Don’t you know the feeling when you’re just on cloud 7 with your Amiga?

Maybe you remember the action replay for Amiga 500 which let you scan memory for lives and mods? Or you miss a nice and handy debugger when debugging that latest 68000 assembly of yours?

ikod.se had the right solution for your Amiga 1200 or 4000: an int 7 adapter. It is easily assembled with only a 52pin PLCC socket, 3 1n4148 diodes and a pin header and switch.

The thing is, it’s hardly worth, or even possible, to order anything in single quantities when doing PCBs. The price for 10 might just be the same. So let’s find solace in the soothing effects of soldering

Indiscriminate use of solder paste

This was one of the projects that I used to practice working with solder paste and hot air. In the picture above I used a little bit too much in some places.

I recently upgraded from a 40$ 858D clone to the beatiful Quick 861DW

Let’s get to work and make a few of these thingies…

Hot air was immediately my favorite way of soldering, when I found out how much nicer it is do attach sockets this way rather than soldering 52 individual pins. And a few months later, I still really like this method for SMD PLCC sockets. But you have to do your due diligence after soldering and check if the legs are attached right:

Tweezers, a pincer or in my case, a set of dentist’s tools really work wonders. These can be bought online for less than 10 bucks and they’re super useful to get into the small spaces.

Some of these don’t look right, yet

On the ikod.se adapter it’s actually OK if some pins are not perfect, you really only need to make sure that the ones with actual signals coming off of them, going to the diodes, are soldered correctly. But for stability and the sake of learning to do it correctly, I suggest to not take shortcuts.

PLCC-52 solder stencil

There’s a better way of applying solder paste than just smearing it across the pins: stencils. My first experiments, however, were so, so. The stencil and the PCB have to be fixed to keep them from sliding around. I used a few pieces of the kapton tape that I had lying around. The stencil I got from DigiKey didn’t entirely fit the pads on the ikod.se adapters’ PCBs. But… close enough.

Alright, let’s see how that went..

Not too bad…

It didn’t come out perfect, but much better that just applying the solder paste with a syringe. But soldering with the hot air gun didn’t come out as great. Somehow the sockets were not even enough on the PCB so some pins did not attach to the pads evenly.

Time for testing… the adapter is plugged on top of Paula. Connect a little switch that we can use to, e.g. enter a debugger.

You can use it with any software that has an INT7 (NMI) handler. Some Assemblers have them. I think I read ASMone can use INT7 to interrupt hanging programs, but I didn’t verify. I used HRTmon 2.37 that I found on WHDLoad. It’s possible to embed WHDLoad into the Kickstart ROM and even interrupt while you’re for example at the boot screen or in the boot menu. I didn’t try that yet, but an easy start is to just load HRTmon from s:startup-sequence. And then, the big moment….

Great! That worked. Thanks to ikod.se and the authors of HRTmon. Even Katsu approves:

And if you need one of these, let me know… I have a few left over.


Back in the late 80s and early 90s, when the Amiga was relevant as a technical revolution, I was never able to lay my hands on anything beyond an 68000 with 7.14MHz. Years later, around 1997, I acquired an Amiga 3000 with 25MHz as part of one of my university side gigs of porting software from various UNIXes (in this case SCO Unix) to Linux. But a 040 or even 060 was far out of reach until I was well into my first full time job at SUSE Linux when I got a Cyberstorm MK1 that – as we know – doesn’t fit into the A3000. Long story short, the first time I actually ever ran an Amiga with something faster than the 68030 @ 25 was around …. Christmas 2019.

As life happens, and we sometimes overcompensate for our youth’s desires as we grow older, I added one of Chucky’s A3660 rev 1.1 to my collection, (built by Nicolas Baumgardt who lives in Switzerland, but only few miles from where I grew up and hacked on the Amiga back in 1987) that so far consisted of the A3640 that screamed for pad replacements and recaps.

Along the way I learned that the Amiga CPU local bus is really a 68030 bus, so memory access on everything above a 030 has to be translated and is then slightly slower than with an actual 68030. Ouch.

I also learned that the Zorro III slot is not really all that great. Well, Super Buster is not in its current implementation. While the theoretical maximum of Zorro III beats the first PCI standard, the actual implementation is stuck at 8-10MB/s memory access speed. We need an update Dave Haynie! Then our BigRAM+es could be really super awesome!

But back to … back to the 68060. Once I tasted the sweet excess of the Motorola flagship’s raw CPU power, and when I got my beautiful Hakko soldering station, I had to upgrade my 3640 to a 060 processor as well.

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Or was it “Hyper, hyper!“? Scooter, please help a child of the 80s and 90s out here! This episode is about shuffling hardware, and what it takes to make your Amiga really fast!

I was lucky enough to get my hands on a Cyberstorm MK2 card (and I still have all my organs). I almost despaired when I put the card into my Amiga and nothing happened. Turns out, the Amiga wants J100 jumpers to internal despite an oscillator being present on the card. What a shock and what a relief when dummy me was told by the internet to read the manual that came with the card. Who does that anymore these days?

The previous owner parted with this piece of 90s magic with an 68060 revision 1 at the factory frequency of 50MHz.

That’s no fun, thought this silly old lad, and after some journey to the Nightfall Crew and Cosmos’ Blog I felt the best possible thing I could do is to risk destroying another piece of ancient hardware and overclocking a poor 68060 CPU by no less than 100%.

For that I would have to exchange the 68060 rev 1 with the rev 6 from my A3660 (Thank you, Nicolas from Switzerland). But how to get the CPUs out of their sockets without destroying CPUs or boards. With the A3660 I was less nervous. The card is somewhat solid and I had been able to remove the CPU with my Hakko CHP 7-SA tweezers (6.50USD on Amazon, great investment), but the Cyberstorm MK2 just made me a lot more nervous, as it was starting to bend under the pressure. The Cyberstorm is super packed, there is not much room left and right, unlike the 3640/3660 design. So I found these Intel Overdrive chip removers on eBay:

One on each side, and any 68060 will follow your lead easily.

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… and even more obviously, everybody needs a second recap in their quarantined life. After the recap of my A3640 went surprisingly well, and even ripped off pads were replaced and reconnected, I felt confident enough to do a board that’s a little bit bigger and a little bit more involved than that poor little 040 accelerator: My Amiga 4000.

As my Amiga 3640 processor card, the Amiga 4000D board was previously recapped in a job that replaced the SMD capacitors with their through-hole siblings.

I know, I know, another recap story, REALLY? Haven’t we heard enough of that already? Let’s just twist the caps off, the recap trolls on Facebook will tell you. Come on, folks. You are lucky enough to have the chance to operate some 30 plus year old machinery. Think about it for a second. What else that you have today will still be good in thirty years from now? Your iPhone or Android phone? Certainly not. Your MacBook? Your Chromebook? This stuff is going to be in the landfill and long forgotten in much less time. So PLEASE, treat these machines carefully. They are witnesses of a very different time, when reality consisted of the cold war and 1200 baud modems. If you have doubt about what to do, let someone help you. There is a friendly community of folks keeping these machines alive. And if you want to do it yourself, practice with something else first. Something that is ok to break. I heard there are a lot of cheap Ataris out there (just kidding!!)

It’s not visible in the picture, but many of the legs of these caps were not attached to the board anymore

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The heat wave has hit Mountain View these last few days and caused a power outage for the better part of the weekend, so between 40C/105F and no electricity to power a soldering iron we enjoyed mango ice instead of working on all the projects.

Delicious mango shaved ice and jelly noodle shaved ice from Meet Fresh

None the less, after laborious project cat Katze (カツ)  dropped all static charges to climb into a box and help me unpack my latest Digikey order, I couldn’t just sit around.

Katze survived. Even though we all looked.

A while ago I ordered one of Edu Arana’s A4000DB daughter boards at amigastore.eu. These are an easy way to lower the temperature in the already hot Amiga 4000D case and the power consumption a little bit. Plus, as Guillaume pointed out, I’m an arananet fan boy.

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My keyboard is missing a key. There’s no escape!

Well actually it wasn’t escape that was broken on my nice click-a-dee-clack Amiga 4000 keyboard, but CAPS LOCK! And bit even the key itself, it was the LED that just wouldn’t show the status. No problem, let’s take it apart

So many screws!

At first I thought the LED might have died after my recent diode intermezzo on the Amiga board. But measuring with my multimeter I see that the LED is just not getting any power. Let’s look at the membrane.

It seems I forgot the before picture

There was a piece of the trace missing. It seems it had corroded away. The previous owner probably spilled Coke on it. My first approach was to scratch the green cover of the existing trace so I can connect to it.

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Lots of things happening at work, so it’s good to do a little meditation by soldering in the evening. Guillaume sent me a Greaseweazle kit but the STM32 still looks like the next level of soldering to me. It makes 0805 components look large. I’m missing a 74F257 that was lost in the mail, so the 060 adapter has to wait for a while. But there are other ways to treat an A3640 rev 3.1.

First, a socket for the oscillator will make it easier to test a little overclocking.

The 68040@25MHz worked nicely with a 60MHz oscillator, pushing it up to 30MHz.

Since the A3640 provides the clock for the Amiga mainboard, the chipset and memory will get a tad faster, too. This hack is super easy and will cost you 2 bucks for a socket and an oscillator.

The next and a little more involved one is an upgrade of the v3.1 card to v3.2. Gladly this is a simple GAL update, but unfortunately the GALs are not socketed. This leads to a brief intermezzo with my favorite tool ever, the hot air rework station.

The kapton tape job was a bit sloppy and over eager

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When I got my A4000 late last year, I could not have been a happier kid. I fleas surprised to get it for a fabulous price and it arrived just in time before the holidays.

The A3640 was a good first victim. Notice the through hole caps that ripped off the pads

That joy lasted until I noticed that there was no mouse, a Super Buster r6 (WTH) and a semi-professionally done replacement of all the capacitors on the board. Unfortunately through hole caps were used in the recap process.

You will find enough discussion about this on the internet, and people will suggest all sorts of craziness, like twisting off old caps or putting through hole caps on SMD pads. These are all terrible ideas. Don’t do it. If you have an Amiga (or any 30yr old computer), do it right or pay somebody to do it right. Recap services are not expensive and are definitely worth it.

One of the tricky parts is that the silk screen on the A3640 is incorrectly showing the direction of three capacitors. Make sure to consult the schematics.

Ruined! It is ruined! Or is it?

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