update #2 compact flash addon, deathly quiet but no smoke this time

Well,having sorted out the smoke 🙂 I managed to convince one of my original floppy drives to become a ‘was’ floppy drive. it is no more, it’s deceased.

Where the smoke came from. It must have been under some pressure because there was a lot of smoke!

Having recently had a big clean up, throwing out several 3.5″ drives in the process, I eventually unearthed a couple. One of which worked a treat. Just had to refit a connector on the floppy cable to allow for the 34 pin on the drive being upside down and sideways to the previous drive <sigh>. It’s a one third height drive so it’s rattling a bit in the case ( old drive was a half height ). But all is now good again.

My 8 (new) 41256 dram chips arrived so I added them to the core board as per the 512k upgrade instructions by Peter Broughton. I did get caught out a little bit as the floppy drive died in the middle of all of this, my ancient eyes and shaking hand produced a dry joint ( solder ) and the PAL on the coreboard was from a CIAB which didn’t support dual dram banks. I had made a variation on the 512k upgrade way back in the ’80s that compnesated for this but only for a single dram bank up to 256k. So luckily the other coreboard I had was complete with the required PAL.

I’ve also completed the 6.7 MHz speed mod.

I decided to try and use the PJB system along with the IDE/CF bootroms and bios code modified by Kalvis Dukmanton as a base. So I’ve now switched from my original code, bios and boot roms to this.

The bootrom is ok as is for the moment but it, along with the bios, will need a little tweak as my CF mod uses the 8 bit data xfer mode rather than the traditional 16 data mode.

I’m just working through the h/w interface ( physical side of things ) for a CF ( only ) ide adaptor and a few of the s/w things.

Keeping with the simple and cheap as possible theme, i’m using a ide to cf adaptor from ebay, some standard 40 pin ide cable from a PC, some vero board and some single row header.
It should all fit onto a 128k coreboard ( 8342 ).

Bare board where the header will be fitted.

Right angle header, left hand end will have small piece of vero board with extra pins to pick up pins 36, 38 & 40, gnd and maybe +5v that are on the other row next to the 34 pin connector.

Right angle socket under vero board, just visible at left. vero board needs to be this short so that it clears the FDC to allow it to be unplugged. Also need to keep the height down so it clears the top of the case

Where i think ‘ll mount the CF-ide adaptor or ontop of the next connector space to the right, closer to the DIN connector. Give or tack a smidgeon, the CF bracket mounting holes are the same spacing as the x3/x4 15 way sockets for the SCC serial ports. So it should be possible to mount the CF holder on a couple of spacers and have it accessable from the rear of the case.

Not shown are the cabling between the cf-ide adaptor and the vero board. Nor the power cable for the CF. most likely i’ll use a standard floppy power connector and plug into the cf-ide adaptor direct or I’ll add another small regulator.

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