My new ROBOTRON! working again (woot!)

[Q*Bert_OP]

The title says it all...my power supply voltage spiked up during a game, smoke pours out of the back from the pcbs...

F*CK

F*CK

F*CK

F*CK William's Power supplies!!!!

 

[Q*Bert_OP]

$550 down the drain up in smoke

[leapinlew]

You have my condolences...


 

[Q*Bert_OP]

the thing that really pisses me off is that I just got it this past Saturday, and that I have only played it about 30 times

[NightGod]

Ouch. That sucks hardcore.

[Ken Layton]

Was the power supply rebuilt? Did it have new connectors installed?

This is exactly the reason I like to yard out the original power supply and convert the cabinet to use a switcher instead.

[MaximRecoil]

$550 down the drain up in smoke

Make that $542.50...

Seriously though, Robotron boardsets aren't that expensive are they? If you rationalize it to yourself that it would have been a good idea to convert it to a switching power supply either way, then the only thing you are out is the cost of a replacement board, right? I don't know what those boards go for, but I wouldn't think it would be $550.

[MYX]

Also the whole thing may not be toasted either. Was it your house power that spiked or the game? How do you know?
I wpi;d pull the boards and look for visible sines of damage. Also a fried chip will smell like rotten eggs, sounds silly but sniff around the board.

Does the game do anything at all right now?

Like Ken said (cause he is the man!) get a switching powersupply in there first before you do anything else.
Then If you have the skillz, (and the time) then pull the board and start to trace it out. It will take a while but it can be done. If there is a big black circle burnt through the main board then... you may be up the creek.

But even if you do opt for new boards, get the new PS no matter what.

I am sorry, Robotron is a rockin game. One of my favorites. 

[Ken Layton]

Usually it's the bank of ram chips (socketed!) that cook.

[Texasmame]

Was the power supply rebuilt? Did it have new connectors installed?

This is exactly the reason I like to yard out the original power supply and convert the cabinet to use a switcher instead.

Yeah, you really need to convert the old PS to switchers in just about ANY game, just in case.  Heck, if the PS is working when you get a game, eBay it and you might even MAKE money in the end! 

[RayB]

Don't say that man! I like to keep my Ataris original!
 

[ChadTower]

Me too.  Rebuild the AR board, replace the big blue, repin the connectors and the PS will run another 20 years.

[Texasmame]

Don't say that man! I like to keep my Ataris original!
 

Yeah, I know there were guys who were into the "all original" thing.  Me, I just wanted stuff that would WORK all the time (if possible) for the insides.  Had a few switchers in my games and it didn't bother me one bit. 

Now, on the EXTERIOR, I always went for original stuff, with the exception of a couple repro overlays I had for Stargate and Centipede. 

[Q*Bert_OP]

$550 down the drain up in smoke

Make that $542.50...

Seriously though, Robotron boardsets aren't that expensive are they? If you rationalize it to yourself that it would have been a good idea to convert it to a switching power supply either way, then the only thing you are out is the cost of a replacement board, right? I don't know what those boards go for, but I wouldn't think it would be $550.

Nah, That $550 is what I payed for the machine...

[Q*Bert_OP]

bad resistor smoked...replaced...now working (woot!)

[ChadTower]

All of that drama over one resistor?

[Lutus]

Sometimes it is pleasently simple.  Comically simple in fact.   

[danny_galaga]

bad resistor smoked...replaced...now working (woot!)

huzzah!

[ChadTower]

Well, simple for now, until the resistor fries again because he didn't track the cause.

[Stingray]

bad resistor smoked...replaced...now working (woot!)

Excellent!

-S

[Ed_McCarron]

Well, simple for now, until the resistor fries again because he didn't track the cause.

You are starting to sound like Marvin.

Is it not a possibility the resistor failed because it was old?

[ChadTower]

Not if it burst into flames.  They fail when they get old, yes, but they don't freakin explode.  The only way they burst into flames is when something overloads them. 

[Q*Bert_OP]

I'll still get a swithching power supply in there...

[Texasmame]

I'll still get a swithching power supply in there...

Good man.   

Don't delay on that!  The machine has given you fair warning already! 

[ArcaMan]

Ok, I sound stupid, but what is a "switching powersupply?" .... I just inherited a Robotron that was litterally in the trash and my neighbor saved it for me. (I owe that guy a KEG of beer for his kindly thinking of me!)

Oddly enough, the guy apparently chose to replace it with the Target cabinet.  I can't imagine downgrading from a working Robotron to a half assed one, but I am glad he passed the Robotron on to me

I am 90% certain that at least part of the problem is the power board because the person said that it "stopped working suddenly" and only 2 of the 3 LEDs are lit. (hoping it is just a matter of getting a new fuse!).

Anyhow, while I am doing the whole restore and clean up (also needs new bulbs for the marquee and one of the coin returns), I figure I'll also upgrade what ever might cause probs in the near future.



James

[BUCKETHEAD]

This is a Switching Power Supply,

[SirPeale]

Ok, I sound stupid, but what is a "switching powersupply?" .... I just inherited a Robotron that was litterally in the trash and my neighbor saved it for me. (I owe that guy a KEG of beer for his kindly thinking of me!)

Man, what a find!  I can't believe he was going to bin it!

[ArcaMan]

Thanks for the picture, I was more interested in ...

1. What does it do ... why is it worth upgrading?
2. What one do I need for a Robotron (also I probably need one for my Op Wolf that I am slooooooowly restoring by combining two cabs that I rescued and hoping I have one set of working parts between them )

I wasn't sure if PSUs are like they are on PCs i.e. almost all the same, just different wattage or if I need game / manufacturer specific ones.

BTW sorry for sorta hijacking the thread, but it looked like the original poster and I had / are having a similar experience

James

[RayB]

It's a modern power supply used in almost ALL arcade games. Puts out +5, -5, +12 voltage. More reliable than the old setup.

[CheffoJeffo]

If the "2 out of 3 LEDs" refer to the Wlliams power supplyboard, then it could be as simple as a blown fuse. Of course, you'll want to know WHY the fuse blew in the first place.

ArcadeShop has these nice easy adaptor boards that you screw into a switching PS, then plug the Williams power harness into. Literally a 10-second job:

http://www.arcadeshop.com/pics/wms-ps.jpg

Cheers.

[ArcaMan]

Yeah, that is exactly where the LEDs are located.  LED 1 is off, the other two are on. I"ll check that thing on arcade shop out.

Thanks,

James

[ArcaMan]

Well, I tested it out (took the fuses out of the sound board and put them into the blown fuses place on the power supply board).

Game booted and promptly blew (because the fuses weren't the right strength).

So that basicly confirms that the immediate problem was the fuses.

My friend who was looking at it / testing it with me suggested that probably the fuses were just "old" and they can sometimes lose their vacume, so that may have been the problem.

also, btw it looks like this may have been one of the original games ... the inspection marks say April and May of 82 (cab and later on the CP).  A parts manual I found was published in May of 82, so I am wondering if maybe this was in the first batch.

[SirPeale]

Fuses aren't like light bulbs; they aren't vacuum sealed.

You can actually run a properly operating device for a bit on a fuse that's underrated.  Depending, of course, on just how under rated the fuse is.  Say if you're drawing 3A, and you have a 2A fuse in there, you'll be okay for a while, but if it's drawing 3A, and you have a 1/4A fuse, likely it'll toast rather quickly.

I suspect other issues.

[ChadTower]

It is other issues.  Peale's answer is exactly right.

There's rarely, and I mean rarely, any issue that is "simply a blown fuse".  Fuses almost never blow without reason.  They aren't vacuum sealed, they are a tiny exactly rated conductor protected inside glass.  Fuses are sometimes bad right out of the box but if they were ever good they don't just blow without cause.

Putting in the wrong fuses is not really going to get you much.  If the fuse is more than a little lower than the rating, it will blow immediately.  If it's higher than you're going to do more damage than good.  It won't blow at all and something further down the line will fry.

[_) (V) (-)]

On more than one occasion I have actually seen a fuse melt the solider off the inside of the end cap and open the circuit. Upon visual inspection, the suspect fuse 'looked' good and had to be tested with a DVOM to verify the problem.

[ChadTower]

Never eyeball a fuse to see if it's good.  Too often they look fine but are no good.

Anyone working on a board should know how to use the continuity check on a DMM.

[RayB]

I don't. How do I test a fuse?

[Texasmame]

Set your multimeter to test for CONTINUITY.  Place one lead on one end of the questionable fuse, the other lead on the other end.  No "beep" or whatever your meter does to denote continuity, then the fuse is bad.  Best done with the fuse out of its holder or whatever it's connected to - on its own.

[ChadTower]

It's simpler than that.

Set DMM continuity.

Touch two things.  If they are connected with near zero resistance, it will beep or display something like SHORT. 

If they are not connected, it will not beep or it will say something like OPEN.

[Texasmame]

Not if it burst into flames.  They fail when they get old, yes, but they don't freakin explode.  The only way they burst into flames is when something overloads them. 

Or when they're in a G08.   

[RayB]

OK, I knew that much. "Continuity". Thing is, this meter has symbols. i don't know what the symbol is for "continuity".

There's an area where it says hFE. Another where it looks like a square wave. Next to that there's a symbol that looks like this:  .))) with a  ->|-  symbol under it.

There's an area with an Omega symbol and 5 different ratings.

So which is it? I thought the logical thing to do was to try each one and touch the probes together, but NONE make a beep. (Maybe the battery is getting weak)

[ChadTower]

Your DMM has a manual.  It should explain the settings there.

[CheffoJeffo]

You can use Omega to measure for zero resistance.

Cheers

[ChadTower]

It will work, as that is how the continuity check is done... won't beep, though.   

[RayB]

Your DMM has a manual.  It should explain the settings there.

I just checked my house, cuz I got this creepy feeling Chad is in here.

Nope, he's not here. *phew!*

And no, I don't have a manual.

[ChadTower]

Does it have batteries?

[RayB]

Does it have batteries?

There's no visible battery compartment, but the back does say it's powered by a 9volt. (I don't see how a digital multimeter would work without power. Geez Chad, sometimes you're so smart and then sometimes...  )

[ChadTower]

That was sarcasm.  And keep in mind that ohm meters (older instruments on which the DMM is based) did not use batteries.  So it's a valid question since it is entirely possible there are stripped down DMMs that also are not internally powered.

[_) (V) (-)]

hFE is most likely a capacitor tester

square wave is most likely dc voltage

.)))  I don't have a friggin' clue what that is 'sposed ta be.

->|-  is most likely a diode test, this may also be your Continuity test

Otherwise I think you could use the Ohms scale, just look for a very low reading, like 00.1.

[RayB]

QBert: My apologies for this! 

(PS: This meter, when I set to the OHMS section, it displays "1", then if I touch the two probes together, the number quickly "counts down" and stops at 0.0)

[2600]

Sometimes I can't tell if people are serious or joking on this forum.


hFE tests transistors

))) ->|- is continuity and diode test.  The ))) is suppose to be a sound wave like the symbol on your pc where you plug your speakers into.

The square wave is probably a pulse generator.  V and A (AC and DC) are usually pretty standard signs.

A google for your model should turn up a manual.  If not, go to the Fluke website and look at some of the manuals for DMM's.  They usually operate the same and it will give you instructions on how to use it.  When testing transistors and diodes, it's just easier to see a picture.  I've seen lots of DMMs where you have to take the case apart to get to the 9 volt.


Chad,
I would of thought an ohmeter required a battery?  A volt meter I could see not having one, but it's been a long time since I've seen them.

[Lutus]

In order to hear a beep, you must turn it to "ohms" or "continuity" setting and then press a button to denote that you wish to hear a beep.  Hope that makes sense.

[ChadTower]

That changes from DMM to DMM... neither of my newish DMMs need a button pressed.

[Lutus]

Really?

Well then, don't take my word for it 

I have an older multimeter.... obviously!

[Buddabing]

FYI do not test fuses in-circuit! You may get false good readings.