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eMac 800Mhz -> 1.33GHz conversion

Originally posted by bigbadmac
Try the PDF from my site...eMac TS Guid and Manual
May just be a bad connection or something... :confused:
Click to expand...

That's my hope, but so many things went wrong in the operation (at least 4 or 5 things that I would never repeat now that I've learned), it's only a hope. I'll tear it all apart again when I get the chance (not until Sunday), and try to clean up the solder job and make sure the connections go together correctly when I reassemble it.

What exactly does that mean? No picture, but a startupsound and the LED...I don't think it's a dead monitor.
 
If it all became messy try to measure resistance between pads then you will see where the "jumpers" are. Also did you plug the video cable back if you have taken it off (flat connector in the top left corner)?

Good luck!
 
Originally posted by lbodnar
If it all became messy try to measure resistance between pads then you will see where the "jumpers" are. Also did you plug the video cable back if you have taken it off (flat connector in the top left corner)?

Good luck!
Click to expand...

Yes I plugged the video back in. And I don't think it's a monitor problem because a) I waited for a while then hit the volume keys to listen for the beep and I didn't hear it, and b) The air coming out the back isn't warm.

And I will need luck, thank you. :)
 
Plastic Chicken,

My 700Mhz -> 850Mhz attempt resulted same as yours. eMac would "chime" but no video. What I believe is we have one of earlier steps of 7451 processor thus very limited in oc capability. Mine is stable at 800Mhz now.

Here are list of 7451 revisions:

XPC7451RX700CE (my eMac's rev)
XPC7451RX700CER2
XPC7451RX700RE
XPC7451RX700RER2
XPC7451RX800CER2
XPC7451RX800PE
XPC7451RX800PER2
XPC7451RX800RE
XPC7451RX800RER2
XPC7451RX800SG
XPC7451RX867PE
XPC7451RX867PER2
XPC7451RX867PG
 
Let us know... I have a 700 I want to convert as well

I would try to do this but am an amatuer at motherboards... let me know what I need and what to solder and I will give it a shot.

Want to convert 700/128/40 to as high as possible with good stability
 
Exellent detail on the website lbodnar! I decided to give it a whirl last night and took my 800 up to 1066. I'm not the greatest at soldering, and my electronics bud is out of town at the moment... But the 800>1066 jump was a no brainer (just one little dollop of solder...) Perfectly stable so far... And quite a bit quicker.

I hope I can get mine running stable at 1.33, as another 266mhz boost would really make this eMac a bang-for-the-buck winner.

Like yours, I bought a leftover stock 800... Not sure of the production date, but I would assume pretty late.
 
Re: Let us know... I have a 700 I want to convert as well

Originally posted by jaybonner
Want to convert 700/128/40 to as high as possible with good stability
Click to expand...

the first thing you might want to do is max out the RAM. 128 is hardly helping you.
 
Re: Re: Let us know... I have a 700 I want to convert as well

Originally posted by Rod Rod
the first thing you might want to do is max out the RAM. 128 is hardly helping you.
Click to expand...

A good point, but we run filemaker databases and processor speed and hard drive speed are a premium... I have found that networking with OS X is slower than 9 and processor speed is very important. We have other 700 emacs with more memory, and they are faster with more memory, but not sufficiently to approach OS 9.
 
Re: Re: Re: Let us know... I have a 700 I want to convert as well

Originally posted by jaybonner
A good point, but we run filemaker databases and processor speed and hard drive speed are a premium... I have found that networking with OS X is slower than 9 and processor speed is very important. We have other 700 emacs with more memory, and they are faster with more memory, but not sufficiently to approach OS 9.
Click to expand...

my bad for guessing you were in X. it was in the back of my mind that you'd probably be in 9. I guess if virtual memory is off, and 128 is enough to run filemaker and OS 9, you're all set. 128 in OS X makes for a very crunchy sounding hard drive which of course is bad for a computer's health.
 
eServe

As a step towards eServe :) I have managed to measure voltages on eMac motherboard PSU connector shown here.
Pinout considered to be:
08 07 06 05 04 03 02 01
16 15 14 13 12 11 10 09

Code: 
Pins   eMac ON   eMac OFF
----   -------   --------
01 02  +20.3V    +12V
03 04  +12V      +12V
05 06  GND       GND
07     +19V      +11.5V
08..12 GND       GND
13     +0.3V     +8V 
14     +0.3V     +0.3V
15     +5V       +5V
16     GND       GND
1,2 and 3,4 looks like high current main power
7 ???
13, 14 - control signals to/from down converter board
15 +5V TTL logic power

Anybody willing to discuss that here or in e-mail?
 
Originally posted by soonbaek
Plastic Chicken,

My 700Mhz -> 850Mhz attempt resulted same as yours. eMac would "chime" but no video. What I believe is we have one of earlier steps of 7451 processor thus very limited in oc capability. Mine is stable at 800Mhz now.

Here are list of 7451 revisions:

XPC7451RX700CE (my eMac's rev)
XPC7451RX700CER2
XPC7451RX700RE
XPC7451RX700RER2
XPC7451RX800CER2
XPC7451RX800PE
XPC7451RX800PER2
XPC7451RX800RE
XPC7451RX800RER2
XPC7451RX800SG
XPC7451RX867PE
XPC7451RX867PER2
XPC7451RX867PG
Click to expand...

That's encouraging, because well, I beat up my motherboard a lot (even got a static shock at one point), so that fact that yours is working at 800 is encouraging. I'll see what happens tomorrow.
 
blah

Back to 700Mhz and still no picture.

Here's everything bad I did to it the first time around (which I managed not to the second):

1. Used a magnetic screw driver (I thought it wasn't for a long time, because it wasn't as powerful as I'm used to)

2. Gave the logic board a really really nasty static zap one morning...I was hoping it all went into the heat sink, but...:\

3. Got one end of the jump off, then tore the other end. So tried to complete the circuit with a (relatively) large solder bridge.

4. Hit the PMU reset switch a whole bunch of times before I read that one should only hit it only once.

5. There's probably a number five, but I don't remember.

I should also note that I never removed the heatsink at all, as I have no thermal paste handy.

I guess I'll disassemble when I can and take a picture of the solder work.
 
I've removed the battery and reset the PMU...still no video.

The battery reads about 280 mV, which I think means that the PMU did crash the first time around.
 
Plastic Chicken woes...

Hey! contact me via private post. I'll be glad to get in touch with you via phone, email, AIM or whatever to help you out... The ZAP thing is bad but may not be the end of the world.

If it were me, I would clean off the solder mess and use the alternate jumper points instead... the original jumper pads are way too small AND there are other pads too close to them for my comfort... See my site for alternate jumper locations...Motherboard Prep...

Contact me, I'll help if I can.:)
 
this whole thread reminds me of the excitement when i tried to overclock my Tbird back when AMD was in its infancy...

overclocking--nothing quite like it. And it doesn't even matter what platform you're on :)

'course, my Tbird was a B version and could only hit 110 fsb...you look like you got alot more luck on your side ;)
 
Numbski,

I've put back my eMac but I do not remember seeing that particular chip. I do know eMac has other chips which I have posted pictures on page 2.

The main suspect at this time is the second picture (IMIC5003BY) from page 2, since I was able to compare with Leo's.

I've send a request to Cypress regarding the pinout of it.

Good job! Maybe I'll have a weekend project :D
 
Bah. I'm going to have to go probing the motherboard's leads to find the right resistor to remove. :( The board (according to Tycho) has 4 (!!!) layers to it, and thus I see no traces leaving the pins in question. I have to find some way to secure one of my multimeter's probes to a pin, and then go probing with the other while running a continuity test (I think).

We're now into new territory for me, so if anyone has past experience probing around like this, I'd be interested in hearing some insights.
 
Oh, and if anyone knows of some cheap 10 switch, and 3 switch dip switch banks I can buy I'd be interested in hearing it. I didn't count the number on the eMac, but I get the feeling we could all use this.

Remember kids: Desoldering braid is your friend. As is ribbon cable. And hot glue.

and duct tape.
coffee.
a good magnifying lense.
ooh ooh! and kynar wrapping wire.
some wooden clothes pins (the spring loaded kind).

;)
 
Remember kids: Desoldering braid is your friend. As is ribbon cable. And hot glue.

and duct tape.
coffee.


;) [/B]
Click to expand...

I find scotch more effective for hand-stabilization, coffee makes me zip all over the place with the solder tip. But ya, what you said :)

Just wanted to report all is running well at 1066. I'm considering 1333 in the next few weeks... Need to get time to pick up a faster HD, might as well do that while I'm in there!
 
Heat removal exercises

I have cut out a couple of perforated internal walls that sit right where the air flows through processor heatsink. Hopefully it will increase CPU cooling efficiency.

The other thing: after removing the speakers and leaving those holes open the EGT - OAT difference dropped from 16C to 12C. Since amount of generated heat is still the same it means the cooling fan pumps about 1/3 more air per minute. Looks like cooling efficiency leaves much to be desired.

The idea is to optimise (facilitate) the airflow and drop fan RPM to reduce noise.
 
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