• Updated 2023-07-12: Hello, Guest! Welcome back, and be sure to check out this follow-up post about our outage a week or so ago.

Mac Plus/SE Performer accelerator build

JC8080

Well-known member
I just finished my build of a Performer accelerator clone for the Mac Plus/SE. Enormous thanks to @Bolle, he reverse-engineered an original accelerator and posted the board file online, along with the GAL files. Thanks to @DrGonzo, his thread on his Performer build inspired to do my own. Link to his thread below.

I started by uploading the board files to JLBPCB. I left all the options at their default setting, except I selected the blue board instead of green. After a new-user $10 discount, including shipping, five boards cost me right about $50.

Front
Bare board.jpg

Back
Bare board back.jpg

I started by installing the passive components (resistors/capacitors). I selected black tantalum capacitors to match the board color, I didn't like how the yellow ones would look.

Board with passives.jpg

Next I moved on to the GALs. I purchased a T48 programmer on Amazon for $72, there are multiple versions/sellers, I selected one that had the correct 20-pin PLCC socket. The GALs were purchased from eBay, $12.99 for 15 GAL16V8D-15LJ chips. As mentioned in DrGonzo's thread, the "A" version will not work, but anything "B" on should work. I programmed the chips and installed them.

Note if you are using this board in a Mac SE you do not need GAL U7, and you DO need to bridge the SJ2 pads. If you use it in a Plus you will need to install U7 and make sure the SJ2 pads are not bridged.

The Xgpro settings I successfully used are not shown in the image below. I used the "GAL16V8D-@SOIC 20", not "GAL16V8D" as shown in the photo. I un-checked encryption, and when I clicked the PROG. button I left both default options checked (FLASH and LOCK-bit).

Programmer.jpg

I don't have a lot of SMD soldering experience, but I am pretty decent at it. That being said, I could not get some of the GAL pins to properly solder to the pads. No amount of solder and flux was doing it. I used a small chisel tip on a good Hakko iron. Finally I bought some ChipQuik solder paste and it worked great. I used my $40 hot air station (from Amazon) to remove all the GALs, and re-installed them with the solder paste. I followed up on each pin with my iron to make sure all the flux/solder mix melted properly.

GALs installed.jpg

Next I installed the 68-pin socket to attach to a Plus logic board, and the 96-pin header to fit the SE PDS slot. In DrGonzo's build he used a Euro DIN male connector for the PDS instead of the PIN headers and had problems with the socketed CPU interfering with the case. I went with the pin headers to add a bit of extra clearance. In my machine there are no clearance issues, there is probably 1/16" or 1/8" of space above the CPU. I believe there are two different SE chassis, mine seems to have extra space, I don't know how to identify which is which. In my case I could have used the Euro DIN and been fine. Also worth noting, the CPU does not need to be socketed, it can be soldered directly to the board and this will eliminate any potential clearance issues. I went with the socket since I was buying my CPU off eBay and did not trust that it would work. I don't have the proper equipment to un-solder the CPU, so I played it safe with a socket.

I then moved on to the CPU and FPU sockets. Both were very straightforward through-hold jobs. For the first test I left the FPU out. The photo below with the FPU was taken later.

Completed board, front and back
Completed.jpgCompleted back.jpg

I switched the machine on, and... Checkerboard screen. 😣

Clearly this was not the desired result. This board is pretty simple, there is not a lot going on, so I hoped the troubleshooting wouldn't be too bad. I started by checking all the traces on the whole board with my meter. I also went over the whole board with my microscope to check for traces I might have damaged. This was extremely time consuming, and in hindsight I should not have done this as my first step. I powered the machine on and still got the checkerboard screen. At this point the GALs seemed like the likely culprits, it was unlikely there was an issue with any of the resistors or caps. I removed the GALs and re-programmed them, this time I used the "GAL16V8D-@SOIC 20" chip selection rather than the regular "GAL16V8D". I also left the LOCK bit in it's default checked setting, the first time I un-checked that box. I re-installed the GALs, crossed my fingers, and got the beep-of-life.

I already had the GemStart accelerator driver installed on this machine so it booted right up and Tattle Tech showed a 16mhz 68030. Without a driver, the '030 will run at 3mhz, so the driver is very important. I later switched to the proper Performer driver from Macintosh Garden. I ran Speedometer 3.06, the CPU test showed 3.3x faster than a Classic. I then installed the FPU, leaving off the crystal oscillator for the moment. Without the oscillator the FPU will run at 16mhz, with an oscillator you can increase the FPU speed to 25mhz. If you are running without the oscillator you must bridge pads SJ1.

I booted and everything worked fine, Tattle Tech recognized the FPU. I ran some Speedometer benchmarks and the math increase over a Classic was substantial. Then I installed the 25mhz oscillator (after un-bridging SJ1), and the results were not quite as expected. The math benchmark was actually lower with the 25mhz oscillator installed. This mirrors DrGonzo's results on his build. I do not know why this is, the overall math score was about 5% lower. The difference is tiny and won't affect anything I will do with this machine, so I left the chip in place, partly because I didn't want to deal with removing it, and partly because I think the board looks better with it installed.

Benchmark with and without FPU oscillator
Benchmark.jpg

Photo of finished board installed on an SE logic board
Installed.jpg

The CPU, FPU, CPU socket, and GALs were purchased from eBay, all the other components came from DigiKey. The total cost for the build came to about $85. This does not take into account some of the components needed to be purchased in multiples (boards - 5x, CPU socket, 2x, GALs, 15x), so my actual out-of-pocket cost was higher.

Some thoughts... This accelerator is slower than other '020/'030 accelerators running at the same speed. It uses logic board RAM, so it lacks the 32-bit data path to RAM that boards with onboard RAM have. It also lacks onboard cache, so I expect it would be slower than a Radius '020 16mhz card which also uses logic board RAM. That being said, it is quite a bit faster than stock. With this board an SE no longer feels slow in normal use, it feels like it "should".

If you are just looking for a way to speed up your SE, you would be better off finding an accelerator on eBay, Radius '020 16mhz boards seem to go for around $200. If you enjoy soldering, this is a fun project with a very useable end result. If you need to buy a hot air station ($40) and GAL programmer ($70), you will be around the same cost as a Radius card off eBay.

The next step is to see if it will work in my Plus. Originally when these boards were new they would have had a "Killy clip" which clipped over the 68000 on the Plus board. Those are no longer available, so using it on a plus will require a 64-pin female DIP socket on the bottom of the board, and then pin headers installed on the 68000, as shown in the photo below. I will update this post after I try installing on my Plus.

Plus pin headers.jpg

Link to DrGonzo's thread:

 

Attachments

  • Sockets installed.jpg
    Sockets installed.jpg
    1.7 MB · Views: 113

JC8080

Well-known member
I put the card in my Plus and ran a quick benchmark. I wasn't able to run the full test, I was unable to use my BlueSCSI since I haven't added the needed diode to the Plus logic board, so I was running off my Floppy EMU. The disk test didn't like the Floppy EMU, and I didn't like all the image swapping, so I only ran the CPU, graphics, and math tests. I also wasn't using the proper Performer driver, I was using Gemstart 2.2.

The CPU test was the virtually identical to the SE at 3.3, graphics were 1.23 vs 1.87 (34% slower), and math was 6.52 vs 7.74 (16% slower). I'm not sure if the scores would have been higher if I was using the Performer driver rather than the Gemstart driver, likely there would be no difference.

Plus performer.jpg
 

teemaw

Member
Thanks for documenting your build and results with the 25MHz oscillator. I just finished this build myself and this helped me decide to leave the oscillator out although I agree it looks nicer installed. I wanted to note for prospective builders that ATF16V8C-5JX worked for me as PALs for U3-U6. (I didn't end up populating U7.) These were also programmed with a T48 and Xgpro but using the "ATF16V8C" (no package specified) IC setting. At first, my card was only running at 2MHz even with the driver installed. This was due to some bad joints on U6. Reflowing U6 got the card running at 16MHz.

I also used the Euro DIN male header along with FPU and CPU sockets and the board seems to fit. It gets caught against the chassis sometimes if it's installed when trying to remove the logic board. There's some wiggle room to angle the card towards the logic board which allows it to clear the chassis and be removed. My chassis is the type with an opening for the PDS.
 

Admiral Ackbar

Well-known member
This is amazing work. Thank you for sharing. One advantage to your work is that the parts/tech are new and don't have a history of wear and tear.
When there is a way for a dopey Mac Plus owner like me to get a finished one, I'm buying. :)
 

JC8080

Well-known member
Thanks for documenting your build and results with the 25MHz oscillator. I just finished this build myself and this helped me decide to leave the oscillator out although I agree it looks nicer installed. I wanted to note for prospective builders that ATF16V8C-5JX worked for me as PALs for U3-U6. (I didn't end up populating U7.) These were also programmed with a T48 and Xgpro but using the "ATF16V8C" (no package specified) IC setting. At first, my card was only running at 2MHz even with the driver installed. This was due to some bad joints on U6. Reflowing U6 got the card running at 16MHz.

I also used the Euro DIN male header along with FPU and CPU sockets and the board seems to fit. It gets caught against the chassis sometimes if it's installed when trying to remove the logic board. There's some wiggle room to angle the card towards the logic board which allows it to clear the chassis and be removed. My chassis is the type with an opening for the PDS.
I'm glad my work could help you out! Good to know about the GALs you used, any info added to this thread will help the next person that builds one.

The Euro DIN connector is definitely the way to go, especially considering it costs $3 vs. $13 for the pin-header. I'm planning on building one more and will definitely use the Euro DIN. If someone really wants to avoid scratching the CPU the pin-header would add a bit of clearance, but realistically I think it is unnecessary. I would feel differently if I was using a ceramic case CPU since those are much nicer looking, but I decided against the ceramic CPU since a ceramic FPU won't fit this board. If I had one I would want both.
 

JC8080

Well-known member
This is amazing work. Thank you for sharing. One advantage to your work is that the parts/tech are new and don't have a history of wear and tear.
When there is a way for a dopey Mac Plus owner like me to get a finished one, I'm buying. :)
Thank you!
 

WakelessFoil

Well-known member
This is amazing work. Thank you for sharing. One advantage to your work is that the parts/tech are new and don't have a history of wear and tear.
When there is a way for a dopey Mac Plus owner like me to get a finished one, I'm buying. :)
I second this. I would be interested in trying this project for my Plus, just need more time for my hobbies!
 

pezter22

Well-known member
Very nice. I just ordered some boards today. Looking forward to building. Thanks for the inspiration and the write up.
 

JC8080

Well-known member
Very nice. I just ordered some boards today. Looking forward to building. Thanks for the inspiration and the write up.
Great, I'm glad people are benefiting from the writeup. Feel free to ask me any questions, I'm in the middle of building my second one right now.

Are you building this for a Plus or SE? The one I am currently building is for an SE, I am using a proper Euro DIN PDS connector this time rather than the pin header in my writeup. I haven't finished the build, but it looks like the Euro DIN will be a much better option.
 

pezter22

Well-known member
I am still researching, but I buy my sockets from Phoenix Enterprises for a while. They have great prices. I will be buying the CPU and FPU sockets from them and was looking for the PDS socket. I was thinking of just a 3 row snap header, but there are some options.
Here's a link for their EuroDIN 3 row sockets.

 

LaPorta

Well-known member
I'd be interested in doing this, as it would be cost effective....provided someone can write those GALs for me at a reasonable price.
 

falecore

Member
Great, I'm glad people are benefiting from the writeup. Feel free to ask me any questions, I'm in the middle of building my second one right now.

Are you building this for a Plus or SE? The one I am currently building is for an SE, I am using a proper Euro DIN PDS connector this time rather than the pin header in my writeup. I haven't finished the build, but it looks like the Euro DIN will be a much better option.
Can you link to the DIN? I have an original performer but it is the classic version. Was going to mod it for an SE. Ty!
 

Chopsticks

Well-known member
Can you link to the DIN? I have an original performer but it is the classic version. Was going to mod it for an SE. Ty!
you can get the DIN41612 from pretty much any major parts supplier, i linked a search for mouser, butothers like digikey, element14 usually have stock too.

 

ruthsarian

New member
The next step is to see if it will work in my Plus. Originally when these boards were new they would have had a "Killy clip" which clipped over the 68000 on the Plus board. Those are no longer available, so using it on a plus will require a 64-pin female DIP socket on the bottom of the board, and then pin headers installed on the 68000, as shown in the photo below. I will update this post after I try installing on my Plus.

View attachment 59436

I am going to attempt assembling one and installing it into my Plus. Could you share more details on how you handled the connection to the 68000?

Is that an inverted socket over the 68000 in the picture? Or is that some special type of socket/header that has male pins on both sides? If it's a special type of socket/header is there a name for it that I can use to search for where to buy one? If it's an inverted socket, what are you using for the pins between the 68000 and the socket?

Thanks
 

JC8080

Well-known member
That part on the 68000 is a male-to-male pin header. The guy who installed it for me just found it in his parts bin, he wasn't sure where it came from. I found what appears to be a similar part on DigiKey (link), however it is expensive at $25.

What I was going to do if I modify my other Plus board to fit an accelerator is to use single-row 40-pin headers cut down to 32 pins (link), $14 delivered for 10pcs (they come in a 10-pack). Alternatively you can buy 32-pin headers (link) for $6.50 each plus shipping. Since I have not done this yet myself I cannot guarantee that any of those solutions will work, but I put a bunch of time into picking parts I thought will work. If you are going to only build one board I would recommend just spending $25 for the 64-pin header, it will be much easier to install on the 68k and won't cost a lot more than the other options.

For the single row headers, it would be difficult to get the alignment correct by eyeballing it, so my thought would be to take the 64 pin female socket before it is installed on the accelerator, insert the two single-row pin headers into the socket, turn that upside down and set it on top of the CPU so the pins are held in proper alignment, and solder the pins. Again, I think it is worth an extra $10 or so to buy the 64-pin header and avoid this hassle.

I hope that helped.
 

JC8080

Well-known member
Can you link to the DIN? I have an original performer but it is the classic version. Was going to mod it for an SE. Ty!
Here is the exact part I used (link). As @Chopsticks showed, there are many manufacturers of similar items. The one I purchased was under $4 from DigiKey and seems to be good quality.

I think the Classic version of the original Performer is pretty uncommon. Do you have a picture of the bottom? I am curious to see how it clips to the Classic's 68000.
 

ruthsarian

New member
That part on the 68000 is a male-to-male pin header. The guy who installed it for me just found it in his parts bin, he wasn't sure where it came from. I found what appears to be a similar part on DigiKey (link), however it is expensive at $25.

I think this part on Mouser is also similar to that double-male 64P DIP socket. I think I'll order a few of those and see if they do the job. I did find a seller on alibaba also selling them, but in lots of 1,000 only. Couldn't find anything else.

What I was going to do if I modify my other Plus board to fit an accelerator is to use single-row 40-pin headers cut down to 32 pins (link), $14 delivered for 10pcs (they come in a 10-pack). Alternatively you can buy 32-pin headers (link) for $6.50 each plus shipping. Since I have not done this yet myself I cannot guarantee that any of those solutions will work, but I put a bunch of time into picking parts I thought will work. If you are going to only build one board I would recommend just spending $25 for the 64-pin header, it will be much easier to install on the 68k and won't cost a lot more than the other options.

For the single row headers, it would be difficult to get the alignment correct by eyeballing it, so my thought would be to take the 64 pin female socket before it is installed on the accelerator, insert the two single-row pin headers into the socket, turn that upside down and set it on top of the CPU so the pins are held in proper alignment, and solder the pins. Again, I think it is worth an extra $10 or so to buy the 64-pin header and avoid this hassle.

That was my thought as well. I found the double-male single-row headers and thought that might be the way to go, exactly as you described. If the header from Mouser isn't what we're looking for I'll go the single row header route.

I hope that helped.

It did, thanks.
 

JC8080

Well-known member
I just finished my second accelerator, this one is SE-specific, meaning I used a proper Euro DIN connector instead of the pin header, and did not install the socket to connect to the Plus CPU. A couple thoughts...

GAL related - as with my first build, the first round of GALs I programmed did not work, I just got a checkerboard screen on boot. I programmed a second round and things worked fine. For the first round of GALs that did not work, I used the same settings as the successful GALs from my first build. For the second set of GALs that did work, I dropped the vpp voltage from 16v to 12v, based on a couple google searches. I don't know what is going on here. For all the GALs I programmed (both builds, both working and non-working sets) xgpro verified the programmed GALs so they seemed fine. The soldering job was thorough (using solder paste), and I confirmed no bridged pins. Based on my experience, if you are going to have someone program a set of GALs for you, have them do two sets (10 GALs total) in case one doesn't work.

Fitment related - on my first build I used the pin header instead of the 96 pin PDS Euro DIN connector. The board sits lower with the pin header, and looking at the clearance I thought the small amount the DIN connector would raise the board would be fine. The DIN connector actually raised the board quite a bit more than expected and caused clearance issues between the CPU and the two screws at the back of the floppy drive bracket. This caused the inward edge of the accelerator to be bent down and was putting some force on the PDS connector, in addition to the CPU being pressed against metal screws. Removing the two floppy bracket screws alleviated most of this interference, though I think the CPU may still be rubbing the chassis a bit. I see three options when it comes to PDS connectors and CPU fitment:
  • Use the PDS pin header (not DIN connector) and a CPU socket
  • Use the PDS DIN connector and CPU socket, remove the two rear floppy bracket screws
  • Use the PDS din connector and do not use a CPU socket - solder the CPU directly to the board
The third option is probably the best and is the one I will use if I build another of these. The original Performer boards did not have a socketed CPU, I added it just because I like socketed things.
 

ruthsarian

New member
I think this part on Mouser is also similar to that double-male 64P DIP socket. I think I'll order a few of those and see if they do the job. I did find a seller on alibaba also selling them, but in lots of 1,000 only. Couldn't find anything else.

This came in the mail yesterday. I can confirm it is exactly what was expected, a dual-male header/socket that fits over the 68k. It should do the job. I have most of the parts for the board, just waiting on a 6882 a couple more components then I'll have a go at putting it all together.
 
Top