Micromac Performer Clone - Issues with Mac Plus

Garrett

Tinkerer
Oct 31, 2021
135
138
43
South Carolina
I've been trying off and on for the past year to adapt one of these wonderful Bolle clones to my Macintosh Plus. I am running out of things to try, so I figured now is the time to throw out a request for help! I've got GAL16V8Ds installed (including the optional one at position U7), the 68030, and no FPU on the board. I have headers installed for both the SE PDS slot, and the 68000 "piggyback" install method. No photos at the moment but I can take some after work.

What works: running this in my SE under both System 6.0.8 and System 7.0 (with tune-up 1.1.1). I know that System 7.0.1 will not work, and I haven't tried System 7.1 because it uses too much RAM.

What won't work: The Plus, ever. I can boot up into System 6 or 7, but only with extensions disabled. With the extension loaded, it will start, but freeze as soon as the desktop tries to load. I'm booting off the external BlueSCSI, and when this freeze happens, the activity LED appears solid, like it's seeking or loading data.

I'm using the Performer 2.2.1 extension. I have not tried other versions, as I thought this was the latest and greatest. At first I was thinking my troubles were due to a clock integrity issue. I probed both the SE's internal 16MHz and the 16MHz generated by the GAL. While the GAL clock signal isn't as clean as the signal generated from the SE, that machine still functions when I let the GAL generate the 16MHz clock for the accelerator's CPU. According to Bolle, I shouldn't be worried about the GAL clock, as it's inherently not as clean due to GAL propagation delay.

I guess all I can think of now is to try another Plus logic board (if I can find one). I could also install pin headers on the 68000 CPU of my SE and see if there's a difference in how it connects to the logic board? I know others have had success using these on a Plus - really scratching my head here.
 

Attachments

  • GAL Output.jpg
    GAL Output.jpg
    830.8 KB · Views: 28
  • Internal Clock.jpg
    Internal Clock.jpg
    833.8 KB · Views: 26

Garrett

Tinkerer
Oct 31, 2021
135
138
43
South Carolina
I'm throwing in the towel on functionality beyond the SE. I built an entirely new board, tested it on the SE, and it still didn't work on the Plus. I bought another 68000 socket, installed it on a different known-good Plus board, and still nothing. It boots into System 6 but will crash upon opening pretty much anything. The hardware is fine, so I am guessing it's a driver/software issue.

For "fun" I also modified a stock Classic logic board to allow a Performer to be soldered to the CPU. Checkerboard screen at boot... wonderful.

1.jpg


The screenshots are of the boards I tried in the Plus and Classic with no luck. As you can see, they are working great in an SE. To close the loop on my previous post regarding clock integrity - I have tested both using the GAL clock double (not the SE's built-in 16MHz signal), so the clock isn't the problem.

2.jpg
3.jpg
 

Builde68

New Tinkerer
Oct 19, 2025
2
0
1
Had a very similar issue with my modded version of this Performer accelerator for the Macintosh 512ke (It has a SCSI interface and 128K ROMs, along with a RAM expansion board of 4MB, so practically it is a Mac Plus). The Performer 2.2.1 extension makes the machine freeze right after the welcome screen. The only extension that works without issues for me is the one made for the Dove Marathon Racer 030. In case you haven't tried it yet, you can grab it from the garden or here: https://vintageapple.org/macdrivers/accel.shtml. And another thing, you must recap the analog board if you haven't done so yet, especially those caps in the rails outputs (+5V, +12V, −5V). Good luck!
 
Last edited:

Garrett

Tinkerer
Oct 31, 2021
135
138
43
South Carolina
Hello and thank you for the reply! I gave this a shot yesterday... no dice. The extension does load properly in System 6, and it will boot, but the second I try and do anything, the system gets unhappy. Trying to open the "About this Macintosh" window resulted in an illegal instruction bomb. Rebooting again and attempting to open the control panel, I get "There is not enough memory to open the Control Panel".

Oh well, it was worth a shot!
 

phipli

Tinkerer
Sep 23, 2021
288
207
43
Oh, another thing, the Total Systems version of that board (same firmware and schematic, different layout) has an auxiliary power header for when you're using it in older macs like the Plus if I remember correctly - is there something similar on the Performer?

TS_Mercury_Plus_Power.png
 
Last edited:

Builde68

New Tinkerer
Oct 19, 2025
2
0
1
The problem is not on the Performer board's side. You should try to boot the Plus with a PicoPSU or an ATX PSU to discard issues related to the analog board itself. Also, the symptoms you describe are quite frequent due to poor connections caused by micro-cracks in the solder joints of the power connectors on the AB and LB. Give a good reflow to all those big solder points on both boards. Finally, the performer board installed on a Plus requires a healthy power supply; otherwise, the +5V rail will struggle to output a stable and good voltage.
 
Last edited: