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intric8
Seattle, WA, USA
Website

Posted Sun Jan 27, 2019 12:10 pm

The 128 support is not as rock solid as for the 64, but it's getting there. If you aren't running REUs I think it's fine as the 1541 emulator (which is what I use it for the most on my 64).

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Mr.Toast
Roseville, CA

Posted Mon Jan 28, 2019 3:29 pm

The Ultimate 64 is looking tastier and tastier :/

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Zippy Zapp
CA, USA

Posted Wed Jan 30, 2019 6:54 am

This article about an in development RAM expansion for the 64/128 by Jim Brain might be of interest. This was posted last year but there has been no update since. Still, it sounds cool and I may ping Jim Brain to see if it is still ongoing.

http://www.go4retro.com/2018/05/21/ram- ... r-the-c64/

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Dynamic_Computing

Posted Sat Feb 02, 2019 12:06 pm

I found an REU from a guy in Canada,and bought it and a Aprotek expander for $100 plus shipping! I am looking forward to getting it next week.

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BertyFromDK

Posted Sun Feb 17, 2019 1:13 am

intric8 wrote:This leaves me with a few questions.

1. Should I de-solder the plugged holes and solder in a socket for a function ROM? I wouldn't ever want to solder in a function ROM as there'd be no way to disable it. If I installed a socket for a function ROM, would I need to remove a section of the heat shield for it to fit?
2. And look at that area above the ROM bay. It looks like it's made for a jumper - for adding an on/off switch, perhaps? Does anyone reading this know if that's for enabling/disabling the function ROM when it is installed? I found the schematics if you're skilled in reading those.
Hi, I may be able to shed a bit of light on question 2 here:
If the jumper area you are referring to is the one labeled J2, then it is not for enabling/disabling the ROM, but for selecting the size, either 16Kbyte or 32K.
I'm afraid that in order to be able to disable the ROM, it is necessary to cut the trace on the board that connects /CE (Chip Enable) to ground, and install a switch there so that this pin can either be grounded or pulled up to Vcc (5V) via a resistor, as I have shown in this excerpt from the diagram:
Image

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intric8
Seattle, WA, USA
Website

Posted Sun Feb 17, 2019 10:48 am

Ah - thank you for that information, BertyFromDK!

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Dynamic_Computing

Posted Tue Feb 19, 2019 9:31 am

Zippy Zapp wrote:No, that's cool, I thought you might have had one already. Yeah, I wouldn't open it again unless I had to either as those plastics get brittle too. The resistor is on the schematics I was just curious if they actually put it in or if all of them, even the C128 versions, are left off.

I have heard of people using the 1764 on a 128 with no problems so it was just a curiosity.
I am using a 1764 on my C128, and it is even on an expansion board with four slots, one being shared with my 64NIC+ - I have had no issues, and GEOS recognizes and uses the RAM with no apparent problems.

I really like the extra 256K in GEOS on my board - it makes reboots a very fast thing.

User avatar
Zippy Zapp
CA, USA

Posted Thu Feb 21, 2019 7:55 pm

@Dynamic_Computing,

Cool! Thanks for the info. Have you thought about upgrading the 1764 to 512k? I know you can go higher to I think 2MB, but to 512k is super easy as it just requires soldering in some DRAM. I updated one of mine and it works good.

User avatar
Dynamic_Computing

Posted Sun Feb 24, 2019 4:59 pm

Zippy Zapp wrote:@Dynamic_Computing,

Cool! Thanks for the info. Have you thought about upgrading the 1764 to 512k? I know you can go higher to I think 2MB, but to 512k is super easy as it just requires soldering in some DRAM. I updated one of mine and it works good.
I am not sure to do with the 256k that is in there! I suppose that when I start playing with video playback from the REU I will want to upgrade it.

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Zippy Zapp
CA, USA

Posted Mon Feb 25, 2019 1:59 pm

Dynamic_Computing wrote: I am not sure to do with the 256k that is in there! I suppose that when I start playing with video playback from the REU I will want to upgrade it.
I hear ya, I probably don't have a need for it at this time, although GEOS and Maverick make use of it and is especially helpful for duplicating 1581 disks with only 2 swaps.

I upgraded mine back in the 80's because I ran a Color64 BBS in my city and it enabled me to store all the overlays and BBS games in memory so that there was zero disk access. It was a long bootup as everything from a couple of disks was copied into RAM but it was such a huge helper. I still have the BBS and all the files as it was in 1989 but I haven't had to time to see if I can boot it up since it was sort of a semi-complicated configuration at the time with 1764, 1581, 1571, 1541C, 1541-II all in use at the same time.





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