MacPlus won't fully boot after removing upgrade board

[rabid cabbage]

So, I have this old Mac Plus I’m trying to fix up and ran into this weird issue I’ve never encountered before. The mac turns on and I see the floppy disk with the question mark blinking on it. The odd thing is that around the floppy disk it is all black, instead of the black and white checker pattern. If I insert a floppy disk I get the happy mac, and I can hear the floppy drive, but it doesn’t go beyond this. The mac was mostly working until I removed an upgrade board that was attached to the main board, so I’m guessing that I screwed up something when I removed the board. Any ideas? Could this be some issue with the rom?

There was nothing really wrong with the upgrade board, I removed it mostly because it make it difficult to open the machine and remove the mother board -- I basically had to bend part of the chassis to open it up enough to remove the board.

I'm attaching a few pictures of the screen and the board I removed.

 

[rabid cabbage]

I also tried a sequence of keys that suposedly disables the board (holding down reset and interrupt keys, then releasing the reset key), but that got me an unhappy mac with the error 0F00D

 

[MOS8_030]

Check the floppy drive connection. Also check where the Novy board was attached to the 68000 processor to make sure there's nothing loose or broken there.
That's a nice Novy card, 50Mhz '030.
And yes, you have to bend the frame a bit to install or remove the board with the card attached, that's normal for that card.

 

[Byrd]

Reseat the ROMs, and put the RAM form the Novy030 accelerator onto the Plus itself - check the resistors are clipped/removed for the right configuration.

 

[demik]

You probably didn't mess anything. Some boards did require modifications on the Logic Board, and so the original board cannot work as it without the upgrade. I don't know about this one.

Does your plus works correctly with the upgrade back in ? As @MOS8_030 That's a very nice upgrade.

As @Byrd said. Try reseating the ROM. Are they Apple ones ?

 

[cheesestraws]

Are the ROMs the stock ROMs?

an unhappy mac with the error 0F00D

That is the normal "someone pressed the interrupt button before the computer knows what to do with it" error, not a symptom of anything wrong with the hardware. See the list here: https://udcf.gla.ac.uk/~gwm1h/Error_Codes/Sad_Mac_Codes.html

 

[rabid cabbage]

@Byrd moving the RAM from the Novy board to the main board did the trick! Getting those RAM chips out of the Novy board was a real pain though.

@cheesestraws Thanks! I had found that webpage but didn't know what to make of the error description "NMI"

 

[Byrd]

@rabid cabbage that's great! Let's assume the Mac Plus was at 4MB, then the user added the accelerator board and moved the SIMMs over. They could have dumped the older ?256K SIMMS back into the Plus. Adding anything over 256K/1MB total required a resistor be chopped off the board for proper operation.

Getting the RAM out of those plastic diagonal sockets is a pain! I usually use a small phillips screwdriver to lightly pry the latch off then flip it up - in a warm room, as they can be brittle and snap so easily.

 

[Realitystorm]

Cool another Novy board surfaces. I have two Mac Plus systems with these installed. I've been hunting for the manual for the Plus version (found the manual for the classic), so if you got any paper work with your system let me know. Also as part of my google searches found someone who did development work for these: https://www.linkedin.com/in/garrettclark/details/experience/

• After inheriting our support nightmare- the Quik30 accelerators for the Mac Plus & SE, I turned our buggy driver code into a software package that won us "4.5 Mice" and Editor's Choice for our category in an important MacWorld review article.
• Re-wrote significant portions of Apple's virtual memory code, to allow the relocation of the ROM and video memory, and to support up to 64Megs of system memory and 4Megs of video memory on the Mac LC and the LC II.

I sent him a linkedin note, be interesting if he has any docs from those days.

 

[desertrout]

After inheriting our support nightmare- the Quik30 accelerators for the Mac Plus & SE, I turned our buggy driver code into a software package that won us "4.5 Mice" and Editor's Choice for our category in an important MacWorld review article.

Hmmmm... I wonder what that award winning software package is, because I have a Quik30 in one of my Pluses and it's generally good using the Railgun drivers but, you know.

 

[Realitystorm]

He actually replied to me on LinkedIn, so I can ask what article he's referring too. I had hoped he might have some documentation, but unfortunately, he doesn't, what he has was lost in a move about 25 years ago he said. Which is really a shame since he said he had the source code for the drivers. He did give me another contact name to try https://www.linkedin.com/in/john-bowes-5701a09/, so I've now reached out to him.