Possible cause for Bridge Rectifier failure?

Angry_Radish

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I had to pull my Frankenstein off location last week when it went dead, turns out it was the bridge rectifier on the PS board. All voltages look great and the machine is running fine now, but what could the possible causes for failure be? An electrical hit at the location? Heat? I've been thinking of swapping out the backbox bulbs with LED's for awhile now to bring down the heat back there, with that giant backbox with all it's lamps and over-sized DMD there is a fair amount of heat.

Thoughts?
 
Heat, age, a short circuit causing an overload, bad filter cap, barometric pressure, alien electromagnetic disturbances, marginally defective part, butterfly flapping it's wings in Indonesia, bad solder joints causing intermittent contact, power spikes... Pick one. :)

I wouldn't worry about it. If possible, use a higher rated part. If there was no heat sink before, installing one might help. If it's never failed before, and it just did - I don't think it's anything unusual. They are parts that do fail. If it blows again in a month, then I'd worry.

-Ian
 
leds wont change, the thing itself usually gets hotter than a lightbulb ever will :)
install a heatsink (and don't forget to add thermal paste !!)
 
Good point about the LED's, I never thought about the heat they create.
Since I've already soldered the BR on the board adding a heatsink with the traditional nut and bolt might be difficult, I remember reading about thermal adhesive somewhere, I'll look into that, or maybe find some sort of clamp heatsink.

Thanks for the responses guys!
 
Good point about the LED's, I never thought about the heat they create.

Even if the LEDs themselves were the same temperature as the original lamps you would still have less heat coming from the power supply and there would be less strain on the bridge (in the case of switched illumination).

Install a beefy bridge and replace connectors where necessary then use #44s. That's what I would do :)
 
leds wont change, the thing itself usually gets hotter than a lightbulb ever will :)
install a heatsink (and don't forget to add thermal paste !!)

I meant the bridge rectifier itself will get a lot hotter than lightbulbs ever will..
not leds, sorry for the confusion

and yes if you have a bridge that has already has a heatsink installed (like the 2 on WPC games) you need to add thermal paste when you replace them - just screwing the heatsink on the new bridge is not enough and it'll burn after a few months

with bridges that don't have a heatsink installed it's less important but still a good idea
 
Well crap, just went to fire it up for a last once-over before folding it up to put back out on route and now no CPU controlled lighting or DMD again, time to dig deeper it seems.
 
More strangeness. Checked all the fuses and the BR, all good, voltages are good. Only back-box and GI lights though. I left it on, started a game and the ball kicked out as it should. THEN, the insert lights started acting normal, I started getting intermittent sound which then became normal, and the DMD flickered a few times, then came on.... WTF?

So now the game is acting fine, but I can't put it out on location with that kind of strangeness hanging over my head....
 
Have you removed the boards and checked them for cracked solder joints?

Cracked joints will act intermittent like that with things. Being on location and ON for hours on end, I would bet you got some and possibly some burnt connectors.

Regarding the heat issue in general with a machine, install an old computer fan in the back box to help circulate heat out.
 
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In many cases where I thought the BR was the problem it was actually the connectors which had to be reseated due to removing the PCB, or bad solder joints. I tend to think the BR's on WPC pins go bad much less often than alleged.

Wade
 
The BR WAS shorted and it fixed the issue, but I'm still having issues with it having to "warm up" before it's playable.
I haven't had any time to really look at it lately though, today was day 4 on the phone with Microsoft tech support, all I want to do when I get home is drink :)
 
either a capacitor or resistor is bad, or you have some burnt pins somewhere on the connectors..
time to take out the schematics and check voltages at startup..
 
That's the plan (when I have time)
I figure since I have so many damn meters I'll hook probes to ALL the voltages off the board and fire it up to see which one is lagging then backtrack down that part of the circuit.
 
backtrack

dont forget the possibility that the plated through holes could have been damaged during replacement of the old part with new or even in the past

verify

one would think the rectifier would just work and not need to "heat up"

look for hairline cracks in the traces is what im constantly on the lookout for
just because there's continuity from one point to another, when a "load" is placed on the circuit, electron flow is slowed and maybe when that heats up theres better flow

did you test the new rectifier ?
 
It tested fine, though I bought a few spares when I got my replacements just for future needs :)

I'm leaning towards caps, but I just haven't had time to look at it again. Between my regular work, route work, and doing the timing belt/water pump on the wife's Subaru it has been taking a back seat unfortunately.

Good thought on the trough holes, I did have a bitch of time getting it de-soldered, worth a look!
 
The BR WAS shorted and it fixed the issue, but I'm still having issues with it having to "warm up" before it's playable.
I haven't had any time to really look at it lately though, today was day 4 on the phone with Microsoft tech support, all I want to do when I get home is drink :)

The warmup problem could still be caused by bad solder or by the connectors I suggested.

Wade
 
Have you removed the boards and checked them for cracked solder joints?

Cracked joints will act intermittent like that with things. Being on location and ON for hours on end, I would bet you got some and possibly some burnt connectors.

You need to do as I suggested...
 
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