2021 C64 Repair-a-thon #1: "It stumped me!"
Рет қаралды 64,989
Күн бұрынWelcome to my 2021 edition C64 repair-a-thon! In this video I fix machine #1 (of 5) This time it's an interesting problem I haven't run into before. A tricky fix!
Part 1 / Machine #1: This video
Part 2 / Machine #2: • 2021 C64 Repair-a-thon...
Part 3 / Machine #3 and 4: • 2021 C64 Repair-a-thon...
Part 4: Coming soon
Support the channel on Patreon:
/ adriansdigitalbasement
0:00 Intro
0:37 Tools I use to repair machines
4:09 The first machine
40:28 Outtro
-- Video Links
My video on damage-free chip removal:
• How to remove chips wi...
Jonard Tools EX-2 Chip Extractor:
amzn.to/2VazxDS
www.jonard.com/Products/EX-2-...
Wiha Chip Lifter:
amzn.to/3a9ftWw
www.wihatools.com/precision-c...
Link to desoldering video
Sven Petersen's Github (for the Diagnostic test harness files)
github.com/svenpetersen1965
C64 diagnostic ROMs (including Dead Test and regular diags)
blog.worldofjani.com/?p=164
Elenco Electronics LP-560 Logic Probe:
amzn.to/2VrT5lW
- 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
@flow221 3 жыл бұрын
Dead Test: The Betrayal. If nothing else, it's a good action movie title.
@Fuzy2K 3 жыл бұрын
Why did "Written by Michael Bay" pop into my head?
@danielmantione 3 жыл бұрын
The Dead Test does a very limited RAM test, because the C64 is in Ultimax mode. In Ultimax mode only 4KB of the C64's RAM is available and this is what the Dead Test tests. (This is documented.) The Diagnostics Cart does a full RAM test. Therefore don't assume all of the RAM is good if the Dead Test passes.
@mal2ksc 3 жыл бұрын
I recall the IBM PC diagnostics only testing the first 256 KB because that's all the original 5150 shipped with, and that could cause similar issues, especially because anything above that would be in another bank or even on an expansion card and thus could not be assumed to be good just because the machine boots or passes basic diagnostics.
@XLV750RD01 3 жыл бұрын
Even if only the first 4kB were tested, the test would come back negative because of the faulty D0 bit. Your comment makes no sense.
@danielmantione 3 жыл бұрын
@@XLV750RD01 With D0 bit fully faulty, the dead test would flash the screen rather than boot up with the tests. So the D0 RAM chip was partially working for sure, the fault was in memory cells with higher addresses.
@XLV750RD01 3 жыл бұрын
@@danielmantione Do you even understand how the binary system works ?
@danielmantione 3 жыл бұрын
@@XLV750RD01 Dude, I know the C64 from left to right and top to bottom. Carefully read again what I write, it is exactly what was going on in that machine.
@VVerVVurm 3 жыл бұрын
I noticed a pattern: it is always the last chip you swap that fixes the issue. Why don't you just start with the last one? It would save you some time ;P
@catriona_drummond 3 жыл бұрын
Brilliant! :D
@brentboswell1294 3 жыл бұрын
It would make his videos too short...😝
@VVerVVurm 3 жыл бұрын
@@brentboswell1294 yes .. scratch my idea .. the longer videos the better :)
@hjalfi 3 жыл бұрын
I've always said that one day, when looking for something, I'm not going to stop looking when I find it, just so I can say it wasn't in the last place I looked.
@brentboswell1294 3 жыл бұрын
@@hjalfi U2 has a song about that..."I Still Haven't Found What I'm Looking For"
@ericvenneker 3 жыл бұрын
@16:30 gracefully de-soldering the shield, and immediately tosses it to annoy the shield lovers. I love it.
@youdontneedtoseehisidentif4939 3 жыл бұрын
Y'know, I would've thought he'd learnt his lesson after his troubles with the Macintosh Colour Classic… ;)
@awilliams1701 3 жыл бұрын
I don't get why people love that trash. It doesn't do anything. It's not even like it makes a heat sync.
@SpearM3064 3 жыл бұрын
@@awilliams1701 My guess is that it's about originality. In the 1980s, the RF shield was required to bring emissions down to FCC standards. Of course, it's no longer required, but it's an original part.
@awilliams1701 3 жыл бұрын
@@SpearM3064 Well yeah that's why it's there, but it's not required anymore and the FCC doesn't give a crap about these machines. So the question isn't why is/was it there. The question is why do people care about it going into the trash can where it belongs?
@ericvenneker 3 жыл бұрын
@@SpearM3064 I am not an C64 enthusiast nor capable of fixing them and I understand the originality sentiment. That said: Adrian at least tries to revive these machine's while others don't give a toss (pun intended).
@misterkite 3 жыл бұрын
Here's a tip for testing the 74LS chips. If you have a TL866-PlusII eeprom programmer and use the Xgpro software, under Device->Logic IC Test there's a logic tester that can not only detect the IC, but verify that all the pins are working properly.
@retrolabo 3 жыл бұрын
I have seen Adrian using that before, I wonder why he didn't use it that time :)
@VVerVVurm 3 жыл бұрын
@@retrolabo he needs to keep himself a handicap so his powers would not frighten us
@neilbradley 3 жыл бұрын
The risk is that those chips can be marginal - test just fine in the TL866 but don't in circuit. Same with DRAMs. Had that happen WAY too many times to trust chip testers.
@Calphool222 3 жыл бұрын
@@neilbradley Yeah that stupid tester in the TL866 is flaky. I've had it lie to me several times. I think it might be due to the fact that it's not really using the chip in the same way that the motherboard is. In other words, it's maybe flipping the CE and doing a few tests, and that's it, whereas that CE line might be left on in circuit, and the chip might get warm over time and have a thermal issue because of that.
@neilbradley 3 жыл бұрын
@@Calphool222 Yes, exactly. Each system that uses the chip will have different loading and timing characteristics - something the TL866 (I assume) does not.
@uomoartificiale 3 жыл бұрын
"would you look at that!" Ah the sweet endorphins release everytime I hear those words after a 40 minutes troubleshooting video! Nothing beats that.
@idj20 3 жыл бұрын
I got totally engrossed in this video, it's far more interesting and stimulating than Saturday Freeview TV here at the UK.
@chri-k 3 жыл бұрын
Not related, but; Was that rickroll monitor at the back always there???? ( 28:20 )
@bodolevente2246 3 жыл бұрын
@@chri-k It's been there for a long time but it's always changing i.e sometimes it's a rickroll, other times it's just a clock, etc.
@jarrettrodriguez5341 3 жыл бұрын
Thanks fir bring us on this journey today. It was great to feel like we were there at the bench with you!
@bitoxic 3 жыл бұрын
You just made my day Adrian! Big commodore fan here! Best way to cross 100k mark with this video!!! 😁👍
@bobhope1160 2 жыл бұрын
Its crazy how much content I keep discovering. Legit I've been binge watching your channel for months now
@martijnthie3087 3 жыл бұрын
Thanks for picking up the Commodores again! I know that you've done these videos already, but... I really love them! You can't have enough of these.
@taltechchip5827 3 жыл бұрын
I'm very happy to see this C64 marathon :) Thank you!
@00Skyfox 3 жыл бұрын
For those schematics that span two image files, just load them into a graphics program and merge the images, and then save the resulting complete schematic. If the original scans weren’t perfectly square you might need to tweak one or the other with some rotation or skewing to make things line up right.
@Dorff_Meister 3 жыл бұрын
You'r "off by one" aside was the really useful observation. This must demonstrate a bit about your failure and HOW dead-test is checking RAM. There is something interesting there that I suspect the Dead-test author could learn from that bad RAM chip. I would send it to them. (too late it's in the bin, but I knew it would be)
@macdaniel6029 3 жыл бұрын
I could watch your C64 repair-a-thons all day long :) Can´t wait for the next video.
@museum1401 3 жыл бұрын
Congrats on 100K Adrian! This channel has really helped me through these strange times. 🙌
@markwrightrf 3 жыл бұрын
I waited so long to hear your catchphrase, "would you look at that? It's WORKING!!!" only to be hugely disappointed. I'm now doing a sad 8-bit dance shuffle to the Monty on the Run high score theme. "Would you look at Black? He's SHIRKING!!!!" :-) :-)
@ChrisFaulkner 3 жыл бұрын
thank you for doing this video. this is an excellent video for troubleshooting and where things go wrong and the steps you are doing in a good positive way. thanks for your time doing this, it helps us all out
@theimitanturproject8310 3 жыл бұрын
Very engaging video. I was at the edge of my seat every time the C-64 was booting to see if the replaced chip was the right one. :)
@terosaarela4555 3 жыл бұрын
Thanks for the video! A cold beer after sauna and watching your repair videos really make my Saturday evening!
@tim_nj_devil176 3 жыл бұрын
70's Shag carpet...beautiful green & gold mix - Jeff Foxworthy (1993)
@aaronkosharskyswhiteknight5224 3 жыл бұрын
It really tied the room together
@tobiwonkanogy2975 3 жыл бұрын
if anything this is the best way to know exactly what each logic chip affects , with an accompanying visual representation. Very cool Adrian
@milandjukic88 3 жыл бұрын
100K! Congrats! Love your channel! Greetings from Serbia! 😊
@petesapwell 3 жыл бұрын
As always great to share this journey. Sharing is everything. Cheers Adrian 🤓
@pipschannel1222 3 жыл бұрын
"It LIED!" Darn you Deadtest! Lol! Could've been me, getting stumped by yet another crusty old machine :-)
@maltoNitho 3 жыл бұрын
Whoa, so close to 100k!! Congrats and thanks for the years of entertainment
@wimwiddershins 3 жыл бұрын
These are always enjoyable and compelling viewing. Thank you Sir.
@MrGtagangster 3 жыл бұрын
Aaaaaaaaaah, a great video to watch with a cup of coffee after dinner with a cookie. 41 minutes of entertainment and fun. Love to see another repairathon!
@drkilmerx 3 жыл бұрын
Really enjoy watching your videos. Thanks!
@ConnerBurns 3 жыл бұрын
Adrian is doing another repairathon? Finally, something to look forward to during human malware!
@briangleeson1528 3 жыл бұрын
Another awesome video. I really enjoy your videos and applaud the effort you put into keeping these machines going.
@djdublo 3 жыл бұрын
Fascinating, genuinely absorbing! Never had a c64 but it's interesting to see how all the components interact.
@projectartichoke 3 жыл бұрын
Always love all your videos, but especially anything Commodore! Words to live by: "Run every diagnostic you can, first." :) I can't wait for you to hit 100K subscribers! At least I won't have to wait very long. :)
@melissa.merritt 3 жыл бұрын
My desoldering gun gets blocked just the same as yours, what I do to reduce the blockages is when I suck the solder off the components I continue to hold the trigger On for same time after and sometimes pointing the nozzle upwards with the trigger On, this gives it time to clear the gun,,, keep up the good work 👍
@claudioquintanilla1471 3 жыл бұрын
I enjoyed this video a lot!!! Better than a suspense movie!!! Thks Adrian!!!
@krnivoro1972 3 жыл бұрын
Loved the part you got confused with the three suspected chips in you ZIF motherboard just because some poor chip legs contact. That's the worst "I'm lost" moment you can get... 😁
@jonathancombe9991 3 жыл бұрын
One thought I had when you were checking the outputs from that chip where the signal from 2 of the pins looked odd - compare it with the output from the known working Zif c64. If they are the same on that one, then that could be ruled out as the problem.
@jimhewes7507 Жыл бұрын
Fun video! A couple days ago I watched this video as the first Adrian's Digital Basement video I've seen. I was surprised to see there was such an inexpensive scope, not that I keep up with these things. I bought a C64 new in 1984 and when it stopped working in the early 90's I just boxed it up and bought a C128D to replace it. After watching this I got a little excited and started thinking Hey I could buy this little scope and break out the old C64 and see if I can fix it. But now after watching the repair-a-thon videos 1 thru 3 I realize it takes a lot more. Adrian repairs these C64's mostly by narrowing down which chip is likely bad and then swaps chips to find the bad ones. So you really need to have these extra chips on hand not to mention the sockets, dead test cartridge, and soldering and desoldering iron. And if the PLA is bad another video suggests it might cost about another 60 bucks to manufacture a substitute for that. So all-in-all not really worth it just to try to fix a single C64 unfortunately. :(
@frugalprepper 3 жыл бұрын
Congrats on 100K Subs Adrian. You deserve more subs, but I am glad to see you got to 100K!
@LFOSyncToo 3 жыл бұрын
Testing the dead ram chip in the ZIF64 would have been fun... for the giggles :)
@BigDaddy_MRI 3 жыл бұрын
Great video!! 100K coming soon I hope!! And your skills with troubleshooting C64’s are just fine. Test equipment can sometimes lead you down a path that takes you away from the actual problem. The old saying (from when I was in the Navy) is: trust your test equipment, until you can’t. Working on aircraft fire control computers ... sometimes our TE would lie to us and make the job harder. But, it happens, and you did a superlative job working through it. Maybe the dead test module needs an upgrade? Really liked this one, Adrian!! Great job!!
@notneb82 3 жыл бұрын
Congratulations on 100K!
@danieltufvesson1349 3 жыл бұрын
Just a quick tip since you have the wonderful HP 547A current tracer. I have luck with it sometimes detecting bad RAM without any de-soldering or test programs. If all RAM chips are the same type/manufacturer/batch, you can use the 547A to "feel" the center of each RAM chip, setting the sensitivity so that it juuust lights up and compare the chips back and forth. It takes little while to get the feel for it, but if one chip makes the 547A light up easier than the others it is often bad (as in more over all current flowing through it). I've found this method to be more reliable than trying to compare chip temperatures by hand. Other chips can sometimes be detected in a similar way. Love your videos. Keep up the good work.
@FHolloran 3 жыл бұрын
Heck yeah repairathon! Pretty soon I’ll be able to have a repairathonathon.
@The.Doctor.Venkman 3 жыл бұрын
Great video, Adrian! You know there is always going to be some creep that is sitting there shouting "It's the RAM allocated to the screen. One of the chips is bad...." - I have to admit, that it was me this time and boy, was that a very lucky guess as I'd be crying into my pillow if it had been something else lol! ;o)
@TheSleepyCraftsman 3 жыл бұрын
As someone who worked in configuration management...manufacturing will say that a part is a part is a part, regardless of the revision. You're lucky that you get a revision on anything. If a change doesn't affect form, fit, function, interchangeability, etc, you won't get a new part number either.
@thunderbolt10031 3 жыл бұрын
If you're like me and don't have a solder sucker, there's a neat trick to desoldering an IC with solder wick. On the underside of the board, of course, start there and get as much solder off as you can. Then flip to the top side and if there's enough room, run the wick against the legs on the IC to suck up any more that may have been left behind on the top side. Typically when I do it on 14 or 16 pin ICs, there's always at least 1 pin that doesn't completely desolder, but with a little patience, it'll clean up and the IC will just lift right out.
@jameslewis2635 3 жыл бұрын
I have been told that the C64 was the most successful home computer ever made. While I don't know how many were made it does seem that sometimes between Adrian or Jan Beta have at some point half of them have been repaired on KZfaq.
@MarcoHandleidingManuel 3 жыл бұрын
Adrian, i like your channel a lot. I am still flabbergasted by the way you are not using a ESD wristband, and tossing away the shielding. After fixxing i would put everything back to be a as close to the real machine. CIA's are vulnerable to static discharges known when touching the joystick ports. I like the way of your aproach with the hot air not to lift any traces. I would use the TL866-II to check the logic chips for faultiness.
@xiphias256 3 жыл бұрын
Maybe he has it attached to his leg instead of the hand? ;-)
@mikeuk666 3 жыл бұрын
@@xiphias256 he said in previous videos he finds them awkward when filming so avoids them
@GORF_EMPIRE 3 жыл бұрын
I suspected a ram chip from the get go, but since I never did any C64 repairs, I figured I'd watch and see. The period characters on the test screen is why I thought a ram chip was bad.
@mikeuk666 3 жыл бұрын
keep up the great work Adrian 🕹 ♥
@P5ychoFox 3 жыл бұрын
Great journey. Glad you got there in the end. Another C64 fixed :))
@dunebasher1971 3 жыл бұрын
17:43 Love how the sound of the desolder gun forms part of the rhythm track on the music.
@AureliusR Жыл бұрын
What? It's not in sync at all. I must be hearing something different
@OzRetrocomp 3 жыл бұрын
0:44 Is that a new record for earliest Rick Roll in an ADB video? 😁
@TheRetroChannel 3 жыл бұрын
Approx 1 minute later: dead test is not always accurate 😉
@adriansdigitalbasement 3 жыл бұрын
HAHA -- It's time I update the display to show some different things. Maybe I can install my own logo or face on it. KZfaq-Ception.
@thoraldshib4393 3 жыл бұрын
@@adriansdigitalbasement when is mac portable from macreparathon happening
@IanSlothieRolfe 3 жыл бұрын
@@adriansdigitalbasement What is that gadget? Do you have a video on it?
@adamwheeldon 3 жыл бұрын
Love a good repair-a-thon 👍👍👍
@lougarou007 3 жыл бұрын
Great informative and entertaining video. Thank you
@cyruscuckler3495 3 жыл бұрын
Adrian in the last video: I should do another Repair-athon. The very next video: Is a Repair-athon! This is why you're the best man!
@IRTheBorg 3 жыл бұрын
You did well on this one. If it was me I would have went nuts! Great video - thumbs up! -Larry
@kd5byb 3 жыл бұрын
I love repair-a-thon! :) When it comes to troubleshooting...some days you win...some days you don't. The key is to keep on keeping on. :)
@TechBench 3 жыл бұрын
For testing 74-series TTL and 40-series CMOS chips, you can use the MiniPro 866. Under device, select the "Logic IC" and then select or search for the one you need to test. Works for all gate-type chips (not counters, for example).
@XLV750RD01 3 жыл бұрын
Congratulations on 100k subscribers.
@deborahberi3249 3 жыл бұрын
Oh boy, I learned that a few years ago. Full Diag Cart is my goto UNLESS it won't run at all. Too bad Dead Test failed me in the past so I don't rely on it for RAM Tests. -Mark.
@warmsteamingpile 3 жыл бұрын
Fascinating video.
@capitanschetttino8745 3 жыл бұрын
Oh my god, how I love your videos!! Nothing else to say!!
@coyote_den 3 жыл бұрын
U26 and U16 are the bus interface to the color RAM, and they explain why the color RAM is "special" and the VIC doesn't use DRAM for the color in text mode. U26 latches the A0-A7 of the color RAM address from the VIC when AEC and RAS are low (because that is when the VIC has the low byte on the MUX bus. A8/A9 are available as discrete outputs, this is important later... ) U16 disconnects the color RAM from the CPU data bus when AEC is low, so only D0-D3 from the color RAM is on D8-D11 at the VIC. This is also really important. It is a genius design that allows the VIC to fetch the color and character codes at the same time via a 12 bit data bus. The C64's memory actually runs at 2 MHz, with the CPU getting it half the time and the VIC fetching the character patterns or bitmap the other half of the time. Every 8 scan lines, the VIC halts the CPU for an entire scan and also fetches the character pointers (or color data for bitmaps) from screen memory: A10-A13 are set to the screen base register and A0-A9 increment over that row's addresses... but those lines also go to the 1k*4 color RAM so the matching color data appears on the VIC's D8-D11.
@Dorff_Meister 2 жыл бұрын
I recently got a C64 with one of the S100 PLAs. Nifty.
@mdofxds 3 жыл бұрын
Great work, Adrian! RAM issues may be really hard to diagnose. The worst case I meet time to time is when the most of available tests pass, everything seems nice and working but real programs glitch occasionally and randomly. This lead me to start making own tests for the machines I repair. I found kinda good heuristics which reveals such hidden problems: fill RAM with increasing bytes, check, cyclically shift the contents of RAM byte-wise, repeat from "check". Usually a couple of iterations is enough to reproduce the glitch.
@-CrippledNinja- 3 жыл бұрын
Ooo, this was like an episode of Hercule Poirot! Which chip is the faulty one? Damn RAM chip again! What a thriller!
@sausageeater9357 3 жыл бұрын
Knew it would be a ram issue, that was my first impression. It's the same with many issues with the Sinclair Spectrum. Bloody ram lol. BTW, love the videos Adrian 😍
@Halftrip 3 жыл бұрын
I anxiously await any and all of your Commodore 64 videos, regardless of their content. But I especially like these fixit videos. Pulled my breadbin out to try and get it running. Deadtest says everything is fine but diagnostic cart (with harness) says both CIA chips are bad. Awaiting some replacements in the mail to see if that’s right. Can’t wait for your next video!
@RoelvandenBergWillemWasbak 3 жыл бұрын
For everything is a first thing to happen. So now you know that the death test does not always work well at one test, so next time test both or more versions of the death test. It makes you only a better troubleshooter with extra experience. I loved the video again so thumbs up!
@Gorgen2k 3 жыл бұрын
Dunno why i find these vidoes fun to watch when i dont even have a c64. I had when i was younger, but i think remember ours died because the fuse was going always. And i think it was imposible to get new ones in my town at that time.
@johue2458 3 жыл бұрын
Perfect Sunday afternoon!
@petewilliams2998 3 жыл бұрын
Yayyy!!! Repairathon time!!!
@Dukefazon 3 жыл бұрын
After years of dreaming an accessible and affordable desoldering gun, I could finally get one (wasn't too cheap but cheaper than a professional one with a station). This week I used it to desolder one of the analog stick in a PlayStation 4 controller. It has 3+3 legs for 2 potentionmeters, 4 legs for a button and 4 structural points of the whole analog stick housing. It used to be a very difficult process but now that I have this desoldering gun I'm so happy and I can do jobs like these much easier and makes repairing stuff fun again.
@UberAlphaSirus 3 жыл бұрын
Yhea. I really need to get one, solder suckers are ok for a few joints but otherwise are a PINA. What did you get?
@cubeflinger 3 ай бұрын
The first thing youll need is a working c64. *Sighs in piles of broken c64*😅
@80lab38 3 жыл бұрын
The bad SID and control port readings are in deed caused by a failed paddle test. I had the exact same reading when I replaced an 8580 with a 6581 and forgot to change the caps for the filters and the paddles (I didn't neglect to change the zener for the supply voltage, so the chip itself was working fine). So the test seems to be quite thorough.
@mldalex 3 жыл бұрын
congrats on 100k
@Marcel38281 3 жыл бұрын
Oh I'm looking forward to this video
@herdware 3 жыл бұрын
My first thought was bad RAM but then the Dead test said it was OK. At least it made an interesting video.
@loginregional 3 жыл бұрын
Haven't watched any of it YET (and I will!), and I tend to criticize dialogue/monologue: you say (regularly) "let's get right to it!" But then you roll the retro (icky smeary video the type I haven't seen since 1994) intro. You see, you don't get *right* to it. I know this is going to be a great episode.
@xKatjaxPurrsx 3 жыл бұрын
HELOOOOOOOOOOOOOO ADRIAN! HAPPY WEEEEKEND!
@RavenWolfRetroTech 3 жыл бұрын
Nice, I love a good repair!. My "Luck" on fleaBay has been terrible. I keep buying "Dead" machines only to discover they work fine or have a bad power supply. I need a Fix Fix!
@schm4704 3 жыл бұрын
Oh come on... that opening shot of those stacked 64s is just flexing. :-)
@televiciousgoober 3 жыл бұрын
Funny, last week I pulled out my 4 dead c64's and decided it's time to fix them too.
@rfmerrill 3 жыл бұрын
If it were me I would get out the heat gun and freeze spray and see if I can turn it from working to non-working or vice-versa by heating/cooling specific chips. Very good general tool for debugging as often a fault in a chip will fix itself at high or low temperature (usually low).
@SocrateTheCat 3 жыл бұрын
Thanks Adrian for your video. Dead test cartridges don't always tell the truth. I have a commodore where the cartridge tells me that everything works (with harness) but when I run the load command to load floppy it hangs and does not give up control. I tested several disk peripherals (1541 and pi1541) and I have the same thing. The cable is good too. The u8 (7406) is good too. I tear out what little hair I have left. :)
@HeyBirt 3 жыл бұрын
Heat the tab on the shied and pry it up with a small screwdriver. Very quick and easy.
@arithium 3 жыл бұрын
At least it made for a good video. Glad you got it working.
@e42_channel 3 жыл бұрын
Like your repair-a-thon. Thx for it. Please keep in mind that you can test the TTL Logic IC (LS258 / LS373) also with your TL866II programmer (The software has the test function build in).
@douggale5962 Жыл бұрын
A bad machine can't always test itself. If you use 1 to mean failed, and bit 0 is stuck 0 at that address, it becomes OK. On a modern machine, the internal caches have ECC, so the BIOS has a chance of correctly testing RAM, while configured for cache-as-ram. If the cache is bad, it will most likely MCE (machine-check exception).
@LeftoverBeefcake 3 жыл бұрын
Wish I had watched this video before ordering my chip lifter... I could have used your link to help support your excellent channel. :(
@winstonsmith478 3 жыл бұрын
Your mention of schematic version vs PCB version difficulty brings up my question about no available 'scope images taken at various key test points. After all this time, with all of the people repairing the huge number of broken C64s, I'd have thought someone would have taken some photos to do that by now. Maybe they have and I just don't know it. Don't own a C64 myself.
@douro20 3 жыл бұрын
The 82S100 was actually the very first user programmable logic device.
@pa4tim 3 жыл бұрын
I have such a HP logic probe set (old and new type probe, old type tracer., new type pulser) but not such a beautiful HP storage etui. The old type pulser is nicer because it can make pulstrains/patterns. Very handy tools (not only for homecomputers)
@jamesmaddox7902 3 жыл бұрын
Haven't seen any Ransomeware attacks on Commodore 64, so reliable. 😎
@SidneyCritic 3 жыл бұрын
The IC puller is probably not good for large IC soldered on to PCBs. Saw that Parfractive guy snap a 40 pin in half when he didn't desolder a center pin properly - lol -. For the RF shield I was thinking a large 100W hardware iron with the copper tip hammered flat to a chisel shape, so it can heats and get under the tab on one motion.
@Foobar_The_Fat_Penguin 3 жыл бұрын
Late to the party, just wanted to mention that this a common issue with software RAM testers. If they don't find errors, it just means they found no errors. Not that there aren't any. It's not the fault of the dead test cartridge, just a limitation of the technology. Whether a memory cell can keep its value depends on many factors (values in neighboring cells, access patterns and timings, temperature, voltage fluctuations, etc). "Real" RAM testers are big machines that can simulate all those different conditions and cost 5-6 figures. Cheap software solutions can't do that. It's the same with programs like Memtest86 on the PC. It's also why these tests loop and don't run just once. The idea is that you let them run for a while (12-24h) to cover a wider range of randomly fluctuating factors, some of which will hopefully trigger the problem at least once. Software tests still have value, however, because if they *do* find errors, then there's definitely a problem.
@wendellporter4875 3 жыл бұрын
i had c64's about 20 years ago and repaired them, trying to find one now is crazy expensive
@Dukefazon 3 жыл бұрын
26:28 - I though your thinking was on the right track but not the chips that are bad but one or more trace is. Check continuity between the chips' legs. Those pesky RAM chips, making things complicated... Can't wait for next weeks episode!
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