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Arcade & Retro Repairs & Mods, all new recipe, with no added MSG...

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  • Registered Users Posts: 8,846 ✭✭✭Steve X2


    I think my macintosh classic is showing signs of capacitor leakage.
    It boots up fine when I first turn it on after been powered down for weeks/months but once I turn it off and then back on a few mins later I get the classic checker-board screen and no boot. Now, if I leave it powered up it will eventually boot(after 2-3 hours). This can be a ram/ram connector issue or more than likely a leaky cap or caps.

    Now I've opened her up and I thought it was fine as there was no obvious signs(very clean and in great condition actually).
    But after a closer inspection there might be some around a couple of the caps(kind of looks like a little bit of oil was rubbed around them).



    I cleaned the board with cotton wool buds and cleaning alcohol stuff and still the same problem.

    So I've decided to try out a bit of a more risky fix but one that has proven successful with issue like this in the past(on old macs anyway). I'm going to run the main board through the dishwasher :eek:
    It's not as crazy as it sounds as long as certain precautions are taken. I'm going to pop out any rom chips that are socketed(hence easy to take out) and if it had any removable ram on the board that would come out as well(it doesn't).

    So the plan is to put the board in the dishwasher now, run it through on a warm but not hot wash(eco wash on my dishwasher). I only put a very small amount of detergent in with it(less than half a tablet). Once the wash is done I'll dab dry it and then dry it again with cotton buds.
    Once that's done I'll put it on a non metallic oven plate and put it in the fan oven at a very low temp, like 30-40 degrees for 20-30 mins(while keeping an eye on it and the temp inside the oven.

    That's the plan, hope it works this time as it did the last couple I did 5 or 6 years ago.

    I'll post up some pics a little later.

    Edit:
    I've posted lots of pics and more info over here:
    http://www.retrovia.ie/showthread.php/9214-Apple-Macintosh-Classic-Risky-Repair-Job%28not-really%29

    Few pics(many more at the above link):

    Click for full size.

    DSC_0809b.jpg

    DSC_0813b.jpg

    DSC_0836b.jpg

    Right, so its washing away in the dishwasher as I type this. More updates later on I guess :o


    Edit 2:

    Fresh out of the dishwasher

    DSC_0840b.jpg

    DSC_0841b.jpg


    And now into the oven:

    DSC_0844b.jpg


    Check the temp is just right(it is):

    DSC_0842b.jpg


    Right, going to leave it in the oven with the fan on for 30mins. I'll be checking it as it goes to make sure it doesn't get to hot.

    .



    .


  • Registered Users Posts: 8,846 ✭✭✭Steve X2


    So, an update on my dishwasher/oven fix.

    It hasn't fixed the issue but at least its ruled it out(and the board is nice and clean ;))
    The next possibility is the RAM or RAM board but I don't thing this is it. I think it might be the PRAM battery as there is an issue that some people have come across that if the battery is dead or on its way out it doesn't hold the settings(which is normal) but they also say that SoftPower circuit is not getting enough power from the battery to start the Mac and apparently the PRAM battery also handles the ADB control and the SoftPower circuit.

    So I've ordered a new battery on ebay(about 5 euro) and I'll replace it and see what happens.

    More pics and info:
    http://www.retrovia.ie/showthread.php/9214-Apple-Macintosh-Classic-Risky-Repair-Job%28not-really%29

    .


  • Registered Users Posts: 894 ✭✭✭Dale Parish


    You Sir, are a legend.
    Edit:
    That checkerboard problem doesn't have the same pattern as my one; just curious when you said you'de the same problem, did you mean the checkerboard problem or the one I had?


  • Registered Users Posts: 8,846 ✭✭✭Steve X2


    You Sir, are a legend.
    Edit:
    That checkerboard problem doesn't have the same pattern as my one; just curious when you said you'de the same problem, did you mean the checkerboard problem or the one I had?

    Can you post a pic of the prob you had. I just have the checkerboard problem at the moment(that goes away if you leave it on for a few hours).

    .


  • Registered Users Posts: 894 ✭✭✭Dale Parish


    I don't have physical possession of it yet but this is what the seller sent me:
    KGrHqRnwE8OT3e5sBPMmS5L60_12.jpg


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  • Registered Users Posts: 8,846 ✭✭✭Steve X2


    I don't have physical possession of it yet but this is what the seller sent me:
    KGrHqRnwE8OT3e5sBPMmS5L60_12.jpg

    Looks like it might be caps, ram/ram board(if it has a ram board) or battery related just off the top of my head.

    The first thing I'd do is open that bad boy up and see if it there's any leakage inside. If there is then that's more than likely the issue(cap replacement job which is a pain or dishwasher/oven job like I did). Definitely get a battery, order it now so you have it(I ordered an hour ago on ebay for 7.50 inc delivery from the UK).

    What are the specs? 4mb ram or 1 or 2?

    Opening up the mac classic can be a problem as the top 2 screws are really far inside a long hole. Plus they use non standard screws so you might not have the right screwdriver and even if you do it might not be long enough. I just used a regular flat head and it worked fine with some effort.

    I've a good few pics on the link to retrovia that shows the insides of my classic. It might be helpful to have a look at them.

    But definitely get that battery.

    .


  • Registered Users Posts: 894 ✭✭✭Dale Parish


    Cap rep? Me? Soldering irons?
    Will seek parental guidance.
    Fair enough thanks for the info, I'll have a good look at it to see what the story is when I get hold of it.
    Edit:
    I'v no idea at all about the specs


  • Registered Users Posts: 8,930 ✭✭✭Doge


    Steve SI wrote: »
    So I've decided to try out a bit of a more risky fix but one that has proven successful with issue like this in the past(on old macs anyway)

    Most unorthodox repair ever!

    This is meant to be a good method of cleaning keyboards also.



    Hehe I've the exact same infra-red thermo, maplin i presume? ;)

    DSC_0842b.jpg



    Besides buying it for electronics I bought it to measure the temperature of hot water so it's at the perfect temperature for adding to Herbal Tea.


    When I saw the character Gale in Breaking Bad using his for the exact same purpose afterwards it was one of the funniest and mildly embarrassing self-geek realization moments I ever had! :p


  • Closed Accounts Posts: 33,733 ✭✭✭✭Myrddin


    How does this rule out a capacitor problem? It'd clean any gunk off the board in terms of leaking caps etc, but how does it actuaqlly restore functions to capacitors?

    They are smd caps, you should be able to get a repair kit easily enough :)


  • Registered Users Posts: 8,846 ✭✭✭Steve X2


    EnterNow wrote: »
    How does this rule out a capacitor problem? It'd clean any gunk off the board in terms of leaking caps etc, but how does it actuaqlly restore functions to capacitors?

    They are smd caps, you should be able to get a repair kit easily enough :)

    It doesn't rule out a cap issue or restore the caps. We're just working the known issues with mac classics here.
    So issue 1 on the list is cap fluid on the motherboard causing a non boot or delayed boot(needs to be cleaned), issue 2 is the RAM or RAM board causing similar problems(needs to be removed or replaced to test). And issue 3 which is most likely the problem with my classic, the PRAM battery is causing problems with the SoftPower circuit as it is very low or empty(so needs to be replaced). Issue 3 is not very well known but is definitely a possibility.

    Obviously if caps are on the way out they will eventually need to be replaced and the dishwasher/oven fix is only temporary and may get you a few more weeks/months/years of life depending on how bad the leak is.

    In my case I'm not even sure the caps were leaking but i was just working the numbers.

    .


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  • Closed Accounts Posts: 33,733 ✭✭✭✭Myrddin


    Steve SI wrote: »
    It doesn't rule out a cap issue or restore the caps. We're just working the known issues with mac classics here.
    So issue 1 on the list is cap fluid on the motherboard causing a non boot or delayed boot(needs to be cleaned), issue 2 is the RAM or RAM board causing similar problems(needs to be removed or replaced to test). And issue 3 which is most likely the problem with my classic, the PRAM battery is causing problems with the SoftPower circuit as it is very low or empty(so needs to be replaced). Issue 3 is not very well known but is definitely a possibility.

    Obviously if caps are on the way out they will eventually need to be replaced and the dishwasher/oven fix is only temporary and may get you a few more weeks/months/years of life depending on how bad the leak is.

    In my case I'm not even sure the caps were leaking but i was just working the numbers.

    .

    So its really just a case of using the dishwasher to clean the board of any corrosive cap fluid, that may have been interrupting circuits etc. For me though that wouldn't eliminate any cap problems, as the board could be spotless without two or three failed caps.

    Nice starting point though, its handy that they used socketed proms etc


  • Registered Users Posts: 8,846 ✭✭✭Steve X2


    EnterNow wrote: »
    So its really just a case of using the dishwasher to clean the board of any corrosive cap fluid, that may have been interrupting circuits etc. For me though that wouldn't eliminate any cap problems, as the board could be spotless without two or three failed caps.

    Nice starting point though, its handy that they used socketed proms etc

    But if you have experience fixing the mac classic or classic II you just know the standard problems and fixes, and this is them.

    Work from experience, not logic :D


    .


  • Closed Accounts Posts: 33,733 ✭✭✭✭Myrddin


    Steve SI wrote: »
    But if you have experience fixing the mac classic or classic II you just know the standard problems and fixes, and this is them.

    Work from experience, not logic :D


    .

    I see how washing the board eliminates cap leakage problems, but it doesn't eliminate cap problems. So it's a first step diagnosis, albeit a good one. The electronics of Macs don't differ to electronics of anything else. Sure it's a known problem & it may fix it temporarily, but you'll be back to square one before long as you know.


  • Registered Users Posts: 8,846 ✭✭✭Steve X2


    EnterNow wrote: »
    I see how washing the board eliminates cap leakage problems, but it doesn't eliminate cap problems. So it's a first step diagnosis, albeit a good one. The electronics of Macs don't differ to electronics of anything else. Sure it's a known problem & it may fix it temporarily, but you'll be back to square one before long as you know.

    If its a cap issue, yes. Personally this one looks like its the PRAM issue.

    If by washing the board it was fixed I'd know it was a cap issue and could look into getting them replaced at a later date, but have a working classic in the mean time.

    Anyway, it is as you say a good first step in diagnosing the problem. I'll see when the battery arrives if it fixes it. And if not its time for another look.
    I still stand by my "work from experience" statement. It's served me well over the years in IT, business and life, although a little logic is required every so often :D

    How are you at replacing these particular type of caps? They look like a pain to do.
    dsc0839y.jpg

    .


  • Closed Accounts Posts: 33,733 ✭✭✭✭Myrddin


    Same type of caps on the Mig boards, it's time consuming because they are surface mount. You have to desolder them evenly, remove them, clean the solder pads, & position the replacement correctly before resoldering. There's a good few of them on the mig boards, not sure how many on the Mac board though so maybe not too bad.


  • Registered Users Posts: 8,846 ✭✭✭Steve X2


    Well, I got the new pram battery for the mac classic and still the same problem :(
    Looks like I'll need to research more but it's probably just the caps need doing(and my soldering skills are crap).


    The batteries(clicky clicky for biggie):

    DSC_0855b.jpg


    Old battery on the left.

    DSC_0858b.jpg

    .


  • Registered Users Posts: 894 ✭✭✭Dale Parish


    Any idea where I could get 2 PLA chips for C64s from? Guy on eBay won't reduce his postage (it's not that I don't have £10 for the postage, it's the fact he refused to bring it down, it's an extra chip in the packet..)


  • Registered Users Posts: 4,056 ✭✭✭Sparks43


    Need 2 caps kits for the game gear but rewind bits is sold out

    Any ideas guys?


  • Registered Users Posts: 8,930 ✭✭✭Doge


    Sparks43 wrote: »
    Need 2 caps kits for the game gear but rewind bits is sold out

    Any ideas guys?


    Buy caps with the same values from an other source...

    But you probably already thought of that!


  • Registered Users Posts: 8,846 ✭✭✭Steve X2


    This ones for Enternow really.

    Is this Sega Multi Mega mod doable?

    http://wolfsoft.de/wordpress/?p=478

    Seems to be region free on the carts, cd's and 32x carts. It'd be pretty cool to have this done on my one. Looks like there's a lot involved in it though.

    .


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  • Closed Accounts Posts: 33,733 ✭✭✭✭Myrddin


    Steve SI wrote: »
    This ones for Enternow really.

    Is this Sega Multi Mega mod doable?

    http://wolfsoft.de/wordpress/?p=478

    Seems to be region free on the carts, cd's and 32x carts. It'd be pretty cool to have this done on my one. Looks like there's a lot involved in it though.

    .

    It looks doable alright, but given the work involved & the rarity/expense of a Multi Mega...I'd have to wonder would the cost be justified? It's essentially all the usual mods, jumpers, leds, replacement bios for the mega cd...I've done them all seperately.

    Personally speaking if I had a Multi Mega, I'd not bother. Instead I'd mod the console versions seperately. Imo the Multi Mega is too expensive/rare to mod.


  • Registered Users Posts: 8,846 ✭✭✭Steve X2


    EnterNow wrote: »
    It looks doable alright, but given the work involved & the rarity/expense of a Multi Mega...I'd have to wonder would the cost be justified? It's essentially all the usual mods, jumpers, leds, replacement bios for the mega cd...I've done them all seperately.

    Personally speaking if I had a Multi Mega, I'd not bother. Instead I'd mod the console versions seperately. Imo the Multi Mega is too expensive/rare to mod.

    yeah, valid points all right.

    And if I had 2 Multi Mega's??? :D:D:D

    .


  • Closed Accounts Posts: 33,733 ✭✭✭✭Myrddin


    Steve SI wrote: »
    yeah, valid points all right.

    And if I had 2 Multi Mega's??? :D:D:D

    .

    If you've two & are interested in having it done, I suppose there's no harm in discussing it :)

    It'd make for an interesting project, thats for sure.


  • Registered Users Posts: 8,846 ✭✭✭Steve X2


    EnterNow wrote: »
    If you've two & are interested in having it done, I suppose there's no harm in discussing it :)

    It'd make for an interesting project, thats for sure.

    I don't have 2 yet. But its a possibility I will soon.
    You know, with my condition and all :rolleyes:

    .


  • Registered Users Posts: 8,930 ✭✭✭Doge


    After a possible short in my mains power strip (4 socket adapter thingy),
    my Model 1 Megadrive is sick. :(

    The first thing I noticed is while playing all sound in the YM2612 stopped and only sound effects from the PSG remained while playing Super Hang On.

    After discovering the electrical fault and binning the power strip I tried re-powering the Mega Drive several times.

    The TMSS screen comes up, but most of the time, the screen would go blank after both with my Everdrive Cart, and original golf game cart.

    The few times I could get to the everdrive main screen, the cart itself behaved like normal,
    I could browse all the directories and flash the cartridge with a new game.

    But only certain games would run after they were flashed. Others won't run at all no matter how many times you try.

    Super Hangon seems to crash as soon as you take off from the starting line.


    In Revenge of Shinobi some sound from the PSG, but any music on the YM2612 fails to play.

    In other games like Sonic the Hedgehog and Zero Tolerance I have no sound at all.

    When playing Zero Tolerance for a few mins it crashed,
    and it displayed what looked like a dump of Memory Addresses on screen with one of the fonts for that game.

    I checked the power supply with my multimeter and voltage seems stable,

    so I definitely think something has blown inside the megadrive, or one or possibly more of the chips have shorted.


    Just before this post, I tried re-powering it a lot of times again, and this time it never makes it to the cart after the TMSS screen is shown.

    Have yet to open it up to see any signs of physical damage, but none the less

    Looks like I'm in the market for another Mega Drive! :(


  • Registered Users Posts: 8,930 ✭✭✭Doge


    Okay opened her up, and the first booboo I discovered was that after I did the 60hz mod I had forgotten to screw the voltage regulators to the heatsink.

    So they weren't making a good contact, and were possibly overheating.

    And with my limited electronics knowledge I decided to try the most obvious thing first...

    I did a voltage test between Pin 2 and 3 (GND and Output) of each of the 7805 regulators,
    and each fell just shy of 5V, it read @ 4.90V.

    Does this seem a bit too small to you Retro, or anyone else who has tested the 7805s on a megadrive?

    This is regardless of wether I set my 1200ma multi voltage PSU, to 9V or 12V.

    There is absolutely no improvement at 12V.

    Plugged it back into the TV, and hurraw! The Everdrive cart comes up, and I can start games now each time.

    The Sound is back in is fullest, but....

    after I play a game for a few minutes, I start to get a progressively more garbled output through the RF Port.

    Haven't tried SCART yet but I'd imagine it's the same.

    Maybe the Video chip is not getting enough juice.


    Delighted now that it seems to be some sort of power issue, either from the PSU,
    or some component on board that's knocking down the voltage.

    I think the time has finally come to order an official power supply!


  • Closed Accounts Posts: 33,733 ✭✭✭✭Myrddin


    Why had you got the regulators unscrewed?


  • Registered Users Posts: 8,930 ✭✭✭Doge


    EnterNow wrote: »
    Why had you got the regulators unscrewed?

    I had fully disassembled the unit before doing the mod,
    and impatiently rushed putting it back together with the anticipation of playing those games in full speed! It was late at night also, and the job just couldn't wait until the next day. ;) I had been putting it off for long enough!

    Also the top RF shield wouldn't fit back in over the new switch so I left it out,
    and as a result I had more than 2 screws left over, so it wasn't as obvious!


    The good news is that I'm in the process of buying another model 1 with an original PSU on adverts.

    And when I'm giving that a clean, I'm going take my time and log every single screw size and location when I'm taking it apart.

    Once I've fully diagnosed the current MD1, I'm going to cut out a hole out of the RF shield and put it back together properly.

    It still may just be the PSU afterall, if not I'll probably swap in new 7805s and take it from there.

    I think the moral of the story here is to never rush a good thing!


  • Closed Accounts Posts: 33,733 ✭✭✭✭Myrddin


    It definitely sounds voltage related. Either that 3rd party PSU isn't entirely doing the job right or you've hurt the voltage regulators by allowing them to overheat.

    Should be an easy fix either way though


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  • Registered Users Posts: 8,930 ✭✭✭Doge


    Update:

    Today I received a courier delivery with the new Model 1 console and accessories I bought courtesy of the Wang Me Up Retro Computers, Consoles and Games shop on O'Connel st in Limerick. :)

    I used the original 10V PSU that came today to test the older model 1 that had issues,
    and now it's working perfectly! :)

    The voltage regulators now barely get warm, but are still putting out 4.90V.

    I read it's actually quite common for a certain amount of Voltage Regulators to be a bit off, per parts per million (ppm), the many years of use they have had could also be a factor. I might do a voltage test on the new Console to compare.

    Since the 3rd Party PSU has the same current rating as the Mega Drive PSU = 1.2A
    It must have been damaged when the Power Strip shorted, and now can't put out that much current, as it was never an issue before with that supply

    Even when I screwed the VRegs back to the heatsink they were still getting just as hot,
    when using the Damaged PSU.

    So I guess when the current draw exceeds the current thats available it means the voltage regulators get hot as well as the external transformer.

    I knew transformers get hot when this happens,
    but had forgotten that every component of a Power Supply Circuit will get hot regardless of wether those components are inside a console or not.

    So next time anyones music stops, or your mega drive develops graphical glitches,
    check to see if the PSU is failing!

    Was a nice learning experience and glad it had a happy ending!


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