Nice job! You were also lucky :) My Mac Plus had the logic board full with corrosion from the battery, I had to scrap all the corrosion with a scalpel, re-tin the tracks and cover them with solder mask. Also had to the replace the serial ports (Din-8), they were full with green corrosion on the pins, and remove the logic board connector to clean underneath the plastic. Low melt solder is your best friend in this cases.
Yes, this was caught just in time! Next video should be a Color Classic and that was also - IMHO - caught just in time, though I haven't fully tested it yet :)
Hi Tony, if you get a broken ferrite in a coil or a broken former, it is ok to superglue them back together, it will not affect it's function. Careful with selecting capacitors with a higher working voltage than required as it affects the value, the rated value is stated at it's working voltage, if you purchase a capacitor at twice the working voltage you will effectively halve it's value. Bob
Thanks, it's nice to know the inductor is going to be ok! On capacitors, I find evidence that this is correct for ceramic capacitors but not for electrolytic? Panasonic FR datasheet doesn't mention anything - besides the expected 20% tolerance. Do you have a link where I can look? Thank you!
@@tony359 hee,hee, I would have said the other way around Tony, most likely for elecro's, not so much ceramic. I'm not quoting from a data sheet, I'm quoting from college training in electronics, granted it's some years ago now, but I wouldn't think it would have changed. Prove me wrong I would be happy to accept it. Bob
I'm not able to prove you wrong, I asked some friends and looked online. Online I found evidence of the non-electrolytic for sure, there are datasheets showing the massive change in capacitance for them. Ceramics are indeed the worst. But I cannot find evidence of the electrolytic. I'll keep an eye on this subject!
Nickel plating at home is actually quite easy and not terribly hazardous. You can't chrome plate, but nickel is pretty good for battery contacts and the like. Ask me about mistakes not to make, if you consider doing that, because i have. It is possible to recondition gears and other PA mechanisms to like-new condition and prevent them from splitting. They come out of the casting undersized and brittle; then they're airtight bagged with some water placing them in a moist atmosphere for a few days, they gain about 4% in weight/volume of water and expand a little correspondingly. As they're run hot in use and stored dry, they lose some of this water and shrink, at first gripping around the shafts tighter, and finally getting split by the force of the shaft as they continue losing moisture and shrinking and becoming more brittle. You can do the same moist atmosphere conditioning to prolong their life. I made the experiment, i found a bag of zipties that went super brittle crumbling right in my hands because they were stored on top of a heater for 10 years, and i reconditioned them this way and now they're tough and flexible again, and several years later they still feel perfectly good.
thanks for that! I'd love to explore the plating but I really haven't got space for that. I know, it's just a container but I don't have space for that! :) One day I'd love to have my little "plating station" :)
@@tony359 I don't actually keep a permanent setup, in part because i'm not convinced that i have a tub that i can trust to keep the nickel citrate contained. I kept it in a mason jar for a little but it started corroding the lid, although the lid was rubber lined. I keep nickel citrate in a drain cleaner bottle and just build a tub, electrodes etc as needed and then funnel it back into the bottle when done. Obviously the things are lab use only and won't be used for foods; but except that one bottle they aren't strictly dedicated to plating. This HDPE bottle has been doing quite well, i don't have concerns with it.
@Tony359 I came across such contacts on my Amiga 1000 keyboard and they fooled me. That little trigger dimple that you pointed at (23:19) only pushes at the grey plastic tongue, the actual contact plates are on the BACKSIDE. So to clean them properly you have to spray contact cleaner between the plates on the REAR. I was lucky to find a pack of NOS original Amiga 1000 key switches in February 2024 and I was like a kid at the christmas tree xp PS: Oh whoops you figured that out yourself. Sorry!
eheh no worries! Someone had an interesting suggestion: use a sheet of paper to fit inside between the two plates as a very mild abrasive, with contact cleaner too. Then flood with contact cleaner. I like that!
I do hope caps hold on much longer than expected. I have some 30+ years old DC power supplies (>1000 Watts) and some of the caps are as big as a beer-bottle. Replacement would cost more than the unit itself 2nd hand. /Edit: Regarding the accuracy of the component tester ... lets say i had a similar problem and the component tester was unable to give correct results. A known 15 mH coil was reported as 0,01 mH and 14,97 mH with my dedicated LCR-Tester.
I know what you mean. I had a 2400W amplifier once, some of its bulk capacitors had swollen. Replacing them all would have cost a fortune! And yes, I do need a proper LCR meter for sure... Thanks for watching!
I started to suggest you get a $129 de-5000 LCR meter (which is vastly better for inductors and caps), but then I checked the Amazon UK price. £283! I will never understand global trade.
but there is one for £103 posted for FREE from JAPAN! :D I'm sure there are good ones around. The difficult part is to find the one which is not too much of a copycat :) But thanks!
This device is a faithful reproduction of a German open source community project. 0.01mH is simply the very lowest inductance value it's able to measure, so from its point of view, it's right on the edge between being an inductor and not being an inductor. Small placement differences in the socket and how clean the socket and the legs are of course make a substantial difference for an inductance this tiny, and in general a lot of components will have flaky measurement outcomes in principle for this reason, it's not really a fault of the device per se, it's just fundamental measurement difficulties.
Think the inductor core is made from ferrite and not graphite as you mention at 9:40. It has some magnetic properties. There is a way to calculate the inductor value based on resistance and capacitance readings of your DMM. 24:10 for light mechanical cleaning using some regular paper might have worked if you are able to get that between the contacts. Nice result in the end.
0.01mH is the lowest value Mikrocontrollerforum-AVR-Transistortester (aka LCR T4 and similar devices) can measure. If it falls any lower, it doesn't recognise inductance. And of course there is a little bit of measurement variance from run to run from how you place the component to be tested, and you're RIGHT on the edge there, so you shouldn't be surprised that it's sometimes an inductor and sometimes isn't.
Gotcha - though I'm not so convinced that the inductor should read 0.01mH :) But it works so happy days! That component tester was like £5 ages ago so I cannot complain!
The vents at the top are NOT fake. They are offset. You can prove this by feeding a piece of paper between them. Also when you said the AV board caps were obviously leaking, I couldn’t see any evidence of that in the video. People are too eager to replace all caps but in my experience these ones are fine. It’s the cheap surface mounted caps from the 90s that need replacement.
I don't normally change caps "just to change them" but I think I have explained that clearly at 0:45. The leaky cap on the AB (I suppose AV is a typo) is shown at 3:11 but I then say it probably wasn't at 7:05 where I also say again that the capacitors seemed to be in good shape. The vents... you are right! ahaha! Though the actual slot is super tiny! Thanks for watching!
Breaking an inductor's core will create unwanted air gap, thus a decreased inductance. It can be glued back with maybe super glue, but i think the better choice is some epoxy glue. Even so the air gap will be there, and the decreased inductance is unavoidable, but how much does that affects the circuit, it depends on how much that circuit relies on the fixed value of that inductance. Components tester is not very reliable when it comes to test inductance, the LCR meter is the best at this. PS: Most of the digital electronics power supplies that have multiple power outputs do not like being loaded on only one of them, so...
The glue I used was epoxy and I think I made sure the crack was aligned perfectly. The bottom line is that I don't see anything on screen which might point to an issue (I was told that that inductor is for linearity) so hopefully the remaining inductance is enough! :) Yep, I need to get a proper LCR meter! On the PSU, absolutely, I guess I'll bear that in mind for the future. I think my Macintosh SE (Sony PSU) was similar, I had to load everything to get the correct voltages. Thanks for watching!
My concern is heat. The flyback is getting hot, the inductor is adjacent. And basically there are no vents there (Apple!). I'd also imagine the inductor would get hot per se so I hope the glue holds.
@@tony359 as far as i know epoxy glue holds up to a considerable temperature ( some of the versions i have pretend to work up to 100*C, others to 150... ). If you still have the MAC then one thing you can do to make sure it does stand up, is to use some silicone glue on the inductor, that would keep it in place even if the epoxy fails. But, honestly, i very much doubt the epoxy would fail anytime soon...
@@tony359 Yeah I had a couple. Never got the chance to fix the caps, both had catastrophic battery leakage and they are DEAD. Learned the hard way to remember to remove all batteries from stored computers.
Absolutely love seeing you work on Apple stuff! I have a Macintosh plus that’s in need of love also and I have the skills but not the money or time to be able sort it so it’s sitting in storage. It was once working, but by time I got a blueSCSI It stopped working 😢 I would love to have it working as I have always wanted one but never got the chance to be able play with it
@@tony359 yes the battery was removed before I purchased it back in 2020. I think it needs a recap but I can find any kits to sort it out. Hoping someone has some capacitors from there recap spare. It just clicks now when turned on with strange lines on the screen
well, you have lines on screen! :) That means a lot! Lines should be RAM but I'm not the best Mac expert! :) Yes, selecting capacitors is a pain. A kit would be much more convenient. That's one of the reasons I don't like recapping. It takes forever to GET the capacitors!
@@tony359 it could be ram as I did mess with them when it happened but they are fully seated and it’s the same as yours being 4mb. But I can give it a shot to see thank you. But I’m sure it will be capacitor related
The SE I fixed in a previous video had RAM issue even after scrubbing and re-seating the modules as there was corrosion in the slots. It took me quite some time to get rid of that. The capacitors on the Plus motherboard don't really need anything and if you have cap issues on the analogue board, then you have bad voltage delivered to the motherboard. I'd say because it displays a picture, the analogue board is "good enough" :) Be careful with mains and the CRT BTW :)
