SGI: Hardware

Hi, I just acquired a 1600SW + MLA (both as "Junk"), and i'm trying to test it out,
It all does work just fine with my MacBook Pro 15 via DVI-D cable, but there is some horizontal noise - flickering lines.

I tried capturing this on the video below:

http://vimeo.com/33275597

The MLA makes silent hissing noise when I put my ear up to it - I'm just trying to figure out whether this may be MLA or 1600SW issue.
I don't have any other MLA nor 1600SW to test - unless any members are from Tokyo (or Guam - I'll be there for a week from tomorrow) .

Thanks

Perhaps a capacitor in the MLA is about to die?
Open it and check if any of the capacitors on the board have any bulges or leaks.

The hissing noise is definitely from the 200 6V capacitor - I'm going to replace it soon, I only wonder if this is just going to fix the hissing, or the picture noise as well....

Having had several MLAs go bad on me over the years, I'm now of the opinion that they have a design flaw of some sort that does not promote long life. Or maybe I've just had bad luck with eBay.

And there's really not much to the inside of them to examine...but I'd be interested to see what you find out!

Reporting full success, the capacitors are: Sanyo OS-CON 6SVP220M and 16SVP100M, I had no trouble ordering perfectly matching ones from http://www.logic-d.net/ (Japanese), it cost me some 147 and 273 JPY respectively a piece (ordered 3 of each just in case).
Datasheets (in Japanese) are here: http://www.edc.sanyo.com/pdf/oscon/J32_33.pdf (the form factor matching the ones from MLA is F8).

Replaced them just now and the monitor works flawlessly, no hissing noise, and no noise lines in the picture either.

Looking at the board closely, it seems it may be possible to mod the MLA to accept ordinary 5V (with enough current) and simply get rid of all those capacitors, voltage regulators etc.
I'm pretty sure there's no special reason for those other than being able to use the same power supply as in 1600SW...

It also makes me wonder what is the second power socket for - it's not soldered anywhere, but I checked and the respective pins are short with the same pins in the working one...
(for a moment I thought that may have been direct 5V input - but it doesn't seem so).

One important point - my cheapo (sparkfun) 30W soldering iron was not really able to melt the existing solder - it's very likely SGI used lead-free solder with some relatively high melting point (could be even 20C above ordinary).
So even though my soldering works I will need to resolder them again with better iron to ensure good contact (I have Weller stashed somewhere in my office so this won't take long).
Also, the original capacitors are soldered ALL THE WAY along the contact pins (underneath too), so depending on your iron you may simply end up ripping part of it away from the board - and with an ordinary soldering method you will not be able to resolder it in exact same way (unless you have SMD kit)..
The original capacitors have this little (red in my case) glue which holds them during manufacturing process - this one can be scraped off easily with any sharp object, you don't really need to apply any new glue, but it is helpful if the capacitor doesn't move while you solder

Updated wiki with a link to this post: http://www.nekochan.net/wiki/MLA

Cheers and good luck if you dare to try .

Most printed circuits manufactured after 2000 use SnAgCu solder alloys. Whatever the melting point, it can be difficult to reflow joints attached to ground planes.

I recently discovered a tool that simply cuts off chip capacitors, it might work on the smaller OSCONs as well.

I am experiencing the same problem with my 1600SW. But the monitor also turns on/off randomly.

I plan on replacing those two capacitors in the MLA, however I am not really clear how I am supposed to take them out. (I am a novice using the soldering stuff).

For example, I am looking on the backside under the 220 capacitor. I see 4 pins underneath it (C608, C607, C605, C605). I'm not clear which one I am supposed to de-solder. It doesn't even look like the normal soldering stuff I have seen. Looks very clean (hard to describe without a picture).

Any detailed up would be appreciated

from kubatyszko's remarks, and the Sanyo datasheets, these are surface-mount electrolytic caps. they need SMD techniques.

kubatyszko wrote: It also makes me wonder what is the second power socket for - it's not soldered anywhere, but I checked and the respective pins are short with the same pins in the working one...
(for a moment I thought that may have been direct 5V input - but it doesn't seem so)..

I'd suspect the second socket was intended to use one power supply for the monitor and the adapter, with just a cable between the multilink and the screen.

Timmy wrote: I am experiencing the same problem with my 1600SW. But the monitor also turns on/off randomly.

I plan on replacing those two capacitors in the MLA, however I am not really clear how I am supposed to take them out. (I am a novice using the soldering stuff).

For example, I am looking on the backside under the 220 capacitor. I see 4 pins underneath it (C608, C607, C605, C605). I'm not clear which one I am supposed to de-solder. It doesn't even look like the normal soldering stuff I have seen. Looks very clean (hard to describe without a picture).

Any detailed up would be appreciated

The caps are surface mounted - so you only need to look from the top on the same side of PCB, doesn't matter what's on the bottom of the PCB.

Ideally to remove you would need a heat gun or chipquik, I made it work with an ordinary soldering iron though.
Looking from the top, you should see two contacts that stand out a little from the plastic base - heat one and keep on lifting the capacitor with some tool, after a while it would be high enough and should pop up, then repeat with the other contact.
You may also see some red glue on the PCB - this is what holds it in place during manufacturing process.

Remember that the contact area of the capacitor is pretty big (not only what you see from the outside), it goes some 2mm underneath the base so this method will likely rip the solder away and if ou're not careful you may permanently break the PCB this. It worked for me but doesn't guarantee it will work for everyone...

Soldering new caps back - again I used my old soldering iron, as robespierre mentioned, SGI might have used different alloy with higher melting point which means my iron couldn't make very good contact - the MLA does work, but I will definitely get a heat gun or a better iron and fix that.

Again - to do it properly you would need a heat gun, clean the surface, apply solder, glue the capacitor to hold it in place - and then you point heat gun which will melt the solder and make it connect both things together into a nicely looking contact.

Beware - with a heat gun you may break other areas of the PCB, so if you're not confident with your soldering skills - find someone who is and ask them for help.


Now that I think of it - I will definitely give it one day a try and mod the MLA to just accept 5V skipping all those nasty capacitors and voltage regulators
Oh well - now I also bought GFX1600 - the PCI version of MLA, together with another 1600SW

Cheers