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I am replacing the electrolytic capacitors in an old Atari video game, c. 1981.

The manual has a complete parts list, which is what I used to order the parts. There's a problem with the last two capacitors. In the manual, they are

C60 1 uf 10% 35V Tantalum (I wasn't going to replace this one, but read on)

C62 1 uf Aluminum Electrolytic 50V

On the PCB board, both C60 and C62 are actually 22 uf 25V electorlytics.

The game used to work fine with what I assume are the original parts. These two capacitors appear to be in the video monitor driver section of the board.

My dilemma: replace with what's there, or replace with what the parts list says they should be?

Any advice would be appreciated.

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  • \$\begingroup\$ Those parts cost in the neighborhood of $0.50 each. Just try one way, and if it doesn't work, try the other way. \$\endgroup\$ – The Photon Nov 21 '15 at 19:37
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    \$\begingroup\$ If it works with what's in there and Atari made no attempt to update their documentation past version Vx.xx (if that's the case), I'd go for replacing what's in there with equivalents, since it obviously worked back then. If it still works it ain't broke, and you may have lucked into some really robust electrolytics, so why fix what ain't broke? \$\endgroup\$ – EM Fields Nov 21 '15 at 19:46
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Likely better to replaced with what had been working.

Manufacturer's of hot products (like video games back in the day) would sometimes make changes and improvements on the fly and never get the time to properly update all the documentation. So it might easily be seen that the documentation has more bugs vs what was actually coming off the production floor at the time. There is also the possibility that your device is an older or newer revision as compared to the documentation. There may be dates or revision information on the PCB or device housing, try matching this up with the documentation. But again, if there is still confusion err on the existing values.

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  • \$\begingroup\$ I think you're right, this is the way to go. \$\endgroup\$ – user92359 Nov 22 '15 at 15:20
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These are probably decoupling capacitors, and their value generally isn't critical. Risk is that too large a value (e.g. 5x the 'correct' value) could cause large inrush currents and weaken something, but that's not likely.

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