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Very neat potential solution for our 30-pin Macs and wanting ALL THE MEMORY


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Oh no! That's an ugly, ugly way to use solder paste. It is normally applied by using a squeegee over a stencil that applies a controlled amount to each pad rather than blobbed out of the syringe bridging all the pads. I can't believe this guy has so much gear (EEVBlog DMM? Hot air?) and so little idea of how to use it.

 

edit: oh, and let's just crack open the Mac and work on it with no warning of the voltages around the CRT...

Edited by aeberbach
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I think he plainly acknowledges that SMD work is new to him. Plus it's also good to see what "not to do" (and he says, don't take this as a soldering tutorial in this video).

I'm more interested in the kit he bought possible availability of DIY (for the enterprising) SIMMs as a nice third way other than the good deal from a forum member or eBay price gouging that runs rampant.

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35 minutes ago, aeberbach said:

I can't believe this guy has so much gear (EEVBlog DMM? Hot air?) and so little idea of how to use it.

Normally, this guy seems to know what he is doing. I think he just doesn't have much experience with surface-mount soldering. He has done many other videos about Macs which provide some pretty good advice and show proper techniques. He has also provided CRT warnings in many of those videos too. I found the Classic Mac Repair-athon series on this channel to be quite entertaining.

 

There are definitely better ways to solder down SMD chips than the way he did things in the video though. Everything worked out well in the end at least.

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44 minutes ago, aeberbach said:

Oh no! That's an ugly, ugly way to use solder paste. It is normally applied by using a squeegee over a stencil that applies a controlled amount to each pad rather than blobbed out of the syringe bridging all the pads. I can't believe this guy has so much gear (EEVBlog DMM? Hot air?) and so little idea of how to use it.

 

edit: oh, and let's just crack open the Mac and work on it with no warning of the voltages around the CRT...

Please explain how the hobbyists of us out here would obtain said squeegee and masks...I'd love that, but when soldering an SE/30 SCSI chip or the like, what other method can I use? I don't use anywhere near the amount that guy put on (too much bridging), but I have successfully done it by applying it across the pads with a toothpick.

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1 hour ago, LaPorta said:

Please explain how the hobbyists of us out here would obtain said squeegee and masks...I'd love that, but when soldering an SE/30 SCSI chip or the like, what other method can I use? I don't use anywhere near the amount that guy put on (too much bridging), but I have successfully done it by applying it across the pads with a toothpick.

 

If you really want to use solder paste - like for example you have a reflow oven - any PCB house will make a solder paste stencil for you and it doesn't cost more than a PCB, often it is part of the package. An art store silk screen and rubber squeegee is the only other thing you need. I used this method in about 1995 on a modem product based on the Motorola 68356 in a BGA package, the first one the company had used. (I thought it up; it may also have been in use in other places, but the PCB house had to specially figure out how to make the stencil.) After getting the mask made I squeegeed the paste onto the board, placed the BGA very carefully by hand and ran it through the reflow. This was early days for BGA and I was able to see the gaps between each rows and columns to verify that the method worked before powering on. With some modern BGA devices - especially FPGA and RAM - this is the only prototyping method, but placement by hand is getting very iffy. You almost need an overhead arm lowering the chip with exact steadiness, to at least guarantee placement in one axis while making tiny adjustments in the other axis. Having a contract manufacturer place fine pitch BGAs is often a better idea.

 

A lot of people call one alternative drag soldering. Imagine a conical soldering iron tip with a cut taken across it at an angle, the resulting flat being slightly hollowed. This can hold solder. As a liquid, solder exhibits surface tension and you use that to apply solder to pads. Flux is essential to "wet" the joints. With the chip in place, everything fluxed and a moderate amount of solder melted and in the iron's tip the iron is wiped down the side of the chip. Solder sticks to the places it should stick (between chip and pad) and does not bridge the pins because the surface tension separates it. If it doesn't go right the first time, especially at the beginning or end of the row, more flux and do it again with less solder on the iron in case of bridges or slightly more in the case of incomplete soldering. This is pretty common with hobbyists in the Atari/Amiga scene, making various things with .5mm pitch TQFP packages. I have a ReAmiga 1200 board build in progress right now and there is plenty of this technique.

 

Another method is to get some solder on each pad using flux and an iron and then to apply plenty more flux, then the chip. Hot air is then used to melt the solder. The chip drops down into the molten solder and again the surface tension works in your favour as the chip tends to centre itself, the molten solder's surface tension forces act on all the pins together. This can be more attractive for devices where the lead is curled under - PLCC or SOJ etc - but you have to be very aware of the total temperature being applied... the device and the board tend to be exposed to more heat when all the solder is being melted at once, compared to drag soldering.

 

If not reflowing or stencilling - there isn't a lot of call for solder paste. It is messy to apply and can't be done precisely. There is nothing wrong with applying ordinary solder with an iron and simply making sure there is flux around at the time of attachment, and doing it that way makes it much easier to apply the right amount to each pad.

Edited by aeberbach
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Those sticks are cool, But i'll be dammed if I can find anywhere selling suitable RAM ic's in any quantity at a reasonable price

The ones he uses in the video I just flat out cannot find, I have found some others on ebay that should be suitable but aren't exactly cheap

 

Kinda disappointed I can't find the IC's, I had already added the boards + a stencil to my basket on JLCPCB, I'll have to spend some more time tomorrow searching for them at a more reasonable price

 

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I wonder if the viewer got them on Alibaba or something like that. You could also remove the chips from 72 pin versions.

 

If you search for DRAM 4mx4 on ebay a few sellers turn up. You'll want to verify foot print and package match the Gerber's.

Edited by karrots
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7 hours ago, davidg5678 said:

Normally, this guy seems to know what he is doing...

 

Oh no he does not! He does not follow safety precautions or anti-static protections. Most of the time he's seen it somewhere online and decide to see if he can do the same thing himself.  In short he has thrown out recoverable machines that he could have saved but thought they were too much work to fix them. Like the Classic II frame frame that was rusted out from the battery explosion - some Naval Jelly and some phosphoric acid would have saved that frame and case but no - it went to the trash bin.

I've been fixing Macs since '88 and 8Bit Machines since '79 (start out on a broken PET in HS), and watching him work make me cringe. His work is very sloppy. Sometimes I wonder how he hasn't done the dance of the High Voltage/Amperage yet. Working the for NYC Bored of Ed and my own computer center in both teaching and fixing computers, I have been bitten dozens of times and had to fix machines I inadvertently damaged further during a repair.

 

As for the RAM, it is doable. But if you heard him, he confuses Parity Bit RAM with Regular RAM. And this only does 4MB RAM chips for a total of 16MB per bank. You need a different SIMM board for 16MB RAM chips for 64MB per bank if your machine can support it. You do not need Parity RAM on 90% of all 68K Macs out there, there are a few in high altitude areas that do need it but those are rare machines. If you are going to do it, take your time with it and take it slow and double check your work.

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I’m no expert at all when it comes to soldering. I’m still learning. However when I watch that guy I feel like I’m a total pro. 
 

I would have applied a good amount of liquid flux, and 400’c iron and added solder to the tip of my iron, and dragged across the pads to tin them. Then I would have added even more flux and held the chip in place and heated one leg while I held the chip down precisely on the pads. That leg would then have held it down and I would have heated the legs on the opposite side and moved along to melt the solder down with the leg and the pad. Then I would repeat on the other side. A good amount of IPA99 and it would look far more professional than his. I don’t understand how hard that could be. 
 

I’ve removed and resoldered a 68020 CPU this way. 

Edited by MrFahrenheit
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3 hours ago, Elfen said:

You need a different SIMM board for 16MB RAM chips for 64MB per bank if your machine can support it.

 

I made one that uses two 16M*4 chips. I used to source those chips from 128MB 72pin modules. One 72pin SIMM will give you enough chips to build 8 30pin SIMMs this way.

If you go for parity 72pinners you will even get some spare 16M*1 chips which will usually fit onto the IIfx SIMM design that's floating around.

 

 

30pin2chip.zip

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7 hours ago, MrFahrenheit said:

I’m no expert at all when it comes to soldering. I’m still learning. However when I watch that guy I feel like I’m a total pro. 
 

I’ve removed and resoldered a 68020 CPU this way. 

As someone who's learning, too, how did you remove the '020? I imagine you'd use hot air + lots of flux, but I'd be extremely worried about putting too much thermal stress on '020, I'd expect it to be the most fragile component.

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Flux only needed to resolder. Removal with hot air would just be hot air evenly applied and a pick tool to give light lifting pressure.

 

Or you can buy some chip quick rework solder and use an iron instead of hot air.

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49 minutes ago, rplacd said:

As someone who's learning, too, how did you remove the '020? I imagine you'd use hot air + lots of flux, but I'd be extremely worried about putting too much thermal stress on '020, I'd expect it to be the most fragile component.


I use lots of good quality liquid flux and good solder braid. Several presses sucks up solder. No dragging, it will bend pins. 


Resolder same thing. Clean pads. Tin them. Lots of flux. Hold down chip and heat each leg and pad. The tinned pad melts and the leg gets absorbed. 
 

I don’t use hot air at all. I’m too afraid of heating things too much and ruining them. 

Edited by MrFahrenheit
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I think we can all agree there are plenty of better resources on soldering techniques, from users here, and from YouTube as well. I actually like that a lot of times his videos are the whole learning process. I'll admit, too, that while I know little about using paste, I could see it wasn't the correct way, but I waited to see if he'd correct himself. I think Adrian is just a normal everyman, and his only weakness is not saying up front w/re: specific skills—what to take and what not to take away—but that said, a few minutes in (it appears some commenters aren't watching the whole video) he flat out admits that his soldering isn't good technique and that he's learning. I don't see him as some malicious fountain of authority here, but he's someone with a lot of passion for their hobby; learning as they go. I know I can relate to that.

For decent camera work on SMD soldering/desoldering, I'm impressed with BranchusCreations channel. I don't watch every stream he does, but I have yet to see a Mac he hasn't fixed. He also has standalone tutorial and safety videos (which are much less than 2 hr stream lengths ;) and easy to digest).

 

6 hours ago, Bolle said:

I made one that uses two 16M*4 chips. I used to source those chips from 128MB 72pin modules. One 72pin SIMM will give you enough chips to build 8 30pin SIMMs this way.


THANK YOU for posting your SIMM design. I was going bonkers trying to find any contributions on that Vogons thread Adrian links to in his vid description…

 

W/re: to the SOJ memory, it might be good to keep track of P/Ns here, too, that have compatible pinouts—this, in transparency, is coming from a novice. I was attempting to look for the P/N Adrian was using for the SIMM PCBs he had and found maybe one exact, but I'm feeling in the dark there. Maybe I'll get better as the days go on… I've seen a few listings of tubes of NOS SOJ-26 memory, but for the eager, but technically lacking, it's a gamble without some guidance.

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35 minutes ago, jessenator said:

I think we can all agree there are plenty of better resources on soldering techniques, from users here, and from YouTube as well. I actually like that a lot of times his videos are the whole learning process. I'll admit, too, that while I know little about using paste, I could see it wasn't the correct way, but I waited to see if he'd correct himself. I think Adrian is just a normal everyman, and his only weakness is not saying up front w/re: specific skills—what to take and what not to take away—but that said, a few minutes in (it appears some commenters aren't watching the whole video) he flat out admits that his soldering isn't good technique and that he's learning. I don't see him as some malicious fountain of authority here, but he's someone with a lot of passion for their hobby; learning as they go. I know I can relate to that.

For decent camera work on SMD soldering/desoldering, I'm impressed with BranchusCreations channel. I don't watch every stream he does, but I have yet to see a Mac he hasn't fixed. He also has standalone tutorial and safety videos (which are much less than 2 hr stream lengths ;) and easy to digest).

 

Definitely agree with this.  I've been watching him for a couple of years now, and overall I find his videos very good and he typically, while maybe not having the best technique for certain things, can get things working.  It's not like he ruined a non-replaceable part.  He realized he wasn't using the right tool for the job/his skillset, and switched over to a tool/method he's familiar with

 

I also don't think him throwing out the rusted frame of a Classic II is a huge deal either.  It was pretty rusted, and he did keep the case itself.  Plus it's not like the Classic II is a particularly rare or sought after machine.  He got 6 broken machines, and got 5 of them working.  I'd say that's pretty good

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11 minutes ago, Torbar said:

I also don't think him throwing out the rusted frame of a Classic II is a huge deal either.  It was pretty rusted, and he did keep the case itself.  Plus it's not like the Classic II is a particularly rare or sought after machine.  He got 6 broken machines, and got 5 of them working.  I'd say that's pretty good

 

People complain about that?  Wow, there are a lot of frustrated hoarders in this hobby, aren't there...

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There are some people who just can't throw anything out no matter how broken and useless it is. 

 

Are standard 4MB 30 pin SIMMs that hard to find these days where making new ones is economical? I would like to see somebody make some PAL 30 pin SIMMs (4 or 16MB) so I can use them on my Mac II/IIx machines.

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I can't imagine why it would be worth making 4MB SIMMs.  Even 16MB SIMMs are not *that* expensive, relative to what a lot of us spend on this hobby.  4x4MB sticks are readily available on eBay for less than $30... not worth the hassle to roll your own.

 

It is a cool project though and certainly worthwhile for RAM that is not available or just uncommon - IIfx memory for example.

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3 hours ago, Unknown_K said:

I would like to see somebody make some PAL 30 pin SIMMs (4 or 16MB) so I can use them on my Mac II/IIx machines.

I am on it, it’s just at the very end of the to-do list and other stuff seems to crop up ahead of it everytime something else actually gets done.

 

This reminds me, I was going to look into modifying the II logicboard to accept standard RAM as well... I made up a mod in the sketchbook which would be completely reversible but didn’t actually try it yet.

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12 hours ago, Bolle said:

 

I made one that uses two 16M*4 chips. I used to source those chips from 128MB 72pin modules. One 72pin SIMM will give you enough chips to build 8 30pin SIMMs this way.

If you go for parity 72pinners you will even get some spare 16M*1 chips which will usually fit onto the IIfx SIMM design that's floating around.

 

 

30pin2chip.zip 90.48 kB · 6 downloads

 

Never a LIKE Button to press when you need one!

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This topic makes me wonder about something else, but similar.

 

The Macintosh LC has solder pads on the motherboard for RAM, and Apple only populated one half of the pads.  I wonder if anyone has (or if it would even work) soldered on same size RAM modules onto the other pads to have 4MB soldered onto an LC board, instead of just 2.

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11 minutes ago, MrFahrenheit said:

This topic makes me wonder about something else, but similar.

 

A former user did something similar with the IIsi: they took faster, higher density RAM off a dead 6100 board and replaced the IIsi on-board RAM. I think they also did something similar with a Classic board, now that I'm looking for it and failing to source the 6100-IIsi thread.

You have plenty of LCs though ;) let us know what the results are!

Edited by jessenator
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47 minutes ago, MrFahrenheit said:

This topic makes me wonder about something else, but similar.

 

The Macintosh LC has solder pads on the motherboard for RAM, and Apple only populated one half of the pads.  I wonder if anyone has (or if it would even work) soldered on same size RAM modules onto the other pads to have 4MB soldered onto an LC board, instead of just 2.

I tried it before, it didn't work (You get chimes of death iirc)

I never did any testing besides soldering the chips on and flicking the power switch so I'm not saying it's totally impossible, but it's not just as simple as dropping some extra chips on to the board

 

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