ROM_SIMM_Connector_Retrofittin' =8-D

[Trash80toHP_Mini]

Like the title says: retrofitting a ROM SIMM Slot Connector to thru-holes left unpopulated by Apple during manufacture will be the next big thing! :lol:

I was surprised to discover this (assumpion) early production MoBo in my more recently acquired Quadra 605, henceforth to be referred to as Q605x.

How many more of these boards do we have in the inventory, comrades?

I'll have to take MUCH better pics, locating where Apple placed a select/deselect option for the ROM SIMM is next on the list.

The header at J18 is for 605/475 Gestalt ID selection, correct?



"Stock" MoBo:





< more pics to come >

Methinks that my original Quadra 630 restoration project will be getting the first Connector_Refit.

 

[dougg3]

The Quadra 700 automatically detects whether ROM SIMM is installed or not. I would guess it uses one of the ground pins to detect it or something. It's possible that the newer Macs don't need the jumper.

The Quadra 840av has these ROM SIMM pads too. I have a Quadra 840av ROM SIMM and unfortunately its pinout is slightly different so it won't work with my SIMM -- the 840av's motherboard presumably supplies 5V on the ROM SIMM chip select pin which would deactivate it. (It must because 840av ROM SIMM has the chip select pin tied directly to 5V). Probably wouldn't hurt anything but the chips wouldn't respond correctly without a hack done to the SIMM.

 

[Trash80toHP_Mini]

That's good news, can't wait to give it a whirl to see if that's the way it works for the 605/475.

I've been reassembling and putting away someting on the order of 11.375 MicroQuadras, Duos, PowerBooks and the odd, eviscerated Mac Plus . . .

. . . very odd, I'll be posting pics of that one real soon now! [] ]'>

Ahyhoot, it seems like the Q605x may actually have been an LC475x (note the missing jumper block on J-18) machs nix . . .

. . . it's now officially the Q605x . . . because it just sounds . . .

. . . and will be interposed between the RAM/Heat Sunk 68040 and bottom plastics of the the DOA MicroQuadraFeetsMac#1 before the week is out.

Heh! )

edit: I just reassembled and tested the Q605x, everything is hunky-dory!

 

[onlyonemac]

Mines got the pads on it-no socket. Also, you're right that the jumper's for the Q605/P475 selection. (I've always wondered what those pads were for-I thought it was so that you could add an extra RAM bank.) It's odd that yours as got the socket on it...

 

[uniserver]

mcdermd is in the middle of scrounging around for dead boards with a ROM SIMM slot he can scavenge, He is looking to desolder this ROM SIMM and then Solder it on a LC475,

for some really cool testing!

So my question is:

Will a SE/30 Romm Simm Slot work on the LC475?

I would assume the Rom Simm slot was standardized?

Here is a picture of a q605 and IIsi together,looks like it should work...

 

[Trash80toHP_Mini]

Same slot, same SIMM, but you'll need to tweak the Quadra's ROM image, AFAIK. Check the DevNotes for the signals/pinouts for confirmation.

Dunno about the drivers for accessing the additional ROMdisk space.

Dr. Braun is your man.

 

[mcdermd]

I've got it fitted. Nothing to test with but it's available now.

 

[uniserver]

you are the man!

 

[Trash80toHP_Mini]

That makes two ROM SIMM enhanced MicroQuadras available for flight testing.

How easy/hard was it to scavenge that connector off the DOA board?

DQ, do you need a MicroQuadra to borrow for to to give this a spin? :?:

olePigeon, is there any chance you might be able to round up some more of those SIMM Sockets?

 

[dougg3]

Nice work guys!

Unfortunately, according to bbraun's testing, it's looking like 040 Macs won't support addressing ROM bigger than 1 MB in size -- at least in the Quadra 650 or the Quadra 700. It appears to be a limitation in the actual ASICs on the logic board :-( That pretty much eliminates the possibility of a ROM disk on these models. You could still use a custom ROM to change the startup chime though...

 

[mcdermd]

How easy/hard was it to scavenge that connector off the DOA board?

Quick and easy with this:

It must have been under 5 minutes to get it out. I cleared the unpopulated holes on the 475 board with a traditional sucker, though. That took a while longer.

 

[dougg3]

That is a *great* tool. Same thing I used to initially add sockets for my IIci's DIP ROMs Well worth the cost especially if you do a lot of soldering.

 

[Trash80toHP_Mini]

That makes sense, FDD only was a thing of the distant past and HDDs were plenty big enough that ROM Disk was silly by that time.

Custom chimes and imagesw for startup on the small ROM SIMMS would be a good way to chew through your small ROM SIMM inventory though! :approve:

 

[techknight]

Been looking for one of those vacuum desoldering irons for a looong time. Never found one.

 

[uniserver]

I have an El-Cheapo version.

It mostly works

 

[MinerAl]

Couldn't you take the rubber bulb off that and attach a dust-buster size vacuum?

 

[techknight]

those bulb irons SUCK.

They really really do, even if you attached a vacuum pump they just dont have enough heating power....

 

[CelGen]

those bulb irons SUCK.

Agreed. they have driven me nuts.

 

[Trash80toHP_Mini]

I love the play on words.

I've got one that looks similar to this.

IIRC, mine cost something like $30 or $40 from Jameco back in 1989-90. I need to put a new tip on it again, but it has worked fairly well for a long time.

That snazzy continuous duty vacuum pump unit looks like it'd be a lot better, especially for removing EuroDin PDS Connectors.

edit: Yep, Jameco is listing it as a new product.