Alternative parts : Replacing SID with a SwinSID ( and building one )

I've been fascinated for years with the original attempt to replicate the SID, the SwinSID.  I've always wanted to build one but I found my lack of knowledge of electronics and lack of detailed step by step instructions on Swinkels website was quite a stumbling block for me.

Years later and with quite a few electronics projects under my belt, this little gem from Tolaemon appeared in my search while trolling around the myriad of shared projects at PCBWAY.

Tolaemon's nano SwinSIDb tutorial . . .

And so before I even went to website I ordered the PCB from PCBWAY

I must admit I was a little worried that this wouldn't work but hey I'm giving everything interesting a go that I can and here is what I ended up with.  After soldering MiSTer I/O boards and SDRAM boards this project proved to be a very easy build.

The version of the Microchip software I used was a little newer than that used in the tutorial and it was here that I became unstuck.

I burnt the firmware fine and the lockbits but when it came to the fuses all of the options had been renamed.  I left everything default and selected the correct external clock setting (EXTCLK_6CK_14CK_65MS) and burnt it to the chip.

Putting the SwinSID in the c64 I got a horrible horrible tone that didn't change.  The good thing is when you go to re-program the chip you can re-read the settings and for some reason the external clock hadn't changed from the default.

So I changed it and burnt it again and this time there was silence when the power went on.  On loading a game I found it would make a little noise then silence then some more noise but was nothing close to the music I expected.

Again I put the chip back on the programmer and one of the fuses that was default on needed to be turned off ( the CKDIV8 ).

This time I got success!!!

So what do I think about the SwinSID . . . well it's actually pretty good, the project was a lot of fun and I learnt quite a bit doing it.  For my C64's however I think I'll stick to the ARMSID as my SID replacement of choice.

I found the SwinSID did pretty well on the games I tried, but it just sounded a little off in some places also for ShadowFire it just didn't work at all.

Alternative parts: Replacing 6526 with 8520 cia

I found it hard to find 6526 CIAs to replace the dead ones in my C64s.  Scouring the the Internet hoping for an alternate I found this Forum discussion about using an Amiga 8520 CIA instead and what was different between the two chips. As 8520 chips are abundant on AliExpress I thought I'd give it a crack.

For the most part they work pretty well. Ive found some weirdness with my Ultimate 64 cart where the auto run doesn’t work, but mounting and loading normally is fine.  I wonder if it’s the clock?

Overall they seem like a good substitute until someone builds a better one.

Alternative parts : Replacing SID with ARMSID

The biggest problem with retro computers is sourcing parts, which haven’t been manufactured since the 1980s.  SIDs and CIAs are pretty expensive to replace these days so the new awesome alternative parts are fantastic.

I’ve got two c64s both with broken SIDs, so I thought I’d give the ARMSID a red hot go. I’m pleased to say everything I’ve read about them is true. I’m not an audio aficionado but they sound great to me.

You can read about them here and you can buy them from here.

It took about 3 weeks to get to me from the Czech Republic, most of that was probably spent in customs in Australia.

C64 : Another Black screen with signal . . . Complete

A few months ago I went out on Ebay looking for more dead c64's.

This time I got two, one looked like a really simple fix with a logic chip the other was a black screen. Fortunately ( or in my case Unfortunately ) I was sent the wrong for the logic chip issue and instead got a working c64 with one key missing, as a bonus the missing key was really easily replaced with one from https://www.retroleum.co.uk/.

The second c64 proved to be another black screen, however unlike the last one I was getting a PAL signal. The first thing I did was pull the SID and tried it in my newly created test board.  The SID was dead and only with the volume turned up to maximum could any sounds be heard, even then one of the voices was static.

Pulling the SID however didn't fix the black screen.

Putting in my trusty 1541 ultimate, I got a really clear normal menu with the Kernel overlay in place.  So I de-soldered the kernel and tested it in my test board.  The Kernel proved to be just fine so I put it back in place.

The next thing I did was de-solder CIA 1.  This also proved to not help as the CIA worked fine and I still had a black screen.

I had previously tried the put the memory chip over another memory chip to look for bad RAM so I tried it again on one of the two RAM chips.  I pushed the pins in so the made a good connection and nothing happened.  After mucking about pushing the RAM onto each of the RAM modules, the C64 sprang back into life.

So at this point in time I am thinking that I need to socket the left most RAM module as there maybe a dodgey solder connection there.

. . . Update . . .

After much playing about I simply can't reproduce the problem at all.  I've put in an ARMSID to replace the broken SID.  I've also put in brand new capacitors and installed a 5V powersaver.

Another unit working.

Indulging myself with a C128D

A while ago I bought a pretty cheap C128D keyboard on Ebay.  I have been using it a lot with my MiSTer using an Arduino as a USB HID interface.  The recently I got an Amiga 2000 keyboard to build a new interface for my MiSTer ** so the C128D keyboard was about to become surplus to requirements.

There is something about the C128D that I really liked so I picked up a working one all the way from Germany.  I'm really happy to say that it arrived safely and it works beautifully.  I am going to set this up with my 1084 monitor as my center piece for my Commodore retro collection.

It's so pretty!

** If you haven't seen the MiSTer project, you are missing out.  It is an Open Source project with a FPGA the runs a huge amount of retro computers, console and arcades.  I've been using it since it was first released, having been a Mist user previously.
MiSTer on Atari-Forum
MiSTer on GITHUB