(Help!) Atari 7800 Won't Power on after clipping "cart cup"

[Jorlando]

Hi;

Today I received a shipment of imagic carts for my 7800 and found that none of them would fit well enough to run.

I researched a bit on the forums to find a solution.

 

The given solution was i.e:

• Remove external housing
• Find "cart cup"
• clip corners with scissors

 

 

I did this to one of the corners and tested before proceeding any further to limit any damage.

It worked for most of the games, but one, cosmic ark. So, I clipped another corner of the "cup" and when I went to test it the console wouldn't turn on!!!

 

As far as I can tell (have not removed shield) there is no pieces lose.

 

I ordered a Atari jr. in the mean time so I could still play most of my library, but I would really like to be able to fix the console; It ran beautifully before I mutilated it (no sticky buttons, no game problems, etc.)

 

My Question;

 

Any suggestions to what may be the problem?

Any similar experiences?

 

Thanks,

- Justin

Edited December 3, 2017 by Jorlando

[DanthWader]

Do you have some photos to go on, did you completely remove the cart guide to clip the plastic or did you leave it on the board while you did the mod?

[+Mitch]

Check and see if you cracked the solder joint on the voltage regulator. It is attached to the big heat sink right behind the cart port.

 

Mitch

[Jorlando]

I left it on the unit. I didn't know how to remove the shielding at the time.

 

Update:

 

My father and I opened up the unit to see if there was any internal damage. Everything seemed fine,

but we did find the source of the problem, a piece I totally overlooked.

 

The transformers cables got stripped right below the neck. The wires most of crossed and shorted the unit.

We read the transformer to see how many volts it was outputting; It read at 14 volts.

 

We tested to see if the unit shorted, or if it was just the transformer by taking two 9v batteries wiring them in parallel and running it through the unit.

It didn't turn on.

 

Do you think it could be just the voltage regulator that got shorted, or the whole unit got fried?

 

p.s

 

 

Thanks for all the help, I'm fairly new to console repair. I have a little experience in electrical engineering for sound circuits, but my father's an electrical engineer.

We may just take it to a local electric repair shop soon. If nothing fixes the problem, I might just send someone here the console deck for 10$ and shipping, Don't want it to go to waste, being a limited supply.

 

- Justin

[Jorlando]

Check and see if you cracked the solder joint on the voltage regulator. It is attached to the big heat sink right behind the cart port.

 

Mitch

 

I'll double check to see if that's case.

 

Thanks for the help.

[nick3092]

There is no service manual with troubleshooting steps available for the 7800 that I am aware of. But the schematics are readily available. Given your dad is an EE, he should be able to use that to accomplish basic troubleshooting.

[+Mitch]

Here is part of the service manual. Curt found it several years ago.

 

Mitch

7800 service manual 2.pdf

7800 service manual.pdf

[Inky]

 

 

 

[Trebor]

Here is part of the service manual. Curt found it several years ago.

 

Mitch

 

For posterity's sake...

 

http://atariage.com/forums/topic/216763-7800-theory-of-ops-ts-guide/

 

...plus the above thread includes your awesome parts list for the 7800.

[+wongojack]

An easy test is to see if the 5v line on the joystick port is getting 5v. The pin diagram is easy to find everywhere and ground is pretty much connected (as per usual) across the entire 7800 board. You can pull this test off without even removing the case if you test the right pins. At least then you could tell if power was getting into the 7800 at all. Of course, testing voltage right on the regulator would probably tell you if that Heatsink is the issue. Still, exploring carefully with voltage readings is a good first step.

 

I have one 7800 where the previous owner tried to BYO power adapter and got the polarity crossed (or something). It's fncked (power socket removed), but still plays 2600 games in B&W when I hook the voltage up correctly - weird.

[Jorlando]

Thanks for all the help! I'll put some more work into it this weekend and report back.

[Jinks]

Capture.PNG

 

 

 

Thats how I fix em..