How knowledgeable are you?

[rosetintedglasses]

Okay, time for a good story.
Seven years ago I bought a dual 1.42GHz FW800 G4 tower that had been left behind by an evicted tenant. It was my first tower Mac, after I got sick of trying to work on bulky iMac G3s and eMacs. I slowly got just about every period-correct Apple peripheral and internal upgrade for the thing (including two awesome 23" ADC Cinema Displays that I still use every day). I used it as an occasional gaming/experimenting machine for four years until I moved house and shoved the Mac into storage.
Last week I pulled it out and fired it up. It now runs for ten minutes or so at a time, then kernel panics, irrespective of load or connected devices. I pulled it apart expecting it was overheating and needed new paste or something, but then I found the logic board has let the magic smoke out.
I can't seem to find schematics for this board anywhere, so I'm asking if anyone does so I could get
The board version is 820-1474A, and the failed SMD is "L16". It is on the underside of the logic board, near the ports, and appears to be an inductor for a FireWire 400 port, though I could be wrong. If anyone knew what the part specs could be so I could get another that would be amazing. Living in NZ I can't really just buy another board, these things appear to be quite rare here.

 

[Eriamjh1138@DAN]

Find the schematic (google the PCB part number, etc. and see what you can find). L16 is a surface mount inductor, likely fried by excessive current. A little skill is required to desolder and replace it, but it’s very doable. Any TV repair shop that actually does PCB Repair. Mouser will have the component for a dollar or two with shipping IF you can identify it.

If you have a similar FW PPC mac, it may actually be labeled L16 or just try to find the same part near the FireWire circuitry.

I should check mine. Two of the three ports don’t work. It’s probably something simple like is.

 

[rosetintedglasses]

That’s why I came here, I couldn’t find schematics for any G4’s, to be honest. I thought maybe some kind soul could have one, or has an induction meter and could measure their board. The more I think about it the more silly it sounds that a FireWire port can bring the whole machine to its knees, but I guess anything’s possible.

 

[pl1984]

That’s why I came here, I couldn’t find schematics for any G4’s, to be honest. I thought maybe some kind soul could have one, or has an induction meter and could measure their board. The more I think about it the more silly it sounds that a FireWire port can bring the whole machine to its knees, but I guess anything’s possible.

This is my thought too. Given if worked prior to being put in storage and now, three years later, it does not suggests it may need recapped. I assume you didn't see the magic smoke released?

 

[rosetintedglasses]

I did not, but like I say, I'm only guessing it has to do with FireWire as it is near to those ports.

 

[Eriamjh1138@DAN]

I enjoy a challenge. Let’s start with trying to find the schematics for this mobo.

What’s the Apple numbers for the computer itself, the model, the specs, etc?

Edit: I hit the mother lode here: http://schematic-x.blogspot.com/2018/04/apple-schematics-pack.html but no 820-1474-A.

 

[Traace]

oh a burned firewire circuit, now I need to check my powerbook for a similar issue.

btw i searched for three fw 800 boards. 820-1474A, 661-2781, 661-2839. No schematics found yet..

 

[Eriamjh1138@DAN]

Looking for anything from 2002-2004 is difficult on the internet without very specific information.

PowerMacs were such a small part of the total PC Market back then. Like 2-3%.

 

[rosetintedglasses]

It is an 820-1474A board. M8570, though by memory I think all MDDs were. It's not a CTO model, just your regular 1.42DP model. Only FireWire devices I ever used was an iSight, and an 800 cable for TDM. Define "specific information", not really sure what to give further.

 

[Eriamjh1138@DAN]

I’m not having any luck. Found a mobo for $20, refurbed, but you’re in NZ, SO...

 

[Eriamjh1138@DAN]

OK. The best I can do is a 2011 MBP schematic. It has FW800, but it's BW compatible, right?

The only inductor symbol I can find is L4310, a 250-ohm ferrite device near pin 8 of the connector. There is a capacitor nearby like in your pic. It is part of the power feed. It’s a power filter inductor and must carry 5A DC current.

To find a replacement, you'd have to verify the package size with calipers. Common sizes are 1206, 1210, 0805, etc, which the first two digits being the length divided by 10 in thousands of an inch and the second two divided by 10 the width. 0805 is 0.080" x 0.050". There is no metric conversion. Again, Mouser.com is a good place to look for parts.

I don't think it is the source of your kernel panics, though. A dead FW port with nothing connected should not matter. Nothing is connected. There's no drain.

 

[AphoticD]

I don't think it is the source of your kernel panics, though. A dead FW port with nothing connected should not matter. Nothing is connected. There's no drain.

Great response @Eriamjh1138@DAN

I would agree here - I have a 12” PowerBook G4 which has a burnt out component on the logic board near the Firewire port and that port is non responsive. The machine is rock solid otherwise and I use it practically every day. I just can’t use the Firewire port.

 

[tigerintank]

I enjoy a challenge. Let’s start with trying to find the schematics for this mobo.

What’s the Apple numbers for the computer itself, the model, the specs, etc?

Edit: I hit the mother lode here: http://schematic-x.blogspot.com/2018/04/apple-schematics-pack.html but no 820-1474-A.

Those look really interesting - thanks vm for posting!

 

[tigerintank]

Found this for the iMAC G5 ALS

APPLE IMAC G5 A1058 M39 MLB IMG5 - 051-6482 - REV C.rar

Page 2 on PDF shows this -

SATA - EDUCATION: NOT USED GOOD,BETTER,BEST: HARD DRIVE
SATA - FOR DEVELOPMENT ONLY
UATA - EDUCATION: HARD DRIVE GOOD,BETTER,BEST: OPTICAL

Not sure if I knew at the time that the Education version used a slower PATA HDD.

Find the note re SATA - FOR DEVELOPMENT ONLY even more interesting - as someone who replaced the DVD drive in mine with a SATA converter to get 2 x SATA disks attached.

Later in the PDF it shows that the development SATA is on

NOSTUFF
J8302
LD18077-S04
M-ST-TH

So I'm left wondering if it might be possible to access J8302 on the logic board and with a bit of soldering add a second SATA port at J8302?

Would it be supported in Leopard or Tiger?

Would there need to be an additional 'development' kext?

Would it be supported in the standard Open Firmware?

Would be interested in others thoughts.