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ROMSIMM for Macintosh SE/30 aficionado [message #4662]

Thu, 26 April 2018 12:18

rhkoolstar
Messages: 276
Registered: October 2015

Senior Member

Now for something completely different...

I am the proud owner of a Macintosh SE/30 and I wanted to experiment wit a 32bit 'clean' ROM. Off course you can buy such a beast, but I decided to make my own. After some soldering woes I got it to work, but as per usual, I now have about 25 SIMM boards left over. (3 SIMMs fit on a 10x10 board. Wink

If somebody is interested, they are available for 50 cents per SIMM (plus $3 for shipping). You can cut them yourself if you want.

One word of warning.... I used SMD PLCC32 sockets, which are a pain to solder without special tools. I ended up using the 'hot plate' soldering method, which worked surprisingly well. I intend to just solder the flash ROMS (AM29F010B) directly to the board when I'm done for the final product.

I also made gerbers for a TH version from the same design (untested). If you like those, you can order then yourself (use 1.2 mm board) - 1 TH plus 2 SMD SIMMs per board.

Rienk

Attachment: ROMSIMM_TH.zip
(Size: 52.97KB, Downloaded 290 times)
Attachment: 20180426_211051.jpg
(Size: 543.17KB, Downloaded 363 times)

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Re: ROMSIMM for Macintosh SE/30 aficionado [message #4679 is a reply to message #4662]

Thu, 03 May 2018 11:10

quarterturn
Messages: 86
Registered: April 2018

Member

I'd be interested in one if I could also buy from you pre-programmed EEPROMs. I can easily solder them in my reflow oven, but would prefer not to buy more gear just to program them once.

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Re: ROMSIMM for Macintosh SE/30 aficionado [message #4680 is a reply to message #4679]

Thu, 03 May 2018 12:04

rhkoolstar
Messages: 276
Registered: October 2015

Senior Member

Can do...
I currently only have AM29F010B Flash (makes for a 512k SIMM)

4x AM29F010 $2.52
4x socket $0.94
1x board $0,50
shipping $3.00

Total 6.96

you can get an extra board for the same shipping charge

Is that agreeable?

You also have to select unmodified ROM or RAMcheck disabled. I suggest the last one, because the original ROM does not clear the video RAM during the RAM check. This shows garbage, before the video initializes.

I you want, just PM me a shipping address.

Rienk

ps. you own a reflow oven but no programmer????

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Re: ROMSIMM for Macintosh SE/30 aficionado [message #4711 is a reply to message #4680]

Fri, 18 May 2018 06:13

quarterturn
Messages: 86
Registered: April 2018

Member

For the benefit of other members, this worked out great. I just applied solder paste manually under my microscope, placed the sockets and bypass caps, then put it in the reflow oven. My SE/30 is now 32-bit clean!

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Re: ROMSIMM for Macintosh SE/30 aficionado [message #4712 is a reply to message #4711]

Fri, 18 May 2018 14:06

rhkoolstar
Messages: 276
Registered: October 2015

Senior Member

I just tinned the pads on the board, put rosin flux on the socket legs, placed the board on an aluminum sheet on a hotplate, turned on the power on low and waited until the solder melted and the sockets sunk to the board. Then removed the aluminum sheet and let it cool down. The hotplate itself stays hot far to long.

Then I put the caps on by hand.

You can probably do this in a skillet over a gas flame Smile

No fragile components to worry about, but you want to heat up slowly to prevent the PCB from curling up

Rienk

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