Vintage Computer Festival(s)

2022-08-14 Stefan No Comments

Hi there, it’s been a while. Somewhere down the line life happened and wait, not one, not two, but three Vintage Computer Festivals have happened since my last blog post. Three that I participated in, that is.

Seeing people that are not projected on square glass pieces was more time consuming than anticipated, and so typing text into this little square glass piece had been down prioritized. After a distant panic of one of my readers about “All good things…” meaning an end of this blog, I did promise some updates.

Last year I had signed up for a booth at VCF east to show off some of my little adapters, like the ROMY redesign that I had made as a starter project. I got a bit of cold feet last minute as three tiny PCBs on a large table are everything but impressive, and so – as there were no other Amiga booths present – decided to just bring a few machines. It turned out to be a great event and I got to know a lot of the local vintage community in person, including the amazing Liza Loop, who told me about the BBQ parties she had with Jay Miner back in the day. These stories are what we are here for, at the end of the day. There is a lot of technology out there, and a lot of PCBs everywhere, but the history of our technology tells us the tale of Silicon Valley and its dreams.

In October Chris Hooper and I made it up to AmiWest in Sacramento. It turned out to be a lot smaller than I anticipated (and I anticipated for a good 30 some years here, this was my first AmiWest), and a lot better. I had just picked up an A4091 SCSI controller on my travels to Germany before, and we were chit-chatting that with the Dave Haynie Archives and this board, we could indeed do a reproduction of the board. That’s crazy talk. Or is it now.

It was a busy winter for Chris and me, and by April I traveled to VCF East with three reproduction A4091 boards in my bag and equipped with a slide deck to give a talk about this project.

All good things …

2021-03-21 Stefan 4 Comments

… come in threes, they say, or “Aller guten Dinge sind drei” in my native tongue German. And so I set out to make a third and final attempt at reliably delivering great 68040-to-68060 adapters. Remember, earlier in my adventure I built one of these adapters with a PCB made by OSHpark. I was so excited, that I sold it on eBay and started to make another one. And failed. And another one. And… Well, you get the story here.

In my second attempt I found out, that I had forgotten to refresh the fill zones in KiCAD – What a rookie mistake, that left half a dozen 68060 PGA sockets dead, soldered onto PCBs where VCC and GND were never connected to the mainboard. The good news? No Amigas, and no 68060s were harmed in the production of that episode. But I promised, I would get this working. At least to myself. I had also disliked some of the characteristics of the old design.

I had to dremel the sockets I got into shape because they tried to occupy the same space as the other parts on the PCB, in clear violations of the physical laws of this time-space.
The interconnect between the two boards was oddly misaligned with the rest of the pins, making it impossible to use the substrate of the socket to keep them nice and tidy (and giving another reason for more dremeling. UGH)
Compared to the original design the KiCAD version by richx used single resistors instead of resistor networks. For the sake of space, those could be replaced by nice little 0603 RNs.

An evening with KiCAD and a few more days of waiting on a PCBway delivery, and here it is:

Exciting! New PCBs (with GND connection!)

iKod.se int7 adapter

2021-01-18 Stefan 1 Comment

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

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.

68040 to 68060 – Upformation

2021-01-18 Stefan 9 Comments

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.

Cyber, Cyber!

2020-09-01 Stefan 4 Comments

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.

Everybody gets a second chance

2020-09-01 Stefan No Comments

… 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

¡Una hija para mi Amiga!

2020-08-16 Stefan 1 Comment

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.

Keyboard fun!

2020-07-29 Stefan No Comments

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

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.

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.

Just a small upgrade

2020-07-28 Stefan No Comments

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

Recap of a revised recap

2020-07-26 Stefan 3 Comments

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.

Amiga in the 21st century

Category: Amiga 4000