Do Amiga 500 motherboards 'need' to be recapped?

[demolition]

What exactly do you mean with "didn't seem to have any problems"?

I mean that there was no functional problems with the machine (any instability) which is what I would expect when the caps get too far off the rated spec. I don't see how the rest of the components could be actually damaged by excess ripple, unless it is very severe (which it won't get to if you're using the machine regularly).

Edit: And yes, of course the caps will degrade over time and it won't hurt to replace them as long as you know how to replace them and are using quality replacements. Having non-skilled people trying to replace them because they think they need to could easily do more harm than good. Then I think it would be better to just leave the old ones in until they actually start becoming a problem.

 

[chaos]

demolition: Ok, I agree with you, maybe unskilled persons shouldn't attempt replacing the caps. I just think 25 years is a long time for electrolytic capacitors. Well, talking is cheap , so I'll try to borrow an ESR meter and measure the old caps from my A500. I'll also bring one board to work, where we have a quality oscilloscope with huge bandwidth to look at the supply lines waves. Will report what I find.

 

[Bryce]

Several people here in this thread and other threads have stated that a failed capacitor can damage other components and I assume they are not talking about the physical damage that the leaked electrolyte can cause. Can someone explain to me how on earth a failed capacitor could possibly damage other components, as I can't see any way this could occur (other than possibly damaging the powersupply).

On the general subject of leaking capacitors: If you are regularly using the computer, then you shouldn't need to "preventatively" replace the capacitors. The computer will start displaying problems long before anything leaks out of the capacitor. If you are very rarely using the computer, you may not notice the capacitor has failed until it's too late.
I do believe that the A600 and A1200 had capacitor problems, but preventative replacement is a waste of time and money if you regularly use the computer. On other computers it's always a waste of time and money unless the computer is having problems. Although some manufacturers only give a minimum lifespan of 2000 (that's less than 3 months!!), I own computers from the 70's that are still running fine with their original capacitors. My A600 and A1200 also still have their original caps.

Bryce.

 

[demolition]

The aluminium electrolytic caps may damage other components a long time before you'll notice any problems if you do not inspect them physically for leakages. The NOS A1200 I got some months ago worked fine, but had several caps leaking significantly. One track was even broken, but the Amiga was still functioning as it should, at least in a plain setting without any addons. Needless to say, I had to recap it immediately to stop the destruction from continuing.

 

[Bryce]

That's very unusual. What part of the circuit were the capacitors for? Usually a visible leak will mean almost no function of the capacitor, which should cause obvious problems.
I fix quite a bit of vintage stuff (analogue stuff like radios / amps). I've seen some of these still working with bulged caps, but on digital devices even a bulge usually causes some sort of noticable malfunction.

Bryce.

 

[demolition]

All the aluminium electrolytic caps in the 1200 except for the 22uF ones had leaked, and the 10uF ones the most (also where there was a broken trace). No bulges on any of them. Both my 600s also had leaking caps and had developed some problems but the problems were not the caps directly, but due to corroded traces. One of them had no sound on one channel for example, and a simple cap replacement would not fix it since the trace just below one of the AC coupling caps was broken.

 

[Bryce]

Wow, you really did have any luck with those purchases.

Bryce.

 

[ptp170]

I've done both my 500+'s in the past as part of a preventative maintenance measure. Nothing was wrong with the original capacitors but at least if something does malfunction in the years to come I could rule them out straight away.

There is the old saying "If it aint broke...etc etc", but I don't function that way . I apply the same principle to vehicles...if there is something which I know lasts for 'x' years or 'y' miles I tend to replace it as a matter of course..leaving stuff until it starts making knocking sounds and then playing the 'drive it till it fails' game never makes sense to me... but then again, I am a little odd

 

[demolition]

In some cases it is best to sort things out preventatively, as they could destroy other things along with it. Like only putting oil in your car once the oil light comes on is not a good strategy.

Dying caps, as long as they're not leaking, will usually not pull anything with them into the abyss, so it makes sense to me to not replace them until they start acting up. But if you just like to keep things in top shape, then by all means replace them. I also prefer to replace stuff before they break as I would like to choose when and where I have to do the repair. Having the car break down on the highway is never the right time and place. And if you're having the MB out anyway for other repairs, it not a big deal to just replace the caps as well if they're getting old.

 

[Bryce]

Like only putting oil in your car once the oil light comes on is not a good strategy.

But it hasn't drank all the oil I gave it last time yet!

Bryce.

 

[droopy]

I can not blindly accept the things said in the thread.. that A500 do not need a recap. I have serviced quite a lot of them and even if caps seldom leak and destroy something. Caps are changing values and cause mailfunction on different parts of the board. Common areas are graphic output get bad and also the sound can be less quality and distorted.

Taking some caps out and measure them shows that it is not uncommon that the values are more than 20% wrong, some caps as much as 50-60% wrong.
measured with an esr capacitance meter (and double checked).

BUT if anything need a recap it is the a500's powerbrick. Many times recapping the powerbrick gives a "boost" and less "gurus" on any a500.

Capacitiors of today have many options like solid state ones and polymer and so on, and choosing good quality caps and do a recap is never wrong and future proofing your a500, also giving it a higher economic value on the second hand market.

 

[darefail]

@droopy

This thread is 10 years old.
It’s normal after 10 years for this kind of deviation in capacitor values to happen.

 

[jochen]

A good indicator is the sound output. If there is too low level, the capacitors are to change.
In all case, give your A500, A2000 power any hours will help the capacitors to recreate themself. Also new capacitors need power to be stable!

If you have no problems with your A500/A2000, don't touch the capacitors!

Ah, lol, haven't see the date ... it was popping up in the newer threads...
But it's actual theme, because anyone aks this question frequently again.

Please use only ordinary THT electrolyte caps!

 

[Xanxi]

Don't worry, i will come back here in 20 years to confirm if my A500 is working or not.

 

[jokersad]

Common areas are graphic output get bad and also the sound can be less quality and distorted.

100% agreement.
Over the past three years, I have replaced the capacitors on many A500 boards. Even though the boards were not malfunctioning, C401 and C402 often showed signs of leakage on the underside. There was also a slight fishy smell. The effort involved in installing new capacitors is minimal, so there is no reason not to replace them.