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Post by mirkosoft on Mar 6, 2015 17:40:46 GMT
Hi! I was trading on Amibay, also Lemon64 for Commodore 1750 RAM Expansion Unit. I know models 1700 and 1750 as REUs with free EPROM socket to use it as External ROM. Look at photo of PCB: One seller explained me that when he opened REU 1750 there was pinout for EPROM socket but nothing soldered in... So, I'm confused and really disappointed that this way is maye unreal. I own REU 1764 modified to 1,5MB (1536K) RAM expansion, so the place for socket is not free and at first I don't know if REU 1764 targetted to C64 had anytime socket or place for socket. So, what I need? Simple explaining how to use and place own EPROMs as external to work. I don't want always open my 128DCR to extract and insert new EPROM to U36 socket, even I have there Megabit ROM Adapter... My meaning was that it will be solved by exchanging my modified 1,5MB 1764 REU to 512K 1750 REU... Thank you for explaining me whole problem. Miro
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Post by hydrophilic on Mar 9, 2015 5:21:44 GMT
First, nice photo... upon close inspection, the top chips are labeled "41256"... at first I was thinking they would be 4464 chips... well either way, you need 16 of them (as shown) to make full 512K (of 8 bits each). One interesting thing is the top row seems identical, and the bottom row is identical, but each row is different brand of chip... VERY INTERESTING!
Second, from seller's description, it sounds like you just need to solder a socket onto the board (like the socket at the bottom-right of your photo). With a socket, you can insert/remove (EP)ROMs whenever you want (well, you have to open the 1750 case...)
You've told me you are not good with soldering, but I hope you can find somebody local to do it for cheap/free. I would solder a socket for free, but you would have to pay shipping both ways (so not very cheap).
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Post by mirkosoft on Mar 9, 2015 6:29:28 GMT
Thank you Robert!
So, it's really so that REU socket can be used as external ROM. OK, so in this case it needs only to solder socket into place for socket... Now I'm awaiting 64NIC+ with EPROM socket for boot, it can be used with EPROM 256K large in config 16× 16K EPROMs by rotary switch. I'll see if is it possible to use in case of C128 or is it only NIC...
Miro
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Post by motrucker on Aug 12, 2015 18:01:11 GMT
Hi! I was trading on Amibay, also Lemon64 for Commodore 1750 RAM Expansion Unit. I know models 1700 and 1750 as REUs with free EPROM socket to use it as External ROM. Look at photo of PCB: One seller explained me that when he opened REU 1750 there was pinout for EPROM socket but nothing soldered in... So, I'm confused and really disappointed that this way is maye unreal. I own REU 1764 modified to 1,5MB (1536K) RAM expansion, so the place for socket is not free and at first I don't know if REU 1764 targetted to C64 had anytime socket or place for socket. So, what I need? Simple explaining how to use and place own EPROMs as external to work. I don't want always open my 128DCR to extract and insert new EPROM to U36 socket, even I have there Megabit ROM Adapter... My meaning was that it will be solved by exchanging my modified 1,5MB 1764 REU to 512K 1750 REU... Thank you for explaining me whole problem. Miro Just ever so slightly off the original topic - do you know about the 16Mb REU project that has been discussed at www.lemon64.com ? It sounds like Jens may take this project on www.lemon64.com/forum/viewtopic.php?t=36367&postdays=0&postorder=asc&highlight=16mb+reu&start=200I would sure rather have a big REU, without the added features of several other existing cartridges that are really aimed at the C-64 anyway. This beat me current 2Mb 1764 REU by a long shot. www.lemon64.com/forum/viewtopic.php?t=36367&postdays=0&postorder=asc&highlight=16mb+reu&start=200
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Post by hydrophilic on Aug 13, 2015 7:08:58 GMT
Thanks for your post, motrucker!
I need to investigate your link, but a simple 16MB REU expansion would be awesome! (Better than 2MB hack, and simpler than 1541 Ultimate)
[Edit] Your Lemon link is very lengthy... still reading it to understand all the possibilities... anyway, thanks again! [/Edit]
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Post by motrucker on Aug 13, 2015 19:27:09 GMT
Thanks for your post, motrucker! I need to investigate your link, but a simple 16MB REU expansion would be awesome! (Better than 2MB hack, and simpler than 1541 Ultimate) [Edit]Your Lemon link is very lengthy... still reading it to understand all the possibilities... anyway, thanks again! [/Edit]Here is another thread on a different forum. This one is newer, there fore somewhat shorter. I don't believe Jens has joined this one yet, that was a big reason I posted the thread from Lemon 64. You can a feel for this project here too however: www.melon64.com/forum/viewtopic.php?f=12&t=2376&start=20
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