Bridges and caps should be replaced when they have failed. I've fixed a lot of boards for people where they thought the'd just go through and replace all the caps... and they caused a ton of problems along the way, because they shouldn't have been working on the boards in the first place.

If they are clearly leaking or bulged, I replace them.

Electrolytic caps were designed to last about 10 years. For most games, it's been 2-3 times that. They dry up and don't supply the required voltages in many cases, and can cause all sorts of wonky behavior. For a thorough restore job, yes, it's probably a good idea to replace them.

However--like John alluded to, this comes with the caveat that you are familiar with doing this sort of work on boards.

Here is some measured results showing caps that are going to die, and why:

https://pinside.com/pinball/forum/topic/vids-guide-quick-bally-driver-board-repair-bulletproofing#post-592748

I replace them if they are original or if the game it hitting the 10 year mark or more when I shop it.
I also like doing board work and have the equipment to do so.

The parts are inexpensive but if your skills are limited ( or equipment ) that cheap capacitor or bridge rectifier could result in a damaged board if heavy handed.

If working on boards ALWAYS use a temperature controlled soldering iron / station.

Just use decent equipment and don't get in a hurry or heavy handed.
Never force ( pry ) things off the board. This is usually how traces and plated thru holes get ruined.

A solder sucker and some solder wick ( or copper ground braid ) works well for getting solder out of plated thru holes. Flowing fresh solder in 1st then sucking out works good.

I find that caps on 20 year old WMS boards often measure closer to spec than new high quality caps using my esr meter!

I agree with you on that one, John. I also find that true with Gottliebs, believe it or don't.

Greg

A great question, and one I've wondered for a long time. If the electrolytics haven't been stressed and pushed past their recommended value of what they are rated at. Is it possible they run much longer than we think?

My personal experience is that it all depends on the quality of the capacitor. I have an NEC video projector that was loaded with about 350 Panasonic capacitors that were from a bad batch. Many were leaking when I took possession of the projector. The caps were all shot after about 10 years. This is based on age and not actual use as the hour meter only had 800 hours. I did replace most of the 350 capacitors with high quality replacements. So far after two years the device is solid.

All this being said I wouldn't re-cap a board unless there was visual evidence, caps testing bad, or a history of failed devices in the pinball machine in question.

An ESR meter is on my toy list someday....

I re-capped my Samsung DLP TV power supply boards. Bad caps from the factory and bulged and leaking right outside warranty. $25 in caps from Mouser is WAY better than boards.

I wouldn't.
If it ain't broke...and...far more problems are caused.
--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The new place for pinball repair info

I agree with not recapping unless necessary.

I restore old vacuum tube radios and recently pulled out a vintage military receiver (BC-348). These boat anchors were used in B-24 bombers in WWII. As the caps in this thing were over 70 years old, I fully expected they would need replacement. Well not so, after a bit of reforming the radio worked perfectly.

Capacitors can and do go bad but until you have a problem there's no need to risk damage as they may very well outlast you.

Randy

Caps are so cheap, just do it and spare yourself the trouble. And yes, I have seen ancient ones survive. I still have the original wax filter caps in a Hammond M3 organ.

There are some caps that typically are still good 35 years latter.

But the important ones, like the 5v circuit on the power supply, really should be changed

If your table resets during your highest scoring game, you won't be happy.

The critical power supply filtering caps, change regardless if the game is a used game with original caps. If they are not bad already they probably will be soon. The others I don't worry about unless there is a problem. Totally recapping everything if there is not a problem is really a waste of time and money.

I wasn't specific enough, I only bother replacing the power filtering elecrolytics 98% of the time unless I know of a particular cap that has a high failure rate or I am pouring over schematics and notice what is in the board is too close to the capacitor voltage threshold (often times whatever is available got used,even if it was only rated a few volts higher than operating voltage, hardly enough to prevent a spike). I never replace any other caps unless they physically look like they need to be or the do need to be due to a repair.

There ya go.
When I get a board in the shop, I generally replace C5 (the 5VDC filter cap) and C4, a 10 cent cap that can sometimes cause resets. Unless one of the other 15,000uf caps is known to not be doing it's job, bulging or exploded, I don't mess with them.

To fully "bullet proof" a WPC P/D Board, I'll also replace the headers at J101, 102, 103, and 114, if they are tarnished/corroded/worn out.
--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The Place to go for Pinball Repair Info

I also replace C2. joe

Am going through a Wms 6A boardset currently (MPU, driver, sound, PS). Tested all the electrolytics. What was bad? The 12kuf caps on the PS and type 1 sound board and C23 on the MPU board. For the latter I didn't really need the meter to tell it was bad as there was evidence of leaking.

DSCN7002.jpg

The rest? All tested fine.

viperrwk