOME

its a great job!!! I love a good rescue story!!!!!

AND HIRES UBER DETAILED HARDWARE PR0N.... before breakfast too!!!!!!!!

indeed I am a truly blessed Zetty

chiark · 19 July 2008, 13:56

Here's a strange one: one of my Rev B motherboards has different caps on them for the 22uF caps: rather than having black writing and paint, they've got blue writing and paint on 'em.

And they haven't leaked!

Those are on the board with the white simm sockets. Pics later.

Thought you'd like the detail, Z

da9000 · 25 July 2008, 06:19

Quote:

Originally Posted by rkauer

Like I always sustain, caps 433 and 443 must be swapped for non-polarized types!

They leak because the alternate current over 'em. That's not a fast-to-appear problem, but they will surface at some point (like those caps on A3640).

Sorry Rogerio, but I have to remind you of these two links:

http://www.amiga.org/modules/myalbum/photo.php?lid=3713
http://www.amiga.org/modules/newbb/v...orumpost502778

I use polarized tantalums. No explosions yet.

@chiark:
Nice rescue! Love the before/after screenshots and the crisp close-ups!

rkauer · 25 July 2008, 09:24

I know, m8.

But if you look at the schematics, those caps are in the "exit" of the OP-AMPS, so the current/voltage at that point is alternate.

Of course the polarized caps will not blow out, but they will fail, someday. In defence of tantalum caps, I must admit they don't leak and have a lot more precision than those ordinary counterparts.

FOL · 02 August 2008, 00:00

1 thing I would say, is twisting the SMD caps off, isnt always wise. As I used to do this until the tracks started ripping off the boards.

What I do now is braid the solder off, then with a thin screwdriver, leaver each leg as I heat them and they normally pop off.

EDIT:- Also just noticed, you put a cap in the wrong way round. Cap next to C408.

18 July 2008, 21:34	#1
chiark Needs a life Join Date: Jan 2008 Location: England Posts: 1,707	A4000 audio fix - pictures (pr0n for Zetr0) Well, I tried to repair my 4000s audio last week, and took some pics to keep the Beardy One excited... First off, this is what it looked like before treatment To remove surface mount caps, you can simply twist the cap off, then clean up Clean up with solder wick etc.. And add the new caps! Attached Thumbnails

02 August 2008, 00:00	#9
FOL PSPUAE DEV Join Date: Nov 2006 Location: Wales / UK Age: 45 Posts: 5,999	1 thing I would say, is twisting the SMD caps off, isnt always wise. As I used to do this until the tracks started ripping off the boards. What I do now is braid the solder off, then with a thin screwdriver, leaver each leg as I heat them and they normally pop off. EDIT:- Also just noticed, you put a cap in the wrong way round. Cap next to C408. Last edited by FOL; 02 August 2008 at 02:22.

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18 July 2008, 21:53	#2
Paul_s Registered User Join Date: Nov 2006 Location: Amigaville Age: 46 Posts: 3,334	Blimey they really make a mess when they leak . The CD32 uses similar caps if I'm not mistaken... hmm should check those out sometime Good work tho chap

18 July 2008, 22:02	#3
keropi . Join Date: Oct 2004 Location: Ioannina/Greece Posts: 5,040	nice work!

18 July 2008, 22:55	#4
rkauer I hate potatos and shirts Join Date: Oct 2007 Location: Sao Leopoldo / Brazil Age: 58 Posts: 3,482	Like I always sustain, caps 433 and 443 must be swapped for non-polarized types! They leak because the alternate current over 'em. That's not a fast-to-appear problem, but they will surface at some point (like those caps on A3640).

19 July 2008, 12:09	#5
Zetr0 Ya' like it Retr0? Join Date: Jul 2005 Location: United Kingdom Age: 49 Posts: 9,768	@chiark AWESOME its a great job!!! I love a good rescue story!!!!! AND HIRES UBER DETAILED HARDWARE PR0N.... before breakfast too!!!!!!!! indeed I am a truly blessed Zetty

19 July 2008, 13:56	#6
chiark Needs a life Join Date: Jan 2008 Location: England Posts: 1,707	Here's a strange one: one of my Rev B motherboards has different caps on them for the 22uF caps: rather than having black writing and paint, they've got blue writing and paint on 'em. And they haven't leaked! Those are on the board with the white simm sockets. Pics later. Thought you'd like the detail, Z

25 July 2008, 09:24	#8
rkauer I hate potatos and shirts Join Date: Oct 2007 Location: Sao Leopoldo / Brazil Age: 58 Posts: 3,482	I know, m8. But if you look at the schematics, those caps are in the "exit" of the OP-AMPS, so the current/voltage at that point is alternate. Of course the polarized caps will not blow out, but they will fail, someday. In defence of tantalum caps, I must admit they don't leak and have a lot more precision than those ordinary counterparts.

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