Super Cobra keeps resetting

Luddite

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My super cobra was working and then I moved it across the room and now it continually resets. When the game is powered on I get a white grid on startup, the attract mode starts then resets. Over and over. I read about this happening on other posts but no solutions were discussed. Thanks for any help.
cobrainside.jpg
 
Reseat all connectors and check all grounds secure. If that doesn't fix the problem then check the power supply for +5 vdc.

Looking at the pic of your cab I'd immediately suspect the ribbon cables or edge connector on the board...
 
Your power supply is at fault, make sure it is putting out +5vdc. I have had this happen to my Super Cobra twice and both times the power supply had crapped out. Finally broke down and put a decent switcher in it instead of old crappy switchers.
 
Your power supply is at fault, make sure it is putting out +5vdc. I have had this happen to my Super Cobra twice and both times the power supply had crapped out. Finally broke down and put a decent switcher in it instead of old crappy switchers.

OK don't laugh but this will technically be my first official arcade repair. What is involved in putting in a decent switcher? What parts do I need and where should I buy them? Is there a guide somewhere? I think I need the book "Arcade repair for dummies". lol Thank you very much for the help also.

*more* There is a note inside the cabinet that was left by someone who repaired it at one point long ago. It is a check list that says:
1. Adjusted power supply to 4.9u at logic board
2. Rewired Power suppy to AC primary

Not sure at all if this affects what I need to do.
 
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To put in a switcher you will just be replacing the black box in the upper right hand corner of your picture. The wires going to it will need to be seperated out and wired to the +5, +12, AC, ground, and maybe -5 of the new switcher. However, I think the old switcher may still be good or rebuildable. You will need to adjust the power supply output power anyway so you should check what you have currently and see if it needs to be bumped up.
 
ok so how exactly do I check the power supply? I am guessing I need a multimeter. I am going to radio shack in a bit to get one. Any suggestions what I am looking for in a multimeter?

Once I get one where exactly am I touching the leads to check the power supply? Thanks again.
 
For this test virtually any meter will do. I would get one with a digital display for the accuracy. Once you get the meter you need to set it to read voltage, locate the ground and +5 vdc output of the switcher (it should be marked), if the meter is not automatic set it to the appropriate range (most likely 20vdc), then power on the cabinet and place the leads ground to ground and voltage to voltage.
 
pRS1C-2265643w345.jpg

OK I got a new digital multimeter. I set it to read voltage and then I touch the screws in this picture. So which screws exactly am I touching together? And this is while the cabinet plugged in and turned on?
powersupplyw.jpg
 
Yes, plugged in and turned on. You are going to go from the top GND position to the +5v12A position. YOu are looking for approximately 5vdc. While you are there you should also check from the GND to the +12v2a and the -5v1a positions. These are DC readings you are looking for, ensure the meter is set to read DC voltage.
 
When I make those contacts with the leads the meter goes to 0. Does that mean I did it wrong or does that mean it is broken? lol
 
If you have the meter in the pic make sure your leads are in the ground and voltage locations. If you are in the amperage location you won't get a reading. Also, if you are on AC your reading will be zero or near zero.
 
multimetero.jpg

Here is the actual multimeter and setting I am using. Set to DC and measuring voltage. I am touching the top GND to the +5v12A, +12v2a and the -5v1a. I tried the bottom GND to those with the same results. Meter keeps reading 0.
 
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What changes do you get when you push the select button? Either you are measuring AC (depicted by the squiggly line) or their is no power coming out of the switcher...
 
If the meter fluctuates numbers then stops fluctuating them when the leads are touched together then it appears to be working right. Try leaving it on DC voltage and checking a AA/AAA or some other type of battery. If it reads correctly then check the power supply again.

If it doesn't read correctly or if the numbers don't stop fluctuating when you touch the leads together then check the fuse inside the battery compartment of the meter. If it is OK then take the meter back and swap it for a new one.

RJ
 
The squiggly above the minus sign means he is reading AC and needs to hit select to read DC.


Is there more than one pic? (Seriously, I am on an SSP computer and many pics are blocked.) I only see one pic Dave and I don't see the AC symbol... I thought about just having him check the AC on the switcher to verify if it was reading AC but...
 
ok so I held in the cherry switch that switches off when the back door is opened. Now I get a reading. Not sure if that is correct but I get a reading when the switch is held in. The readings below are in the DC setting.

When I touch the Top ground to the +5v12A I get 5.21
When I touch the Top ground to the +12v2a I get 12.45
When I touch the Top ground to the -5v1a I get -5.04
 
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OK, you can just pull that switch out for it to stay on. Those voltages look OK but due to the note left by the tech I'd adjust the +5 v down to 4.9v to 5v and try again...

Some boards like to have lower voltage levels than others.
 
BAAAAAAHAHAHA!

WHOO!!!!

Been there done that... Don't ya just love those "safety" interlock devices on the cab doors? You'll remember those the next time. :p:p:p
 
OK, you can just pull that switch out for it to stay on. Those voltages look OK but due to the note left by the tech I'd adjust the +5 v down to 4.9v to 5v and try again...

Some boards like to have lower voltage levels than others.

How do you adjust the +5v down to 4.9v to 5v? The little dial at the top?
 
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