eMac System Board Compatibility

[christo930]

I did quite a bit of looking around and I didn't find anything because it just brings up endless unrelated stuff. But my question is can you put any eMac MB in any eMac? I have the 700mhz (CDR)version and I wouldn't mind upgrading it to 1.42ghz. I know I could probably just buy a 1.42 machine cheap, but I really don't want to pay shipping for such a large and heavy machine, not to mention mine doesn't have a lot of hours on the CRT. The shipping could easily double the price of the machine.

Another question it is a bitch to get it to turn on. I basically have to turn it upside down take off the ram access cover and screw around with the reset button and power button to get it to turn on eventually. Sometimes it takes hours. I figured it was the PRAM battery. So I opened a G3 Mac that I have and it uses the same battery. I measured the voltage and it was 3.6, but putting that in this machine didn't change things. I don't see any leaking caps and once it's up and running it's usually OK. Is this normal for an eMac if the battery is weak? The original was dead for sure, but the one I stuck in it is not new and is old in fact, though it did give the right voltage and current on a 375 ohm load, but perhaps it just needs a brand new battery? Ideally, I probably would rather just replace the MB with the 1.42ghz version assuming it goes for reasonable prices.

Also, does the 1.42ghz version have the analogue audio stuff? does it use the same connector block on the side of the emac? That is what I want to use it for mostly. Also I use it for writing (mac, not Audio) CDs using a firewire external CDRW.

It REALLY sucks that iTunes cannot connect to the iTunes server or run any of the radio stations. It has such a nice sound system.

 

[amagichnich]

my eMac works just fine with an empty battery, so it definitely is not the battery

 

[DeltaMac]

The two generations of eMacs have very different chassis. The video connects through a different path (the ivad cable that causes issues with the 700 Mhz, is not present in the later eMacs)
Speaker location is very different, and, of course, the faraday cage that tries to cut your hands every time you touch it, has a very different version in the newer eMacs.
The power button on the newer eMacs is NOT that ridiculously short wire that you have to connect just by feel. (I've fumbled around with that many times, and broke more than a few power buttons
Bottom line, the logic board might be swappable, if you can figure out where everything connects, and modify the chassis (and the logic board itself) to fit the other parts that are also different, such as the down convertor board - so the outside looks the same, but much of the "guts" are different, with parts in different locations. I seriously doubt that you could ever get the swap to work.

I have two 1.25 GHz eMacs, worked on quite a few 700 Mhz, but never owned one.
I get what you mean about the shipping weight of the complete eMac. I really wouldn't ever pay for shipping for that either.

 

[christo930]

my eMac works just fine with an empty battery, so it definitely is not the battery

So then what could cause it? It seems fairly stable once it turns on. Turning it on is the only problem. It does crash occasionally, but it is not so often that I suspect caps or something.
Is the 700mhz model known to have bad caps? I know a lot of computers from that time frame have cap issues and I know the 1.25ghz model is known to have bad caps, but I haven't seen anything about the 700.
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The two generations of eMacs have very different chassis. The video connects through a different path (the ivad cable that causes issues with the 700 Mhz, is not present in the later eMacs)
Speaker location is very different, and, of course, the faraday cage that tries to cut your hands every time you touch it, has a very different version in the newer eMacs.
The power button on the newer eMacs is NOT that ridiculously short wire that you have to connect just by feel. (I've fumbled around with that many times, and broke more than a few power buttons
Bottom line, the logic board might be swappable, if you can figure out where everything connects, and modify the chassis (and the logic board itself) to fit the other parts that are also different, such as the down convertor board - so the outside looks the same, but much of the "guts" are different, with parts in different locations. I seriously doubt that you could ever get the swap to work.

I have two 1.25 GHz eMacs, worked on quite a few 700 Mhz, but never owned one.
I get what you mean about the shipping weight of the complete eMac. I really wouldn't ever pay for shipping for that either.

Thanks. I had a feeling this was going to be the case. There is a guy on YT who does a "sled swap" from a 1ghz to a 1.42ghz model, but it was the entire sled and drives and not just the MB. In my experience, Apple has never been good with documentation either. I worked for an authorized service company and supported a couple hundred Macintoshes and the only stuff I ever had access to was the quarterly update disks.

 

[DeltaMac]

Back in the day, I have replaced hundreds of eMac logic boards for swelling caps. None that I recall on 700 Mhz eMacs. Not saying that can't happen, only that I have never fixed a 700 Mhz with that issue. It was not part of Apple's repair program at the time, only the later USB 2.0 (mostly 1.25 Ghz, but that was what I typically saw in schools at that time.)

The older design eMac (PowerMac4,4) was available as a 1Ghz model - and the later eMac (PowerMac6,4 - with USB 2.0), when first released, was ALSO sold with 1 Ghz processor, along with the 1.25 Ghz. That later model would certainly be a "sled swap" to the last 1.42 Ghz.

 

[christo930]

Back in the day, I have replaced hundreds of eMac logic boards for swelling caps. None that I recall on 700 Mhz eMacs. Not saying that can't happen, only that I have never fixed a 700 Mhz with that issue. It was not part of Apple's repair program at the time, only the later USB 2.0 (mostly 1.25 Ghz, but that was what I typically saw in schools at that time.)

The older design eMac (PowerMac4,4) was available as a 1Ghz model - and the later eMac (PowerMac6,4 - with USB 2.0), when first released, was ALSO sold with 1 Ghz processor, along with the 1.25 Ghz. That later model would certainly be a "sled swap" to the last 1.42 Ghz.

Thanks. My days of supporting Macs was in the late 90s and very early 2000s. Mostly G3 beige macs and 604 based machines. This was before all of the bad caps came into the electronics industry. Power problems are always difficult.

 

[amagichnich]

So then what could cause it? It seems fairly stable once it turns on. Turning it on is the only problem. It does crash occasionally, but it is not so often that I suspect caps or something.
Is the 700mhz model known to have bad caps? I know a lot of computers from that time frame have cap issues and I know the 1.25ghz model is known to have bad caps, but I haven't seen anything about the 700.

What happens when you reset the pram when booting? (should be cmd alt p r ater pressing the power button)

I have to eMacs up and running a lot - a 1GHz (ATI) and a 1.25GHz (USB 2.0) model. The CRT of the first one begins to loose it's correct colors in the corners, the latter has no problems whatsoever. And honestly, I haven't been that nice to this machine: it was in my garage for well over 14 months, had overheated due to the fan not running, was exposed to repeated overcurrent and I even dropped it a few inches once. Maybe some models are affected by bad caps or something similiar, mine is not at all. Quite the opposite it seams - I cannot kill the beast whatever I try

 

[z970]

I cannot kill the beast whatever I try

Well... It was built for the education market...