Ultimate 1MB upgrade - questions

[+DrVenkman]

Can you install a U1MB in a 1200XL? I didn't see anything on Lothorek's website.

Yes. FJC’s videos are a great resource.

 

Basically you need to move two jumpers on the motherboard and remove a third entirely, then solder a couple jumper wires under the board between two chips and one point of the jumper you remove. This basically converts the OS access to mimic that of an 800XL so the the entire OS rom can be addressed to one socket instead of the two sockets used by the 1200XL.

 

Of course if your 1200XL has 24-pin OS sockets rather than 28-pin, you’ll have to replace the existing socket or at least solder in some female header pins to make up the difference.

Edited March 5, 2019 by DrVenkman

[hueyjones70]

I believe I have read that the U1MB has 4 possible OSes. Are the pre determined, if not how do I go about getting it programmed with the OSes that I would like to have?

[+DrVenkman]

I believe I have read that the U1MB has 4 possible OSes. Are the pre determined, if not how do I go about getting it programmed with the OSes that I would like to have?

 

Get the four 16K OS roms you want to use, then use Jon's wonderful UFLASH tool to install whichever OS ROMs (and BASIC versions) you want.

[hueyjones70]

Does "get" mean download? Do I need to be hooked up by USB2PC or some similar process?

[Stefan Both]

Does "get" mean download?

Yes, as an option. Yiu can also ask someone to get it on disk.

 

Do I need to be hooked up by USB2PC or some similar process?

No. You can use a disk drive or a SIO2SD or something like that.

 

You need the (flash) program >>uflash<<.

Start it, access the disk (or whatever) and use it

to "burn" the roms into the 1umb.

 

Stefan

[hueyjones70]

I hope the RF shield on the 1200XL is optional. I just finished installing the U1MB on mine and I couldn't possibly fit the shield back on. I also have a UAV-D installed and I would have to make a cutout just for that.

[+DrVenkman]

I hope the RF shield on the 1200XL is optional. I just finished installing the U1MB on mine and I couldn't possibly fit the shield back on. I also have a UAV-D installed and I would have to make a cutout just for that.

 

It is. I've got a U1MB and UAV in one of my 1200XLs and it's been running completely shield-less for the past 20 months or so, problem free.

[Kyle22]

I hope the RF shield on the 1200XL is optional. I just finished installing the U1MB on mine and I couldn't possibly fit the shield back on. I also have a UAV-D installed and I would have to make a cutout just for that.

Cut a hole in the shield to clear the U1M. The shield protects the computer from incoming cosmic rays which are known to flip bits in EPROMs. The shield also stiffens the board and makes it less prone to damage.

If you can fabricate a little sheet metal cap to fit above the U1M, then that's all the better.

[SS]

The shield also stiffens the board and makes it less prone to damage.

 

This is probably the best reason to consider keeping the shilding. I don't have a 1200XL myself but I do know that 800XL ALPS made keyboards have been know to flex when the top shilding is removed.

 

I kept my bottom shielding intact on my U1MB 800XL because it wasn't in the way of anything and I thought that it might give better support to the motherboard if I left it alone.

 

..

Edited March 24, 2019 by SS

[flashjazzcat]

This is probably the best reason to consider keeping the shilding. I don't have a 1200XL myself but I do know that 800XL ALPS made keyboards have been know to flex when the top shilding is removed.

In contrast to the 800XL, the 1200XL's keyboard receives no structural support from the RF shield, so with regard to keyboard rigidity it makes no difference whether the shield is present or not. I suspect Kyle was talking about the motherboard rather than the keyboard.

[Kyle22]

I was referring to the motherboard. I have seen bent keyboards, but not sure about the cause.