Lambda 8300/Power 3000 Mutlirom

User avatar
sirmorris
Posts: 2664
Joined: Thu May 08, 2008 4:45 pm
Location: oxon, uk

Re: Lambda 8300/Power 3000 Mutlirom

Post by sirmorris » Wed Mar 13, 2013 9:43 am

Looks like a nice example.
--=== ZXpand+ ... A more moderner all-in-one upgrade solution for ZX81 ===--
* SD/MMC storage * 32K Hires-capable RAM * AY sound chip * Joystick port * Serial *
* BASIC enhancements - plug & play * Reset button * Auto-boot facility *

gozzo
Posts: 444
Joined: Fri Jul 08, 2011 7:52 pm

Re: Lambda 8300/Power 3000 Mutlirom

Post by gozzo » Wed Mar 13, 2013 1:45 pm

There's something missing from that Lambda...the 'print' from around the keys...see this pic of what it should be.... maybe someone 'overcleaned' it and it came off... I have 2 Lambda's although strictly speaking they are the 'Your computer' version, but they are really one and the same, and one has no print around the keys and one has..
Attachments
Lambda8300.jpg
Lambda8300.jpg (102.42 KiB) Viewed 688 times

User avatar
TMAOne
Posts: 119
Joined: Thu Aug 16, 2012 5:56 pm
Location: Waterloo, Ontario, Canada

Re: Lambda 8300/Power 3000 Mutlirom

Post by TMAOne » Wed Mar 13, 2013 3:45 pm

Yes, having read the (thin) manual that came with it I've discovered the "shift" functions, including the editing commands. (I was wondering how to do that,...)

I've put tiny stickers on in place of the missing overlay.

Sorry Sascha2000; I didn't mean to interrupt and monopolize your thread. It only took a very short time with my new toy to be able to see your motivation in creating the multi-ROM. It would be so very cool.

Ian

sascha2000
Posts: 57
Joined: Fri Jul 22, 2011 1:13 pm

Re: Lambda 8300/Power 3000 Mutlirom

Post by sascha2000 » Wed Mar 13, 2013 4:28 pm

>I didn't mean to interrupt and monopolize your thread.

No problem, really! (I have put this thread anyway in the wrong area of the forum. )

To see the pictures of your machine is a big pleasure, I think not only for me.

So please go on!

@sirmorris: Wouldn't it be possible to use the zxpand in conjunction with the multirom in the lambda? I mean something like an adapted zxpand-rom for the Lambda burned in the eprom...

Sascha

User avatar
sirmorris
Posts: 2664
Joined: Thu May 08, 2008 4:45 pm
Location: oxon, uk

Re: Lambda 8300/Power 3000 Mutlirom

Post by sirmorris » Wed Mar 13, 2013 5:05 pm

That should be quite possible. I sense perhaps a mini-project at mahlerts :D
--=== ZXpand+ ... A more moderner all-in-one upgrade solution for ZX81 ===--
* SD/MMC storage * 32K Hires-capable RAM * AY sound chip * Joystick port * Serial *
* BASIC enhancements - plug & play * Reset button * Auto-boot facility *

sascha2000
Posts: 57
Joined: Fri Jul 22, 2011 1:13 pm

Re: Lambda 8300/Power 3000 Mutlirom

Post by sascha2000 » Tue Mar 19, 2013 9:03 am

>That should be quite possible. I sense perhaps a mini-project at mahlerts

Hey, that would be great if you could do, and I may learn a lot!

sascha2000
Posts: 57
Joined: Fri Jul 22, 2011 1:13 pm

Re: Lambda 8300/Power 3000 Mutlirom

Post by sascha2000 » Wed Mar 27, 2013 6:50 pm

The proto PCBs arrived!!!!

Here first pictures. So far it seems to work, further tests will be done in one week ......
1.jpg
1.jpg (108.92 KiB) Viewed 632 times
2.jpg
2.jpg (48.99 KiB) Viewed 632 times

User avatar
TMAOne
Posts: 119
Joined: Thu Aug 16, 2012 5:56 pm
Location: Waterloo, Ontario, Canada

Re: Lambda 8300/Power 3000 Mutlirom

Post by TMAOne » Tue May 07, 2013 5:36 pm

It looks right at home in there Sascha. Don't forget to tell us how it's working out!
Ian

sascha2000
Posts: 57
Joined: Fri Jul 22, 2011 1:13 pm

Re: Lambda 8300/Power 3000 Mutlirom

Post by sascha2000 » Wed Jul 17, 2013 12:45 pm

Hello,

here a video of a ZX81 board equipped with a Multirom (it works now on both Lambda + ZX):

http://www.youtube.com/watch?v=J-f26z8Vqo4

I will now have to do some minor layout changes and than it will go into production.

Regards
Sascha

sascha2000
Posts: 57
Joined: Fri Jul 22, 2011 1:13 pm

Re: Lambda 8300/Power 3000 Mutlirom

Post by sascha2000 » Sun Jul 21, 2013 12:26 am

Hello,

the multirom now works on a ZX81 well too.



Following limitations exists::

* The Forth Rom + Assembler ROM won't work together with Karls 32K Ram expansion. thats cause of his 32k intit circuitry.

* Genereal every expansion that modifies the internal ROM during runtime or switches it off will not work.

* ZX-Pand won't work, cause it switches the internal ROM mostly off.

* The PCB only fits in a Lambda if the original socket is unsoldered, the 27512 Rom is directly soldered on the multirom + the case of the lambda is changed. I have not test this but it seems to work. However I suggest not to do the same.

* Alternatively I suggest to use a flat cable + special sockets like shown in the picture below. I will give the information where to obtain the same for some €.

* The reset pulse to savely change the roms must last 1sec.

The mods on the ZX81 are not too big (Like on the Lambda).

To change the boot rom the keys 1, A, Q + reset have to be pressed by the user.
On some ZX81 computer the 8th Rom does not work (pressing 1 + A + Q + Reset). I won't investigate this, 7 Roms should in my opinion be enough.

Here you can see a prototype setup of the same:
ZX81_small.png
ZX81_small.png (495.46 KiB) Viewed 522 times
1 --> Fiffy implementation of a Reset switch. Will be connected to the modulator case for reset.
2 --> Reset Leitung taken from the expansion bus. Can also taken from other places of the ZX81 board.
3,4,5 --> Connectors for 1, A and Q from keyboard.

3,4 and 5 are soldered here:
zx81_Keyb.png
zx81_Keyb.png (14.95 KiB) Viewed 522 times
2 the reset I have soldered here:
ZX81_Res.png
ZX81_Res.png (6.33 KiB) Viewed 522 times
I have finished the layout now and will test it the next days. If it has no bug I'll probably go into production. Price I can tell when I know the number of PCBs. I won't earn on this one cent, so they will become more or less cheap.
I will not solder the PCBs (exceptions may be there, but it will last very long until they are finished).

Current 13 PCbs are preordered. If no additional order will come in, I will produce 20 pcs.

If anybody else wants a multirom please send me a pn or write it here in the forum.

ROM images, burned Eproms + GALs I will provide of course on demand, for the prices like thos chips can be obtained at reichelt.de

Regards
Sascha

Post Reply

Who is online

Users browsing this forum: No registered users and 2 guests