G4 Case Mod

G4 Drive Activity light

One of the things I miss the most from older computers is the disk drive activity light. Most especially on a G4, with very quiet drives, sitting under a table, there are times when I don't know if it's locked up or not. I've got a crick in my neck from bending over to listen for the drives running. I decided to do something about it.

Snooping around inside the case, I found what looks like solder-pads for a dip jumper, right next to the IDE connector for the hard drives. This connected to pin 39, labeled "-DASP" in the ATA spec.

Sure enough, there was activity signal there, but it came FROM the drive, not the motherboard. You can see it's labeled "DS 6".

It is also reverse-logic. Normally high, and goes low on disk activity. So I needed to invert it.

I soldered an IC wirewrap pin to the driver-side solder pad.

The wire you see there is leading to the prototype board.

Here's the prototype. All that's really needed is a single inverter, to "right" the logic, but I wanted the be able to add the internal SCSI card, and any future internal ATA card to the same indicator.

So I uses a triple 3-input NOR gate, 74LS27N, and cobbled the three to allow mixing of 2 more positive logic signals.

The other 2 gates are unused for now.

The quick-n-dirty test used a surplus red LED. It worked!

Before taking things apart, I needed to know where vertical "center" was in the logo, so I put a piece of scotch tape across the face of the G4, then slit it at the side-panel seams.

Now, with the front plastic off, I could just hold a ruler across the 2 pieces of tape on the sides, and scribe a horizontal line.

Withe the same ruler, I could eyeball the horizontal center.

Next, the DVD and Zip drives had to come out.

Then the plastic faceplate could be removed.

This required removing the front top and bottom handles first.

Masked off the inside and out. Didn't want any metal shavings to get away!

And drilled a 7/64 inch hole (slightly smaller than the LED), to fit a T-1 (3mm LED).

The Blue LED mounted in the hole.

Good ole' Silicone Sealer!

And a view from the inside.

The clear Apple logo would have leaked light around the edges, which would then have infiltrated behind the graphite plastic, and I didn't want that, so...

Fortunately the Apple logo popped right out!

And I was able to "paint" the skirt with black magic marker.

And here it is, remounted in the front faceplate. (rear view)

Everything was reassembled at this point.

The chip and socket were wrapped in bubble-wrap, and scotch taped to the top of the DVD carrier.

Crude, but effective.

Ta-da!

No more strained neck!

And as a closing touch, since I had so many of these old rainbow decals, I stuck one at the bottom of the metal chassis.

The graphite plastic is quite translucent.

Snooping around inside the case, I found what looks like solder-pads for a dip jumper, right next to the IDE connector for the hard drives. This connected to pin 39, labeled "-DASP" in the ATA spec. Sure enough, there was activity signal there, but it came FROM the drive, not the motherboard. You can see it's labeled "DS 6". It is also reverse-logic. Normally high, and goes low on disk activity. So I needed to invert it. I soldered an IC wirewrap pin to the driver-side solder pad. The wire you see there is leading to the prototype board.
Here's the prototype. All that's really needed is a single inverter, to "right" the logic, but I wanted the be able to add the internal SCSI card, and any future internal ATA card to the same indicator. So I uses a triple 3-input NOR gate, 74LS27N, and cobbled the three to allow mixing of 2 more positive logic signals. The other 2 gates are unused for now. The quick-n-dirty test used a surplus red LED. It worked!
Before taking things apart, I needed to know where vertical "center" was in the logo, so I put a piece of scotch tape across the face of the G4, then slit it at the side-panel seams. Now, with the front plastic off, I could just hold a ruler across the 2 pieces of tape on the sides, and scribe a horizontal line. Withe the same ruler, I could eyeball the horizontal center.
Next, the DVD and Zip drives had to come out.
Then the plastic faceplate could be removed. This required removing the front top and bottom handles first.
Masked off the inside and out. Didn't want any metal shavings to get away!
And drilled a 7/64 inch hole (slightly smaller than the LED), to fit a T-1 (3mm LED).
The Blue LED mounted in the hole. Good ole' Silicone Sealer!
And a view from the inside.
The clear Apple logo would have leaked light around the edges, which would then have infiltrated behind the graphite plastic, and I didn't want that, so... Fortunately the Apple logo popped right out! And I was able to "paint" the skirt with black magic marker.
And here it is, remounted in the front faceplate. (rear view) Everything was reassembled at this point.
The chip and socket were wrapped in bubble-wrap, and scotch taped to the top of the DVD carrier. Crude, but effective.
Ta-da! No more strained neck!
And as a closing touch, since I had so many of these old rainbow decals, I stuck one at the bottom of the metal chassis. The graphite plastic is quite translucent.