I have located and purchased a couple of broken G4 modules with the idea to have them repaired.

I have found a couple of locations that can do reball work and so this is my plan.

Purchase a cheap mac mini (or other mac) with a 7447A cpu inside and have it swapped on to the A1 module.

The slowest mac mini seems to be 1.25 Ghz and fastest is 1.5 Ghz, but looking at A1 dip switch settings, the highest CPU frequency allowed would be 1.06 Ghz ( 8 x 133mhz)

Is my logic right or am I missing something, because I have seem some people claim to run G4s at higher speeds and do not see how they did this.

Thoughts and opinions?

@busytech,

I could be wrong but I swear I'v seen someone on either A.org or AW that had 1 set for 1.25Ghz. Maybe Paul.

Chris

@QuikSanz

Quote:

Maybe Paul.

Who, me?

Nah, I've done quite a bit with my XE, but one thing I've never messed with is the CPU speed. It's still at 800. I have a 7441/7451 Vger.

Paul

_________________
Builder of Frankenthousand, the monster A1000
The Young Frankenthousand A1-XE G4
X5000

@Paul,

Just a guess, I know I've seen it some where in here. White paper w/black letters, must be true. Well, maybe blue/grey background and and black letters. Lol

Chris

@busytech

Crisot seems to be the right guy to ask questions about A1 overclocking.

http://amigaworld.net/modules/newbb/viewtopic.php?topic_id=32393&forum=33

@smf

Replacing the chip and clocking it at its nominal speed is hardly overclocking, but I guess he's the right guy in any case.

The 7457 datasheet lists all the multiplier settings from 2 to 28. For a 1250MHz it's either 9.5*133 (1264, DIP setting 01110) or 12.5*100 (1250, setting 11111).

The good thing about those are that you don't need to know which is LSB and which is MSB, as they are symmetrical. As long as you have all 5 DIPs available, which I don't remember if you do.

multiplier of 10.5 (for 1.4GHz with 133MHz FSB) is 10001, also symmetrical.
11.5 (1.53GHz@133) is 00000.

Now ain't that a thing of beauty?

_________________
This weeks pet peeve:
Using "voltage" instead of "potential", which leads to inventing new words like "amperage" instead of "current" (I, measured in A) or possible "charge" (amperehours, Ah or Coulomb, C). Sometimes I don't even know what people mean.

@olegil

The problem I am seeing is that there are only 4 dip switches on the module for setting the A1 CPU speed.

@busytech

Quote:

busytech wrote: @olegil The problem I am seeing is that there are only 4 dip switches on the module for setting the A1 CPU speed.

I bet there is a pull-up or pull-down resistor somewhere on the module that forces the 5th PLL input to the given level. The problem is just to find out, where this resistor is.

_________________
A1SE: G3@600MHz, 2GB, 1GBit network card
A1XE: G4@933MHz, 2GB, refitted AC'97 codec
microA1: G3@800MHz, 1GB

- A1 Linux support -

@Geri

Quote:

I bet there is a pull-up or pull-down resistor somewhere on the module that forces the 5th PLL input to the given level. The problem is just to find out, where this resistor is.

And if someone is removing CPU to replace it anyway, then that's a convenient time to probe around and find it, when you have easy access to the BGA pads and your multimeter.

_________________
All glory to the Hypnotoad!

@billt

Quote:

billt wrote: @Geri And if someone is removing CPU to replace it anyway, then that's a convenient time to probe around and find it, when you have easy access to the BGA pads and your multimeter.

Exactly!

_________________
A1SE: G3@600MHz, 2GB, 1GBit network card
A1XE: G4@933MHz, 2GB, refitted AC'97 codec
microA1: G3@800MHz, 1GB

- A1 Linux support -

@Thread

Crisot can reball a G4 CPU module, he can even overclock it. My former G3 XE was upgraded to an G4 XE and Crisot overclocked it to 1,26 Ghz. His XE is overclocked @ 1.4 Ghz.

_________________
PowerMac G5 2,7Ghz - 2GB - Radeon 9650 - MorphOS 3.14
AmigaONE X1000, 2GB, Sapphire Radeon HD 7700
FPGA Replay + DB 68060 at 85Mhz

@billt

chrisot already did this exercise, but he failed to document it for the rest of us.

_________________
This weeks pet peeve:
Using "voltage" instead of "potential", which leads to inventing new words like "amperage" instead of "current" (I, measured in A) or possible "charge" (amperehours, Ah or Coulomb, C). Sometimes I don't even know what people mean.

@busytech

I thought so. Chrisot wrote something in that OOOOOLD thread to indicate that you can't go over 9.5 multiplier (1266) but this doesn't seem correct to me. If you select 0000 and the non-DIP pin is also a 0 you would get 11.5, which is 1530MHz at 133MHz FSB. So with a 1.5GHz chip and a ton of cooling I don't see why not.

If you can find the missing pin and get it high then world == oyster. Edit: I might add, wiring a missing pad under a BGA isn't actually neither rocket nor quantum science. We're talking LARGE pads here compared to most of the things I have to mod when I mess up a design. Take wire, make loop at one end, lay on pad, place BGA over, heat up and then wire the other end of it.

Btw, this is 1.42GHz, might make it to 1.53 with very little luck needed:
http://www.ebay.com/itm/Apple-Mac-Mini-A1103-2005-For-Parts-Repair-No-Power-Supply-Powers-ON-/201403861977?hash=item2ee49b0bd9

Can't argue with that price, but the shipping price to Norway was simply out of the question.

Last edited by olegil on 28-Aug-2015 at 11:43 AM.
Last edited by olegil on 28-Aug-2015 at 11:39 AM.

_________________
This weeks pet peeve:
Using "voltage" instead of "potential", which leads to inventing new words like "amperage" instead of "current" (I, measured in A) or possible "charge" (amperehours, Ah or Coulomb, C). Sometimes I don't even know what people mean.

@olegil

Quote:

olegil wrote: @billt chrisot already did this exercise, but he failed to document it for the rest of us.

It would be good to have another broken G4 CPU module to reverse engineer the connections of the PLL pins (does somebody have a broken module for a reasonable price?).

I would also like to reverse engineer some other pin connections. The MPC7455 errata sheet lists some signals that need to be forced to a specific level to avoid data corruption in the L2 cache and IIRC this errata has been added after the production of the CPU modules.

_________________
A1SE: G3@600MHz, 2GB, 1GBit network card
A1XE: G4@933MHz, 2GB, refitted AC'97 codec
microA1: G3@800MHz, 1GB

- A1 Linux support -

@olegil

Quote:

olegil wrote: Edit: I might add, wiring a missing pad under a BGA isn't actually neither rocket nor quantum science. We're talking LARGE pads here compared to most of the things I have to mod when I mess up a design. Take wire, make loop at one end, lay on pad, place BGA over, heat up and then wire the other end of it.

I guess you would have to cut a trace somewhere too, otherwise I would expect the pin to be floating. Instead I would expect that there is a pull-up/down resistor somewhere so that simply one end of it would have to be rewired.

_________________
A1SE: G3@600MHz, 2GB, 1GBit network card
A1XE: G4@933MHz, 2GB, refitted AC'97 codec
microA1: G3@800MHz, 1GB

- A1 Linux support -

@Geri

I recently purchased 3 broken CPU modules, and I am trying to find out as much information and options as I can before they arrive.

I have been trying to contact Crisot, but the 2 e-mail addresses I managed to find are now both out of service.

@busytech

ACube in the past have offered a CPU module fix service for A1s with broken CPUs, the available options were:

- 7455 @ 1 Ghz - 256 Kb 2nd level cache
- 7457 @ 1 Ghz - 512 Kb 2nd level cache
- 7457 @ 1.267 Ghz - 512 Kb 2nd level cache

See here (at the bottom of the page): https://web.archive.org/web/20070227163013/http://www.acube-systems.com/eng/hardware.php

Might be worth asking them for an advice on how to configure any module for a 1.2GHz CPU.

Varthall

_________________
AmigaOne XE - AmigaOS 4.1 - Freescale 7457 1GHz - 1GB ram

@Varthall

He just got that advice from us here in this very thread.

_________________
This weeks pet peeve:
Using "voltage" instead of "potential", which leads to inventing new words like "amperage" instead of "current" (I, measured in A) or possible "charge" (amperehours, Ah or Coulomb, C). Sometimes I don't even know what people mean.

@busytech

It might not be worth the expense of re-balling if you can find a NOS cpu chip.
While the list price of these chips is high, they don't sell for nearly that price.
When they were current, I could have arranged to get one or two from Freescale for free in order to do design work - they are a very supportive company for developers (and I have maintained a relationship with Motorola and its successor since the MC6829 MMU was released).

@olegil

Quote:

olegil wrote: @Varthall He just got that advice from us here in this very thread.

Ah, sorry, I have seen Crisot being mentioned as the person to get in touch with, but not ACube, I have missed that.

Varthall

_________________
AmigaOne XE - AmigaOS 4.1 - Freescale 7457 1GHz - 1GB ram