AlanGrassia

Retro Friends, is there anything I should watch out for with with regard to to electrolytic caps vs. tantalum caps? It seems like they are effectively interchangeable.

Interested in working as it should rather thanbeing period accurate.

I'm starting to buy tools and supplies to repair my #Vintage #Apple #Macintosh #LCIII by replacing the electrolytic caps.

I am considering the tantalum cap kit from Consoles5.com.

#NewEnglandVintageComputing #RetroComputing #VintageComputing

Nov 25, 2023 at 4:36pmWeb
Show threadJazz Rabbit 🐇🏳️‍⚧️Nov 25, 2023
@AlanGrassia here is what I’ve learned in my own prep research: Tantalums can be a tiny bit off in size, and thus may require some extra care to solder into the existing pads. I watched a number of board recaps by Branchus Creations, who uses tantalum caps, and talks through the process and challenges well. For example, check the solder mask on the traces under the cap, and be sure that you aren’t going to accidentally short one to the pads of your new tantalum cap.
Show threadAlanGrassiaNov 25, 2023
@madrabbit
That's some really good advice. Thanks for the tip! I appreciate it.
Show threadvga256Nov 25, 2023
@AlanGrassia console5's replacement kits are 👌 i've never had an issue with them
Show threadBigBadBiologistNov 25, 2023
@AlanGrassia I pretty much always use tantalums when possible at this point. I haven’t been able to find any about the electrical properties that says you shouldn’t replace electrolytic with tantalums. I like that if a tantalum dies, it dies short which will just prevent the computer from powering up. Whereas if an electrolytic dies, it starts eating your board. Also, if you decide you need help with this project feel free to take a ride up!
Show threadAlanGrassiaNov 25, 2023

@BigBadBiologist
There's an old junk board that I want to practice on and see if I can pull some chips, sockets, and caps from.

I may take you up on that offer. I only have the one LC III board and I don't want to mess it up right out of the gate.

Let's see how I do on the practice boards and that SP][SD I picked up.

Show threadDrew GilmoreNov 26, 2023
@AlanGrassia @BigBadBiologist I have exactly the same computer that I want to recap but so far lack the skills. What’s your method/tool for cap removal?
Show threadBigBadBiologistNov 26, 2023
@dotsandlines @AlanGrassia I use hot air (380 degrees C). I did a lot of it on this stream if you want to see a lot of decapping action: Starting the preservation of Macintosh IIsi, LC, LCII, LCIII, Performa 400, LC475, and Quadra 605
https://youtube.com/live/FDdhJ0omMoo?feature=share
Starting the preservation of Macintosh IIsi, LC, LCII, LCIII, Performa 400, LC475, and Quadra 605

YouTube
Show threadDrew GilmoreNov 26, 2023
@BigBadBiologist @AlanGrassia Much appreciated - I’ll check it out :)
Show threadAlanGrassiaNov 28, 2023

@BigBadBiologist @dotsandlines
My hot air kit, flux, tape, and desoldering wick arrived yesterday.

Now, the hard part, finding the time to work on the practice board!

Show threadBigBadBiologistNov 28, 2023
@AlanGrassia @dotsandlines nice; good luck!
Show threadShredNov 26, 2023

@dotsandlines I found the safest way for me is to just carefully twist off the electrolytic caps with pliers (just twisting, NO pulling!). Hot air will do as well, but there is a risk of damaging the old PCB if there is moisture between the layers.

@AlanGrassia @BigBadBiologist

Show threadAlanGrassiaNov 28, 2023

@shred @dotsandlines @BigBadBiologist

I also picked up a pair of pliers for cap removal so I can test whether hot air or pliers works better for me.

Show threadShredNov 26, 2023

@BigBadBiologist Sure, electrolytic caps can leak and eat your board. But tantalums can catch fire or explode, and damage your board. I prefer to use high quality aluminium organic polymer caps, with an expected life of 10,000 h.​

@AlanGrassia

Show threadMike EverhartNov 25, 2023

@AlanGrassia If you’re buying a cap kit from a reputable vendor like Console5 you should be fine. There are differences to be aware of if you’re selecting your own replacement caps.

I’d recommend taking a picture of the board before you start removing anything. Note the polarity of all of the existing capacitors - sometimes the silkscreen on the board is wrong (don’t remember which models have that error). Electrolytics have the marking on the negative, while tantalums have it on the positive

Show threadiiiDIYNov 26, 2023

@AlanGrassia Second vote confidence in Console5, especially for your first project. I've gone tantalum for most projects, but sometimes mix it up depending on what I have on-hand.

I'd say just be aware that the markings are different between the two types -- they use slightly different nomenclature for the voltages, and the stripe indicates positive on one and negative on the other :) Console5 includes a handy reference card with all this info - so great for starters. Good luck with the LCIII!

Show threadJason P 🌈Nov 28, 2023
@AlanGrassia I believe you need to over rate the voltage somewhat more when using tantalum caps.
Show threadAlanGrassiaNov 29, 2023
@compu85
Good to know. Since I don’t know much about the voltage side of things, I plan on using the LC III recap kit from Console 5.