128cdr internal drive id change

[BloodyCactus]

So today when the kids were napping I dropped the jiffydos roms into my 128DCR, then hooked up my new 1541 Ultimate-II... And I have a sd/uIEC to hookup but no extra drive connect...

My problem is I want the 1541Ultimate to be drive #8, a lot of things just dont like not being drive #8 (infocom games come to mind!), so I have read about installing two switches. I see two circle pads with a line in the middle, so I assume from what I read, I need to carefully solder 4 wires, one for each half circle, to give me two switches?? then I have a selectable internal drive..

But I was thinking, instead I should just butcher an IEC cable, and wire the 1541UltimateII directly to the internal drive #8 IEC header with the rectangular header pin then use uIEC into the back with a normal cable..

I dont user the internal drive, and now wonder how much I will use the uIEC that I have the 1541 UltimateII...

I am thinking cable butchering, first I need to figure out what wire is what on the internal IEC pin header... anyone know? I have some books from bombjack but nothing would seem to document the 128DCR internals...

[BloodyCactus]

I see on schematic;
http://www.zimmers.net/anonftp/pub/cbm/schematics/computers/c128/manual/86.gif

CN12 has 10 pins, IEC has 6 pins, and I can't tell from the schematic how to wire the external 6 pin IEC to the internal 10pin.. I dont think I can?? Has anybody done this?

Also looking at the drive number mod, on this pic I see the two solder pads
http://www.softwolves.pp.se/pics/c128dcr-floppy-1061x651.png

but I also see C114..

looking at this pic here
http://www.softwolves.pp.se/cbm/minaburkar/c128dcr.en.html

I see 3 wires, one on each of the pads next to the CIA and 1 coming off C114... I dont quit get how you wire the two switches up to 3 wires, does C114 wire to both toggle switches? Im confused at wiring up the two switches to give 4 states (8/9/10/11) off two or 3 wires...

[polbit]

I just did the drive switch on my 128DCR (although I just did one - 8-9 toggle).  The two pads you see on the motherboard are basically two jumpers. They are closed  at the factory, so all you have to do is cut them open, then wire a simple switch to open/close the jumper. Do one for each pad. The one closest to the front is for 8-9 toggle. So, 4 wires, 2 switches.

Ray Carlsen has a good write up on it, amongst other things, on his website: http://personalpages.tds.net/~rcarlsen/cbm/drv8to9.txt

Here's the important part:

C128DCR INTERNAL DRIVE:
     The internal 1571 in the metal case USA version C128DCR has no
external switches for drive select. It is factory set for device #8.
There are drive select "jumpers" inside the computer however, on the
motherboard near the drive. They are the two tiny silver half-circles
with a bar between them. Cutting the bar opens the jumper. If you look at
the PC board just under the left side of the drive, you will see them. It
is not necessary to remove the drive unless you plan to solder in there.
The jumpers are located near ICs U106 (a 6522), U114 and U112. DS (drive
select) jumper #1 is nearest to U112, towards the front of the computer.
     Electrically, the jumpers connect two pins of IC U106 VIA chip
(65C22 or 6522 in some models) to chassis ground. Jumper 1 grounds pin 15
and jumper 2 grounds pin 16. That information is helpful just in case the
foil pad(s) jumpers on the PC board are accidently damaged when you are
installing a drive select switch. If the pads lift off the board, you can
still make connections directly to the IC pins for your switch.

Hope this helps.

If you figure out the wiring for the uIEC, please post it here, that's my next step, and I can't find the pinnout either

PolBit

[BloodyCactus]

thanks, so my initial post was right, cut the lines joining the two pads, then wire one wire to each half moon pad, 4 wires... ? can I ask you to take a pic did you solder in a switch or just cut a pad to make it drive #9?

[maraud]

I've done this mod to my 128D and am happy to take a snap of it on Friday if  no one else does before then.

[BloodyCactus]

thanks maraud! I've read all the texts, I just need a pic to 'see' what I'm really doing.

Never soldered anything in my life so I picked up
40watt pencil soldering iron
reson core flux (very thin stuff)
22awg wire (I think I messed up as I got single/solid strand)
and picked up two stsp switches (3amps 120vac)

just wondering if it isnt better to do the disable mod vs the drive number change mod..

[polbit]

BloodyCactus, please practice on something other than a 128DCR if you never used a soldering iron before It really makes a difference.

Once you are ready, all you have to do is cut the trace between each of the two pads, then soldier wires between the pads and switches, so that a switch will either open/close each pad. The pad closest to the front is 8/9, the other one 10/11.

PolBit