Thank you all for responding to this.
As another update - well it wasn't the +5v that was causing the problem.
It was the Mitsumi 56-3217 keyboard mylar that apparently decided it had enough of being pulled in and out of the slot.
The joys of working with >30 year old electornics
Also this is now the 3rd Atari of mine where the power led stopeed working (suspected for same reason - worn/cracked mylar)
A little bit of 8 Bit: 65XE upgrade to 128k RAM
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- rubber_jonnie
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Re: A little bit of 8 Bit: 65XE upgrade to 128k RAM
Another fault diagnosed
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
Re: A little bit of 8 Bit: 65XE upgrade to 128k RAM
Sorry to resurrect an old post but I'm curious on which 65XE motherboard this expansion works? I'm particularly puzzled by the connection between GAL pin 7 (PB6) and PIA pin 16 (PB6) as on my mother board that PIA pin isn't connected to anything. So what is that connection supposed to do?tfhh wrote: ↑Thu Aug 31, 2017 12:26 pmCode: Select all
CHIP XE_320k GAL16V8 SIMPLE_MODE A14 A15 pb2 pb3 pb4 cas pb6 pb7 mode GND mhalt ra8 map casbank casmain fa_14 fa_15 pb5 phi2 VCC fa_15 = A15 + A14 & pb3 & /pb4 & mode & mhalt + A14 & pb3 & /pb5 & mode & /mhalt; /fa_14 = /A14 + /A15 & /pb2 & /pb4 & mode & mhalt + /A15 & /pb2 & /pb5 & mode & /mhalt; casmain = /phi2 + cas + /A15 & A14 & /pb4 & mode & mhalt + /A15 & A14 & /pb5 & mode & /mhalt; /casbank = /A15 & A14 & phi2 & /pb4 & /cas & mode & mhalt + /A15 & A14 & phi2 & /pb5 & /cas & mode & /mhalt; /map = pb4 & pb5 & /pb7; ra8 = /phi2 & pb6 & mode + phi2 & pb7 & mode;
The LS7495 must be placed at the positon of U35. The GAL - bent pin 7, 8, 9,12 and 13 up - will be placed in U34. Connect pin 7 of the GAL to pin 16 of PIA and pin 8 of the GAL to pin 17 of PIA. Pin 9 can be left open (expansion enabled) or closed by switch to ground to disabled the expansion. Pin 12 via 33 Ohm resistor to the pin 1´s of the 8 DRAMs (memory addressline A8) and pin 13 to the pin 6 of MMU. This pin must be also bended, so better is to desolder the MMU, fit it into a socket and replace it with pin 6 bend up.
I make several years ago an article for the ABBUC magazine no. 95. You can download it here, but the text is only in german - sorry.
Jurgen
I just wonder because I'm considering upgrading my 65XE using this. The motherboard I've got is a CO70067, exactly the same mother board used in a 130XE with 128k of memory.
Regards,
JGroth
Re: A little bit of 8 Bit: 65XE upgrade to 128k RAM
Hi,
sorry beeing late to the party. I read you already fixed the problem
sorry beeing late to the party. I read you already fixed the problem
Yes, these is "usual" with the XE keyboards. Don´t know if somebody point it out, but new (really new - not "NOS") mylars are availible from Retronics and some other sellers, just search at eBay for "atari membrane" and you should get it.ChaoticBiker wrote: ↑Wed Jun 10, 2020 1:37 pm As another update - well it wasn't the +5v that was causing the problem.
It was the Mitsumi 56-3217 keyboard mylar that apparently decided it had enough of being pulled in and out of the slot.
The joys of working with >30 year old electornics
Also this is now the 3rd Atari of mine where the power led stopeed working (suspected for same reason - worn/cracked mylar)
Re: A little bit of 8 Bit: 65XE upgrade to 128k RAM
Hi,
Some XE mainboards have only 4 resp. 2 DRAMs in place, these are 4-Bit DRAMs. My solution would work here, too - but Atari didn´t include the location U35 on these mainboards. If you have such model, I can modify the GAL code, but you need then a 22V10 instead of a 16V8 and two more wires.
But, just to have say it, there are much easier ways to get 512 KB expansion memory based on SRAM instead of the DRAM expansions. Removal of the eight 4164 DRAMs at the 2nd bank, de-soldering/empy the holes, install new sockets, the 41256 DRAMs, a GAL... it´s a nice way to tinker around, sure, but more effective are SRAM based expansions today.
This expansion worked that way in all XE versions where an unpopulated U35 is found. By default all XE models are possible, which have the places for 16 pieces of DRAM. Some rare XE mainboards have only one column with 8 DRAMs, these are models where "900XLF" is found on the solder side of the PCB and they have no ECI - only a cartridgeport.JGroth wrote: ↑Fri Jun 26, 2020 7:48 am Sorry to resurrect an old post but I'm curious on which 65XE motherboard this expansion works? I'm particularly puzzled by the connection between GAL pin 7 (PB6) and PIA pin 16 (PB6) as on my mother board that PIA pin isn't connected to anything. So what is that connection supposed to do?
I just wonder because I'm considering upgrading my 65XE using this. The motherboard I've got is a CO70067, exactly the same mother board used in a 130XE with 128k of memory.
Some XE mainboards have only 4 resp. 2 DRAMs in place, these are 4-Bit DRAMs. My solution would work here, too - but Atari didn´t include the location U35 on these mainboards. If you have such model, I can modify the GAL code, but you need then a 22V10 instead of a 16V8 and two more wires.
But, just to have say it, there are much easier ways to get 512 KB expansion memory based on SRAM instead of the DRAM expansions. Removal of the eight 4164 DRAMs at the 2nd bank, de-soldering/empy the holes, install new sockets, the 41256 DRAMs, a GAL... it´s a nice way to tinker around, sure, but more effective are SRAM based expansions today.
Re: A little bit of 8 Bit: 65XE upgrade to 128k RAM
Hello everybody! i found this great thread about 65XE ram upgrade, but just discovered mine has a 130XE(64x4) motherboard with unpopulated U11, U12 and U35: since aren't more available on ebay the C25953, is there a way to program a GAL for replacing it?
- rubber_jonnie
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Re: A little bit of 8 Bit: 65XE upgrade to 128k RAM
If you look earlier in the post, somebody has used a GAL to do a 320KB upgrade. Personally I have upgraded to Ultimate 1MB since I made this post, so haven't followed up any further along those lines.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
Re: A little bit of 8 Bit: 65XE upgrade to 128k RAM
I red about 320k upgrade, but I think a different gal (22v10) and a new jed files it's needed for mb without c34 like mine.rubber_jonnie wrote: ↑Sun Nov 15, 2020 10:51 pm If you look earlier in the post, somebody has used a GAL to do a 320KB upgrade. Personally I have upgraded to Ultimate 1MB since I made this post, so haven't followed up any further along those lines.
Anyway, I followed your suggestion, and just ordered an ultimate 1mb! Thank you!
- rubber_jonnie
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Re: A little bit of 8 Bit: 65XE upgrade to 128k RAM
I have an 800XL and a 65XE, both with Ultimate 1MB, I am very pleased with them. Also recently upgraded to VBXL/XE for super clear video out on both too. I also got a Side3 cart and whilst it has some minor issues that FJC is working on, it really is great.aotta wrote: ↑Sun Nov 15, 2020 11:03 pmI red about 320k upgrade, but I think a different gal (22v10) and a new jed files it's needed for mb without c34 like mine.rubber_jonnie wrote: ↑Sun Nov 15, 2020 10:51 pm If you look earlier in the post, somebody has used a GAL to do a 320KB upgrade. Personally I have upgraded to Ultimate 1MB since I made this post, so haven't followed up any further along those lines.
Anyway, I followed your suggestion, and just ordered an ultimate 1mb! Thank you!
I can also recommend an SDRIVE-MAX too.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
Re: A little bit of 8 Bit: 65XE upgrade to 128k RAM
I have the sdrive max, that I use with 65xe and with my 800xl, but I think I'll upgrade only the 65, because the 800 is boxed and I take it out from its polys rarely, to preserve them!
I'm very interested in VB/XE too, I use RGBtoHDMI for most of my retrocomputer, and I am waiting for the OSSC+koryuu i bought some days ago for digitalizing the composite output of the Atari's ones, but if it won't work as expected, I'll go for the VB/XE solution too!
I'm very interested in VB/XE too, I use RGBtoHDMI for most of my retrocomputer, and I am waiting for the OSSC+koryuu i bought some days ago for digitalizing the composite output of the Atari's ones, but if it won't work as expected, I'll go for the VB/XE solution too!