1/12 C64 repair: "Out of memory" problem - the RAM chip conundrum
ฝัง
- เผยแพร่เมื่อ 22 ก.ค. 2022
- #c64 #commodore #repair
I've ended up with another 12 broken breadbin C64 machines! I figured I'll start making some videos repairing them and this is the first of those machines. I'll probably only briefly show the simple and boring fixes - but will make full videos on the interesting ones.
Episode 1: This episode!
Episode 2: • 1/12 C64 repair: "Out ...
Episode 3: • 3/12 C64 repair using ...
Episode 4: Coming soon!
--- Video Links
Hakko Drill bit cleaner:
Part Number B1303 (sorry no link)
Adrian's Digital Basement Merch store:
my-store-c82bd2-2.creator-spr...
Adrian's Digital Basement ][ (Second Channel)
/ @adriansdigitalbasement2
Support the channel on Patreon:
/ adriansdigitalbasement
-- Tools
Deoxit D5:
amzn.to/2VvOKy1
store.caig.com/s.nl/it.A/id.16...
O-Ring Pick Set: (I use these to lift chips off boards)
amzn.to/3a9x54J
Elenco Electronics LP-560 Logic Probe:
amzn.to/2VrT5lW
Hakko FR301 Desoldering Iron:
amzn.to/2ye6xC0
Rigol DS1054Z Four Channel Oscilloscope:
www.rigolna.com/products/digi...
Head Worn Magnifying Goggles / Dual Lens Flip-In Head Magnifier:
amzn.to/3adRbuy
TL866II Plus Chip Tester and EPROM programmer: (The MiniPro)
amzn.to/2wG4tlP
www.aliexpress.com/item/33000...
TS100 Soldering Iron:
amzn.to/2K36dJ5
www.ebay.com/itm/TS100-65W-MI...
EEVBlog 121GW Multimeter:
www.eevblog.com/product/121gw/
DSLogic Basic Logic Analyzer:
amzn.to/2RDSDQw
www.ebay.com/itm/USB-Logic-DS...
Magnetic Screw Holder:
amzn.to/3b8LOhG
www.harborfreight.com/4-inch-...
Universal ZIP sockets: (clones, used on my ZIF-64 test machine)
www.ebay.com/itm/14-16-18-20-...
RetroTink 2X Upconverter: (to hook up something like a C64 to HDMI)
www.retrotink.com/
Plato (Clone) Side Cutters: (order five)
www.ebay.com/itm/1-2-5-10PCS-...
Heat Sinks:
www.aliexpress.com/item/32537...
Little squeezy bottles: (available elsewhere too)
amzn.to/3b8LOOI
--- Links
My GitHub repository:
github.com/misterblack1?tab=r...
Commodore Computer Club / Vancouver, WA - Portland, OR - PDX Commodore Users Group
www.commodorecomputerclub.com/
--- Instructional videos
My video on damage-free chip removal:
• How to remove chips wi...
--- Music
Intro music and other tracks by:
Nathan Divino
@itsnathandivino - วิทยาศาสตร์และเทคโนโลยี
I don't know why, but I really like the repair videos. And I feel like the 64 is in that perfect space of being complicated enough that the machine can do interesting things (sound, graphics), but simple enough that you can actually diagnose it by hand.
Adrian is *the* C64 guy of all TH-camrs!
I liken it to binge watching "This Old House" only for 8 bit computers.
I like them because I'm learning
@@dannytipple1232 In '84 was fine for 14 year olds after school, the 64 is perfectly comprehensible😀
I think that’s a great summation, I had a C64 in 1982-3, it was tons of fun, imagine typing in basic game listings from magazines, character by character and then debugging, and then you could save it to floppy if you liked the game! I would love to fix these myself! It was definitely one of the first really good home machines.
I'll always watch C64 repair videos. It's more about the troubleshooting process for me.
+1 I really enjoy every one of those videos, very interesting and informative.
Absolutely agree with You :)
It gives you all the sort of shortcuts to repair knowing which chips are weaker than others.
I know nothing about soldering or repairing electronics but I always watch and enjoy the repair videos.
I am a simple man. If Adrian repairs a C64, I want to watch him do it.
I think it is incredible how you manage to pump out two videos (both channels combined) per week, despite working full time. And your videos are not some random garbage just to satisfy the TH-cam algorithm but very well made and always worth watching, both for their content and also your very enjoyable style of persentation. (I think there isn't a single video listed on either of your channels that I haven't watched..😅) Big thanks from Haribo country!
I came here to say pretty much this so yeah, I appreciate all the work Adrian. You're awesome!
I would pay for this content.
@@BartKliebert Become Patreon if you aren't already.
Adrian is a cyborg. He comes from the past.
@@stevenmitchellproductions8572 an 8-bit cyborg? 😂 👍
Great video Adrian, love the split screen format. For those wondering, the part number for the Hakko drill cleaning tool is B1303. I've had it for a while, and it really has saved me from tossing out expensive tips that I thought were ruined. The spring tool that comes with the gun just wasn't working for them.
Exactly! Thanks for putting the part number
@@adriansdigitalbasement No problem, thank you for all you do!
Adrian: When in doubt about making a C=64 repair video, make a C=64 repair video. :) We love seeing the particular symptoms of each machine and thinking along about the possible causes. It's like trying to solve a mystery before Holmes or Poirot.
Not filler, it's why i watch your videos. Fixing things is it's own reward. Taking a broken thing and returning it to usable condition is just awesome.
12 in a row is fine! Bring them on! These repair videos are may favorite part of your channel.
You can never do too many C64 repair videos! Lots of people have them and they are prone to so many failure modes. And, you're also doing a very good job of imparting general troubleshooting knowledge every time.
The C64 repair videos are always a pleasure to watch.
They're even better when the 8-bit dance parties are included!
The C64 repair videos are always fantastic to watch Adrian - please don't stop making them !
I enjoyed the video. You could look at it as not filler, but a training film. Trouble shooting, diagnosis, repair and testing the repair. It is a great educational video.
Yep, that was definitely an (audible) issue with the low pass filter on that SID. But I would leave it in there. As long as the envelope & tone generators, amplitude & ring modulator and the bandpass filter work it should be ok to listen to.. Those pops give it some personality as you get with a vinyl record ;-) I wouldn't be surprised if that 'fault' has been in there from the factory as not all SID were created equal to begin with and the way the low pass filter behaves is the most variable component in my experience ;-)
In fact my original C64 sounded just like that when I got it back in 1984. After a couple years I wrecked my SID when I tried to hook the audio output up to a phone line, and I got a replacement chip that sounds more like what we're used to hearing. I never liked it as much as my original "crackly underwater filter" SID (probably because I had become so used to it). I think that sound is specific to a certain batch of 6581 SIDs, and it's not broken at all.
I suggest Adrian listen grab the program "Synth Sample" or "Swinth" - a program with a handful of early SID demos. Listen to "Stationary Ark" with that SID. It is glorious. I'd love to find a SID that sounds like that.
C64's and retro repair just go hand in hand. The C64 was so modular, I wish computers were still like that now.
Back in 1986, I designed an IC tester that would test all logic ICs of the time that was programmed into it. In circuit, while powered.
All the user had to do, was to remove the crystal of the CPU or any clocking source, and type in the part number after connecting the ribbon dip connector to the chip under test.
The tester would pulse the inputs and latch in the outputs and compare it with the truth table in memory. It was built around a Z80A.
While testing, I saw a new similar product in Popular electronics from B&K Precision. I became so upset, that I never worked on it again.
B&K pulled it off the market. It was like they came out with it, just to shit on my dreams and then left the room!!
Maybe it's time to bring this back as a open kit of some kind? An in-circuit tester for these old machines would save people some effort.
c64 repair video's are never boring, keep them coming. don't skip anything
For people, like myself who loved them back when they were "the boss" and still do, we love to see C=64's get deserved TLC!
I love these. So satisfying.
Even if I’m not understanding what you’re talking about because it’s far over my head, I love going through the troubleshooting process with you. Will not get sick of c64 repairs!
Adrian: without further ado let’s…
Me: He’s gonna say it!
Adrian: start looking at these machines!
Me: 😳
Haha. I like to mix it up to keep everyone on their toes!
Love c64 repairs it never gets old for me.
Adrian, definitely appreciate these videos - no matter how many you make, I'll watch them. Your channel is one of the ones I've watched over the last couple of years that helped spark my interest in repairing retro electronics. Your various troubleshooting and repair videos have helped me immensely with the information and techniques (soldering, troubleshooting, etc...) that you demonstrate. With what I've learned, I've built a 'new' C64 using a Sixty-Clone board and was able to use an oscilloscope to diagnose an issue I had in the timing circuit for the VIC-II. I've also managed to assemble various project boards for the C64 such as a switch-less kernal switcher and a modern VIC-II timer circuit replacement board.
Thanks for sharing your knowledge and expertise so willingly.
I have not gotten into c64 yet but want to. This has given me insight into what to look for. Thanks Adrian.
We will watch Commodore 64 repair videos like a squirrel stares at a bag of walnuts. Carry on good sir.
Not too much. Looking forward to every single one of the c64s getting repaired.
Please keep up the good job.
I'm not really into the C64 HOWEVER I will happily watch you repair them till the cows come home! Just love hearing your thought process about how you go about fixing issues, it's just great communication and a total pleasure. I like to think your little tidbits it'll come in handy when I start fixing some of my broken machines that I have piling up (Electron, SMS2 and a 48k ZX), so keep me coming!
Thanks for fixing all those machines all the time. I love watching each single one of the repair videos. Even if it is the same error again or another retrobright.
Just as some people enjoy watching the same sport again and again, i love to see this again and again
Love the repairs, Adrian. It’s not filler at all. Great content.
C64 repair video’s are my absolute favorite
I think I'll always find repair videos satisfying to watch, no matter how easy the diagnosis and fix are. The process of zeroing in on the issue using such common tools and a bit of logic is an interesting and useful skill, and one I'd like to learn myself. I've composite modded my father's old TI-99 and I'd like to get it working again someday (it's currently just displaying a solid, light blue screen)
I'm glad you got such a positive response to more C64 repair videos. They're among my favorites on your channel.
ABSOLUTELY keep the C64 Repair Videos coming...! They rank at the top of my personal choice in Videos to watch (along with Amiga Repairs. -Mark.
Love the split screen view!
Repair videos never get old. Everyone you repair another machine you always tend to learn something new. I enjoyed every repair video over the past 10 years.
The repair vids are some of the best content, they are always appreciated. I could not have fixed my own machine if I hadn't watched you fix all-together too many machines on here first !! I am never going to get "tired" of yet another C64 on the bench .. heck, you could just talk about a C64 in bits on the bench and strip it for parts and I would still watch and enjoy it.
Thanks AB (and Patreon's :) for another C64 repair video! I love these as that's what I used to do back in the shop I worked on. Although back in the 80's we usually just replaced the board and sent the defective one back to C=ommodore...specially during the VIC chip "twinkle" era.
I always love your repair videos Adrian, you always explain in such a clear, fun and educative way. Everytime you post a repair video I get a nostalgic trip down memory lane :) I am looking forward to more of them.
Keep ‘em coming! I enjoy this fix videos
I'm just glad that there are a lot of C64 machines that still exist. Awesome videos Adrian, awesome.
I still remember playing Commodore Crunch and Chopper Command as a kid on my VIC20. I remember having to load some games off the tape drive and instruct the computer to load and run the software while others were on cartridges. Good times.
Great video. We love that you care for the computers. That's why we keep coming back. 👍
Side note: that RAM chip was saying "It's not me man. It's the NEC chips next to me. It's not me." 😂
In 1983 MOS Technology used a defective process in chip production: too much boron in the passivation layer, ironically the outer coating intended to protect the chip. Thus, the horrible long-term reliability of many chips in 1983 and 1984 machines.
Wait... are you saying "MT" ram chips are MOS Technology, not Micron? (never knew MOS made DRAM?) All this time I've been trying to figure out why Adrian is always sh**ing on MT ram chips, when Micron was always the most reliable ram brand (perhaps 2nd to Samsung) the 20+ years I had a computer store.
@@cliffshockley4406 No, MOS made ROMs, but not RAMs, IIRC. This is just referring to the issues with the 7400 series logic chips. MT is definitely referring to Micron Technology.
@@cliffshockley4406 MT = Micron, who had their own problems. However... Commodore bought Frontier Semiconductor. Everything made in the Frontier Semiconductor fab in 1983 and 1984 suffers from the boron problem. Well known chips that fail because of the boron problem are the PLA, 8501 CPU and the MOS 74xx clones. Chips made in the Norristown fab during those years are reliable.
@@danielmantione Just so surprising to me, as in later years, I can't recall ever having defective Micron MT ram chips, though I do suppose they later had their Spektec subsidiary which they used to sell their "substandard" (my interpretation, don't sue me Spektec) ram, so maybe they just got better at testing for ram that was off-spec.
Defective to you and me. A literal gold mine for Commodore and MOS when the things failed after a few years and people had to buy new computers, or get new parts.
:)
C64 repairs were the main reason why I found your channel. Could watch them all day long
I appreciate seeing more c64s repaired!
Very good explanation of diagnostics and repairs! Thank you as always for your videos!
Excellent repair as always Adrian! Why are RAM tests so bad on the C64? I've also had all sorts of inaccurate results with them. Is it really not possible to detect them reliably? Maybe I'm going to have to write a C64 diagnostics ROM like I did for the Amstrad CPC 😃
In this case it failed during the stack test on a diagnostic that actually uses it. I suspect they probably are more reliable if the error occurs in general purpose ram
The ram test is just too simple to be that useful .. it likely only quickly writes a couple patters to some pages and calls it a day. That’s not thorough enough but it’s fast.
@@adriansdigitalbasementthis shit is fkn lame
It sounds like the challenge is to do a really good test on the zero page using nothing more than ROM and the registers in the CPU.
Noal that would be awesome to be able to test the ram fully .Like you ive loads of different results . As i believe the tests we have now only write to small random places ..
That was quick! Good work as usual.
Good video!!! Love any and all Commodore content! TY
You rock pal!!! I love watching your videos 😀
Thanks for all your great videos. have a great weekend
I dig the new camera view for showing your face as you narrate!
Agreed! New camera angle is good!
Thank you Adrian another great episode.
Definitely like these repair videos, could watch all day.
Always great to see Commodore 64 diagnosed and fixed :)
I really enjoy all Commodore repair videos! I hope that's not boring for YOU, though. Please enjoying repairing and recording what YOU like; we're here to watch. Aloha!
Great video Adrian as always .. love watching your videos :)
13:40 - The chip tester pro is one of those things that seems like an amazing thing, but it's far less useful in general than people realize. It won't tell you definitively if a chip is good, but it will only tell you if it's definitively bad. Adrian (and many others) have run into this many times. A lot of these older machines rely on the chip's electrical characteristics and each circuit and the retro chip tester just isn't going to exercise the chip the same way the target hardware will. So a chip may test good just fine in it, but bad in context of the circuit.
It's far cheaper to just have a cache of common 244/245s, etc... on hand than it is for the retro chip test's price. If you've gone to the trouble of swapping/removing the chip in the first place, just swap in a known good one to see if it works. It takes less time. The only place I've found the retro chip tester to be appropriate is if you have a pile of chips and want to weed out the bad ones, or perhaps see if a ROM image is good (provided the retro chip tester knows what it is).
Exactly!😁
Also, it's often just not possible to completely test a chip, especially if it, like the SID, has analog output.
Yea!! The RCT!
Great video. Very enjoyable! You are getting so good at explaining troubleshooting! Well done!!
I use it , too. Great device, indeed.
Always love the 64 videos!!
Retro computer repair video's are always awesome!
A note on the ram tests of the dead test and 'official' diagnostics...
The dead test only tests a small part of the system ram, but in such a way that it doesn't depend on the zeropage and stack etc working. The diagnostics tests all ram, but requires you first fixed any issues reported by the dead test cart, because diagnostics heavily relies on the zeropage and stack and some other bits of ram working properly to do the complete ram test (and do a more thorough test). For that matter, the diagnostics copies its ram test to ram, and runs it from ram.
Consequently, if there are errors in the ram the diagnostics relies on to work, the output of the diagnostics will often be wrong, or it will just crash.
So the proper way to do this is to always first run the dead test cart, and fix any ram, pla etc errors it reports, and only after it no longer reports errors, run the full diagnostics to test the remainder of the machine. Starting out with just running diagnostics may give the correct result, or not, there is no way of knowing without first having ensured the things it depends on are functioning properly.
Thank you! I am glad I am not the only one to comment on his "deadtest" comments. I have found since the late eighties that deadtest is the first one to go to if you suspect ram problems. The first test tests each 64k chip and then reports the bad ram by flashing the chip number. It doesn't use any ram (including zero page) until rams tests ok. It requires the vic chip to work (vic pin 17 generates the ø0 for the 6510), PLA mostly to work (otherwise no cartridge would work). The bad part is it stops at the first bad ram and is dependent on ram support chips to work correctly. Just so you know, the first 7 bits are tested and then falls through to show one flash for bit 7. So if the first 7 bits are ok and even if the 8th bit is ok but something else is wrong you get one flash over and over.
@@johnsaller2481 I independently came up with a highly similar bit of code to do a 'ram test' without using ram. Only being able to report the first bit error is a simple consequence of not being able to use ram, and the relatively limited bitwise operations available on a 6510 cpu. My code is intended for the C128, but ended up using an almost identical approach.
@@c128stuff I did the same thing, and I had it for both. Suspended it until I can get back to it because of real world events!
Thanks for the pointer about that drill from Hakko - I have the same desoldering gun (and it's totally great) but recently destroyed a tip when I couldn't unblock it. Ended up breaking off part of the plating by trying to force the blunt wire cleaner it comes with through the hole using way too much force 🤦♂️
The thing about C64 repairs is that every single one is unique in some way. We want to watch that journey of diagnosis, planning, action, success or failure, and followup. Everything is content. Record it all! (Honestly, just give me any reason at all to listen to that intro music - so good!)
Love the C64 repair videos. If I learn any tiny thing Im happy. Also think of the library of repair information you building up here on the channel. Love it.
oh my god you violated that desoldering iron
Can´t get enough of the C64 repairs :)
Totally.. its the best part doing the fixing well watching you doing the fixing and chasing the gremlins..
Ya know Adrian, I don't have nor ever used a C64's, or any game mechanics as I don't play games but I watch your videos anyway.
Anyone that survived the IRQ and Memory wars of the 90's computers and games an still like to play games, I take my hat off to ya. Me, it away all the fun an ruined my game playing as a computer tech years ago sad to say... :-(
The reason I do watch, is I do fix alot of my own electronics as a hobby, if it is still broken when I'm done, well it was broken to start with... LOL
Also mostly because I just plain enjoy your videos and seeing what it takes and how you go about fixing them. Believe it or not I have fixed several thing just from watching your videos, with that I say a BIG Thank YOU!
Take care!
LLAP 🖖
Dude. Love the intro! Been watching alot of your videos lately and the intro gives me 90s TV vibes. It's nostalgic!
Hey @Adrians_Digital_Basement Look at this scammer! You should go through your videos and delete these losers. Some people might fall for it
Nice work. Thank you
LOVE C64 videos! Thanks for showing off the cool tester again; even if it’s not 100% accurate.
I would gladly watch all C-64 repair vids!
You almost always learn something on a repair. Well worth this vid.
I had to Google what your t-shirt was about, bicycles and myself don't get on (twice they've tried to kill me) but that 545 event is such a wonderful thing to do for such a good cause as well!
C64 repairs are some of my personal favorites.
Love the C64 repairs
Keep up the good work
I love your videos. It just struck me, tho, how much I love your intro music!
C64 repair videos are the best for me.
..... Excellent, Well done Mate. Thumbnail, perfection.
So fun! Thanks so much.
Repair videos are always interesting. Definitely not what I would consider filler.
Might be interesting to build a program that analyzes the output of the SID over a microphone port. Could do a waveform comparison between a known good 8-bit dance party and a test one.
Just amazed that you put out 2 videos per week! I so miss the behind the scenes content but I had to downgrade my Patreon tier because money is tight at the moment with being ill again.
I used to repair C=64, Vic 20 and all Commodore products professionally while they were still under warranty. And I have the burned finger tips to prove it. I didn't have any decent temperature sensing devices until years later, and so it was the finger that was used to find hot RAM chips. Went through a lot of sockets repairing these units.
I even repaired Commodore PCs when they came out....at component level. That stopped after the '286.
Also serviced Atari products.
Adrian we ALWAYS want to see your repair videos even if it is on the 100th C64!
By far my favorite repair channel! Do you think one day you could do a video on how you set up your Easy Flash Cartridge? I bought one and a bit confused on it lol
I would watch endless C64 repairs for the rest of my damn life.
Thanks for the video! I was wondering about that 4066/U28 that the diagnostic cart reported bad, when you ran the diagnostic with the harness.
It's just a false reading. The joystick ports work perfectly -- I think one of the ICs has gone bad on my test harness.
I have been using the TL866A/minipro for testing some dozen logic chips and other ICs recently, and while the supported range of IC of course is not as huge as with dedicated testers, the testing results where 100% correct, yet! No false positives or negatives.
We want twelve c64 repair video's in a row! 😄
Love repair videos, the trouble shooting process is like a who done it mystery
Did you notice both times the diagnostic test froze that there was random " ( " instead of " " . If you looked up the Petscii character codes (converted to binary) for both open bracket and space (ie. $20hex ( for " " ) = 0010 0000 binary, and $28hex (for " ( " ) = 0010 1000), you would see the only difference is $8hex (ie. 1000 binary) which is Data bit # 3. From this information you can either check the C64 circuit diagram to determine which RAM is used for Data bit 3 or from the C64 Dead Test manual looking at the RAM error flash code chart again , you would see that this also points to U10 being faulty.
Note: it's not uncommon when you have a memory fault(s) for random characters to appear on screen, and using the Petscii character codes you can determine the offending data bit or bits (if you see more than one random character displayed) and then lookup the offending RAM IC(s). There's always an exception to this rule (eg, bad MUX IC ) but will still help point you in the right direction.
i have a sx64 when warm it shows "&" on the screen but the software is still running fine i think its the U26 74LS373
@@matthewtempest7756 on the SX-64 the 74LS373 definitely can affect the displayed characters , but personally haven't seen it produce what you are describing ... what I have seen is UB2 (that's the SX-64 circuit reference for U26 as on a C64 board) corrupting several / all of the displayed characters. Have you already gone down the Petscii Character code path? Which would suggest if you see an " & " character instead of a space on screen that 2 x Data bits are affected (ie. Data bits # D1 and D2) , which point to RAM IC's UA7 & UB6. On a C64 if the RAM was not socketed I might suggest trying to piggyback the suspect RAM IC(s) , but on the SX-64 access is poor and if you don't have additional diagnostic tools to assist it isolating / confirming the cause of the fault, then just replace the (cheap , readily available) Suspect IC's and test again hopefully confirming the diagnosis.
Subscribed for the C64 repairs stayed for the C64 repairs.
Hi Adrian, did you notice the message in the diagnostics test that says "4066 @ U28 BAD"?
This might have something to do with the SID popping like that.
Haven't got the schematics at hand but I am pretty sure there's a 4066 involved somewhere around the SID circuitry.
Might be worth taking a look at that.
Thanks to your Patreons for saying yes, repairathons are great!
Well, this one is going to be an interesting set of videos, it would be nice if you could also make some videos about deeper diagnostics and repairs, maybe even upgrades?
Take a look at acetylene torch cleaning bit sets. They're cheap and have quite a few different size bits on them for cleaning torch tip holes. They also work pretty well for the older Hakko models that I've used.
Neat! Good “tip” :-)
The 8-bit-dance-party is excellent excercise for a stiff shoulder. ;) Get well soon.
The intro song playing in stereo is just awesome.