ROM Clips for securing custom ROM SIMMs in an SE/30

[JDW]

I am posting this in the Compact Mac sub-forum because most of us tend to use custom ROM SIMMs on the SE/30.

I've been doing the prep work for a video about the ROM SIMM Programmer and ROM SIMMs currently sold today. One big issue is the thickness of the ROM SIMMs and the finicky nature of the SE/30 ROM SIMM Socket. One of my SE/30 motherboards was reworked by my friend @Kay K.M.Mods here in Japan. He swapped out all the RAM SIMMs and the ROM SIMM socket too, using his Hakko desoldering gun (which I don't have). Kay did a fabulous job, and the sockets all have metal tabs. No issues with any ROM SIMM, neither stock nor from 3rd parties.

But there is a problem...

I have other SE/30 boards which still have the stock ROM SIMM socket that is all white plastic and with no metal tabs. I think a good number of you SE/30 owners have this type of socket too. Even if some ROM SIMM vendors could make a ROM SIMM thickness that matches the 1.27mm thickness of stock ROMs (as measured at the pads), the fact is that not all vendors do that, and apparently it is troublesome to get PCB makers to do that too, not to mention the added cost. So people buying custom ROM SIMMs may end up getting something that is as thin as 1.08mm.

Yet another issue is that not everyone will pay somebody to swap out their SIMM socket.

I am now pondering all the cheap solutions to the ROM SIMM socket problem.

Rubber bands or tape are not a long term solutions that we should ever consider.

Some people suggest using lots of flux and then drag soldering a thin layer of solder over the pads. I've done that in the past and it doesn't last for me. That's because I do a LOT of testing and a LOT of ROM SIMM swaps. What happens is the solder breaks up over time and teensy, tiny solder flakes touch adjacent pads, causing a short that prevents the SE/30 from working reliability, if it even boots at all. So I personally dislike the solder hack.

The second solution that stands out to me is the one I have yet to try -- ROM CLIPS. I had hoped that the Etsy store of the creator, @PotatoFi , would start selling them again, but after speaking with him privately, it seems that will not be the case. The license for the A & B type ROM Clips prohibits commercial sales. It only allows us as individuals to print them for personal use. And if you lack a printer, then your only option is to use an online service to get them printed.

FIVE QUESTIONS:

1. Is Shapeways considered to be the best out there in terms of quality and price? And do any of you have experiences using a "service" like that to print the ROM Clips?
   
   
2. What are the required print tolerances supposed to be for the ROM Clips to be most effective on an SE/30 ROM SIMM Socket?
   
   
3. What plastic should be chosen to print the clips, or does it even matter in this application? Since the Clips will press against the SIMM and possibly be taken off and put back on often, I would assume the chosen plastic should be durable. I have zero experience with 3D printing though, hence my question about plastic choices.
   
   
4. If any of you have tried the Clips on your SE/30 ROM Socket, how long have you used them, what are they made of, and have the clips completely resolved ROM SIMM connectivity issues for you, even when you remove and swap out the ROM SIMM multiple times?
   
   
5. Are there other vintage Macs compatible with custom ROM SIMMs (e.g., IIx, IIcx, etc.) which have similar problems as the SE/30 when using thin ROM SIMMs? Or is this issue very much exclusive to the SE/30?

Knowing the answers to the above questions will help me know what I should recommend to people in my forthcoming video. If the ROM SIMM doesn't make good contact, all the fun you planned to have with the ROM SIMM and the Programmer will come to naught.

Many thanks!

 

[JDW]

67 views but no replies as of this writing indicates I have asked an especially challenging set of questions.

Due to the lack of replies, I will now tag a few highly-informed people who might know the answers put forth in my opening post...

@alxlab
@Androda
@Ron's Computer Videos
@PotatoFi

Sorry, guys. But inquiring minds want NEED to know!

 

[This Does Not Compute]

1. Is Shapeways considered to be the best out there in terms of quality and price? And do any of you have experiences using a "service" like that to print the ROM Clips?
   
   
2. What are the required print tolerances supposed to be for the ROM Clips to be most effective on an SE/30 ROM SIMM Socket?
   
   
3. What plastic should be chosen to print the clips, or does it even matter in this application? Since the Clips will press against the SIMM and possibly be taken off and put back on often, I would assume the chosen plastic should be durable. I have zero experience with 3D printing though, hence my question about plastic choices.
   
   
4. If any of you have tried the Clips on your SE/30 ROM Socket, how long have you used them, what are they made of, and have the clips completely resolved ROM SIMM connectivity issues for you, even when you remove and swap out the ROM SIMM multiple times?
   
   
5. Are there other vintage Macs compatible with custom ROM SIMMs (e.g., IIx, IIcx, etc.) which have similar problems as the SE/30 when using thin ROM SIMMs? Or is this issue very much exclusive to the SE/30

I'll try to take a crack at these:

1. Shapeways is probably the best-known, but there are plenty of other print-on-demand services out there. Both PCBWay and JLCPCB offer 3D print-on-demand services. Hubs is another one, and before I bought my own printer, I used a previous incarnation of it called 3D Hubs. (The idea was that it was a network of independent printer owners who would offer print-on-demand services; you could pick someone who was local to you and communicate with them directly. I'm not sure if there are any services like that still around though.) Regardless, the bigger print-on-demand shops all use industrial printers, which is to say, they're going to produce perfectly suitable quality results.

2. According to the project page for those clips, they can be printed at .2mm layer height, which is on the "coarse" side of things (most model slicing software defaults to .15mm, and "detailed" parts are sometimes printed at .10mm). Unless you're using the cheapest, most janky printer imaginable, most anything will be able to print the clips with suitable accuracy.

3. Also per the project page, PLA seems to be suitable, and that's considered the most "basic" of 3D printing filaments. You could step up to PETG if you wanted, but the temperatures inside a Mac aren't going to come close to affecting a PLA print (I use PLA exclusively and have had many printed parts inside Macs for years).

4. Can't answer this one.

5. This issue would conceivably affect any machine with a similar ROM socket. The root of the problem is that original ROM SIMMs use 1.3mm thick PCBs, whereas the modern replacements are around 1.2mm. Thus the new SIMMs are a bit loose in the socket, since the sockets are designed for 1.3mm PCBs. The SE/30's ROM socket isn't a part that's unique to it. Apple did use varying styles of ROM socket, generally just as parts availability allowed; some machines have the nicer sockets with metal latches, while others have the cheaper ones with plastic tabs. My understanding is that the metal latch sockets are a bit more forgiving of custom ROM SIMMs.

 

[JDW]

I sincerely appreciate your time in composing that very helpful reply, Colin!

 

[JDW]

Forgive me, Colin, one quick question. You didn't mention "Resin." Would Resin/SLA be just as suitable for these ROM Clips as an FDM like PLA/ABS/ASA?

The reason I ask is because JLCPCB's 3D printing service complains the ROM Clips are too small for FDM printing!

I am able to choose from various Resins (which offer "Sanding")...

As well as SLS or MJF Nylons...

 

[PotatoFi]

The second solution that stands out to me is the one I have yet to try -- ROM CLIPS. I had hoped that the Etsy store of the creator, @PotatoFi , would start selling them again, but after speaking with him privately, it seems that will not be the case. The license for the A & B type ROM Clips prohibits commercial sales.

It's true! I am no longer selling these clips, as I have moved from the United States to Finland, and decided to not take on the complexity of running my Etsy shop from another country.

To address the licensing issue, I have now changed the license to Creative Commons - Attribution - Share Alike. Hopefully, this greatly simplifies your endeavors here. Please feel free to work with someone to get these clips produced. I sold them for $3/pair, as they are a very fast print and consume very little material.

Is Shapeways considered to be the best out there in terms of quality and price? And do any of you have experiences using a "service" like that to print the ROM Clips?

I'd recruit someone in the forums to help, or get a printer. I recommend either a Prusa MK4, or Prusa MINI+ (in fact, I had to abandon my MINI+ at the last second while leaving the US, and am planning to buy another soon).

What are the required print tolerances supposed to be for the ROM Clips to be most effective on an SE/30 ROM SIMM Socket?

Most modern, mainstream printers have the same stepper motors and drive belts, and thus the same resolution in the X and Y axis. On the Z axis, I recommend a 0.2 mm layer height, although the resolution in this axis shouldn't matter very much.

What plastic should be chosen to print the clips, or does it even matter in this application? Since the Clips will press against the SIMM and possibly be taken off and put back on often, I would assume the chosen plastic should be durable. I have zero experience with 3D printing though, hence my question about plastic choices.

Like Colin said, either PLA or PETG would be fine. I printed them in PETG as it's slightly tougher and a bit springier.

Resin printing is a totally different printing technology that I am unfamiliar with. Usually, the parts require post-print processing, extra chemicals, gloves, etc. My understanding is that the parts have insanely great resolution, but the nature of them being made of resin instead of thermoplastic makes them much less useful for day-to-day usage parts. Think table-top game figures, not brackets and clips.

If any of you have tried the Clips on your SE/30 ROM Socket, how long have you used them, what are they made of, and have the clips completely resolved ROM SIMM connectivity issues for you, even when you remove and swap out the ROM SIMM multiple times?

I've removed and swapped out my Mac ROM-inator II many, many times, and personally had a 100 percent success rate! Additionally, I sold 76 sets of clips, and never had a report of them not working. Nice!

Of course, I'd love to hear additional feedback - both good and bad!

Are there other vintage Macs compatible with custom ROM SIMMs (e.g., IIx, IIcx, etc.) which have similar problems as the SE/30 when using thin ROM SIMMs? Or is this issue very much exclusive to the SE/30?

I'd be curious to hear about this one as well! I only advertised for the SE/30 (I've never seen a IIx or IIcx in person).

 

[JDW]

@PotatoFi
You just posted some incredibly helpful information! The licensing change especially will help encourage availability of the ROM Clips because Sharealike allows for "commercial use" (with attribution). Thank you very much for providing all those details!

 

[alxlab]

I've only used JLCPCB as a 3D printing service and own Prusa i3 mk3s which is an FDM printer.

My two cents regarding FDM 3D printing material for a clip is that I would highly recommend PETG over PLA. As mentioned before PETG is gives a good mix of flexibility, rigidity, ease of printing and temperature resistance. For something like a clip I would definitely choose PETG over PLA. For anything I'd like to last I would choose PETG over PLA.

From my personal experience the JLCPCB's Multi Jet Fusion (MJF) and Selective Laser Sintering (SLS) materials are too flexible to make an effective clip (unless you make the whole clip have thicker plastic to compensate).
The SLA resins would probably give the right flexibility and stiffness but all the resins I've seen give the same temperature resistance or lower than PLA.

Would temperature resistance matter in this case? Probably not unless you transported the computer in a hot car or left the clips out in the sun.

I have not tried the SE/30 clips personally either so I can't comment on that.

 

[PotatoFi]

Hi everyone!

Thanks to some great feedback from @JDW, I have released v2 RC1. I'm calling this a release candidate, because I have neither a 3D printer nor vintage Mac available to test them in. They correct a fitment issue that JDW experienced, and added a slot to clear the LED on the Kay Koba SMC ROM SIMM.

Also, keep in mind that these now have a commercial license. I would be 100 percent fine with someone commercially producing them, as long as you link back to the Printables page.

If you try these, please let me know how it goes!

Macintosh SE/30 ROM Clips by PotatoFi | Download free STL model | Printables.com

Trouble with your Macintosh SE/30 ROM SIMM not working? | Download free 3D printable STL models

www.printables.com

 

[YMK]

Parts like this requiring extreme precision typically need several iterations through the slicer and printer to get right.

I wouldn't expect JLC or any other service to get it right on the first go.

A printed clip that's compliant/springy would be more forgiving on tolerances.

 

[This Does Not Compute]

I wouldn't consider the precision required to be "extreme." The first set of clips that came off my Prusa Mini fit just fine using stock settings in the slicer.

 

[Mu0n]

I checked my SE/30 ROM SIMM bought earlier this year from BMOW and indeed it is a 1.20 mm variant. I'll be doing the drag soldering technique, I don't expect to move it much. My soldering equipment is there on my bench if I need to apply a new coat, which I don't expect to do.

I don't have anything against 3d printed parts, I just don't own a printer or have an easy access to it (a friend covers all my needs but is 20 mins one way from my work or 30-35 from home one way).

 

[JDW]

Obtaining ROM clips is a problem especially because companies in China like JLCPCB refuse to print things that small! I know because I tried and failed to order them. That’s why I think it would be great if every ROM SIMM vendor could obtain the proper permissions to distribute the Clips, a price of course, to anyone who wants them.

I deliberately did not mention the drag soldering technique in my video. The reason why is because I tried it and did not have long-term success, probably because in my work, I need to swap out ROM SIMMs from time to time. And if you like to reprogram yours because you have a Programmer, you would certainly do the same.

To make the SIMM thick enough to function, I had to add a fairly substantial amount of solder, and over time the pins broke up that solder and caused it to flake onto adjoining pins such that some pins would short out, and the machine wouldn’t work; and for the longest time I couldn’t figure out why. ROM clips resolve that headache. But again, the main issue is, as you said, obtaining them.

Some people have suggested rubber bands, but that is not a good idea at all because the rubber breaks down rapidly and eventually breaks.

Another approach is to use the equivalent of a super long and thick paper clip to act as a shim and apply pressure opposite the chip side of the ROM SIMM. I have tried that, but it makes me a little bit leery because it puts a lot of stress on those aging plastic parts at the very left and right of the socket. That’s another reason I didn’t mention that in my video either.

The best solution overall is to pay somebody to swap out the ROM socket with one with metal clips. But ROM Clips remain the best #2 solution.

 

[Mu0n]

I don't plan to swap-in/swap-out ROMs often and I don't plan to own a programmer. If I need a ridiculous amount of fast loaded software with no size limits, I'm just happy with a BlueSCSI v2 rather than the hoop jumping of gettting a programmer. That's just me though. I don't have a case scenario where access to a SCSI drive is compromised or where I need ROM loaded speed at all costs.

 

[JDW]

In that case, simply be sure not to add too much solder. It's hard to quantify how much is too much though, because if you don't add enough, adding solder doesn't work. Adding too much will create tiny blobs on each pad of the ROM SIMM. The pins on the motherboard socket will slowly embed themselves in the solder blobs and that forces the sides of the blobs outward over time. But if the solder blob isn't too big, that outward movement of the solder probably won't be big enough to bridge the gaps between the pads, and then you would be okay.

For everyone else pondering a purchase from BMOW from today forward, it seems the ATOM SIMMs are now back in stock, and as I said in my video, Steve Chamberlin specified a PCB thickness of 1.27mm at the factory, which means that edition should work without solder, shims, ROM Clips, etc.

The same is true of GGLabs, who has been selling a thick SIMM for the past 2-3 years. No need for solder, shims, ROM Clips, etc. for SE/30 installs.

All other vendors have thinner SIMMs only because it is costly and very hard to get Chinese PCB makers to create the 1.28mm thickness that finicky SE/30 motherboards often require, for reasons Kay Koba specifies in his excellent post here:

https://tinkerdifferent.com/threads/smc-rom-simm-prototype.2198/#post-19023

 

[Mu0n]

I added solder to one side this morning. It brought the thickness very close to my stock ROM Simm that has 1.38mm, so I got 1.36mm with the BMOW Simm (from 1.20 mm).

The ROM socket doesn't give great confidence at its age that it even holds the stock one well anymore, let alone the BMOW one (no satisfying click anymore) so I'm 70% happy with this. With both stock and new, I seldom get bad contact and get this gray pattern with some light randomness (not a checkerboard, it's hard to describe).

But I got it stable enough for my needs with the case in. Now that I have a RGBtohdmi set of cables out of the J12 connector, removing and installing the case is added small pain.

I'll probably go the clip route one-day when I get the opportunity to see my friend with a printer.

 

[YMK]

1.6mm PCBs will fit in the white, plastic tab ROM socket.

The fit is tight enough that it's probably unnecessary to snap them in upright.