Dead processor?

[carian]

Hi,
I've grabbed a 68040RC33 processor for my LC 475 but it didn't work. Pulled it out and cleaned pins and the socket but no luck again, no chime, no boot, only black screen. Is it DOA or some jumper adjustment needed? Stock LC025 CPU works as normal.
Thank you.

 

[Phipli]

Daft question - I assumed the computer worked before? I assume it still works with the original CPU?

Did you change anything else at the same time?

 

[carian]

Daft question - I assumed the computer worked before? I assume it still works with the original CPU?

Did you change anything else at the same time?

Yes it works perfectly with stock processor. Logic board and PSU recapped. 128MB RAM, 2X256KB VRAM at 80ns, BluesSCSI V2 installed. Tried without 128MB RAM and BlueSCSI as well but same result.

 

[Phipli]

Then sadly it sounds like it might be the CPU in this rare case.

 

[Byrd]

Rare to die, where did you get the CPU from - known working/tested or from an overseas chip supply company?

 

[carian]

From a local Whatsapp group. The seller didn't know its condition. Never thought it would be defective. I don't have a second devive that I can test it with. Is there a way to test it with a multimeter in resistor or continuity mode?

 

[ObeyDaleks]

Multimeter won’t help. I would inspect carefully to make sure you don’t have damaged or bent pins. I see one in the picture that doesn’t look quite right, but it’s hard to make out.

 

[croissantking]

I see a group of about 7 or 8 pins that are slightly bent, can you very carefully straighten these?



Looking again, there are a few others on this side of the chip that are bent, inspect carefully with a magnifying glass.

 

[carian]

I see a group of about 7 or 8 pins that are slightly bent, can you very carefully straighten these?

View attachment 95662

Looking again, there are a few others on this side of the chip that are bent, inspect carefully with a magnifying glass.

Actually the initial photo was taken when it arrived and I straightened some pins as much as I could before putting it into the socket. This photo was taken now. Do you think slightly bent pins make difference after inserting it into the socket? It seems pretty tight in it.

 

[croissantking]

Actually the initial photo was taken when it arrived and I straightened some pins as much as I could before putting it into the socket. This photo was taken now. Do you think slightly bent pins make difference after inserting it into the socket? It seems pretty tight in it.

Not really. I’m grasping at straws…