AppleSqueezer GS and ROM0 boards

tmtrains

Tinkerer
Jun 21, 2022
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Update: Thanks to Niek's hard work, the latest core for the AppleSqueezer GS fixes the issues those of us with ROM0 boards were having.

Hello!

During the pandemic, I retrieved my old Apple IIgs from my mom's house and decided to tinker on it. I managed to get more RAM, a Booti, and an Uthernet card.
But like most IIgs owners who didn't have one back in the day, what I wanted most was an accelerator, because 2.8 Mhz is still pretty slow.

The AppleSqueezer GS project appeared and seemed to be a great answer. An FPGA based accelerator (with its own onboard 65C816 IC at 14 MHz). I missed out on ordering it a few times, but it finally came through.

So, I installed it and it didn't quite work. It was fast, but it didn't work with the Booti, and anything sound related would cause it to hard crash. A startup from power off would have a 50-50 chance of triggering the same error.

tl;dr, my IIgs is one of the early ones, a ROM0 board. The ROM was upgraded back in the day to ROM01, but the board is original. And the ROM0 board in particular has some quirks. Notably, it has some bodge wires:

IMG_2205.png

These bodges are actually incorporated in the updated ROM01 board that came later with the updated ROM.

But this does add a wrinkle in that it seems that these boards are a bit marginal under acceleration. Niek, who created the AppleSqueezer, noted in a blog post that there were ROM0 board owners who noted the same issues back in the 90s with ZipGS accelerators then.

Then today, I watched Action Retro's video on the AppleSqueezer. And he has a ROM0 board in his transparent IIe to IIgs upgrade machine. I took one thing he said towards the end of his video, that he swapped out the CPU socket with a better one to ensure the AppleSqueezer had a good connection. And if you watch his video, his setup works flawlessly.

Well, I decided to try replacing the CPU socket, because, why not?

After a few hours, because I am particularly terrible at desoldering, I managed to put the new socket in and made sure the stock CPU still worked fine (and it does) and then put the AppleSqueezer back in. It didn't really help. In fact, now the AppleSqueezer and the FloppyEmu's timing was off such that the latter (in smartport mode) was not able to be recognized as a valid boot device in time. This is problematic as that was the way I was installing firmware updates to the AppleSqueezer, and now, that seems to be out as well.

My thinking now is to keep my ROM0 board with its stock CPU, as it seems particularly unstable under acceleration and look for a ROM01 or ROM03 IIgs to put the AppleSqueezer into. I'm certainly open to your ideas, but I think that's where we're at with the AppleSqueezer GS and my particular computer.

I can say that Niek has been great to work with, and although it wasn't the outcome we wanted, he has been fantastic, immediately offering to refund me my money and working to diagnose and try some solutions. I look forward to seeing where this project goes, and I think if you have a ROM01 or a ROM03 IIgs, it is something to strongly consider.

How do you know if you have a ROM0 board? The board identifier is under the CPU, but if you don't want to pry out the CPU, you can also look on the back of the board. If it has bodge wires, it's a ROM0. I think that many of the "Woz Limited Edition" machines (which mine is) are ROM0 boards since the Woz machines were very early in the IIgs run. Of course, these are the machines that are marked up at ridiculous prices on eBay as "rare".
 
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retr01

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Oh yes! The Apple Squeezer GS is on my list to get. :) Thank you for sharing your experiences. I saw that video on YT and bookmarked it. I will watch it when I get the chance.
 

retr01

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Hey @niek! Welcome to TinkerDifferent! Good to see you on here. Your AppleSqueezer GS is on my list for my Apple IIGS. When the time is right, I will get it.
 

tmtrains

Tinkerer
Jun 21, 2022
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Hi @tmtrains! Niek here (creator of the AppleSqueezer GS), thank you for your kind words, and indeed some of these early boards may have an issue with acceleration. Have you already tried the latest v5 core update of the AppleSqueezer? (see also https://www.applesqueezer.com/post/core-v5-in-testing) This update could solve your issue. Let me know if it helped!

Kind regards,
Niek
Hello Niek!

Glad to see you here. I've not tried the update yet, I've been fairly busy with other stuff, but I'll try to give it a shot next weekend.

Thanks for your hard work!
 

tmtrains

Tinkerer
Jun 21, 2022
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Ok, I couldn't wait until the weekend. I installed the Core 5 update from my FloppyEmu. After fixing an issue with the hard disk image on the FloppyEmu, I booted it up.

I did not encounter the dreaded "Sound Interrupt" errors at all this time around. And while before, any sound / music playback (yes, including the startup beep) could crash the whole machine, it has not done so, thus far.

I do still have the issue with it not working with the Booti, but at least the Booti gets further along vs simply crashing to the monitor (I'm currently using the FloppyEmu as the storage device).

Again, many thanks to @niek for his work on the AppleSqueezer GS.
 

tmtrains

Tinkerer
Jun 21, 2022
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A follow up here. @niek worked further on the ROM0 board issues (the Sound Interrupt errors came back for me), and provided a new core to try out.

I finally got time today to try it out and it seems to have resolved the major sound timing issues as well as working with the Booti.

Thanks again to Niek for his work on getting this amazing upgrade working on my literally (factory) bodged board.
 

KennyPowers

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Jun 27, 2022
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tl;dr, my IIgs is one of the early ones, a ROM0 board. The ROM was upgraded back in the day to ROM01, but the board is original. And the ROM0 board in particular has some quirks. Notably, it has some bodge wires:

View attachment 7212

These bodges are actually incorporated in the updated ROM01 board that came later with the updated ROM.

Hah, I was about to post asking "what are these bodges on the back of my IIgs board" when I saw this. I just found that my board has identical modifications: https://tinkerdifferent.com/threads/is-this-iigs-board-a-rom0-that-was-upgraded.2043/
 
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tmtrains

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Jun 21, 2022
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@niek has written up how he was able to fix the issue thanks to a great benefactor who sent over 2 ROM0 boards to him to analyze: