Macintosh SE/30 logicboard recreation (thread revival)

[Garrett B]

I’ve replaced the VRAM with different (faster) chips and the problem is still there.

It takes a few minutes to manifest and gets gradually worse. The artefacts are only visible when the image on screen is changing, if nothing is happening it is stable.

I'm using 120ns VRAM (don't have any faster to test). What I've noticed is it's definitely worse when using the ATX extender. Almost non-existent when plugged directly into analog board. Additionally, after about a minute of runtime, the symptoms go away completely. Reboots don't affect it. This leads me to believe it's temperature related. Now that I'm thinking, I may put the board in the fridge for a few minutes to see if I can make it worse...

 

[croissantking]

I'm using 120ns VRAM (don't have any faster to test).

Some SE/30 boards use 150ns VRAM, so I don't think 120ns is going to be too slow.

 

[croissantking]

Additionally, after about a minute of runtime, the symptoms go away completely.

It's almost as if there's a marginal short (whisker of solder, or poor connection) between data lines somewhere that causes this to come and go.

 

[Cam]

It's almost as if there's a marginal short (whisker of solder, or poor connection) between data lines somewhere that causes this to come and go.

This would be my guess too. The question now is live with it, or reflow all the solder points in the hope it fixes the issue?

 

[croissantking]

This would be my guess too. The question now is live with it, or reflow all the solder points in the hope it fixes the issue?

I can’t live with it. I won’t consider it a finished piece of work until it’s fixed.

 

[Cam]

I can’t live with it. I won’t consider it a finished piece of work until it’s fixed.

I agree, but then I like to solder.

 

[Jockelill]

I can’t live with it. I won’t consider it a finished piece of work until it’s fixed.

Maybe a stupid question, but is your PSU recapped? I’ve had weird video artifacts with flaky PSUs. If you have another one it’s an easy test.

 

[croissantking]

Maybe a stupid question, but is your PSU recapped? I’ve had weird video artifacts with flaky PSUs. If you have another one it’s an easy test.

Interesting idea. I've got two Sony PSUs and one of them is recapped, but I've currently got the un-recapped one in there. I'll try swapping over. Also, a good opportunity to install my recently acquired NOS analogue board.

 

[croissantking]

It’s not the PSU. It’s not the PALs either.

Next, will swap Video ROM and the small surface mount chips UA8-UG8.

 

[croissantking]

@Garrett B are your symptoms happening on a new build board, or original board?

 

[Garrett B]

@Garrett B are your symptoms happening on a new build board, or original board?

This is a reloaded board - sorry, should have specified. I did try a different video ROM and VRAM, but haven't swapped out any of the PALs responsible for video. That was going to be next on my list. Keep us posted with what you find out on yours!

 

[croissantking]

This is a reloaded board - sorry, should have specified. I did try a different video ROM and VRAM, but haven't swapped out any of the PALs responsible for video. That was going to be next on my list. Keep us posted with what you find out on yours!

Did you use any new chips such as the F253s, or is it all taken from a donor board?

 

[Jockelill]

Has anyone attempted to build an SE/30 with "as much new components as possible". And if so, have you sourced from Mouser? And if so, do you have a basket for it ?

Reason is that I anyway need to order some new MUX-chips (LS166 and LS393) for a repair job and thought I could might as well stash up with a lot of other new components for a future new build.

 

[croissantking]

Has anyone attempted to build an SE/30 with "as much new components as possible". And if so, have you sourced from Mouser? And if so, do you have a basket for it ?

Reason is that I anyway need to order some new MUX-chips (LS166 and LS393) for a repair job and thought I could might as well stash up with a lot of other new components for a future new build.

Yes, I have done this. I will put together a saved basket for you and anyone else who needs and also am I able to update the BOM that @Bolle originally shared?

 

[Jockelill]

Yes, I have done this. I will put together a saved basket for you and anyone else who needs and also am I able to update the BOM that @Bolle originally shared?

That would be absolutely awesome!! If you ever are in the southern parts of Sweden I promise to invite you for swedish fika (Coffee and cake)

 

[croissantking]

That would be absolutely awesome!! If you ever are in the southern parts of Sweden I promise to invite you for swedish fika (Coffee and cake)

Thank you, that’s very kind!
Give me a couple of hours and I’ll get to work on a basket

 

[croissantking]

@Jockelill Here's my parts list:

https://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=33f1fdf304

Hope it's useful.

 

[Jockelill]

@Jockelill Here's my parts list:

https://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=33f1fdf304

Hope it's useful.

Wonderful! Ordered now . Including the extra chips for the other board I'm repairing

 

[Lyokian159]

Has anyone done an order recently that could sell off a spare board? Certainly looking to get a project off the ground.

 

[Jockelill]

Has anyone done an order recently that could sell off a spare board? Certainly looking to get a project off the ground.

Where are you based? I have a de extra boards, but I’m in Sweden