Commodore Amiga A2000 Video Fault / Zorro Fault / Instability Repair

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  • Опубліковано 12 гру 2024

КОМЕНТАРІ • 108

  • @GadgetUK164
    @GadgetUK164  5 років тому +4

    Note: At one point I started talking about the 74ALS chips - the 2 in the databus area are 74LS (and marked that way on the schematics. I fitted a 74ALS245 in place of the 74F (related to address lines) and that's correct according to the schematics. I am not sure which of the others should be 74ALS chips. As far as I understand, a recommended mod is to swap the databus tranceivers with ALS chips, and depending on manufacturer you might need to add the 3K3 pull down arrays. My main 2000 has ALS chips on the databus side. The schematics show just 1 x ALS chip on some of the upper address lines.

    • @spidermcgavenport8767
      @spidermcgavenport8767 5 років тому +1

      Curious on these Amiga A500+ A2000 when ESD is a consideration which IC's are most susceptible to this form of potential damage? Or would this be more of a concern for newer components? I personally never experienced any ESD sensitivity when I worked on consoles.

    • @GadgetUK164
      @GadgetUK164  5 років тому +1

      ESD sensitivity is something that nearly all chips can have! More modern devices claim to have some level of protection, although often that's just in the form of clamping diodes. The way devices are damaged is often gradually over time - ie. you release some static into a connection - maybe the clamping diode deals with it, but that could damage the diode a little. Over time with multiple charges hitting something it can fail entirely. There is also the risk that the first ESD charge that goes into something could kill it instantly, depending on what gets zapped and the charge. I do agree that it's hard to notice any issues at all on modern systems. It is a real affect, but the likely hood is super rare from my own experience, but not every situation is the same. ie. The charge you can build up and hold / pass is based on many factors - what you are wearing, foot wear, your skin resistance, your own ability to hold charge etc etc. eg. my wife gets static shocks of light switches and car door handles all the time, I've never had that problem!

    • @spidermcgavenport8767
      @spidermcgavenport8767 5 років тому

      @@GadgetUK164 I get those shocks in winter, thank you, much appreciated, this is very informative and knowledgeable.

  • @andrewlittleboy8532
    @andrewlittleboy8532 5 років тому +7

    Can't beat another A2000 video, just watched Jan Beta's video, now yours.
    Super happy things are going better for you now!

    • @GadgetUK164
      @GadgetUK164  5 років тому +2

      Thanks =D Yeah, I enjoyed Jan's video too!

  • @runcmd8851
    @runcmd8851 5 років тому +2

    Great video and another amazing debug... and I am glad everything is slowing getting back. We also love watching Jan as well i hope one day you both can team up for a video one day.

  • @TheErador
    @TheErador 5 років тому +7

    Enjoyed this one... it's always about the chase, but nice to see a good result. Glad to hear things are stabilising a bit work-wise too.

  • @Maxxarcade
    @Maxxarcade 5 років тому +1

    I never have any luck with those PLCC removal tools. They do the same thing to me, even on chips that haven't been messed with. 13:10 great idea with the shrink tubing for making a DIY adapter! I've always just attached the wires to the pins and shrink tubed each one, but I like your implementation better. In fact I'm going to fix the connector on my bench monitor when I go to work tomorrow.

  • @blakecasimir
    @blakecasimir 5 років тому +1

    23:45 A moment of triumph! That was so satisfying. XD another great video Chris. So glad to hear your work situation has improved, too.

  • @osgrov
    @osgrov 5 років тому +1

    Ooh, this was a good one! Love these troubleshooting sessions. It's so much more satisfying than simply showing a solution. :)
    Thanks, too, for all the tidbits of tips and tricks. Love it when you put on the teacher cap.
    Looking forwards to many more Amiga videos!

  • @Mymatevince
    @Mymatevince 5 років тому +2

    Nice fault finding Chris, great tips along the way :-)

  • @Maxxarcade
    @Maxxarcade 5 років тому +1

    I came across a few arcade boards where someone had used a torch to remove components, and they were burned to the point that they were scrap. And one of them was a fairly valuable Atari "Black Widow" PCB.

  • @myeyeshurt1877
    @myeyeshurt1877 5 років тому +1

    Another top vid! I do love these Amiga videos, no matter how many of them I've seen now, especially the fault finding and gradually narrowing things down :).

  • @markwrightrf
    @markwrightrf 5 років тому +1

    I always look forward to these videos. Gets straight to the heart of the matter with lots of concern for the viewer to gets things in focus and explain properly what's going on. No frills. No fancy stuff. Just down to business. Unsung hero here :-) If I had the finances to donate it would be going right here rather than paying towards new studio lights and updated 4K cameras, etc. Maybe one day!

  • @Hagledesperado
    @Hagledesperado 5 років тому +2

    Good call putting the resistor arrays at the bottom side. As you said, more maintainable. They seem to be kind of a bodge anyway, not having their own through holes and all.

  • @dlfrsilver
    @dlfrsilver 5 років тому +1

    another excellent repair :D

  • @ArcticFox63
    @ArcticFox63 5 років тому +1

    Never knew computer repairs were so interesting. I have been binging a lot of your videos since I found your channel.
    Amigas and the Amiga 500 specifically is my most fondest memory of owning a computer and probably my favourite computer I've ever owned.

  • @FloatingFatMan
    @FloatingFatMan 5 років тому +1

    Another great video, Chris! Good to hear your situation is improving a little!

  • @georgelea4297
    @georgelea4297 5 років тому +1

    Another great video as always Chris glad to hear things are getting better for you

  • @keithmcgerr3056
    @keithmcgerr3056 5 років тому +1

    Great vid sir! Last owner must have tried warp3d.lha but lost the instructions and got board!
    One did see you sticking resistor networks on the bottom holy smokes Batman!

  • @Neffers_UK
    @Neffers_UK 5 років тому +1

    Another vid, another board lives to see another decade, excellent stuff as always Gadge. Glad to see the Patreon credits increasing in length too!
    Keep adding to that list peeps, each little bit DOES add up to help Gadge out!

    • @GadgetUK164
      @GadgetUK164  5 років тому +1

      Thanks mate =D

    • @Neffers_UK
      @Neffers_UK 5 років тому +1

      You are more than welcome Gadge.

    • @gregjarvis1232
      @gregjarvis1232 5 років тому

      If he gets video game repairs I will support again I don't find the computer repairs interesting even though he's brething new lif into old computers

  • @jasejj
    @jasejj 5 років тому +2

    Hi Chris, I wasn't sure where to post this so it gets to you, I have a pair of N64, erm, development units that are both broken (a Z64 and a CD64), neither of which are worth bothering with these days but they are interesting pieces of history, I tried to fix them years ago and got nowhere although I think they both power up at least.
    Free to a good home if you want to try to get them working again :) They are going to the waste disposal centre otherwise as I can't be bothered with potential ebay trouble for the sake of £10-20...

    • @GadgetUK164
      @GadgetUK164  5 років тому

      You could get more than £10 to £20 on eBay for those! More likely £100 upwards probably.

    • @jasejj
      @jasejj 5 років тому +1

      @@GadgetUK164 You sure? They are knackered. I'll give selling them a go then, cheers 👍

  • @darkwinter6028
    @darkwinter6028 5 років тому +1

    That bag won’t generate static, but it won’t protect against externally sourced ESD events. For that you need a metalised (“silver”) bag. There’s an EEVBlog video on the subject if you want to know more.

    • @GadgetUK164
      @GadgetUK164  5 років тому

      Correct, it's a step up from no protection or just a plastic bag though =D

  • @janhofmeier9427
    @janhofmeier9427 5 років тому +2

    One thing I like to probe, when I have a black screen is OVL on the CIA or Gary. Looking at the disassembly of Kickstart 1.2 it's the earliest thing the Amiga tries to do. For it only the CPU, KS and CIA and Gary have to work. There are no Bus drivers in the way. If OVL goes low it means the CPU is able to execute Instructions from the KS correctly. The next thing the Amiga should visibly do is turning the power LED brighter, but that takes a few Seconds.
    For the Zorro Card: I would just file down the edges.

    • @GadgetUK164
      @GadgetUK164  5 років тому +1

      Thanks! Nice tips there! Yes, had I kept the ZRAM card I would have done that - I decided to review it and sell it on (described well so someone knew what I disliked about it). Which is what I did! Review will go up soon!

    • @janhofmeier9427
      @janhofmeier9427 5 років тому +1

      @@GadgetUK164 I did make a mistake, before it turns the power led bright it changes the colors on the screen.
      But another thing I noticed is: dim Led and Green Screen could indicate a problem in the communication between the CPU and the (I think odd) Cia. I noticed that when I was tinkering with E, VPA and VMA for a 14mhz mod. I suspect the Cia doesn't understand, that it should turn of OVL, then the KS Rom stays mapped at the chipram Adress and the RAM test fails.
      Do you know what happens with the Power LED normally if you have bad chip ram? (luckily I never had bad chip Ram)

    • @GadgetUK164
      @GadgetUK164  5 років тому +1

      @@janhofmeier9427 Yes, I think I covered that in part 6 of the A500 repairs. I think the power light flashes 5 times if the lower part of the stack has a problem (chip ram).

  • @ExtremeBogom
    @ExtremeBogom 5 років тому +1

    A nice long fault finding video, always a treat Chris :).

  • @AdamSommer70
    @AdamSommer70 5 років тому +1

    Super interesting video, thanks for posting!

  • @SLRModShop
    @SLRModShop 5 років тому +1

    Glad to hear that last bit ! Great video mate.

  • @Channel-Zx
    @Channel-Zx 5 років тому +1

    Awesome video Gadget keep em coming!

  • @refractionpcsx2
    @refractionpcsx2 5 років тому +1

    Great video dude, I did wonder for a bunch of that what you'd done with those resistor packs haha. Glad to hear everything stabilising a bit :)

  • @TheHighlander71
    @TheHighlander71 5 років тому +1

    Whoever burned that board before must have fallen asleep! Or maybe they hated electronics in general. It's a miracle that thr board still works. Well done Chris.

  • @xenonkay
    @xenonkay 5 років тому +1

    You can even see the plastic at the end of the zorro slot bulging outward once you force the card in.

  • @Four_X
    @Four_X 5 років тому +1

    Top video Chris, Another fine repair. Just a shame someone tried to remove those chips with a paint stripping heat-gun, apart from that the battery leak looked to be minimal on this Amiga 2000 board.

  • @104d_3rr0r_vince
    @104d_3rr0r_vince 5 років тому +1

    Nice journey my friend!

  • @darkwinter6028
    @darkwinter6028 5 років тому +5

    I’m thinking someone tried to use a butane torch instead of a proper electronics hot air station to do a rework on this board... 🤨

  • @tenminutetokyo2643
    @tenminutetokyo2643 2 роки тому +1

    That’s nuts!

  • @xnonsuchx
    @xnonsuchx 5 років тому +4

    Seeing botched previous repair attempts on equipment can really raise the blood pressure a bit. :-(

  • @Plan-C
    @Plan-C 5 років тому +1

    Nice work! Looks like they used a paint stripper to try and get that chip off off!

  • @Adrian_Finn
    @Adrian_Finn 5 років тому +1

    Great vid, one thing to mention is that if someone did go and solder on another 3.3k resistor pack on top of those databus tranceivers they would end up with a resistance of 1.65k rather than a doubling up affect, as 2 x 3.3k in parallel equals 1.65k. What effect if any that would have i'm not sure as having looked at the schematic it looks to me like those 3.3k resistor packs (XRP1, XRP2) are creating a voltage divider network with resistor packs RP900, RP901, Please correct me if i am wrong.

    • @GadgetUK164
      @GadgetUK164  5 років тому +1

      Yes, I realised that was not very clear of me! The point I said "doubled up", I meant doubled up as in twice the resistor packs on there, but it does drop the resistance when they are in parallel (same as caps in series). I've not looked at RP900 / RP901 relationship but I will check that out later.

    • @Adrian_Finn
      @Adrian_Finn 5 років тому +1

      @@GadgetUK164 I definitely knew that you would know that, just thought for others that may not necessarily understand, trap for young players. I maybe wrong about the devider network I'm not sure, my electronics knowledge is a work in progress as I'm a young player myself. 😊

  • @HappyCodingZX
    @HappyCodingZX 5 років тому +1

    sorry to hear about your job - good luck for the future I'm sure something will turn up, perhaps now is the time to start your own retro repair business, I'm sure you'd do really well.

    • @GadgetUK164
      @GadgetUK164  5 років тому

      Thanks! I am OK for now! The part time role combined with having more time to do YT stuff is a good balance at the moment. I just won't have lots of money lol. I might later open up to chargeable repairs, I just need to sort lots of things out before I can do that.

    • @HappyCodingZX
      @HappyCodingZX 5 років тому +2

      @@GadgetUK164 You should combine the two - people send in repairs, you feature the interesting ones on UA-cam. Featured repairs mean people get to watch their item being fixed, business grows, everyone wins.

  • @tenminutetokyo2643
    @tenminutetokyo2643 2 роки тому +1

    245’s can be replaced with brand new 645’s which are modern direct exact replacements.

    • @GadgetUK164
      @GadgetUK164  2 роки тому

      I wasn't aware of that model - there must be a difference?

  • @LucaBlightOfHighland
    @LucaBlightOfHighland 5 років тому +1

    1:07 ...I LOVE reconstruction videos from corrosion. Not kidding.

  • @insanedruid3143
    @insanedruid3143 5 років тому +1

    Nice Video. So what temp would you suggest that should have been used here in the first place? I would probably have tried 280 after a bit of prewarming, takes some seconds longer but has reduced risk of damaging plastics. At least thats what i used on my a600 to remove the caps. Maybe 320 if its really stubborn?

    • @rasz
      @rasz 5 років тому +1

      Are you asking about the hotair? Number you set on the tool is meaningless, especially when it comes to cheap Chinese garbage ones. Final temperature depends on air flow, nozzle size, distance from the nozzle etc.

    • @insanedruid3143
      @insanedruid3143 5 років тому +1

      No way, things are depenent of other variables? Lets stop measuring anything then.

    • @rasz
      @rasz 5 років тому +1

      The point is you _arent_ measuring anything meaningful, station setting is an arbitrary number resulting from proprietary algorithm trying to guess what particular heating element temperature and set air flow will translate into after exiting the nozzle without knowledge about any externalities like distance/nozzle size/room temperature/angle.
      forum.ipadrehab.com/forum/right-to-repair-and-industry-news/359-airflow-and-temperatures?p=606#post606

    • @insanedruid3143
      @insanedruid3143 5 років тому +1

      I do understand your point, but really, you KNOW what I mean, too. Setting it to "100" of arbitrary units on that uncalibrated dial WILL result in a predictable different outcome then setting it to the label marked with the glyphs "400", regardless of the other parameters, inkluding ambient temperature. And the range of these other parameters usually doesn't fluctuate that much, too, unless you try to reflow solder from 2 astronomical units away.

    • @rasz
      @rasz 5 років тому +1

      nah, different nozzle and distance can easily mean 50-100 degrees difference

  • @xephorce
    @xephorce 5 років тому +1

    I am so nervous I just got a job as a bench tech. I start this Monday. I have never had the proper tools to test stuff I always just depended on my wits and experience to fix circuits. I know I should have more faith in my skills but I am truly nervous about the job. I will mainly be working on DVR/cable and satellite set-top boxes. I feel like I may be out of my element. I am excited to finally have a job doing what I love. most of my skills are working on older electronics, not the newer stuff. during the interview, I did emphasis this so I hope they give me enough time to adjust. I am just afraid they are expecting a unicorn of a worker lol. do you have any advice? and thanks for the great videos.

    • @GadgetUK164
      @GadgetUK164  5 років тому +2

      Just relax! You will be fine! Take your time with anything you've not come across before, don't feel you cannot ask people for advice either! If you get stuck with something the worst thing you can do is not say anything and keep it bottled up. Worst case - ask me!!!

    • @xephorce
      @xephorce 5 років тому +2

      @@GadgetUK164 thank you for the words of encouragement. I hope things go great and don't be surprised if I hit you up on the offer for advice lol. thank you again you are a knight among men.

  • @YouTubeYouTube-qg6vl
    @YouTubeYouTube-qg6vl 5 років тому +1

    Wow you know something

  • @StRoRo
    @StRoRo 5 років тому +1

    Another Amiga saved from the grave. :D
    My Amiga 600 is very sick. I got some guy in Liverpool having a look at it. I thought it was a couple of pads that came off but it seems to be a lot worse than that.
    And what's happened to the motivational messages you used to put on the things you repaired? I thought this would be a great time to do them

    • @GadgetUK164
      @GadgetUK164  5 років тому

      Sorry to hear about the A600 =/ Regards labels etc - I usually do that on systems I add to my collection, but not always =D

  • @TheMadmagik
    @TheMadmagik 5 років тому +1

    Noticed something. Board with resistor packs on underside has 2 empty RP locations around the slots then one you show right at end those locations are occupied?

    • @GadgetUK164
      @GadgetUK164  5 років тому

      I think those resistor array positions are on the other side of the bus connections though! They are empty intentionally to fix compatibility issues I think.

  • @Nukle0n
    @Nukle0n 5 років тому +1

    That hot air "rework" is just b rutal to look at. What on earth were they thinking?!

  • @johna.dawson709
    @johna.dawson709 3 роки тому +1

    Great video.. I have an Amiga 2000 and during boot the screen flickers grey, white then goes black before going to the monochrome screen..any suggestion to fixing this issue ? thanks for your help.

    • @GadgetUK164
      @GadgetUK164  3 роки тому

      The most common issue with 2000 boards is a corroded trace or via (due to battery leak in the past). You could try swapping the BIOS for Diag ROM - see if that boots and see what it reports for the various tests. You should rule out the CIAs by swapping them around, or swap them completely. A working Amiga will boot without one of them (the one that services FDD). Sometimes that can help if you don't have a spare to test.

  • @Nukle0n
    @Nukle0n 5 років тому +1

    Someone did a battery mod on this but aren't you supposed to replace a cap or resistor with a diode so the board isn't charging the lithium cell? Doesn't seem like that's been done here.

    • @GadgetUK164
      @GadgetUK164  5 років тому

      Yes, there are a few ways to acheive it though! The 470 ohm resistor on these sits between the battery and the 5v rail. The little PCB that sits under the battery holder has a diode on it. So the designer of that just took the 5v that comes from the resistor, feds it to the cathode side of the battery connection. Battery connects to the anode, it's still 1 way - despite the resistor being there. I find it just convenient to remove the resistor and swap for the diode, rather than making a PCB or something like the one used on this board. AmiKit sells the same type of battery PCB!

    • @Nukle0n
      @Nukle0n 5 років тому +1

      @@GadgetUK164 ah, sweet

  • @josephnealescratchcards
    @josephnealescratchcards 5 років тому +1

    ❤️👍

  • @ematech
    @ematech 3 роки тому +1

    desoldering gun model?

    • @GadgetUK164
      @GadgetUK164  3 роки тому

      Anesty ZD-915. For hot air, Atten 858D.

    • @ematech
      @ematech 3 роки тому

      many thanks, last question what is the best desolder temperature set?

  • @geofftottenperthcoys9944
    @geofftottenperthcoys9944 5 років тому +1

    Humidity in the UK? You guys complain when the temp hit 20c! Love from Australia mate.

  • @TheHighlander71
    @TheHighlander71 5 років тому +2

    I gave Jan's video a try but he has integrated ads now...to be brutally honest It put me off a little.

    • @GadgetUK164
      @GadgetUK164  5 років тому +1

      It's worth pushing past the ad as his videos are interesting! But, I get what you mean - glad you said this because it has made me believe my decision was right. ie. PCBWay have been asking me (a few times) if I want to be sponsored. I've politely declined because I believe ads that are part of the video are super annoying - it annoys me lol! I personally don't mine YT adverts on other peoples videos, but adverts part / mid way through videos are just annoying as hell. Yes its free money but despite my situation I cannot bring myself to cash in that way and annoy people more than they are already annoyed from YT ads. Just my take, but I think you've echo'd that?

    • @TheHighlander71
      @TheHighlander71 5 років тому +1

      @@GadgetUK164 PCBWay have been very actively offering sponsorships. Not to me of course, but I automatically assumed they would offer free boards instead of cash.
      Integral ads give me the willies, mainly because it undermines credibility. Perhaps, if I'm brave (or drunk) enough I'll finish watching Jan's video.

  • @raincoast2396
    @raincoast2396 5 років тому +1

    Its all Greek to me! And I don't speak Greek.

  • @StRoRo
    @StRoRo 5 років тому +1

    Argh, seen it already.