Upgrades, Problems, Parts

It’s been an exciting few weeks.


The Archimedes continues to confound me. I finally got a replacement 1772, plugged it in and… No change!
At this point I have swapped out all the chips that feed the floppy disk. If you look at the schematics, I have socketed and tested IC29, IC30, IC38, IC 46, IC47 and RP1. No change. It’s going to be continuity testing from here on out, which won’t be fun.

I have replaced many of these,


Some of the upgrades I recently ordered started flowing in at last as well.

I got an ElkSD128, which brings the Acorn Electron up to an insane 140k of RAM and also adds both a Joystick adapter AND a SD card interface. This makes the Electron a little powerhouse!.

An unassuming white box.
How much RAM?
Press “T”! Press “T”!

I got a TFW8B SD2PET Future which finally adds easy to use storage to my Commodore PET. Files at last! (I promptly loaded a few games to muddle around with. I do like how well documented this was.)

Plugged in
DOS Wedge loaded and now I can see all the software on the SD
Like PETfrog

I also got a set of five Gotek FDD emulators which I have converted to FlashFloppy firmware. So far I’ve only installed one in my Amiga 600, with a nifty external rotary encoder and OLED. (I also have some 3D bits and pieces to make it up into a nice little package. I’ll be covering all the Gotek stuff in a separate post in the next few weeks.)

Many machines will no longer need Floppy disks


Finally, I got a DIVMMC Enjoy Pro. Unfortunately this isn’t working. The DIVMMC isn’t displaying its proper BIOS screen.
Next step was to clean the edge connector, but that didn’t help. (I also reflowed the power connector because I was seeing some unreliability.)
As this still didn’t help, and the next step involved getting a new Z80, I decided to completely resolve the edge connector as being a potential issue. The Spectrum doesn’t have fancy gold plated edge connectors. It has a simple solder plated edge connector. This was looking a bit “well loved” so I took the time to flow and clean each and every edge connector “pin” on the edge connector. My methodology was pretty simple. I dropped some fresh flux across the pin, then ran fresh solder onto the pin, using the hot soldering iron tip to “scrub” the underlying corrosion patches to remove them, finally following up with solder braid to bring them back to a smooth “factory finish”.

The left side has had fresh solder applied. The right has fresh flux. the “marks” in each pin are corrosion into the solder.
Here they are after the solder has been cleaned up with solder braid.

Alas the problems persisted. I was a bit depressed by this and was concerned I’d need to buy a new Z80 just to test. Then I remembered I actually had a spare Z80 in my collection.
Out came the desoldering gun, and with a little effort I was able to desolder the z80, drop in a new socket and test.

New socket under the Z80 CPU. It’s the long chip to the right under the heatsink.

Unfortunately the system still failed to load the DIVMMC BIOS. I’ve reached out to ByteDelight for more diagnostics hints. Hopefully it won’t need to go back to them. It’d be almost be cheaper for them to send me a new one.


I caught up with Brad from the MSPP forums for a coffee (Hi Brad!) and we chatted for a good solid hour and twenty minutes. Brad had very kindly donated me the missing key for the 16K Microbee. It’s keyboard is complete!
I have a potential top and keyboard cover coming, which would nicely finish this system.

I have taken CTRL

I’ve also started work on an evil project to build an adapter that will allow me to use a 27c2001 ROM in the place of one of the ROMs in the PC85 Microbee as a switchable 16 ROMs. Silly but fun.


I also got some PCBs. The biggest one was a full set of boards for the Omega MSX2 which should keep me amused for a few weeks :-). I also got an amplifier I designed as well as two boards designed by Necroware.

All hail the Omega





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