68kMLA Classic Interface

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IIci processor replacement
Posted by: EtherRad on 2017-12-16 15:28:26
I have a IIci that has been recapped but does not work without a Diimo 50mHz accelerator. However, I want to put a carrera in it. An 040 accelerator won't work because it needs the original 030 to initially boot I believe. So...I took of the 68030FE25B processor and ordered a 68030FE33C processor because it was quite cheap. (1) Does anyone know if this replacement processor will be okay? (2) Does someone have words of wisdom for replacement of these processors...you can see my poor removal job and 1 chipped off solder pad. Is there a good method to replace the chipped off solder pad?

IIci processor removed.jpgIIci processor removed up close.jpg
Posted by: IIfx on 2017-12-16 20:24:52
You will need to replace some clock crystals to get the CPU to run at 33mhz. No guarantee that the motherboard will be able to handle other components linked to the CPU clock crystal at 33mhz.
Posted by: Bolle on 2017-12-17 02:42:16
Not sure about the Carrera, but the Turbo040 does run with the original CPU removed or disabled (at least in the SE/30 - it should do so as well in the IIci)

Chipping the IIci to 33MHz is not possible I think.

For the chipped off solder pad I would just go with a tiny jumper wire once the new CPU is in place. You have a via right there so should be easy.
Posted by: Bolle on 2017-12-17 06:03:07
This makes me remember my not working IIci board. It has some traces eaten away and I repaired the broken ones I could find already.

After this it turns on and is just sitting there - no chimes and nothing.

After reading that your board works with an accelerator I did try the PowerCache as well as the Turbo040 in my board and low and behold it did boot up just fine with either accelerator. So it seems my onboard 030 seems to be stuck as well.

I went ahead and removed it. Turbo040 and PowerCache still boot the board even without original CPU. I would guess the Micromac works as well without the original CPU.
Posted by: Bolle on 2017-12-17 07:34:12
On my board it was indeed the CPU... quickly replaced it with a spare 25MHz one and it is back in working state again - never had a dead 030 up to now.



This is how you want to do it: https://www.youtube.com/watch?v=6PB0u8irn-4

Flat tip, a lot of flux and not using too much solder (or go straight for solder paste) help a lot.
Posted by: EtherRad on 2017-12-17 08:00:06
I must have done something wrong while desoldering because now the diimo 030 does not work with the processor removed...maybe i need to wick all the joints?
Posted by: Bolle on 2017-12-17 10:23:17
You should do, just to be sure nothing is shorting out. You want to use fresh solder anyways for putting on a new chip.
Posted by: EtherRad on 2017-12-17 10:26:57
That video was beautiful i'll have to try my hand at that. I also watched a video on using hot air and solderpaste which looks like it would work well.
Posted by: EtherRad on 2017-12-19 13:56:41
I removed all the solder from the pads and now it works with either a DiiMo 030 or Turbo 040 but not a Carrera. I wonder if the Carrera specifically needs an on board processor?
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