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Macintosh SE/30 logicboard recreation (thread revival)

Bolle

Well-known member
The data lines on the PLCC32 socket are reversed, so you can't flash a standard ROM image without reversing its byte order first.
This has been done because routing would have been a mess otherwise. When using the sockets instead of a SIMM close the two solder jumpers on the back near the ROMs at the marked position "V"

The other jumper settings are for experimental in system programming support (for which no software exists yet)
PFW - ADB.PWR
They're just test points in case someone is using a modern power supply replacement and might want to experiment with soft power.
 

Cam

Well-known member
Hey - CayMac on YouTube has a stream up on his Reloaded build, and he's into the troubleshooting part of the build.
 

WillJac

Well-known member
The data lines on the PLCC32 socket are reversed, so you can't flash a standard ROM image without reversing its byte order first.
This has been done because routing would have been a mess otherwise. When using the sockets instead of a SIMM close the two solder jumpers on the back near the ROMs at the marked position "V"

The other jumper settings are for experimental in system programming support (for which no software exists yet)

They're just test points in case someone is using a modern power supply replacement and might want to experiment with soft power.
Thanks so much for the reply Bolle. Guess why I could not get the rom to work even after doing the jumping on the 2 locations. I did not know about it needing to be reversed. A person send me the chips of a IIfx rom that would fit in the sockets I used but its stock ROM and should normally work on the SE30. Does this mean the roms need to be specially made?

The above info would be great to add to the readme of the project.

Thanks again for a great board. I just finished one and it is working 100%. I have a few more boards to do for others so more to come. This was my first. Now I feel I can do the other reloaded boards also.

You can watch the work on my channel CayMac Vintage.
 

WillJac

Well-known member
Hey - CayMac on YouTube has a stream up on his Reloaded build, and he's into the troubleshooting part of the build.
Thanks for the post and yes, the first SE30 reloaded is done and working 100%. First reloaded I have every done. Now more to come and any type I feel I can do.
 

WillJac

Well-known member
Excellent! I don't have SE/30 schematics, but take a look at the solder joints / continuity of the ROM v.s. the SIMM sockets. I would think the connectivity of the two methods is the same (or pick up another 64 Pin SIMM and call it a day).

Does the reset occur when the reset line is held high or low (again, no schematics and haven't been able to afford even a battery bombed board) on the SE/30? I'd hook an oscilloscope up and chase down where the opposite of the expected behaviour occurs, as it sounds like something is resetting, but not coming completely back from that state?

Edit: Sorry just realized you said the machine comes back with the same display showing as before the reset. This strikes me as a video RAM issue (not getting the reset ). Maybe check the reset is being sent to all the RAM?
I got this solved. I checked all traces back to the sound chips and all were good. Then I checked the pin 5 on each sound chip and none were going to low. I removed the chips, cleaned and put them back in but in switched them around and all started working. Guess it was not in the socket good or something. Luck!!!
 

jshardin

New member
Thanks so much for the reply Bolle. Guess why I could not get the rom to work even after doing the jumping on the 2 locations. I did not know about it needing to be reversed. A person send me the chips of a IIfx rom that would fit in the sockets I used but its stock ROM and should normally work on the SE30. Does this mean the roms need to be specially made?

The above info would be great to add to the readme of the project.

Thanks again for a great board. I just finished one and it is working 100%. I have a few more boards to do for others so more to come. This was my first. Now I feel I can do the other reloaded boards also.

You can watch the work on my channel CayMac Vintage.
As the recipient of said recreated board, I can heartily add my thanks @Bolle for your efforts! Will took on this project for me as the donor board came from my late Uncle and was his personal favorite computer back in the day. Sadly it had been severely battery bombed by the time I received it, but your board and Will's expertise have now brought it back to life!
 

Cam

Well-known member
Thanks for the post and yes, the first SE30 reloaded is done and working 100%. First reloaded I have every done. Now more to come and any type I feel I can do.
Thank you for sharing all your experience rebuilding old Macs.
 

Bolle

Well-known member
I added the coordinates for the inductors to the pick and place file. It seems there's two parts with the correct 1806 size that come close to the 92ohm@100MHz that someone measured earlier.
I added C525678 to the BOM for now, but I think C85842 should also be ok.
 

croissantking

Well-known member
And… it’s alive! Beautiful jail bars.

F1883F9D-9102-4BBB-833B-D394A8915EA5.jpeg

I forgot to solder one pad of one of the inductors on the bottom side of the board. Go figure.
 

WillJac

Well-known member
I got this solved. I checked all traces back to the sound chips and all were good. Then I checked the pin 5 on each sound chip and none were going to low. I removed the chips, cleaned and put them back in but in switched them around and all started working. Guess it was not in the socket good or something. Luck!!!
Today I did an ultrasonic cleaning of the board then an IPA soak, rinse and sun shine time for a few hours. Afterwards, I came inside with the board to test and I was getting a chime and after a few seconds I would get fault code chime. 0000000F/00000033 was the code. I let the board soak up more sun to dry better for the rest of the day. Just a bit ago I tested it and still getting the fault. So, I went to inspect each and every leg on all chips to make sure good connection. Yes, I have a process I do to check them as the ultrasonic can loosen up a connection that was never made good and just being held by flux and a little pressure. Well I found on UK11 CPU side midway a leg that was not connected. Soldered this and back to a test and DANG, it worked again. I am still not happy with the ROM SIMM socket so I will try to fix this up tomorrow. To me, it seems a bit loose and some pins not down flush how they should be. Recycled socket so need to adjust best I can.

I hope to complete this soon and move on to other projects being worked on. You can watch the videos of this project and others I do on my channel at CayMac Vintage.
 

croissantking

Well-known member
I installed a CPU, ROM and RAM. Still get jail bars, but the death chimes are heard. That’s good, right? The CPU is executing code and talking to the ROM.

Here is a pic of my board, just in case there’s anything obviously wrong with it that I may have missed:

89D52E0C-7F07-4FBA-AE3C-A920BB6E3673.jpeg
 

croissantking

Well-known member
One step closer! Congratulations!
Thanks. I'm currently troubleshooting this. Are the RAM sockets in the same order as the original board with respect to banks A and B?

What chips are essential/non-essential in order to get a grey screen and flashing question mark? For example, can I leave ADB/Serial/SCSI chips off while troubleshooting? And I know the caps aren't required either.
 

Cam

Well-known member
I can't answer the RAM bank question as I don't have a reloaded board but I would assume they are, hopefully Bolle can chime in.

I would think the CPU, ROMs, and some RAM for video would be the minimum for any 'kind of proof of life' (based on other computers I've worked on). If the caps you're referring to are the ones on jumpers, I would leave them in place. If you mean capacitors, they're soldered to the board and are needed for basic electrical connectivity.
 

croissantking

Well-known member
Check that any parts with polarity are in the correct way around and there are no solder bridges.
Then check the voltage supplies and ground rails to make sure they are working as expected.
If all that checks out OK, I'd move on to checking that the clock signal on all the chips is working / correct.
Maybe take the all the SIMM packages out of the sockets while you do the testing to protect them?
To check the clock signal does one need an oscilloscope?
 

Cam

Well-known member
To check the clock signal does one need an oscilloscope?

These days, that could be a trick question but given the clock frequencies of these older machines . . .

Way back when, before the time of the Macintosh, back when people looked confused when you said you had a home computer, I built an Apple II clone and used a logic probe to determine if a clock signal was present. This worked well enough since I didn't have access to a 'scope (or could afford one!).

So if you already have a logic probe you could get by with it to measure high, low and clock signals. It won't help if the clock is malformed or has noise on it.

If you're looking at buying one, I'd look at one of the single channel scopes from China instead as they're probably close in cost and do a lot more in the long run. Adrian's Digital Basement on YouTube has looked at several models and might be a good place to start researching as he repairs all kinds of stuff 'from this era'.

C
 

croissantking

Well-known member
If you're looking at buying one, I'd look at one of the single channel scopes from China instead as they're probably close in cost and do a lot more in the long run. Adrian's Digital Basement on YouTube has looked at several models and might be a good place to start researching as he repairs all kinds of stuff 'from this era'.
Thanks for the advice. Will look at a scope then, don't want to blow too much money on it though as this hobby is already getting out hand :D
 
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