Hi everyone! I came across this forum when searching regarding the keyboard on my Apple II, and I found this helpful thread about converting to Cherry MX keyswitches. https://www.applefritter.com/content/cherry-mx-datanetics-dc-51-keyboard-switch-adapter
So I figured I might as well sign up and say hi. :)
I recently acquired this early Apple II Europlus (European Plus variant) which had been sat in its original box for over 30 years!
It has quite a few goodies with it. The keyboard is a Datanetics Rev. B with green DC-51-01 keyswitches, which is what leads me to believe it is a very early example of a Plus.
It has a Videx Videoterm (possibly a clone), a Z-80 SoftCard, 64K, its original disk drive and paddles, the shift mod, and a few other bits and pieces.
I have so far had to replace the RIFA, a chip on the disk controller card, and some of the keyswitches took some persuading to come back to life. I then managed to source a period correct green phosphor CRT to go with it.
It has a few small niggles which I think could likely be resolved with some contact cleaner, like the fact that it sometimes won't boot unless I prod a bunch of socketed chips, or remove and re-insert some cards.
Album of images here for anyone interested! :)
I am currently undecided on its fate, but I think I would like to tinker with it and experience a period of computing history that I missed, before I consider moving it on.
Prior to this the oldest computer I had experience with ran Windows 95, so this is all very new to me, and I have already asked lots of stupid questions...
So yeah, hi, I'm Akagi. Sometimes known as Panda. Its nice to meet you!
My first stupid question is:How do I safely remove the space-bar? Does it simply lift off like the rest of the keys, or are there stabilisers that will interfere?
Do not remove the spacebar with the top cover on! Remove the cover, then you will be able to see the stabilizer rod and unhook it.
Having just removed the space bar with the top cover on, and then struggled to put it back on again, I wish I'd been patient and read this reply first. xD
Nevertheless I achieved what I needed to, and I know now for future, thanks!
My next stupid question is, if I have a z80 softcard in slot 4, do I start using it by typing pr#4? If so, what should then be displayed? :)
Depending on the card (pcpi or msft), you need to get the floppy disk image(s) for CP/M and boot from them. I've done this using a FloppyEMU before but there are other ways of course. The Asimov archive has the software disk images available.
...which means you should get yourself a disk image handler like a Floppy Emu: https://www.bigmessowires.com/floppy-emu/
Or a Super Serial Card, serial cable, USB-to-serial adapter and ADTPro: https://adtpro.com
Night Mission Pinball.
Respect, man.
Thanks both for the tips and info. :)
A more pressing issue though is that my Videx clone doesn't work.
The machine boots with it installed, but when doing PR#3, there is no display output from the card, and ctrl + bell doesn't result in a beep.
I have removed all of the chips, cleaned the sockets, re-inserted them, and cleaned the contact on the card and the slot, as well as checking continuity on the cable.
So I am at a loss now. Is there a chip that is a common failure or anything like that?
IMG20230509194221.jpg
IMG20230509194232.jpg
Might be something better suited to its own thread perhaps.
What piggy tail do you have connected to the 4 pin connector on the upper front (keyboard facing) end of the card? The 80 column output should come off two pins of that connector and either go to a "soft switch" that plugs into the mobo or to an RCA jack attached to the monitor or a manual switch.
It is a home-made cable that was already installed on the card when I got the machine.
The top-most pin is connected to the outside of the RCA connector, and the second pin down is connected to the inner post.
The bottom two pins are left empty.
I have an RCA switcher box thingy.
That cable sounds correct, so as long as it has continuity that's probably not the problem.
Have you tried removing and re-inserting the chips? In particular the 74161 on the top back (away from keyboard) of the card looks like it may not be seated very well.
Edit -- re-reading the thread I see you have.
I might check the contents of the firmware in the system monitor.
I'd also probably start swapping various chips because I've got spares of just about everything on there, even a couple spare Videx type cards I could swap the Hitachi video chip out with. But if you don't have that, it's not an option. The 74LSxxx and 74xxx chips are mostly cheap and easy enough to find that it doesn't hurt to stock spares.
Thanks, yeah I was worried my options from here would be either, get an oscilloscope, or start randomly swapping chips.I guess I'll go with the cheaper option haha.
The Videx clone card should be fixable.
But if you want to sell it I would buy it right now because it matches the Unitron motherboard of my Clone II+.
By the way...
If you type PR#3 (with the card inserted in slot 3) and switch the video it SHOULD display the 80 column screen.
If you then type an illegal statement and press return it should beep but the beep is at a much lower frequency than the regular Apple "beep".
If it does that, the card is working and not displaying video. There's an issue with the large CRTC chip or its supporting circuitry.
If it crashes the machine or the machine becomes non-responsive it is possible that the ROMs on that card are faulty.
Pressing RESET after entering 80 column mode via a PR#3 command shoud return you to 40 column mode and restore the familiar "beep".
When I enter PR#3 the blinking cursor on the 40 column display disappears (as expected), however when I then switch monitor inputs to the 80 column card, there is nothing displayed. Ctrl + bell results in silence, any pressing of keys followed by return results in silence, however I can press reset to be returned to the 40 column output. When I switch to 80 column I can also hear a change in the pitch of the electronic hum.
What chips would you start with? I can get...
The CD4013BE, 74LS02, 74LS139 (does it matter if this is an N or AN?), 74LS00, 74LS157, 74LS132, 74LS86 (does it matter if this is an N or AN?), 74LS166, UPD4016C-2, and the main controller chip, the HD46505 SP-1.
All of that comes to about £23 but I won't buy all of it if there are some more likely candidates I can begin with. :)
I can record the behaviour tomorrow if you think it would be helpful!
I have made a seperate thread for this issue, in the hopes some more people might see it. It is here. Thanks!