130XE 512 memory upgrade

[JGRAHAM2]

Has anyone seen this upgrade? Switchable from 128 to 512

 

 

[_The Doctor__]

yes, it's a peterson with some modification. I still have baggie with the stacked chips ready for install

[JGRAHAM2]

41 minutes ago, _The Doctor__ said:

yes, it's a peterson with some modification. I still have baggie with the stacked chips ready for install

What do you think he as doing on U21?

[_The Doctor__]

looks like a 5 volt and ground pick off point... using machine pins for convenience...

[+Nezgar]

Technically it's 576K total (64+512) using portb bits 1,2,3,5,6, so no BASIC or separate ANTIC access to extended memory banks.

 

The switch should reduce memory to 192K total (64+128) using only portb bits 2,3,6 - and restore BASIC & ANTIC functions.

 

Curious to know what OS they programmed onto that EPROM.... care to dump it?

[JGRAHAM2]

6 hours ago, Nezgar said:

Technically it's 576K total (64+512) using portb bits 1,2,3,5,6, so no BASIC or separate ANTIC access to extended memory banks.

 

The switch should reduce memory to 192K total (64+128) using only portb bits 2,3,6 - and restore BASIC & ANTIC functions.

 

Curious to know what OS they programmed onto that EPROM.... care to dump it?

It is the standard and the Expander OS. I have an XL with the same OS. I don’t know what he did with it. He had a very high socket of a type I’ve never seen for the OS. It looked to be high quality, but I couldn’t fit the 4 in 1 OS that I got from you under the keyboard. I removed it and replaced it with a precision socket. I had to add 4 bodge wires connecting to the BASIC ROM as I did damage the board removing it. (Works great, thanks!) It looks to me like this computer was wet at one time. See the picture of the lower shell.

 Posted a dump here: 

 

 

Edited February 20, 2021 by JGRAHAM2

[JGRAHAM2]

8 hours ago, _The Doctor__ said:

looks like a 5 volt and ground pick off point... using machine pins for convenience...

I bought this computer as a lot with some 1050s and a couple XLs from a guy’s son who inherited them. I wish I had asked what he did with them. I’m sure there is quite a story behind them. Two of them were upgraded with memory and the Expander OS that allows multiple RAM disks and to boot from one of them. Someone suggested a BBS in a post I have on this site.

[+Nezgar]

5 hours ago, JGRAHAM2 said:

It is the standard and the Expander OS. ....  Posted a dump here: 

D'oh of course... that OS is still so "new" to me it slipped short term memory. Still need to test that OS myself on real hardware and hopefully documentation turns up eventually.

[JGRAHAM2]

2 hours ago, Nezgar said:

D'oh of course... that OS is still so "new" to me it slipped short term memory. Still need to test that OS myself on real hardware and hopefully documentation turns up eventually.

The thing to remember is you have to choose to boot from your SIO connected device, the same as you choose to boot from the ram disk.

[JGRAHAM2]

After cleaning it up, it looks like this. It was very crusty, like someone really used it, food crumbs and all. I think I’ll keep the badge as it is. A computer that was really used shouldn’t look like it just came from the factory.

 

[+Nezgar]

18 minutes ago, JGRAHAM2 said:

The thing to remember is you have to choose to boot from your SIO connected device, the same as you choose to boot from the ram disk.

Yeah I figured out that much... Just trying to figure out how to access the Mini-DOS that I found evidence of in the ROM, just not sure the key-combination that invokes it...

15 minutes ago, JGRAHAM2 said:

After cleaning it up, it looks like this. It was very crusty, like someone really used it, food crumbs and all.

Very nice! Yeah I had a 130XE that was encrusted in thick smokers tar... dark yellow all over, and the keys were so dark you couldn't see the letters on the keys... Disassembled the case and keyboard (removed the mylar and metal backing) and ran those through the dishwasher. They came out immaculate like just from the factory, not yellowed at all.

 

If there's something to be said for smoking... it protected the plastic from yellowing after all those years.

 

The machine has a Peterson 320K upgrade, having been used for the Eclectic Collective BBS.. so sentimental value to keep that one in there.. Very clean wiring inside - it just needs a multiple OS upgrade added in!

 

(Hmm don't appear to have any pictures of the RAM upgrade handy... will have to take some again next i have that machine open... This was the same machine that had the additional resistors added to "revive" the function keys: