This is just a quick one. I wanted one of these fancy easyflash cartridges for the C64, so I built one and changed some stuff and added a fuse. This post is mostly to keep the project files ready for anyone to download and reproduce the cartridge 🙂
That’s what the cartridges look assembled. They sport a fancy led on the front and big buttons on the top for my clumsy fingers to operate.
The LED is wired through the pcb to a footprint. The hole in the pcb makes room for the LED socket. You can wire a LED normally if you like, the footprint is between the USB port and the SPECIAL button.
I printed to bom to the back, for easier repair. The programming pins for the cpld are also available, just in case you need them for debugging. In addition to that the pcb is now protected by a fuse.
The gold plated connector is chamfered 45° so plugging it in is a big easier on the connector.
I was able to score a sweet sound canvas for my PC setup. Unfortunatly it arrived in a non working order 🙁 But hey, where’s the fun without a nice little repair?
First off – an outer inspection:
The whole thing seemed to be wrapped in tape sometime in the past. The residue is rock solid. Let’s turn it on it’s back…
I was a bit shocked – but the rust is just superficial. And one of the rubber feet is missing, no big deal. At this point I tried to power it and switch it on – but to no avail. It’s dead 🙁
While attempting the repair I let the rusted bottom plate soak in vinegar acid.
Back to the sound cavas!
So, no acid damage on the underside. I’ve read in the manual that the device settings are stored in a battery. So I braced myself for some corrosive damage. Try to pop the hood and take a peek.
Sweet! The battery backed storage relies on a lithium cell (right hand side, in a nice cell holder) which seems to be fine. I removed it anyway, since its most probably dead.
Next up was another visual inspection. So I just unplgged all the plugs and had a look around. Just checking for anything obvious, broken traces, bulging capacitors, all that stuff.
This is the input selection switch. Seems to be dead and hollow. More about that later.
Always funny to find a literal bug! In addition to that I found the power input jack had cold joints and had a bodge wire dangling around.. Unfortunatly I don’t have a picture of that, just took one after removing it and some while the repair.
Next up was the input selector switch. First of all I desoldered it and checked how it was wired inside to find a replacement.
So after prying the outer shell it revealed all of its oxidised beauty.
After giving it a scrub with brake cleaner I got this diagram:
Well, its almost impossible to find a switch that is wired just like this. I’ve searched all the big retailers to no avail. Bummer. So I popped some other switches open to put in just the plastic piece in the broken switch. And hey, that worked just fine!
So I soldered the “new” switch back in and tried to power it up. Bingo! It works just fine. So I focused at the shell again.
Next up I tackled the tape residue with goo gone. Just smeared it everywhere and put the case aside. Next up to see what the metal bottom was doing.
Awesome! The vinegar ate all the rust away. Just wiped it in soapy water and scrubbed the plastic shell again. After that I just put everything together again.
That wraps it up! The sound canvas works nicely with my old PC. Oh, the disk drives works, too. Took a video of it for your hearing pleasure 🙂
Since whdload for the Amiga needs a lot of RAM for some games and my Amiga only sports a meager 2MB in total I searched for a way to get some more.
I stumpled upon the pcmcia-Slot for expansion pretty soon and had a look for expansion cards.
But damn, these are expensive! Even decade old sram cards for the pcmcia slot still cost a pretty penny these days.
But apparently some nifty guys from poland designed a new sram card, called the “Sakura 4MB PCMCIA SRAM”. You can find a link to their website here: https://sakura-it.pl/sram.php
Unfortunatly they stopped producing the cards a while ago. But being awesome dudes they offer the sources on github! So I decided to make an expension card by myself, using their sources.
But bummer, they are using parts you can’t find in 2018. Sure, you can get them from china salvaged from devices but meh, I like to get new parts. So I revised the circuit. It wasn’t that difficult, I had to change the sram IC, one other IC and the pcmcia connector. And since some guy said that the newest revision of the pcb on github seems to have problems I settled on the version 2.1. of the pcb as a base for the new revision.
The last thing to keep in mind is that pcmcia cards have to be exactly 3mm in height to fit into a pcmcia slot. I just designed three 1mm pcbs sandwiched together, you’ll see what I mean in the photos below. It would be nice to have a metal sheet to shield the pcb, but unfortunatly thats out of my realm of possibilities.
To sum things up here are some pictures of the build and a link to the sources:
I do have a favourite manufacturer for pcbs but sometimes its smart to check out the other fabs. I’ll test some manufacturers and write short reviews about them – this time: Seeed Studio Fusion – https://www.seeedstudio.com/fusion_pcb.html
I plan to do something with Nixies in the future but wanted to use a modern driver. After a bit of searching I found this awesome project: https://github.com/dekuNukem/exixe
Damn impressive and even open source! Since pictures are worth a thousand words have a look for the driver pcbs:
The edge cuts are clean, no frizzing at all. That’s pretty nice. Unfortunatly Seed puts a production code on the silkcreen. Meh, I really don’t like that.
Looking very closely you’re able to spot the marks of the e-test probes. Pretty impressive, I’ve never seen them before. I wasn’t even sure if my fab does this test.
Following up are some detail shots. The boards are good, but I spotted a small error at the end. Have a look for yourself:
The drills are all centered, the silkscreen seems to be offset by a bit though. Bummer.
Next up is the error I spotted by chance:
The error is – excuse the pun – microscopic and won’t affect the functionality.
I know it sounds weird, but it’s a bummer you get exactly the amount of pcbs you order.
if you don’t order pcbs often this will most probably sounds weird. But usually you get at least one spare pcb. I like to use them for fitting tests or if something goes wrong while assembling.
Well, thats probably complaining at a high level.
Ah, what’s also pretty nice at Seed is the opportunity to order flex pcbs directly and having your boards plated with hard gold. That’s quite impressive, my fab won’t do that.