Supplies:
· 1 iMac Mother Board (I Used Revision C)
· 1 Old VCR (Broken Doesn't Matter)
· 1 ATX Power Supply
· 1 ATX Power Supply Extension cable
· 1 Hard Drive
· 1 Optical Drive
· 1 Apple Disk Drive Ribbon Cable
· 1 Short IDE Ribbon Cable
· 1 IDE Ribbon Cable (LONG!!!!!!)
· 1 VGA Female Connector
· 1 IC DM7404N (Most Any 7404 Should Work)
· 4 Rubber Feet (I used 8)
· 1 Spool Of Wire, Stereo Or Otherwise
· 1 Audio Jack (If Necessary)
· Assorted Screws
Mod Process:
For this mod I used, or wished I had used, the supplies listed above and the tools listed here:
· Dremel Tool
· Hack Saw (I didn't use one but it would be helpful)
· Power Drill
· Electrical Tape
· Soldering Iron
· Assorted Screw Drivers
I purchased an iMac revision C motherboard off eBay ($19.99 + Shipping) and started looking for a usable case. I decided to check out Good Will and found a VCR for $9.99, which gave me my start.
I needed to remove the stock 24-pin connector and connect wires to each pin. These wires were used to connect to the power supply plus some others covered below. A good tip here is to use some masking tape to label each of these wires with their pin number. This way you don't have to constantly look at the board in the future.
I also needed to solder a wire to one of the connections on J9. This is found right next to the battery, and was the connection closest to the battery.
Next I needed to build a power inverter. This is necessary because of differences between the ATX and iMac power supplies. For this I needed an IC, the number off of the one that I used DM7404N but my guess is most any 7404 would work. Here is the information on this inverter.
Pin
|
Connects Too
|
| 1 |
J10 - P10
|
| 2 |
GND, Group 7
|
| 3 |
GND
|
| 4 |
No Connection
|
| 5 |
GND
|
| 6 |
No Connection
|
| 7 |
GND
|
| 8 |
No Connection
|
| 9 |
GND
|
| 10 |
No Connection
|
| 11 |
GND
|
| 12 |
No Connection
|
| 13 |
GND
|
| 14 |
J20 - P6, Jumper Next to Battery, Group 6
|
Now I had to hook it all together. Below is the wiring diagram for what pins connect to what pin. Including the IC diagram. If you want to do what I did, you can make all the connections with jumper cables and wire nuts to ensure that everything works properly.
For this I needed two items, one was a 20 pin apple disk drive ribbon cable. I don't know where you can find one as I had several. The other is a short IDE ribbon cable. This connected into a 26-pin connector. I had to clip off the last several of the 40 pins and removed the orientation indicator. I next separated all of the individual wires on the ribbon cable and labeled them with their corresponding pin number with masking tape.
I next clipped the wires on the ATX power supply extender, and labeled the wires by pin number using masking tape. The reason I used the power supply extension is so that I could easily replace the power supply in the future if this one dies on me. What I did to make it easier on me is take all pins that connected together, and preformed the same function.
Wire Group
|
ATX Power Supply
|
iMac Power Connector
|
| 1 |
4, 6, 19, 20
|
4, 6, 24
|
| 2 |
3, 5, 7, 13, 15, 16, 17 |
3, 5, 8, 10, 11, 13, 22
|
| 3 |
1, 2, 11
|
1, 12, 14, 16, 18
|
| 4 |
10
|
2, 20, 23
|
5 - Not Used
|
8, 12, 18 - Do Not Combine
|
7, 9, 15, 17, 19, 21 - Do Not Combine
|
| 6 |
9 |
IC-P14, Jumper next to Battery, J20-P6, GND
|
| 7 |
14
|
GND, IC-P2
|
*** - Special note here, pins 9 and 14 must both connect to there own ground wire separate from all others, I did this by grounding the wire to the power supplies case, this caused me a large head each until I figured it out. - ***
| 26 Pin HE-10 Connector |
|
Microphone (White) |
1
|
2
|
Microphone (Black)
|
Microphone (Red)
|
3
|
4
|
Headphones
|
Headphones (Right High)
|
5
|
6
|
Head Phones (Left High)
|
Head Phones
|
7
|
8
|
Head Phones
|
Head Phones
|
9
|
10
|
Head Phones
|
Head Phones
|
11
|
12
|
No Connection
|
Speaker Left
|
13
|
14
|
Speaker Left
|
Speaker Right
|
15
|
16
|
Speaker Right
|
Power Switch
|
17
|
18
|
Ground
|
Power LED
|
19
|
20
|
Sleep LED
|
No Connection
|
21
|
22
|
No Connection
|
24 VAC Phase 1
|
23
|
24
|
24 VAC Phase 2
|
24 VAC Phase 1
|
25
|
26
|
24 VAC Phase 2
|
20 Pin HE-10 Connector
|
SDA
|
1
|
2
|
SDC
|
GND
|
3
|
4
|
?
|
DCO
|
5
|
6
|
T 5V
|
?
|
7
|
8
|
-10V
|
H-Sync
|
9
|
10
|
PFW
|
V-Sync
|
11
|
12
|
?
|
Blue
|
13
|
14
|
B-GND
|
Green
|
15
|
16
|
G-GND
|
Red
|
17
|
18
|
R-GND
|
L/S
|
19
|
20
|
?
|
Video
When I powered up, I found this coming out of the integrated VGA connector.
So, I had to build my own video connector. I don't know why apple put a VGA connector in the iMac if it doesn't work properly, but that is neither hear nor there, I still needed to build my own. I bought the connecter at Radio Shack for around $5.00. I connected the pins as follows.
A VGA connector has 15 pins and is setup as seen below.
To convert the J20 connecter to the 15pin VGA connector, I needed to follow this conversion chart.
VGA To iMac J20 Conversion Chart
|
VGA
|
iMac J20
|
Connection Type
|
1
|
17
|
Red
|
2
|
15
|
Green
|
3
|
13
|
Blue
|
4
|
NOT USED
|
N/C
|
5
|
3
|
GND
|
6
|
18
|
R-GND
|
7
|
16
|
G-GND
|
8
|
14
|
B-GND
|
9
|
NOT USED
|
N/C
|
10
|
3
|
GND
|
11
|
NOT USED
|
N/C
|
12
|
1
|
SDN
|
13
|
9
|
H-Sync
|
14
|
11
|
V-Sync
|
15
|
2
|
SDC
|
After I powered the system up and the screen looked good again, I decided it was time to set up the hard drive and CD drive. For this I needed the LONG!!!! IDE cable. The need for the long cable was because I needed to run the cable all over the case to connect to everything. The first thing that I noticed is that the IDE cable is 40-pin and the connecter on the iMac is 50-pin. What I did was to remove one side of the connector to allow it to fit into the 50-pin connector without removing or bending any pins. I ignored pins 1-10 on the 50-pin connector, and placed pin 1 of the IDE cable starting at pin 11 of the 50-pin connector and pin 40 of the IDE cable on pin 50 of the connector.
Installation
If you thought that the wiring was "FUN", just wait the best is yet to come. After buying my VCR from Good Will, I needed to gut it, cleaning out everything inside to make room for my iMac and it's required components. After removing all of the electrical components I found out that I still needed to remove a lot of plastic that was designed to hold the VCR's components in place. This is where I wished I had to used a hack saw, but I am a knuckle head and used the dremel tool for the hole thing.
Once I finished gutting the VCR, I made a plan to fit the components inside. I can only recommend that you look for openings that already exist for power supply, ports, and CD drive.
You will notice that I have installed two LED lights in this circuit board, this is so that I have power and sleep lights. I also soldered wires to the power button on the motherboard, and eject button on the CD drive. You can find the power button and LED light connection points in the section that covers the ATX power conversion. Below you will see where I soldered the stereo wire to the CD drive to operate the eject button from the face of the VCR.
After I finished all of this, I inserted all of the components and install some method of CPU cooling such as a heat sync with our without fan. I did my best with what I had to support the motherboard. I have no suggestions on CPU cooling because I never installed one. The temperature readings on the CPU have not reached a critical level so I have just decided to forget it.
There is one last thing that I must mention here. Once I had the computer up and running, I found out that the sound out audio jack on the motherboard was shot. I had to find another way to get the sound to the computer, so this is what I did.
On the 26-pin connector, there where 8 pins designated to head phones, and 4 designated to speakers. The speaker connectors on this iMac motherboard where dead as well, but I was pleased to find out that the headphone pins where still working properly. I went to radio shack and bought an audio jack.
All of these connectors come with there own instructions for wire, and should be fairly straightforward. I connected the right and left headphone wires to there respective pins on the 26 pin connector (5 for right, 6 for left) and connected the ground wire to a communal ground wire (pick your favorite, or most convenient).
Below is what the back of the iVCR looks like once the Audio and Video ports have been placed.
To attach my disk drives, and power supply I drilled holes in the bottom of the VCR and screwed them in from the bottom. This created a rough bottom surface, so I Installed some rubber I picked up at Radio Shack for very little money.
Here are my end results, I am happy with them and I hope you enjoy them as much as I did.
Mod Specs:
· 400MHZ G3
· 384 MB Ram
· 10GB HDD
· 52X CD Rom
· 56K Modem
· 10/100 NIC
· 8MB Video Ram
|
