(newb alert!)
I got a //e and replaced the power supply. But recently I've read that all capacitors in a vintage computer (not just the PS) should be replaced because in time they will all fail.
So since I like to do everything right, I thought I am also looking into getting the motherboard, two disk drives and the monitor recapped.
I found a place that will recap the monitor, but in our recent email exchange they said they didn't think the motherboard had capacitors on it.
I'm pretty sure the motherboard does have capacitors on it, ceramic disc caps labeled C1-C50 or so. Should they be replaced, or do these ceremic disc caps not fail like the barrell shaped ones?
BTW, in any forum I am a big fan of looking for information rather than starting a new thread but my searched turned up mainly information on power supply recaps. So if the info I'm looking for is here somewhere and you can point me in the right direction that would be appreciated.
Also...... what about recapping my two disk drives? They are the "newer type". (https://www.applefritter.com/files/Disk5-1L.jpg)
THANK YOU IN ADVANCE!
If everything works don't even think of this "recapping" fashion. It is somewhat related to computers manufactured in the late 90s.
All good questions, and this is assuming you're asking because this is all new to you. If some seems condescending it's not intentional. I'm just tyring to answer with detials given the questions without a good understand of your skills/knowledge.
For all devices including the supply, there is a good chance the caps are going bad. One important thing to understand.... a working supply does not equate to a "good" supply and that all depends on the capacitance of the caps whih changes with time. IMHO the supply should be refreshed, always. Others feel different, but my way gurantees another 10-20 years without problem. I'd also avoid the cap kits because they are created with some bad assumptions and I could go into the EE reasons why but I'll just say I pick my own replacmeents and I have total confidence in their performance.
There are basically only 10 or so 10uF elecrtolytics on the //e motherboard (axial at that which really on Vishay makes these days) and basically they are just used to make the voltage supplying the nearby ICs stable. Are they needed... sure will the computer work if they are bad? That's likely a yes especially if there isn't any extra "noise" generated or picked up by the other devices in the computer. But... there's a good chance there's noise being introduced. I could go either way on this one, but I would look at the 4 caps near the power jack like C11, C19, C12, C13 (sorry I don't remeber the numbers) with a scope (understand you may not have one) just to check how stable signals look they should be stable with small AC componets (this is what all those caps on the motherboard address). That's the "why" they're there.
As retro_devices said, if the board work and works well... you could leave the board caps alone. If you're skilled with the electronics theory and rework that should all make sense and you'd also know that electrolyte in any can cap can and does degrade with time and 40 years is a LONG time. They may still be good, but maybe not. The powersupply caps are more important as they stabalize the power coming to the board and accessories. In general, ceramic caps are like rocks, they aren't changing, if they fail then replace but seriously they're like rocks stable and durable. The electrolytics and the safety caps are the ones that need attention. Also, if you're not good with rework, there's a very good chance you could introduce problems so may want to get help from someoene with those skills. This is all very easy (trivial in fact) for those with the experience, but for everyone else it's doable but far from trivial.
If you need help/guidance where you located? There may be help nearby... this community is great for supporting others!!
AWESOME!
Thanks for the information. I love this place. I posted a question a few months ago and got enough information to keep me busy learning for a couple months.
I originally thought that I would pick up some curbside older electronics to practice on and learn how to do the recaps myself. I started down that road but now I think I'd rather throw money at the problem and get someone else to do it so I can get back to assembly programming my //e (picking up where I left off in 1982).
I'm sure I could buy a scope and learn how to test the caps after 30 minutes on YouTube, but I think I'd rather just get em repalced. I popped the hood and counted 9 of the 10uF elecrtolytic caps on my 1986 board.
So I think I will email the guy (Amiga of Rochester) and ask if he can replace those ones. I'm getting them to do my monitor too.
I am located way up here in the frozen tunrda of Nova Scotia, Canada. I wish I had been into retro Apples when I lived in FL years ago - lots more ppl down there!
Any thoughts on the disk drive caps? Surely there is a power supply inside somewhere.
Why don't you replace all components? They can fail too, especially actives. Will that give you or your children assurance nothing will ever fail? What will be then the MTBF? What is it now compared to our lifespan? Are you sure contemporary components are better?
https://en.wikipedia.org/wiki/Capacitor_plague
Apple II drives don't have power supplies in them. They pull the power from the controller card over the 20pin ribbon or 19pin db style cable. The 5.25" drive you specifically linked to has two boards in in. One on top that handles all the analog decoding and has maybe 3 caps (I think they are all 3 different values) on it, and on the bottom is another board that has 3 caps (pretty sure all the same value) on it that I believe are for the motors.
None are known to go bad. But as Jeff pointed out, at some point they will degrade and could stand to be replaced. Could be another 20 years, could be 2. Ask 50 people about this topic, you will get 50 different opinions.
But if you are looking to really get into this hobby, I'd ditch the drive (or use it sparingly as a novelty) and get some kind of solid state storage. Just like caps, magnetic media has its own lifespan and issues (mold, magnetic coating flaking off, etc). Personally I like the Floppy Emu (or the very similar wDrive) that plug in to the drive controller. But there are internal slot based mass storage options too.
Here's my opinion on recapping:
None of the capacitors on the IIe motherboard need replacing.
None of the capacitors in the disk drive need replacing.
None of the capacitors in the Astec branded power supply need replacing with the following exceptions:
- The RIFA branded safety filter capacitor will blow up. Replace it with a film 0.1uF X-type of similar size.
- C7, the lone 220 uF capacitor between Q1 and R6 is known to fail because it sits right next to a huge 5watt power resistor that generates a lot of heat.
When this capacitor fails the power supply does not start up at all, so it either works or it doesn't. There's no in-between.
Dynacomp branded power supplies sometimes fail more frequently than Astec supplies, but the failure mode is usually in the feedback loop's optoisolator, rather than "bad" capacitors.
Recapping will serve two pourposes - first it parts you from your time and money, and second, it adds a reaasonable probaility that your power supply (or motherboard or disk drive) will come out worse than before you started.
I don't know how many people have posted here and on facebook about how they recapped A, B or C, and now it doesn't work, what ever could be the problem?
Good luck.
P.s. where in NS are you?
We'll there you got a lot of absolutes in that post. Hard to agree with many of your comment because electrolytic capacitors do fail and all will at some point. It's not a qurestion of will but when. I understand why you say that (because these we really well made caps) but when they fail the colateral damage can be trivial or something that can cause additional damage. I'm in the ounce of prevention mindset because I've seen enough caps that fail and the impact from some can be quite amazing. If recapping is done by a untrained hobbiest, 100% agree there's a very good chance they could cause some unintended damage. But when done by someone who knows what they are doing... recapping produces totally different results. I've pro-actively recapped many a supply and all work better when done then when started.
IIRC (and I do) C7 filures are generally not caused from the resistor, whiler there are some 2W resistors which can get hot thier heat is not the prolem. These caps are rated for 105C just like the other primary side parts. The problme is the ripple seen at C7 can exceed the 10V rating and can exceeed the tolerance by 50% or more. This was such a common problem Apple Service published a note that this cap should be replaced with a 16V rated part. I'd say 25V may be better but everyone should do your own analysis and pick something they feel would work best.