Repairing Apple IIc RAM (Also The Stuff I Broke)
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- čas přidán 8. 01. 2020
- This is a basic documentary video of me locating and replacing a failed RAM chip in an Apple IIc, in which I make a number of gruesome mistakes but ultimately am triumphant.
I recommend not attempting this kind of project unless you're experienced at soldering, have removed ICs before, and have watched a bunch of videos about repairing 80s computers, because there are plenty of pitfalls; these machines are very fragile.
I turned the camera off for the trace repair process because I was frustrated and needed to concentrate, but it's about like you'd expect - I stripped a tiny piece of wire, bent it, dropped it into the holes, then pressed the new socket in so it traps the wire ends in the through-holes. The only detail that isn't visible is that the other end of the lower bodge wire had no available hole to drop into, so I had to wrap it around the appropriate leg of the neighboring IC.
I did run a RAM test with the lower trace missing (it took me four tries to get the trace repair right) and the result was *RAM ZP 1 0 1 0 1 0 1 0.
To check your IIc ROM version:
- Boot up with no disk
- Type "print peek(64447)"
- Any response other than 255 means you have the RAM test feature.
Links (not affiliated, just wanted to save you a goog):
- Engineer SS-02 solder pump: www.amazon.com/Engineer-SS-02...
- Apple Floppy Emu: www.bigmessowires.com/floppy-...
Support my channel:
/ cathoderaydude
ko-fi.com/cathoderaydude - Věda a technologie
I think this video has a lot of value in just being the rare example of a DIY repair job on CZcams where the person doing it is willing to show their mistakes and isn't already a soldering master. Seeing someone else make + overcome errors helps make you a lot more confident in your own ability to do something.
I have a couple of those solder suckers, too. I really like them. But, a couple of caveats:
1) Get a refill pack of silicone tube. It is *definitely* a consumable. It starts to fray and split at the end, which ruins the suction.
2) You need to clean it from time to time. Unscrew both ends, thoroughly clean out all the solder dust, and oil the o-rings. I use a Q-tip dipped in motor oil. If you don't keep them lubricated, they'll hesitate while moving, which is no good when you're trying to quickly vacuum up molten solder.
3) This one's a bonus -- no charge. If you are trying to de-solder something with a lot of solder on it, e.g., removing the wire wrapped around an AC inlet's spade terminal, you may end up clogging the chamber with a big glob of solder. This is no fun at all to clear. I have had some luck using a hot air station to liquify the solder and tap it out onto a work surface. That aluminum tube will wick up some serious heat, though, so you need ample fire power at your disposal, and it'll get flippin 'ot!
In light of #2 and #3, I would highly recommend getting two of them, so that when the first one gets clogged or starts acting sluggish, you can carry on with the second until you're done with the job, then properly maintain them. Or, do like I do, and neglect both of them until they're both out of commission, and hastily fix them both while grumbling to yourself and contemplating the purchase of a third as a spare.
6:00 "i could destroy the traces in the process" foreshadowing!
Nicely done! That solder sucker does look a lot nicer than the big blue plastic whatever-the-hell I've had for years.
And I love the production values on your narration and video editing -- a lot better than a lot of these kinds of things I've seen.
Are you an EE prof or something? If you're not you should be. I could listen to your vids for hours, it's super engaging, love your dry humor too. Way better than any lecturers I've had throughout my degree.
He's just a nerd.
Great video! Looks like some of my repair videos - they always turn out fine in the end, but bad things can happen along the way...
I love the genuine excitement in your voice when you fixed it. I am not that interested in vintage computers however it makes me happy to see the joy that repairing them brings to you.
man I've been in a rut lately and just watching/hearing the genuine joy this brings you is enough to make it a little less gloomy for me, I know this is an older video of yours but I dig everything about it, keep on keepin on my dude!
I’ve gotten so meticulous about IC legs that I roll them slightly and check them with a straight edge. An early project I went thru half a dozen with twisted and crushed legs. There’s prolly an op amp somewhere in my shop still laying where I threw it lol.
The legs are splayed slightly so they can sit on top of each other for machine placement I’ve been told.
I love the design style of this computer. It’s got a timeless quality and hasn’t dated.
Knowing that this video is a year old, I just wanted to say that I really appreciate the Violent Femmes reference. You really "proved your love" to that Apple II.
criminally underrated channel. this stuff is incredibly interesting, and important information for preserving and understanding old computer hardware
This video was INCREDIBLY valuable to me just because of that awesome solder sucker you used! I bought one immediately when you showed the model, because the one I have is absolute junk and I hate it. Thank you!
This repair job was not nearly as barbaric as the way I handled my Tempest arcade board repair and somehow I still got that working, so I am not surprised you succeeded.
(I really need to get a solder sucker like yours -- I have one of the Radio Shack ones and it doesn't work nearly that well, so I wound up pulling most of the chips I replaced off the board with a heat gun, singeing the board in multiple places in the process.)
tbh I've since pivoted to a Chinese automatic desoldering gun with a vacuum pump and it makes much much much cleaner holes, and I now cannot recommend anything else in good faith
Great video, and I really appreciated your "honest and upfront" commentary, including the swear words.
I have a IIc that I anticipate I'll have to do the same think you've done, so your video is a big help.
The Apple IIc for some reason has a high failure rate on its RAM chips compared to the rest of the line. Maybe Apple got a marginal batch? Normally the Apple II is a bulletproof machine!
Yeah, they seem really failure prone from what I've seen. Weird, right?
I kind of wonder if it's a thermal issue, since the IIc is a lot more densely packed than the others. They also tend to get moved around more often than other II's, which makes the odds of the system getting banged around much higher.
9:50 That edit was very satisfying. Each time the clear hole around the pin, nice.
For removing chips on an old board like this you can just cut all the pins off each side then remove them individually.
Kapton has poor electrical conductance while also having good thermal conductance(for a tape), making it an ideal isolation tape for electronics.
what a delightful, wonderful ride that was. congratulations. :)
So glad I found your channel, your videos are super interesting, plus your narration is brilliant. Thank you.
Since I have an Apple IIc, this will be useful if I ever do have to repair a bad memory chip. Hopefully it keeps on working, though!
Well done, sir!
I’m a new subscriber but I’ve been watching bunches of your content lately. Great stuff. You’re hella talented and hella intelligent and I’m all about it.
Idk why but I get the feeling you and Clint from LGR would be great friends. You guys both seem like my kind of people.
Thanks for the great content, man.
Keep up the spectacular work!
I had one of these wee computers in the mid 90s, garage sale find. I enjoy your videos, keep 'em comin'.
7:05 I almost thought you'd be "screwing" all day for a moment there!
Anyway, really fascinating video. The kind of stuff I'd hope to find at the top of my search results if I were trying to do a similar replacement -- showing the entire process and explaining what you're doing, the potential pitfalls and errors and whatnot. Really good content!
Edit: that solder sucker looks fabulous! May have to invest in one (planning to completely recap my C64 soon, and could really use something like that.)
I love your videos! You are really knowledgeable and easy to listen to. hope you are doing well, and best wishes in 2021!
I got one of those same solder pumps… I love it! It works so well for things like this.
22:41 I did the same thing when I tried replacing a RAM chip for the first time on a ][e. I tore out 4 or 5 traces! The board had those thin traces on it. I tried again on a different board, and had no problem.
Not referencing Doogie Howser M.D. in the ending sequence was a major missed opportunity :D
...shoot it's been too long, what's the reference i missed
@@CathodeRayDude Every episode ends with Doogie typing a journal entry into his word processor (Probably WordPerfect on the PC). It's classic, but you have to be Xennial or older, I think :) czcams.com/video/N1WnfMFUqWQ/video.html
"Going to brace on this yellow component." is a phrase that makes my butthole pucker so hard that I can carry my chair away if I stand up. That's a tantalum capacitor and those things are not only brittle and the most fragile things on the planet (and that's when they're brand new), but they also fail in the most spectacular display of fireworks and flames.
Love the outro of you just typing on the //c. Kind of reminds me of the ending of the movie "Stand By Me". Something about the combined narration as you typed it out, I think. :)
This video is a journey and I love it
Engineer makes fantastic tools. I have a pair of their terminal crimps and they just work so well. I want to get more of their tools they are just pricey.
enjoyed watching...you have a soft voice like the joy of painting .....
Desoldering like a boss!!
Kapton film is heat resistant and you will often see satellites covered in the stuff with a foil underlay makes it look gold.
Good vid! Only criticism I have is that you were soldering on top of the IIc case, Luckily you didn't burn or melt it, Also, not criticism, but you can test RAM on these old machines by lining up the pins and simply piggy backing a RAM chip on top of the suspected failed chip, rather that having to de-solder everything.
I have been using the same solder sucker for about 5 years, it holds up well!
"Static Shock" sounds like a cool super hero name!
The old lead tin sodier lacks bismuth and the flux they used was more of a rosin acid mix and the oxidation effect of addiction substances on metals like lead and tin can harden the metal or make hardness and thermal properties change
In repairs like this, I always take an hour break after I do something like tear a trace or bend a pin.
those "leaf" contact DIP sockets are HORRIBLE- the ones you want are called "machined" contacts
Hey this isn't Adrian's digital basement lol. If you haven't watched that channel it's easily one of the best on CZcams in my opinion. And my opinion is correct 99% of the time every time lol. 😅 I crack me up.
And omg I just face palm when I see people using anti static straps. It's like tech snake oil for an ailment that doesn't exist. How many volts do you think the human body produces? And what components do you think will be damaged by that 1000th of a watt? Just stop with the straps already.
'ZX Spectrum is boring'
My good sir, I nearly spit out my lukewarm breakfast tea with half-n-half all over this Comfort Inn continental breakfast bar!
I've since changed my mind, in the last year I've done about 20 spectrum streams, one of my favorite platforms now
the zee ecks spectrum really brings out the z's in one
I looooovvee that solder sucker. Ive had one for years now. I had a plastic one before and it lasted about one project lol
Great video! Cheers from Detroit!
Nice floppy emu just got mine and love it
Careful enough to use a static strap after pulling ICs out of jumble in a plastic storage container. 😁
Smack talk about the Spectrum!!!!
Well deserved
Hahaha! "The ZX Spectrum, for instance, is such a dreadfully boring machine, that I'd rather give mine away than risk more damage to repair it."
Europe: * GASP !! * How.... _DARE_ you?!
...
It's _called_ "ZED" Ex Spectrum!
after the gouge 'aaaaah no check continuity before you put the socket on!' but alas it made no difference, good repair!
oh hey, a repair video! i wonder what-
[single-wipe sockets]
oh no
i legit forgot these were a distinct design until i was three quarters through
whats a "single-wipe" mean?
@@Wtfinc The socket makes electrical contact with each pin on only one side. Better sockets make contact on multiple sides.
Hey CRD, I know you don't do this for the money, but do you have a Patreon? I'd love to support your channel in a more direct way than just binge watching
Yup, linked in the description on pretty much all my vids!
Welp, don't I feel like a right idiot, that will teach me to read the description!
I'm surprised you don't have an IC extractor and used a screwdriver. That's risky business.
I actually find the extractors I've used really touchy and feel I have more control with the screwdriver, but I think I just need to bite the bullet and figure out how to do it right because, yeah, it's obvious why this was a bad idea.
@@CathodeRayDude I've not used them too much but I find that the ic extractors work best with a little bit of wiggling while pulling on the chip.
Very useful! I'm having the same type of problem, but I'm wondering where to find RAM chips...?
"not an affiliate link..." Super classy.
I had a 2e with a profile hard drive an 2 fiveish inch floppys, it had prodos on it .
15:35 I’m stealing this phrase thx
A trick you can do to figure out exactly which is bad is you can piggy back a new chip on top of the old ones one chip at a time and see if it passes the test
What kind of switches does the keyboard have? Amber Alps by any chance?
Bookmarked for future reference! 😃
My //c has a RAM expansion slot but I haven't been able to locate one.
Koptan, nice, my dad works in a tape and film factory and they produce Kapton. So he can grab rolls that come up short after running a billet. So i have 2mil and 10mil that ik of offhand, and widths from .5" to 16". Even have a 12" wide sheet of the 10mil without adhesive laid on the back. And another in the 2mil with it.
god that's nice, I would love to have real kapton
@@CathodeRayDude i mean, define "real". He doesnt know if they sell it to 3m, dupont, china, etc. But its polyimide film that its made on. Personally i dont find the brand matters for something as simple as tape, it just has to handle the 400+ degrees celcius that branded Kapton does.
My stuff isnt branded, its short, or wrinkled rolls. Scraps technically, but my dad usually chops the defects off for me on the slitter.
@@Di3mondDud3 Oh, yeah, I just mean if yours isn't The Worst Crap Imaginable, it's better than this. This stuff is just sub-par. I've used real kapton once or twice and the adhesive is much higher grade, though perhaps that's an option?
@@CathodeRayDude apparently their stuff gets sold from ULINE. It is the 3m stuff, they dont use branded cores on the kapton they do for other different materials.
The adhesive on most of the tapes they make is seriously strong. The kapton sticks well but has to have a good clean surface i find.
that's a cool isopropyl bottle, where did you get it?
you can find em on amazon et al, search for "solvent pump bottle"
Hooray!
Thank you so much for not bending to the pressure from the Canadians and British, and pronouncing the Z in ZX Spectrum correctly. 'Murica! 🇺🇲
I later changed my mind and pronounce it zed. :p
It's a British product therefore it's Zed Eks. You want to pronounce it another way, get a Timex Sinclair 2068 instead!
I think Apple soldering ram to the board is one of those universal constants that are annoying as all hell.
hell yeah dude
Flex conduit should NEVER be used for ground! Also clean your flux better. That can ruin stuff.
Whether “c” or “k” those are consonants ?
18:12 I'm not well versed in board repair, but I don't understand why you discarded this RAM, couldn't have been easily bent back to position with some pliers or even by hand?
The elastic limit on chip leads is extremely poor. They can handle being bent once or twice, then they become incredibly brittle. If I'd bent it back and shoved it in again, it very likely would have snapped off - or it would have worked fine, and then broken under light vibration later and created a heisenbug, causing random crashes that can't be reproduced.
I’ll be honest, I’ve seen soldering worse at work at a PCB fab.
Off-brand Kapton tape is pronounced "krap-tawn"
what tv or monitor is that
Why did you throw that dram chip, should just streightened the leg
Cross between a spectrum and BBC model b
Get one of these: en.wikipedia.org/wiki/IC_extractor
Much nicer than levering against the PCB or other components to remove chips
I find your lack of flux disturbing
MT RAM is terrible, it fails all the time. If I have a retro machine that has one failed RAM chip and it is using MT chips I just swap all of them.
I'm just here for the entertainment.
Get a real desoldering pump. Those are known for ripping pads off
Fiiiiiiiiirst