130XE to 320 KB.

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130XE to 320 KB.

Post by redhawk668 »

Well, I successfully completed a 320 KB upgrade on my 130XE and now knowing that the information is very hard to find I thought why not share my experiences doing this upgrade. This upgrade is based on an upgrade by Scott Peterson with a little improvement to make ANTIC banking work again, as this upgrade disables it.

The upgrade itself requires good desoldering/soldering skills, because there is a lot of desoldering/soldering in this upgrade. But, as we're all retro nuts, this shouldn't be a problem, I guess.

So, let's get crackin'.. Ok, what do we need for this upgrade:

- 8x 41256 DRAM's
- 8x DIL-16 turned pin sockets
- 1x DIL-40 turned pin socket
- 1x 74LS158 (or 74HC158)
- 1x 33 Ohm resistor
- Some jumper wire
- Soldering Iron
- A lot of patience

My 130XE board, before the upgrade:

D2dc1zg.jpg (140.58 KiB) Viewed 1151 times

The little PCB in the middle is the Sophia RGB upgrade

On my 130XE, there are two memory banks of 64KB in 16x 4264 DRAM's (rubbish, but as long as they work...) making up 128 KB of RAM. Now, start with desoldering the DRAM chips on the right side of the board. Do this carefully, because Atari used some cheap ass PCB's for the 130XE, so tracks/traces can lift quite easily.

If all the DRAM's have been removed, solder in the DIL-16 sockets, turn over the board and connect all of the pin 1's on the RAM sockets together with jump wires and feed enough wire through the left hole in the board (see image).

ShnCyq7.jpg (178.39 KiB) Viewed 1151 times

All of the pin 1's tied together

Now desolder the 6520 chip and remove it carefully from the board and solder the DIL-40 pin socket in it's place. Bend up pins 15 and 16 of the 6520 chip and insert it in the socket.

Take the 74LS158 chip, bend up all of the pins, except pins 8 & 16. To prevent shorts I recommend shortening the pins of the 74LS158, except of course pins 8 & 16, because we'll need them. Now, place the 74LS158 on top the CD4050 chip and solder pins 8 & 16 to pins 8 & 16 of the CD4050 chip.

Take some short wire and connect pin 15 to pin 8 of the 74LS158;

Take another wire and connect pin 1 of the 74LS158 to pin 30 on the GTIA chip;

Connect using some wire pin 15 of the 6520 chip to pin 2 of the 74LS158 chip;

Now connect pin 16 of the 6520 chip to pin 3 of the 74LS158 chip;

Take the 33 Ohm resistor, solder it to pin 4 of the 74LS158 chip, connect the wire from the RAM sockets we soldered earlier to the other end of the resistor. I recommend some heat shrinking tubing for insulation to prevent shorts.

Insert the 41254 DRAM chips in the sockets.

The end result should look like this:

107ZWJL.jpg (165.59 KiB) Viewed 1150 times

320 KB RAM upgrade in place

We're almost finished now, as stated earlier this upgrade disables ANTIC banking. Fortunately, this can be fixed by joining the solder pads of pins 15 and 16 of the 6520 chip together. Turn over the board and make a solder bridge between pins 15 and 16. This fixes ANTIC banking.

Now, place the board with some insulation on a table, connect all the needed stuff and turn it on. It should come up with the familiar black/blue screen with the READY prompt. If it doesn't, check for shorts or lifted traces or the soldering for cold joints.

Now, reassemble everything and enjoy your 320 KB 130XE :D

To test the 320 KB upgrade try the NUMEN demo. If it runs, you know your 320 KB upgrade works!
My collection: 1040 STE, TOS 2.06, 4 mb, CosmosEx - 520 STFM, TOS 1.04, 4 mb, Blitter, CosmosEx - 520 STFM, TOS 1.04, 4 mb - 1040 STF, TOS 1.04, 1 mb, Gotek - Amiga 1200 with Blizzard 1220/4 - Amiga 500 + ACA500 - Amiga 500 + TF530, 1 mb chipram hack.

Atari 8 bit: 800XLF, stock - 600XL, Ultimate 1 mb, Sophia RGB - 130XE, 320 kb, Sophia RGB

Sinclair stuff: 3x Spectrum 48KB, Clones: Harlequin, JS128, Nuvo128 and Issue3B replica.

Ultimate64, a few C64 breadbins and Pi1541 for storage.
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Joined: Thu Mar 22, 2018 1:34 am

Re: 130XE to 320 KB.

Post by walter_j64bit »

WOW, 130XE gets some 320K love! 8-) I know homesoft have games that can use that 320K!
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Re: 130XE to 320 KB.

Post by rubber_jonnie »


Nice to see some 8bit love, along with the 128k upgrade I did, plus the other 320k upgrade on here, we have options now, and that's got to be good :)
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...
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