Caps caps caps - capacitors , ultimate list?

[Aeberbach]

The smd electrolytics behind the keyboard connector can be a pain to get the iron onto. Be careful not to melt the connector in the process.

These are in a very tight spot. Instead of trying to desolder the leads direct I used some very pointy and sharp Tamiya side cutters and chopped away the capacitor can in about three pieces until the two leads were visible, then heated the centre of the cap and lifted the base away from the internal leads still soldered to the board. The inside of the cap is basically a dry, thick black paste and does not flow when cut, it is easily removed from the leads when heated. Once the leads are exposed they are much easier to remove as they come away individually and it is not hard to melt the solder when the body of the capacitor is not in the way.

 

[Bryce]

Removing the caps isn't the issue, you can just twist them off with a small "long-nosed" pliers. It's the soldering of the new capacitor that risks melting the connector.

Bryce.

 

[RetroPassion]

Ummmmm you are joking right?

Removing the caps isn't the issue, you can just twist them off with a small "long-nosed" pliers. It's the soldering of the new capacitor that risks melting the connector.

Bryce.

 

[Aeberbach]

twist them off with a small "long-nosed" pliers

 

[protek]

I think what Bryce is trying to say that you twist the can of the capacitor off with pliers and then carefully remove the base, leaving the two legs of the capacitor easily accessible for desoldering.

 

[highpuff]

Twisting caps off is plain stupid. The PCB pads for that are not made to withstand the force. The risk to pull a pad off the PCB is high, use proper tools instead-

 

[chucky]

Twisting off caps is as wrong as shooting them off with a magnum! NEVER do that! it is just plain and utter STUPID! not amateur. it is passed that! it is just plain. Stupid.
I have repaired so many machines when people have done that. PLEASE do not tell people to do so.

 

[Bryce]

Please explain why. I work for one of the biggest electronics companies in the world and this is the standard approved process for removing SMD electrolytic caps that need to be reworked.

Bryce.

 

[ajk]

Amiga boards are manufactured with old processes, and possibly compromised by caps that have already leaked... you can get away with it most of the time, but I'd rather be safe than sorry personally.

 

[SolidCore]

Cutting a cap in half then taking plastic stands off, and de-soldering the legs works well for me. never had a issue yet. If there's a real risk there, I'd like to hear it, leak maybe?

 

[Bryce]

Twisting actually puts less strain on the pads than desoldering, because the force is sideways rather than upwards, which could rip the pads off the board if it has already been chemically compromised by electrolyte or if the solder underneath the capacitor hasn't fully melted. You've a much better chance of avoiding PCB damage by twisting them. The manufacturing processes on the Amiga are identical to modern processes, all that changed was the type of solder used. You also can't unsolder both pins at the same time, because SMD solder tweezers will rarely fit in and desoldering individually means you have to bend the capacitor over, putting additional strain on the other pin/pad.

Bryce.


Edit: @Solidcore: Yes, leakage perhaps, or depending on what you cut it off with, possibly excessive force on the pads (if you are using a snips for example).

 

[ajk]

I usually use two individual soldering irons, if there is space, or hot air if it's a tight spot.

 

[Bryce]

I usually use two individual soldering irons, if there is space, or hot air if it's a tight spot.

How do you remove it from the PCB if you are holding two irons? Or have you taught some other appendage to lift components?

Bryce.

 

[ajk]

Simply by holding the part between the tips and pushing it aside. You don't need to be an octopus to do it Just move it off the pads and it's done.

 

[chucky]

Explain why not to twist or cut.. the amunt of boards I have got sent to me broken due to this IDIOTIC tip maybe?
and the boards are old. pads can be weakend by the leaking electrolyte..

there is NO reason whatsoever to use this idiotic method.. none. nada. zip.. it is bad, wrong and stupid and just for people with the wrong tools. hot tweezers is the best way. or hot air.
no physical strain to the pads should be applied.

it is morons putting throughhole caps etc that does this stupid thing.

E O D...

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if you twist on your board. fine. it is your board. but for sure not another persons board. Do it proper or don't do it

 

[Aeberbach]

Thanks Bryce, good to know and next time I get a board that I can experiment on I will try out the twist. Some things in soldering are very counterintuitive...

 

[SolidCore]

Bryce, i only cut at top of can, the legs etc are intact and still in same position, the plastic stand is then carefully lifted off the legs without damaging them or compromising the pads. I don't cut low down at the legs due to the force involved in cutting, the cans themselves are weaker and easily come apart without any force. The only risk I can see is cutting a can 'could' maybe make a mess everywhere invisible to the eye? / hazard to one's own health but I've yet to smell or see anything after cutting them, let alone after cleaning see any corrosion.

I think this is safely the argument about twisting caps..

I assume the reason why you believe twisting works for you is that since the legs come apart from the can (can being weakest point) it results in a seamingly 100% success rate, however I believe this to be 99.99% or worse odds since in the case of a poorly leaked capacitor board like an a600 i once had that had IDE pins falling off!!! I imagine this twist method would result in a disaster whereby a pad that has corrosion would become the weakest link in the chain, bye bye pad.

Reinforcing what Chucky said and others are saying, you have yet to experience this and therefor self-assured it is 100%... one day a brittle pad will tell you otherwise.

This is also why i dont heat one side of cap and lifting... because lifting will result in the pad on other side coming away from PCB. bad!

If I was to put the safest in order...

1. Hot air (safest, if nothing can be melted)
2. Cutting can (safe, requires a good clean)
3. Hot tweezers (risk at level of user experience)
4. Twisting (high risk, smd pads could be brittle)

Chucky can you write a book?

 

[chucky]

haha maybe I should.. damn today I actually recapped one A600. where I just TOUCHED the ide port with my tweezers (normal tweezers not hot ones) and pins fell off... so yeah.. twisting off those caps would be total havoc..

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but twisters maybe force me to do a ReAmiga 600 ASWELL? well. we have to see after the 3000

 

[SolidCore]

haha maybe I should.. damn today I actually recapped one A600. where I just TOUCHED the ide port with my tweezers (normal tweezers not hot ones) and pins fell off... so yeah.. twisting off those caps would be total havoc..

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but twisters maybe force me to do a ReAmiga 600 ASWELL? well. we have to see after the 3000

Yeah ide pins are very close to those caps amazing how on a first glance everything appeared ok and then two weeks later the cf card started losing files only to find the pins were falling off lmao same way you described only I noticed one had left the pcb inside ide cable lol! So yeah corrosion can eat away at ide pins without trouble which someone tried to say was bs, we both confirm this fact . Twisting caps on that pcb would be bad bad bad !

ps. That a600 has a new ide header with the plastic guide , all turned out well for her in the end lol. But the ReAmiga 600 would be nice ��

 

[eteP]

This isn't really a recapping question but related: I have a couple of A500+ motherboards with corrosion from leaking batteries. There are some caps that are also affected and which I want to replace. I have the capacitance ratings from Amiga PCB explorer (http://www.amigapcb.org/) but I'm not sure which types of caps I should get. The caps in question are E102, C10, and C5 (there are more that I want to replace but they're all these types). Would caps like this be ok:

https://www.reichelt.com/de/en/mult...25-c-c3x7r-330na50-p206880.html?&trstct=pos_0