EDOT issues

frytex

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Having problems with my EDOT. Turn it on and it is raining blue lines all around. Not sure why. Went back and pushed all chips in. And checked all plugs and connections. I am getting a steady glow from the second from the left fuse 5 amp. When I say glow I mean you can see a orange glow in the fuse. Not sure why. Any help would be appreciated. Thanks
 

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A glowing fuse?

Wow. Shut the game off, replace the fuse with a new, properly rated. Fuses don't glow. Maybe someone substituted a lamp? There are lamps made for stereo dials that are too close looking to fuses for my comfort.

Use an amp probe if you have one, if not borrow or buy one, and see what the current is on that fuse when you power the game on.

These EDOTs are rare and from what I have seen, twitchy. I never got to play an EDOT or DOT since I never found one working, and I pumped a TON of quarters into arcades BITD.
 
Well went through all boards resitted everything, found 1 cap on the sound board broke. Replaced it and replaced 2 5 amp fuses. Now everything works. That was weird.
 
Lamp, Fuse....?

You know....
The glowing fuse got me thinking.

A lamp is a resistor. So, if you had a lamp where a fuse was supposed to go, you'd have a voltage drop across the lamp (resistor), so the downstream loads wouldn't see the right voltage.

Did you look at the "glowing fuse?" What was it? (e.g., was it marked AGC 5 or something else, or what?)

Congrats on the success in any case. It would be nice to know what came out, so we can get some idea of what the proverbial "smoking gun" was.
 
My guess is it says "Stanley 8v .3a". Common cartridge lamp in 70s stereo stuff for dial lighting.

Not only would you get a voltage drop but a lamp will act as a current limiter too when in series with the load.
 
i doubt he had a lamp there. cdjump saw it all in person and would have noticed...
 
Push back accepted.

Challenge: How do you get a fuse that glows and doesn't blow? It doesn't make sense.

Further challenge: When you replace the fuse, the new fuse doesn't glow and the game works.

Someone noticing something as subtle as the wrong fuse - there are a couple of people I know who would be like that, but they are pretty few and far between. Is cdjump someone who picks up on the extremely subtle? (e.g., checks every fuse rating?)

I'd still like to know what they found. That way, everyone can learn from it, rather than making assumptions one way or the other.
 
I dont think he ever said the fuse didn't blow. A slo-blo fuse near its amperage limit will glow until pushed over the limit. I was messing with a UDOT power supply and for some reason the fuse on the linear power board started to glow when I powered it on and it took about 5 seconds before it actually blew. I popped in another and it did the same thing for a few seconds before I shut off the game and found what my problem was and fixed it. After I did so, the fuse worked (and still works) fine.
 
Push back accepted.

Challenge: How do you get a fuse that glows and doesn't blow? It doesn't make sense.

Further challenge: When you replace the fuse, the new fuse doesn't glow and the game works.

Someone noticing something as subtle as the wrong fuse - there are a couple of people I know who would be like that, but they are pretty few and far between.

I'd still like to know what they found. That way, everyone can learn from it, rather than making assumptions one way or the other.

I dont think he ever said the fuse didn't blow. A slo-blo fuse near its amperage limit will glow until pushed over the limit. I was messing with a UDOT power supply and for some reason the fuse on the linear power board started to glow when I powered it on and it took about 5 seconds before it actually blew. I popped in another and it did the same thing for a few seconds before I shut off the game and found what my problem was and fixed it. After I did so, the fuse worked (and still works) fine.

Exactly. A slow-blow fuse can glow if it gets stressed - like a circuit suddenly pulling more amps than normal because a broken cap closes off a parallel circuit that would normally share the load - without blowing if the amperage spike is just barely above the limit of the fuse. I see it happen a lot on pinballs. Stress it enough and it will finally blow. Fixing the broken cap issue likely took care of the problem, and the new fuse is now sufficient.

Is cdjump someone who picks up on the extremely subtle? (e.g., checks every fuse rating?)

cdjump is an MCR repair expert. When frytex was having problems getting this working, I believe his main problem was blowing fuses. He finally loaded the entire thing up (which is a big undertaking if you've ever moved an EDOT) and took it to cdjump (who'd already fixed the game pcb's). They tracked the issue to problems in the power brick, and I'm sure they went through and replaced all the fuses with new ones, so I'm sure they put the proper ones in....
 
Thanks for the answer.

For the record, I'm an engineer. I ask questions like this to make sure there aren't any unverified assumptions. In my business they can be very dangerous. In electronics, they can result in damage from the minor to the catastrophic.

This all comes down to a simple philosophy that my company has trained me all too well in: I know because I looked.

I'll have to find some slo-blow fuses, and rig them up to a variable current source. I haven't had the benefit of seeing a glowing fuse.
 
Thanks for the answer.

For the record, I'm an engineer. I ask questions like this to make sure there aren't any unverified assumptions. In my business they can be very dangerous. In electronics, they can result in damage from the minor to the catastrophic.

This all comes down to a simple philosophy that my company has trained me all too well in: I know because I looked.

I'll have to find some slo-blow fuses, and rig them up to a variable current source. I haven't had the benefit of seeing a glowing fuse.


No offense, but my worst customer is the electrical engineer. They always seem to think that what they learned in college in 2005 or whenever means they know everything they need to work on 1980's technology. I find that they often try to "upgrade" when doing repairs, or end up doing "workarounds" to a problem, and often cause bigger problems than if they had just repeated what was already known to work.

Now, I know some upgrades have become arcade repair staples, so don't think I'm lumping everyone into a prejudicial stereotype. It's just been said that "a little knowledge is a dangerous thing", and that applies to arcade repair, too. Perhaps y'all can do pcb repairs very well, but for some reason pinball and monitor repairs seem to bring out the worst in "engineer repairs"... ;)
 
Fair enough. I don't lump all arcade types into the "self-taught person who causes more harm than good" category. I figure out who each is. I'd ask you to do the same with me.

I'm an engineer with four things that many engineers don't have (and having worked in Engineering for many years, in my opinion (which is in no way described as humble) desperately need):
1. I can put three words or more together in a sentence
2. I can troubleshoot.
3. I have common sense.
4. I can think out of the box. At times, too far, but I'd rather be there than elsewhere.

Just as important, I can admit when I'm wrong, and learn from my mistakes.

I don't "upgrade" stuff - my job is to get it to work the way it was designed. If I find a glitch (for example, most Gottlieb video games use a dropping resistor to drop the excessive voltage to their sound chip, until the resistor gives up and you blast the sound chip), I'll design a solution around it, or preferably, use someone else's real-world already tested design.

Arcade designers aren't perfect - why else would:

- the early pinballs be designed with tin pins and sockets that corrode, or
- why would the early digital designers mount the batteries right on the PCB (where they can corrode and damage the board), or
- why in the name of all things holy would ANYONE design chips or sockets with legs / receivers that corrode?

The list could go on for ages with all the design flaws (security chips? Really - like someone is going to steal the board WITHOUT the security chip?) but I think you get my point.

Nobody is perfect. At least, I haven't met the person yet who is.
 
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