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I just give you an example of my findings of the day. I hope you are well seated on your chair..... For the TAM, it's questionable. For the Mac classic.;. what a shame !

Hi all ! I'm looking for failed Mcintosh SE so I can repair them and populate with my shiny new boards. I'm looking on eBay, but prices are currently ridiculous (some will try to sell you a failed SE for 500 €.... come on !, or 900€ for an SE/30 !!). If you hear or see any opportunity that is...

Just gorgeous !!! Oh by the way, if you want a fun fact, you know I built two boards, one red and one blue. I did NOT populate C67 on the blue one... so if I had tested the blue one first I may have not noticed anything... Now blue test will be for later.

Too bad I looked at part 1 so long ago.... anyway guys. This is just a fantastic work.

Yes, that was exactly the effect. I should have watched every of your videos... my bad. However, it is such a learning experience.... I'm exhausted for today, will do more testing tomorrow.

ADB keyboard and mouse are fully functional as well. So this validates my unconventionally think filters @JDW :) I must admit I'm so excited I don't really have test plan....

It now BOOTS on my Floppy EMU as external drive. Now I'm on something ! :) :) What a relief !

Guys ! I fixed it totally ! Now starts up great with a crisp picture, perfectly centred. (pictures probably coming soon). Besides replacing U2B, I removed C67, which as marked as optional, but which I had populated. Also, I did plug the floppy drive, but that was not causing the issue. The Mac...

I had strictly nothing else connected than the motherboard, RAM and speaker. So I did some more investigation yesterday. First of all, I reviewed, removed and reseated all ICs. I paid attention to bent pins. Some ICs really have short pins, like GLU and ADB. This did not cause a change. Now...

Thanks for checking. In fact the Mac did not have any disk attached to it, so it is very early in the boot process. I've been far too quick on my tests, I need to be more rigorous now that it is partially alive.

Yep ! Thanks again for your energy and help James ! (maybe I have better news when you wake up ? :) )

I may test the blue board in between. Not sure if reverting the SCC has caused damage to other circuits. But yes, that is always a concern.

I just get a perfect normal bong.

Oh ok. So I used two small screwdrivers, which worked, but did not seem ideal.

I never went past the sad Mac so far. But I only really gave it a couple of tries between two meetings. I may have deeper time to test today and tomorrow (8th May is a bank holiday for us in France).

Sorry if I wasn't clear. This is the root cause for the Mac not booting at all and giving the high pitch hissing. The sad Mac and shift came after "proper" (or nearly as we have a remaining sad Mac) boot up. This is however a huge step forward for me !

Oh also, for those going through the project, I really recommend getting a PLCC extraction tool. I had definitely bent some pins. @JDW I can't remember if you had given a reference ?

Hello all ! The red SE/reloaded board is alive !!!! It was a stupid mistake. I had the 85C30 SCC upside down (plus potentially a few BBU pins slightly bent, but I'm not sure). :( I can't recall how many times I did check orientation of components, especially this one, and could not see it. So...

So, as mentioned just above, first power-on did not go very far. No bong and a weird hissing sound in the speaker. The CRT comes up with a very bright image and very visible scan lines. So at least we have some scanning, so some clocks are working. I'm checking again all soldiers, continuity...

And... first attempt, no boot. Some hissing in the speaker, display turns on, but image is garbage. The tube is scanned, definitely, but it's like half the lines are missing. I need to make a J12 extension cable, otherwise troubleshooting will be difficult ! And back to schematics, now the fun...