Oddly enough, I like the videos that show you are as human as the rest of us. For some reason it bolsters my confidence to jump in and try to work on some of these old electronics and bang away at the issues I run in to. Thanks for another great video!
Hey, thanks! I was hoping that would be the effect. I always try to show all failure and mistakes I make. Everybody does them and it's how we (or at least myself) learn. :D
I've had bad drives drag the 12v line down, before anything else I would try and disconnect most of the drives and try them one at a time to see if that might be the issue
Yeah bad tantalum cap on motherboard or drives would definitely bring down the 12v rail. Also I think if you were to modernize the power supply pico power supply would be a good option as it fits in the housing with space to spare and their are many apple adapter boards that I saw on Adrian's digital basement.
Close but no cigar. Oh well… I'm sorry I don't have the old Performa 637CD and 638CDV that I told you about last time so that I might be able to confirm typical normal operation. Those were last left in the basement of our last house and the wasps had done so much damage to the side door porch that led down to the basement that the rain came on and rotted away the stairs so I couldn't get to anything in the basement when I finally moved out of that place eight years ago. Again, oh well… As it is, I'm working to get all my forty-year-old Atari Home Computer stuff working again that I just got back after thirty years. At least the Atari 400 and the cartridges and joysticks still work. I still have to do some work on the disk drives and cassette drive and 800 and 1200XL computers to get them working right again. I really do enjoy watching your work and I learn a lot from every video. Nowadays a Classic Mac that also runs DOS is quite a novelty so I think it's well worth the effort to get it going again.
Hi Jan, just a tip. Next time you work with removing hot glue, just try warming it first with your hot-air soldering tool set to around 100C. It softens it and you can much more easily remove it,
If you want to go down the "replacing the PSU" path, it might be worth looking into the PicoRC stuff that Adrian's Digital Basement has recently shown (assuming one exists that's compatible with the Performa in any case), get the adapter board, a pico ATX power supply then gut the existing power supply and replace it with a modern 12V supply. It'll look original from the outside and require a minimum of metalwork.
Jan you are 100% correct about modern ultra-low ESR caps. Many voltage regulators and power supplies need a minimum ESR to work correctly, and modern ultra-low ESR caps can cause issues.
Jan. I dont know where you're at with this, but, a million years ago when i worked on PS2 mod 55, 70 and 80, the HDD used to seize. we used to smash the things on a bench and put them back in and off they went. Trying pulling the HDD in case its causing a dead short on 12V due to it being seized and see how you go booting from FDD or whether the CD lights up. if you get further smash the HDD and then chuck it back in and see how you go. I have a towerized A500 which had a similar fault with an IBM deathstar, i smashed the drive and it came good and all was well with the world :) sometimes a bit of forced love brings em back :)
I’d still prefer to keep the neutral and live correct on the IEC inlet for completeness. In the UK we still have to wire plugs correctly even all way to the IEC connector.
Its either the rectified diode on the low voltage side of the PSU, or something short on the drive or main board (or both) I suspect the 12v rail comes off another secondary tap on the transformer and then gets rectified by a single diode and then through the output caps. The 12v may well not be regulated with it just being dependent on the fixed ratio of turns on the transformer. My suspension is it is or was a short somewhere thats then taken out the reftifier diode to being open. I doubt there is a crowbar system on the 12v rail, with probably just a zener to protect against over voltage.
When it comes to that smell of capacitor juice, I've yet to get that out entirely, it seems to soak into boards like those (think it's resin-bonded paper) and never really goes away, which can be a nuisance when you catch a whiff of it and start wondering if another capacitor has given up the ghost... :S
I don't remember who, but I once saw a youtuber repairing an 8086, 8088, 286 or similar 1980s laptop with a reddish vacuum fluorescent screen and it wouldn't work because it's 12 volt line wouldn't work and the problem with the system was there was a tantalum capacitor in the board that died, and when the tantalum capacitors die, they short circuit and run the voltage on a 12 volt rail down to near 0. I bet there may be a dead tantalum either on the mac motherboard, or the power supply, what do you think, Jan?
Frankly, what I would have done: I'd remove the Heatsink(s) to get better access. Then make a Component Diagram, to know where the Caps should be. Then remove all Electrolytics. After that the PCB gets to have a warm shower. And a bath followed by another shower. Just to be safe :)
Coming soonish! I already shot a lot of footage for the next part and worked on the darn thing for days but failed to get the power supply to work so far.
I have lived my childhood in those biege box computer era. I always saw them as boring office machines with eye piercing cathode ray tubes that will someday become forgotten for ever. The internet and time proved me I was quite wrong 😁.
Hasn’t some clever bod somewhere got instructions for faking the 'soft on' signals required so at least some basic checks could be done on the PSU in isolation? If the missing 12V is the power supply and not some other part of the system, I’d be scared stiff of 'fixing' something only to first find out it was massively over voltage when I plugged it in the Mac 😬
I'm working on it. Already shot a lot of footage but didn't have much success fixing the PSU yet. There's going to be another episode as soon as I make any progress.
Unfortunate for you, but great for us as we get to see part 3.
Those psu are famous for cold solder joints on the connectors
Oddly enough, I like the videos that show you are as human as the rest of us. For some reason it bolsters my confidence to jump in and try to work on some of these old electronics and bang away at the issues I run in to. Thanks for another great video!
Hey, thanks! I was hoping that would be the effect. I always try to show all failure and mistakes I make. Everybody does them and it's how we (or at least myself) learn. :D
I've had bad drives drag the 12v line down, before anything else I would try and disconnect most of the drives and try them one at a time to see if that might be the issue
I've had that happen as well so should def. be checked. Heck unplug the fan as well.
Yeah bad tantalum cap on motherboard or drives would definitely bring down the 12v rail. Also I think if you were to modernize the power supply pico power supply would be a good option as it fits in the housing with space to spare and their are many apple adapter boards that I saw on Adrian's digital basement.
It could be a bad 12V regulator.
@@ericpaul4575I think it is a switching power supply ie no linear regulator but I guess may be a separate switching regulator for just 12v
@@christopherdecorte1599 I just wrote a comment about bad tantalums... lol good guess?
Close but no cigar. Oh well…
I'm sorry I don't have the old Performa 637CD and 638CDV that I told you about last time so that I might be able to confirm typical normal operation. Those were last left in the basement of our last house and the wasps had done so much damage to the side door porch that led down to the basement that the rain came on and rotted away the stairs so I couldn't get to anything in the basement when I finally moved out of that place eight years ago. Again, oh well…
As it is, I'm working to get all my forty-year-old Atari Home Computer stuff working again that I just got back after thirty years. At least the Atari 400 and the cartridges and joysticks still work. I still have to do some work on the disk drives and cassette drive and 800 and 1200XL computers to get them working right again.
I really do enjoy watching your work and I learn a lot from every video. Nowadays a Classic Mac that also runs DOS is quite a novelty so I think it's well worth the effort to get it going again.
Well, Part Three ought to be interesting... Thanks!
Hi Jan, just a tip. Next time you work with removing hot glue, just try warming it first with your hot-air soldering tool set to around 100C. It softens it and you can much more easily remove it,
I'd check the voltage regulators, not uncommon for those to fail in a hot power supply.
“Mission failed, we’ll get ‘em next time”
So i shouldn’t bother to watch then.
If you want to go down the "replacing the PSU" path, it might be worth looking into the PicoRC stuff that Adrian's Digital Basement has recently shown (assuming one exists that's compatible with the Performa in any case), get the adapter board, a pico ATX power supply then gut the existing power supply and replace it with a modern 12V supply. It'll look original from the outside and require a minimum of metalwork.
Great stuff Jan. I'm looking forward to seeing part three.👍
Jan you are 100% correct about modern ultra-low ESR caps. Many voltage regulators and power supplies need a minimum ESR to work correctly, and modern ultra-low ESR caps can cause issues.
Hello Jan Beta, nice video and thankx for sharing. I like your content and videos very much. Greetings from Steven from the Netherlands
Jan. I dont know where you're at with this, but, a million years ago when i worked on PS2 mod 55, 70 and 80, the HDD used to seize. we used to smash the things on a bench and put them back in and off they went. Trying pulling the HDD in case its causing a dead short on 12V due to it being seized and see how you go booting from FDD or whether the CD lights up. if you get further smash the HDD and then chuck it back in and see how you go. I have a towerized A500 which had a similar fault with an IBM deathstar, i smashed the drive and it came good and all was well with the world :) sometimes a bit of forced love brings em back :)
I’d still prefer to keep the neutral and live correct on the IEC inlet for completeness. In the UK we still have to wire plugs correctly even all way to the IEC connector.
Have you checked for shorts on the main board / elsewhere on the 12V line? There might be a short and the PSU might automatically cut it off.
Its either the rectified diode on the low voltage side of the PSU, or something short on the drive or main board (or both)
I suspect the 12v rail comes off another secondary tap on the transformer and then gets rectified by a single diode and then through the output caps. The 12v may well not be regulated with it just being dependent on the fixed ratio of turns on the transformer.
My suspension is it is or was a short somewhere thats then taken out the reftifier diode to being open.
I doubt there is a crowbar system on the 12v rail, with probably just a zener to protect against over voltage.
Make sure that there is not a short on the 12v line. are there any Tantalum Caps on the 12v line on the hard drive controller/CD drive!
That’s a funny looking Amiga 600.
When it comes to that smell of capacitor juice, I've yet to get that out entirely, it seems to soak into boards like those (think it's resin-bonded paper) and never really goes away, which can be a nuisance when you catch a whiff of it and start wondering if another capacitor has given up the ghost... :S
I don't remember who, but I once saw a youtuber repairing an 8086, 8088, 286 or similar 1980s laptop with a reddish vacuum fluorescent screen and it wouldn't work because it's 12 volt line wouldn't work and the problem with the system was there was a tantalum capacitor in the board that died, and when the tantalum capacitors die, they short circuit and run the voltage on a 12 volt rail down to near 0. I bet there may be a dead tantalum either on the mac motherboard, or the power supply, what do you think, Jan?
For such an old PSU maybe Nichicon UPS could be a decent choice?
Though when in doubt, the Panasonic FC might work...
Frankly, what I would have done:
I'd remove the Heatsink(s) to get better access.
Then make a Component Diagram, to know where the Caps should be. Then remove all Electrolytics.
After that the PCB gets to have a warm shower. And a bath followed by another shower.
Just to be safe :)
or you could just put it in an Ultrasonic cleaner, if you have access to one that is big enough.
Part 3 please
Coming soonish! I already shot a lot of footage for the next part and worked on the darn thing for days but failed to get the power supply to work so far.
I have lived my childhood in those biege box computer era. I always saw them as boring office machines with eye piercing cathode ray tubes that will someday become forgotten for ever. The internet and time proved me I was quite wrong 😁.
21:35 I think those are Pikachu capacitors.
Why didn't you de-solder the mains wires and put in longer ones instead of extending old dried out insulation wires?
Sorry, I've always removed odd connectors and then soldered to them. A bit of work, yes, but usually worth it.
Awesome 😊
Keep going 🙂 But if possible, without putting a PC PSU in the case.
Hasn’t some clever bod somewhere got instructions for faking the 'soft on' signals required so at least some basic checks could be done on the PSU in isolation? If the missing 12V is the power supply and not some other part of the system, I’d be scared stiff of 'fixing' something only to first find out it was massively over voltage when I plugged it in the Mac 😬
That looks like epoxy rather than hot glue.
Agreed.
Disappointed there’s no update to this
I'm working on it. Already shot a lot of footage but didn't have much success fixing the PSU yet. There's going to be another episode as soon as I make any progress.
@@JanBeta thanks man, enjoying this restore
Nice,almost First.😅😅😅
I think the first comment was a spam bot, so you officially qualify as first. 👍🥇
@@JanBeta Ahhh Thank you for replying and for the great videos!!!!!