Strange A1200 sound issue

illy5603 · 24 July 2009, 03:40

Hello,

I am having an odd sound problem with my Amiga 1200. It seems that the audio volume from the WHITE RCA jack is quieter than that or the RED RCA jack.

I will be digging around inside the system in a day or two installing a new keyboard, anything I should look for?

Loedown · 24 July 2009, 04:07

Greetings,
There was a previous post with a similar issue, look for bad caps, if that doesn't work, sniff around the op amp for the sound. I don't own a 1200 so I can't be much more specific.

kipper2k · 24 July 2009, 04:47

Quote:

Originally Posted by illy5603

Hello,

I am having an odd sound problem with my Amiga 1200. It seems that the audio volume from the WHITE RCA jack is quieter than that or the RED RCA jack.

I will be digging around inside the system in a day or two installing a new keyboard, anything I should look for?

There are 2 silver capacitors right behind each audio jack (one for each jack). Look at the solder pads and see if the solder pads are green, and also check surrounding components. If you see green solder pads it means the capacitors have leaked and need to be changed. Would also be a good time to check all the other capacitors too while you're at it

illy5603 · 24 July 2009, 05:30

Thanks for the replies! I will keep you posted on what I find!

illy5603 · 25 July 2009, 03:27

There was indeed a little discoloration beneath the capacitor behind the white RCA jack. I wouldn't say "green" but definitely not the shiny silver of the red jack. So, what capacitor do I need to buy? Is it a solder job or do they snap in?

Sorry for sounding so dumb, I am hardware n00b.

kipper2k · 25 July 2009, 03:32

Quote:

Originally Posted by illy5603

There was indeed a little discoloration beneath the capacitor behind the white RCA jack. I wouldn't say "green" but definitely not the shiny silver of the red jack. So, what capacitor do I need to buy? Is it a solder job or do they snap in?

Sorry for sounding so dumb, I am hardware n00b.

these caps are in a real tricky area to get at, if you know someone that has good soldering skills then ask them if you cant do it. You really need a hot air rework station to remove those puppies, or at least a nice hot bladed soldering iron. the capacitors you want are 22uf (microfarad) 25V aluminium electrolytic. You may as well change both while you are there in the area.

I'll track down the part number info from digikey for you.

edit, heres the part number (you may have to buy 5 minimum)

PCE3009CT-ND CAP 22UF 25V HA ELECT SMD

klx300r · 25 July 2009, 04:59

Quote:

Originally Posted by illy5603

There was indeed a little discoloration beneath the capacitor behind the white RCA jack. I wouldn't say "green" but definitely not the shiny silver of the red jack. So, what capacitor do I need to buy? Is it a solder job or do they snap in?

Sorry for sounding so dumb, I am hardware n00b.

hi illy, I replaced both my audio caps last year and I do not recommend you tackle this project as your fist ever soldering job...save yourself alot of headaches and possibly a damaged MB & have a friend who knows how to solder (& more importantly has the right equipment) do the job for you

illy5603 · 25 July 2009, 05:04

Quote:

Originally Posted by klx300r

hi illy, I replaced both my audio caps last year and I do not recommend you tackle this project as your fist ever soldering job...save yourself alot of headaches and possibly a damaged MB & have a friend who knows how to solder (& more importantly has the right equipment) do the job for you

I agree. I will buy the parts and let someone knowledgeable take care of it. I am in the market for a PAL mobo anyway as I am tired of forcing PAL everytime I reboot so I might just look for one of those. I currently have a 1D NTSC motherboard with all kinds of other issues (screen flickers and glitches when in 1024X768 for about 10 minutes until the system warms up) etc.

prowler · 25 July 2009, 20:59

Quote:

Originally Posted by illy5603

I currently have a 1D NTSC motherboard with all kinds of other issues (screen flickers and glitches when in 1024X768 for about 10 minutes until the system warms up) etc.

It sounds like that motherboard is in dire need of a thorough overhaul.

kipper2k · 25 July 2009, 21:32

Quote:

Originally Posted by illy5603

I agree. I will buy the parts and let someone knowledgeable take care of it. I am in the market for a PAL mobo anyway as I am tired of forcing PAL everytime I reboot so I might just look for one of those. I currently have a 1D NTSC motherboard with all kinds of other issues (screen flickers and glitches when in 1024X768 for about 10 minutes until the system warms up) etc.

Did you know that you can mod the motherboard so that it will go into PAL mode so you dont have to force pal no more. Again its a little tricky but not too hard. i'll look for the thread.

edit, read this thread. http://eab.abime.net/showthread.php?t=44738

illy5603 · 25 July 2009, 21:37

Quote:

Originally Posted by kipper2k

Did you know that you can mod the motherboard so that it will go into PAL mode so you dont have to force pal no more. Again its a little tricky but not too hard. i'll look for the thread.

edit, read this thread. http://eab.abime.net/showthread.php?t=44738

I think I saw it (pulling the pin from one of the chips) but I also have that problem where the graphics are all messed up for the first 10 minutes that the system is on. I think I read about fixes for this problem but there seem to be so many variations of this problem that I don't know which one pertains to me. A lot of people have the systems flake out after they are on for a while, mine STARTS working fine after it has been on for a while.

kipper2k · 25 July 2009, 21:43

it does sound like the board is in need of a major overhaul, capacitance and resistance values change with temperature so it is possible something is dying on the board. It all depends how much time, effort and money you want to put into it if you want to try to salvage it or not. I am looking for a NTSC board if you decide to buy a PAL board. i dont have a spare PAL A1200 board to trade though.

illy5603 · 25 July 2009, 23:53

Quote:

Originally Posted by kipper2k

it does sound like the board is in need of a major overhaul, capacitance and resistance values change with temperature so it is possible something is dying on the board. It all depends how much time, effort and money you want to put into it if you want to try to salvage it or not. I am looking for a NTSC board if you decide to buy a PAL board. i dont have a spare PAL A1200 board to trade though.

I will give ya a PM when I get the system all sorted out. For my skill level and what I am trying to do, I will probably grab a mobo off of amibay or get a new (or refurbed) system from Amigakit instead of fighting with this one for much longer. It has been working fine for running my bbs because I never turn it off.

rkauer · 27 July 2009, 00:45

Quote:

Originally Posted by illy5603

I think I saw it (pulling the pin from one of the chips) but I also have that problem where the graphics are all messed up for the first 10 minutes that the system is on. I think I read about fixes for this problem but there seem to be so many variations of this problem that I don't know which one pertains to me. A lot of people have the systems flake out after they are on for a while, mine STARTS working fine after it has been on for a while.

Bad (dry) capacitors for sure. Replace all of those little buggers (17 in total). It is a very economic fix: ~20USD + payment for the guy who make it.

illy5603 · 25 August 2009, 19:33

Quick question. If I wanted to do a real thorough cap replacement, do I use the same part numbers for all of them? There will be techs at Ami-west in October doing MB repairs, I just want to have all the parts handy for them.

Thanks.

Loedown · 25 August 2009, 20:30

Quote:

Originally Posted by illy5603

Quick question. If I wanted to do a real thorough cap replacement, do I use the same part numbers for all of them? There will be techs at Ami-west in October doing MB repairs, I just want to have all the parts handy for them.

Thanks.

As long as the caps you get are the same value, ie. 10uF and same voltage, ie. 25V, it doesn't much matter who the manufacturer is.

illy5603 · 25 August 2009, 23:03

Quote:

Originally Posted by Loedown

As long as the caps you get are the same value, ie. 10uF and same voltage, ie. 25V, it doesn't much matter who the manufacturer is.

Yeah I just wanted to know if they are the SAME (all 17 or however many there are) caps. IE Same voltage or less etc?

Your answer sounds like a yes, so unless someone else chimes in otherwise, thanks!

prowler · 25 August 2009, 23:16

Quote:

Originally Posted by illy5603

Yeah I just wanted to know if they are the SAME (all 17 or however many there are) caps. IE Same voltage or less etc?

Your answer sounds like a yes, so unless someone else chimes in otherwise, thanks!

Your replacement capacitors should have the same capacitance value as each of the original components, i.e. 22µF, 10µF, 4.7µF, etc., and the same or higher working voltage, i.e. 25V.

^ This answer really is a yes!

illy5603 · 26 August 2009, 02:03

Got it! Ordered, Thanks!

24 July 2009, 03:40	#1
illy5603 Registered User Join Date: Jul 2008 Location: SPaT CiTY Posts: 557	Strange A1200 sound issue Hello, I am having an odd sound problem with my Amiga 1200. It seems that the audio volume from the WHITE RCA jack is quieter than that or the RED RCA jack. I will be digging around inside the system in a day or two installing a new keyboard, anything I should look for?

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24 July 2009, 04:07	#2
Loedown Precious & fragile things Join Date: Feb 2009 Location: Victoria, Australia Posts: 1,946	Greetings, There was a previous post with a similar issue, look for bad caps, if that doesn't work, sniff around the op amp for the sound. I don't own a 1200 so I can't be much more specific.

24 July 2009, 05:30	#4
illy5603 Registered User Join Date: Jul 2008 Location: SPaT CiTY Posts: 557	Thanks for the replies! I will keep you posted on what I find!

25 July 2009, 03:27	#5
illy5603 Registered User Join Date: Jul 2008 Location: SPaT CiTY Posts: 557	There was indeed a little discoloration beneath the capacitor behind the white RCA jack. I wouldn't say "green" but definitely not the shiny silver of the red jack. So, what capacitor do I need to buy? Is it a solder job or do they snap in? Sorry for sounding so dumb, I am hardware n00b.

25 July 2009, 21:43	#12
kipper2k Registered User Join Date: Sep 2006 Location: Thunder Bay, Canada Posts: 4,323	it does sound like the board is in need of a major overhaul, capacitance and resistance values change with temperature so it is possible something is dying on the board. It all depends how much time, effort and money you want to put into it if you want to try to salvage it or not. I am looking for a NTSC board if you decide to buy a PAL board. i dont have a spare PAL A1200 board to trade though.

25 August 2009, 19:33	#15
illy5603 Registered User Join Date: Jul 2008 Location: SPaT CiTY Posts: 557	Quick question. If I wanted to do a real thorough cap replacement, do I use the same part numbers for all of them? There will be techs at Ami-west in October doing MB repairs, I just want to have all the parts handy for them. Thanks.

26 August 2009, 02:03	#19
illy5603 Registered User Join Date: Jul 2008 Location: SPaT CiTY Posts: 557	Got it! Ordered, Thanks!

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