eMac 800Mhz -> 1.33GHz conversion

[jspivack]

Hi Jeff, voltages are in booted up state.
Don't try to match them to ATX standard (apart from +5/+12) at this stage as it will only complicate things.

ouch. thanks for the heads-up.

PSU seems to be custom-designed so the best approach is to get inop PSU and reverse engineer it (should not be difficult.)

I'm a mechanical, not electrical engineer, so that's going to be tricky. it's too bad that the PSU and the CRT circuitry all so intertwined...my real goal was to try to eliminate the high-voltage CRT circuitry since I won't be using it; the assumption was that since it's on the same board as the PSU the safest and simplest thing would be to replace the whole thing with an ATX. I suppose I could still do that, if I added the proper upconverters (12V to 20V)...

eMac service manuals have troubleshooting procedure where they mention actual voltage on a few pins.

I've got a couple of manuals, but I didn't look that closely. I just scanned for pinout diagrams. I'll go through them more carefully.

I use eMac as my home computer at the moment so cannot have it down.
Maybe after January 22nd

placed your order yet?

Thanks again
Jeff

 

[lbodnar]

placed your order yet?

Yes!

 

[gothicspikey]

Helllllpppppppppppp!!

i have a real problem, i decided to take my emac apart to have a look at the size of the jumpers and see if i was confident enough to attempt soldering, i had it open and decided to read the manual 1 more time so i put it back together, i plug it in, pressed the power button....nothing, i didn't nothing to the mb at all all i did was removed the cd drive to have alook so i don't kno what could have happened, i noticed earlier today tho, that when u plug it in, if u go close, i think the hard drives spinnin even before u press the power button, and when u unplug it it makes strange noises as it slows down can anybody help me??? thanks in advance xx

Spike

 

[yantao]

take apart it again ,to check the line monitor connect to the computer

HI ALL . i 'M CHINESE , my English is poor.I 'M VERY GLAD TO FIND THIS WEB.

take apart it again ,to check the line of monitor connect to the computer .
If you did not connected it the power switch is not work .

I 'm trying to repair a emac, so I had to take apart the computer ,because it have in the H-direction shake.

 

[gothicspikey]

i checked all cables and there all in correctly, there doesn't seem to be abything out of the ordinary, tho it still won't come on, any ideas?

 

[netjosh_granada]

eMac 1st gen and ATX PSU...

I have the next question:

In the 1st generation eMac, the logic board has TWO blind-mate connectors that go directly to the analog module assembly, whereas the 2nd and 3rd gen eMacs have only one.

I don't know if the second connector is of any use (if it is there, it must do something ), or if I can try power up the eMac directly through the main connector (the one which is common in all generations) using an "hypothetical" ATX conversion with the voltage info available in this thread.

If someone has access to a 1st gen eMac, it would be of great help if he could measure all pin voltages in both blind-mate connectors.

And another thing, I've heard somewhere that there is a document only avaliable to Apple techs which provides al the information about the blind-mate conector voltages and on the internal video out (interesting to output video without mirroring), apart from other info that would be really interesting to see

Thank you all...

 

[yantao]

i checked all cables and there all in correctly, there doesn't seem to be abything out of the ordinary, tho it still won't come on, any ideas?

I 'm repairing emac , I' m sure you are did not connect some cable.

Now follow me ,please.
1, connect the power line and swith on , listen carefully , the fan running or the hard disk running, so the power is on .if nothing happen ,that to say you computer did not connect the power.

2. open the emac ,and disconncet the power switch , use some smaller cable to conncet the red and black line.(not thick black one ), if power on , then the switch is not work well.

3, look care for, in the middle of monitor a connecter to main board, and three line , and FBT line CAP and a line at the back of the monitor near the fan connect to the mainboard .

4,check the line at the front of monitor ,

5.if all connect ,you did not power on . your computer is sure erro.

you need a professional help.

 

[netjosh_granada]

eMac and Possible ATX conversion

Today while surfing the net I have found a web page (http://www.ct-scan.com/iMacATX/) where it is performed an IMAC ATX conversion.

What is revolutionary here is that it is performed without any aftermarket solution (see Marathon Computer) and because I've thought this would be a great way to power ANY eMac motherboard WITHOUT the Analog Module.

This new idea is the following:

Before finding this web page, I thought the eMac motherboard SHOULD be powered only through the "Blind-Mate" connectors available in the logic board, and so the down converter board should make it's work of providing the necesary current to each part of the logic board (including both drives power headers). This had lead all of to the problem on HOW to measure voltages in both "Blind-Mate" connectors (only one if 2nd and 3rd generation eMacs).



NOW, the idea is to power the logic board directly through the Down Converter Board's connector, which is the path followed by the author of this web page.


Now the "bad" news that I have for this project:

The IMAC down converter board has 24 pins, all ordered and compared to its ATX counterpart in the diagram above, BUT (and this is a BIG BUT), the EMAC down converter board has 20 pins, and this is where I have problems when assigning each pin with its ATX counterpart.


Now, I'm BEGGING anyone who could have access to an eMac (better if is a 1st generation one), to measure each pin voltage in the Down Converter Board connector, because this is the only thing that stops me from using a wonderfull eMac system out of its original enclosure.

Please, this help would be appreciated and would help me in achieving my next Big Project Goal, which is the rerouting of the internal video to an external monitor (something not too difficult given the great instructions found in this web page http://www.ct-scan.com/iMacATX/).

Thank you all in advance...

 

[guysebfan04]

comments on the eMac???

I am considering buying an eMac and just wanted some opinions from people who may own or use or have used an emac!

Compared to Apple's other desktops how are they? Would it be worth my waiting to see if a G5 model comes out soon.

I have never owned a Mac before and would greatly appreciate any advice or tips you might have!

Katherine

 

[madmaxmedia]

Well, most of the people here will give you positive feedback about the eMac, since we are all owners!

You should probably browse the forum for product buying advice:
https://forums.macrumors.com/forums/54/

In general, the eMac is a fine machine if you don't mind the extra size and weight of the CRT monitor. It is similar to the Mac Mini, but has the advantage of 2 RAM slots and a faster hard drive (which does make a difference.)

Rumors are all over the place on a G5 eMac, but it doesn't appear to be imminent. The eMac is a fine performer as it stands-
http://www.macintouch.com/perfpack/comparison.html

Finally, there are some great deals on refurbished eMacs at Apple.com. I got one for $549 with a full warranty (which I promptly voided by swapping in a larger HD.)

 

[lbodnar]

Guys, I have just took apart my 1.25GHz Mac mini ... correction, make it 1.5GHz Mac mini!
You are welcome to join the new thread if you are interested.
https://forums.macrumors.com/threads/108335/

See you all there! Let's keep this one eMac/iMac - specific. I am going to go back to eMac stuff later after making mini my current home machine

Well, I am writing this from it now.

 

[eryk]

Upgraded my 1GHz eMac (2nd Gen) to a 160GB 7200rpm Maxtor drive with 8/mb cache today. It was my first time taking it apart but I didn't find it confusing. The most difficult part was removing the screws holding the EMI shield on. I almost stripped two of them trying to remove them. I think the shield was improperly aligned and someone/thing forced the screws in there anyway. I didn't have this problem anywhere else.

The rest of the removal went smoothly. I swapped the drives and placed my old drive in a firewire enclosure. Reassemble wasn't difficult. I wish I had labeled the groups of screws I made accordingly but I eventually figured it out.

I powered on the machine and booted the OS X install CD. It installed fine. There was something weird happened to the picture, though. The bottom half of the screen was jiggling when the hard drive was accessed. The drive was also a lot louder than the stock Hitachi. I thought setting the Automatic Acoustic Management to silent mode might stop these vibrations (???) from affecting the CRT. The only tool I could find required a boot into OS 9 so I Googled and found how to do it via OF.

It worked great and the drive booted up as silently as the stock drive with no screen jiggling. It's really nice to have such a large drive inside the eMac now and the Hitachi in my aluminum firewire enclosure is silent as well. Perfect for backups.

Thanks for the helpful and encouraging postings here. Overclocking and upgrading the drives are a great way to lengthen the lives of these great little machines.

 

[VAmin]

G5 overclocking

Thanks man. Unfortunately, until someone opens one up, and pulls off that cover, we can't see what the clock chip is to see what those points control. Perhaps I can google around a bit...see if anyone has an image of the current G5 cpus/clock chips. If we have a very similar number of banks for the cpu/fsb, then it's likely to be the same.

This guy has pics and preliminary jumper settings for the G5 towers. Probably very similar to iMac G5:

http://24.13.230.40/overclock/g5.html

 

[ruben ruben]

bigbadmacs instructions

I realize this is a little late, but does anyone have the pdf or a new link to bigbadmac's instructions for overclocking the 700mhz eMac. I had been visiting the site recently and it seems the webserver has changed or it has been pulled. I did not print it, and I am at somewhat of a loss without it. Thanks in advance.

I have the same problem - I need the pdf-version of bigbadmacs instructions of overclocking the original 700 MHZ eMac. Does anyone have it and is willing to share it. Or is there a new link for bigbadmacs site ?

regards from germany

 

[lbodnar]

OK, I broke loose again! Since I have moved more or less to mini, I am going to finish my plans for eMac ATI 800MHz/1GHz. I have it all in pieces on the floor and I will be tracing low voltage PSU next few days. I'll be posting notes here. Hopefully this thread will not disappear (like 700MHz instructions )

Plans at the moment are:

1) headless emac (in a rack case or pizza box)

2) TFT eMac (replace CRT with 17" flat screen and use empty space for extra 2 HDDs.)

If you want to brainstorm this while eMac is still alive, welcome. Let's make a dent in this universe!

 

[netjosh_granada]

OK, I broke loose again! Since I have moved more or less to mini, I am going to finish my plans for eMac ATI 800MHz/1GHz. I have it all in pieces on the floor and I will be tracing low voltage PSU next few days. I'll be posting notes here. Hopefully this thread will not disappear (like 700MHz instructions )

Plans at the moment are:

1) headless emac (in a rack case or pizza box)

2) TFT eMac (replace CRT with 17" flat screen and use empty space for extra 2 HDDs.)

If you want to brainstorm this while eMac is still alive, welcome. Let's make a dent in this universe!

Hi lbodnar, I have a great mod waiting for a little info I think only you can provide.

My plan is to use a 1st generation eMac (700 Mhz - Geforce 2MX) into a new case, because the analog module died some time ago. I have found the way to power it up and to trace the internal video out to an external monitor.
I'll explain:
1) ATX Power Supply connection. Before (in the middle of this thread), you measured voltages on the BLIND-MATE connectors, because it was the "logic" place to look at. I think we were wrong, because if we see, for example, all the iMac conversions arround the web, the logic board is feed through the Down converter board connector (24 pins for iMac, 20 pins for eMac). I have been looking all around the web for this info but it is not available, and I KNOW that this is where the ATX PSU should be connected to. The voltages on the Blind-Mate connector were a mix of High current lines (which go directly to the down converter board) and video signals (which takes me to the 2nd point).

2) Internal Video Connection. If I'm right (which I don't know), the Blind Mate connector of the logic board is the place to look at when searching video signal, as it goes directly to the Analog Assembly as has enough pins to hold power lines and video signals. I think that Apple didn't complicate itself when it designed the eMac innards, and so they used the same connector as the iMacs (yes, iMacs have Blind-Mate connectors too).

So resuming, I think that if you could post info on the eMac Down Converter board connector voltages, I would be the first to test if it were possible to power an eMac logic board with an ATX PSU, and if it works we would concentrate on wiring the video though the Blind-Mate connector.

Here's a pic of the Down Converter board connector:

And here's a link of an iMac conversion which can help (this is where I thought about feeding the Logic board through the Down Converter Board connector):
http://www.ct-scan.com/iMacATX/

Whatever you think, say it...

 

[lbodnar]

netjosh, very quick answer before I forget...

It looks like 1G and 2G eMacs are quite different. I see where you are going - throw away downconverter board (DCB) and power it all up from ATX PSU as if DCB is the only power source.

Unfortunately in my eMac not all the vital voltages are provided by the DCB. CPU is drawing its power via DC-DC converter on the man logic board and it needs its +12V (called CPU12V) directly off 16-pin blindmate connector (which I have only one)

I'd like to get rid of DCB but it is not going to be easy ...

Basically the whole eMac is driven by two high current voltages - +12V that goes directly to CPU DC-DC and +20V that goes to DCB to be processed further.
There are also trickle +5V, Firewire power +15V and two feedback control signals: DCO (downconverter ON) and PRO (?)

Video cable is not on a blindmate connector as in 1G eMac but on a separate 16 pin connector.

 

[netjosh_granada]

netjosh, very quick answer before I forget...

It looks like 1G and 2G eMacs are quite different. I see where you are going - throw away downconverter board (DCB) and power it all up from ATX PSU as if DCB is the only power source.

Unfortunately in my eMac not all the vital voltages are provided by the DCB. CPU is drawing its power via DC-DC converter on the man logic board and it needs its +12V (called CPU12V) directly off 16-pin blindmate connector (which I have only one)

I'd like to get rid of DCB but it is not going to be easy ...

Basically the whole eMac is driven by two high current voltages - +12V that goes directly to CPU DC-DC and +20V that goes to DCB to be processed further.
There are also trickle +5V, Firewire power +15V and two feedback control signals: DCO (downconverter ON) and PRO (?)

Video cable is not on a blindmate connector as in 1G eMac but on a separate 16 pin connector.

Let's see the differences beetwen 1G and 2G eMacs:

- 1G eMac has 2 Blind-Mate connectors, each with 20 pins, while 2G has 1 BMC with 16 pins.
- 1G eMac has a 20 pin Down Converter Board connector, while 2G has a 22 pin DCB connector.
- 1G and 2G eMacs have the internal video connector on the same place but while the 1G connector is processor-side (and performing 18 pins), the 2G is facing memory-side (with ¿? pins), so I was wrong before (I have just read both apple service manuals).

It's true that both eMacs are really different, and that leaves me without any chance to use a wonderfull 1G eMac logic board until someone measures voltages on the DCB connector of a working 1G eMac (something VERY EASY and without any danger).

When powering the eMac with an ATX PSU, I thik it would be done by connecting one ATX +12V line to the BMC and measuring DCB voltages to connect directly the ATX PSU without having to search for a +20V DC-DC converter.

This is what I think. If I'm wrong, you just have to tell me...

 

[lbodnar]

eMac downconverter pinout (ATI Graphics model)

OK, here is eMac 800/1GHz model down-converter demystified:

Pinout:

1 Return loop for 2.5v voltage sense. Connected to p.3 on the logic board
3 2.5v supply to logic board
5,7 5v supply to logic board
9,11 3.3v supply to logic board
12 enable 12v (to logic board and drives) active high (+2.5v..12v)
13 PRO voltage on this pin signals overvoltage condition on one of the outputs
14 HDD/CD on - active high - switches 5/12v to two attached power leads
15 DCO turns the whole down-converter on - active low (ground)
17,19 20V input from analog board PSU via logic board
21,23 12V supply to logic board (activated by pin 12)
2,4,6,8,10,16,18,20,22,24 GND

Feeding and care of DCB:

apply 20V to pins 17,19
ground pin 15
2,5v 3.3v and 5v are now on
apply some voltage to pin 12
12v is now on (logic board)
apply some voltage to pin 14
HDD and CD drives are starting up

What could have been easier?!

Main DC-DC controller chip is TPS5130

 

[netjosh_granada]

great job lbodnar.

You are a genius...

Now it would be great that someone would measure voltages on a 1st generation eMac so we all that have a 1st generation one (working or not) could do a great variety of mods...

I'll send the best beer I can find by Air Mail to the first who measures voltages on a 1st generation eMac.

 

[lbodnar]

eMac 1.33GHz is running headless

OK, I have good news for you!

After storming the analog board for quite some hours I am basically done.
I have disabled high voltage part of it, disconnected IVAD module (the silver can) and can run it both headless and with external TFT in place of external CRT. Few things to mention:

1. IVAD silver can was tightly integrated in powerup process so some simple hacks were needed to get rid of it.

2. After full powerup the 20V and CPU12V to logic board sag to about 10V and 6V respectively. This is yet unresolved problem. Part of the PSU voltage feedback control is fed from high voltage (Vsync) circuit so I can't fix it (yet). However eMac runs perfectly on half-voltages due to the fact that DC-DC converters can pull it off until their input V approaches their output. To cut it short due to 20V sagging to 10V, internal drives get only 10V instead of 12V and cannot startup. I boot off external Firewire drive with no problems. I understand most of the projects will move away from native analog board PSU anyway so this is not a problem. In theory one good quality 12V 4..5A PSU should be enough to power both CPU and the drives.

3. Even after getting external display connected the resolutions are still those used by internal Mac screen. 1280x960 is filling up my 19" TFT in native 1280x1024 quite nicely leaving small horizontal black borders (I don't want to stretch it up.) However setting something like 800x600 locks you out since you end up with 112Hz refresh rate that monitors do not support and you will have problems getting back in. I had to create autostarting VNC server on a bootable Firewire drive and then boot off it and then get via VNC and reset the screen. I am sure this sits somewhere in OF settings or maybe in Boot ROM... I know you can use SwitchRez-like software to set any resolution but it is still nice to have monitor details read at startup.

4. By keeping Downconverter board, we can get away with just one or two main voltages and all the power control functionality is preserved: power button, sleep, wake up all work as they should.

That's it so far. eMac is quite cool to run with passive cooling as you can see!

OK, I need some rest...

 

[vga4life]

Leo, you rock!

I'm a little confused on your most recent update - are you running the LCD on the external video connector or have you tapped the internal display connector?

Now that the mini is out, the one advantage of the emac is the ability to run dual monitors. It'd be sweet to be able to use an emac logic board to drive 2 TFTs, even if only with an analog signal.

-vga4life

 

[lbodnar]

...are you running the LCD on the external video connector or have you tapped the internal display connector?

I am using internal connector, you can see the blue VGA plug on the picture going into a cable that used to be internal video cable.

Update: I have made a simple internal eMac video <-> standard VGA converter to use until I find a proper new case for eMac, also use SwitchResX to force native resolution 1280x1024, now image is crisp and beatiful (on par with Mac mini's DVI) and fills up the whole TFT screen. We're back in business!! Can't wait to run eMac on two 19" TFT screens side by side!

 

[lbodnar]

eMac driving two 19" TFT screens and running off PC PSU

Here is mighty eMac, running off standard PC PSU and driving two 19" TFT displays at 1280x1024 each. That is 32" corner to corner!
I like the space and the price. If one could only find cheap source of eMac logic boards now...

12 Feb Update: Managed to completely separate logic and analog board! Now all that needed to run eMac headless is just a standard PC power supply. I have tied together Firewire, CPU12V and +20V voltages and feed them all off +12V. eMac runs with no problem! Obviously HDD and CD need to be powered directly off PSU (as downconverter board cannot make 12V from 12V) and Firewire voltage is slightly less the one in stock eMac but still within Firewire specs.

Now all that is required for the project like this is eMac logic board with downconverter and PC PSU. There is no need to take anything else from eMac. Both - VGA and power connectors are easy to make.

Hey, is there anybody out there reading this or I'm just blogging!?..

 

[topgunn]

Hey, is there anybody out there reading this or I'm just blogging!?..

I have been subscribed to this thread for over a year and still enjoy keeping up with it.