Dead XE supercart

[+remowilliams]

I've got a Blue Max cart here that worked exactly twice and now will not powerup on any A8, just gives a black screen. It's a rev B with two ICs (+one mask ROM of course), three resistors and three caps. Resistors are fine, can't really test the caps without replacing them. Anyone know what the likely cause for the thing to stop working might be and/or the value of those caps?

[Atari Smeghead]

Just to state the obvious... I'm assuming you've tried cleaning the contacts on the cart (and perhaps the computer as well), right? Personally, I've never had any cart stop working for any reason other than dirty contacts.

 

Okay, I'm done stating the obvious.

 

Cheers,

Smeg

[+remowilliams]

Okay, I'm done stating the obvious.

S'ok, me and electronics might not be best friends, but we go way back Yeah, everything is pristine.

[+remowilliams]

Bueller? Anyone?

[1050]

I've got a Blue Max cart here that worked exactly twice and now will not powerup on any A8, just gives a black screen. It's a rev B with two ICs (+one mask ROM of course), three resistors and three caps. Resistors are fine, can't really test the caps without replacing them. Anyone know what the likely cause for the thing to stop working might be and/or the value of those caps?

You can cut the caps off, they are bypass caps with a value of .1 uf, if they were shorted your machine wouldn't boot and it doesn't matter if they are open, the cart would still work without them.

 

It's the maskable rom so there is no hope, logic support IC rarely fail but you can try to replace them. I'm not familar with a Blue Max cart, can you post anymore information on it? I wasn't aware of any maskedrom supercarts for the XE, just standard XL 8k and 16k game carts with maskedroms in them. But those aren't called supercarts. The usual XE Supercart is using an eprom equivalent rom last I knew, so I am confused somewhat. And that means my advise might have missed the mark. What are the numbers off of the two other chips?

[+remowilliams]

I'll attach a pic of the cart here, probably easier than describing it.

 

[classics]

I've got a Blue Max cart here that worked exactly twice and now will not powerup on any A8, just gives a black screen. It's a rev B with two ICs (+one mask ROM of course), three resistors and three caps. Resistors are fine, can't really test the caps without replacing them. Anyone know what the likely cause for the thing to stop working might be and/or the value of those caps?

 

The cap marked 104 is 0.1uf, I can't see the value marking on the other one in the photo. All of the caps look like they are attached to GND and 5v+ anyway, which means except for filtering noise the cart would probably work fine without them anyway.

 

The most likely thing to have stopped working is the latch (374) or the rom itself, but you probably wont be able to test either without removing them unless you have a schematic for the cart. In that case you could put various bank values into $D500 and check the outputs on the latch to make sure the outputs matched what was expected.

 

Also try re-soldering everything. From the photo it does not look like the board really got hot enough to get much solder in the holes when it was made.

 

Steve

Edited September 28, 2009 by classics

[CPUWIZ]

WTF is this pin not in the board? Is that normal?

[+remowilliams]

WTF is this pin not in the board? Is that normal?

No, it looks rather purposely bent up. Whether thats normal or not, I couldn't say.

[1050]

WTF is this pin not in the board? Is that normal?

No, it looks rather purposely bent up. Whether thats normal or not, I couldn't say.

It is common for Atari to do that to that pin on some games so yes, it's normal. One thing I noted is that the associated 'resistor' (R2) with the one black band is not a resistor at all but a jumper. You should have noticed the zero ohm reading when you checked it, right?

 

According to Sobola's schematic that 23256 rom needs postive chip enable on pin 22 which is what that jumper to 5+ is doing in the R2 postion. A 27256 eprom would work as U1 if you cut that jumper and grounded the lower hole of R2 (the one closer to the edge connector). That's ground one trace to the south or pin 10 of the 74ls374 latch U3. I really doubt U2 or U3 went bad and caused this, but as I said before you sure can change them out easy enough. No joy then would be the jumper was not a short anymore or the masked rom shot craps. And that covers everything that there is that CAN go wrong.

[+save2600]

WTF is this pin not in the board? Is that normal?

 

That looks extremely odd that they would bend and twist the lead that way. Does the spade part of the

pin look like it's touching the foil on the PCB? And what's that darkness around the area? To my eyes, it

looks as if that pin was 'blown' out of the socket due to a power surge. That scenario would be very

weird because we're talking about relatively low voltages here, but if something happened along the

way to one of the tantalum caps - they're known for wreaking that kind of damage. And the lead that

is bent up, there is a circuit trace there. I wonder if you were to follow that trace and re-connect the

lead what would happen...

 

A few months ago, I was working on an Atari Asteroids arcade machine when something accidentally

shorted. To my amazement, I witnessed a chip (looking just like your example) had one of its pins

ever so professionally BLOWN off the circuit board. Totally clean and looked as if it was meant to be.

I literally saw the spark, heard the explosion and saw the aftermath. Had someone just given me the

board to repair (and not knowing that particular deflection chip was supposed to be that way), I'd have

thought it was factory.

 

Not saying the bent pin on your chip is factory or not - just seems strange. The only purposely

bent pins I've ever seen on console stuff were on the ROMS themselves, not gates or other I.C.'s

unless they were hacks, mods or something...

[+remowilliams]

R2 tested zero ohms. I've removed R2, jumpered the lower hole to ground, and replaced the 23256 with a 27c256 and it's working once again! Thanks everyone for the feedback!

[tjlazer]

If you end up not getting it working I would love to buy your gray XE cart shell. PM me.

Edited September 30, 2009 by tjlazer

[+remowilliams]

Oddly the cart works in the 130XEs and 1200XLs I've tested it in, but does not work on the XEGS that I have handy (which doesn't seem to have issues with any other cart I've plugged into it). Does that make any sense?

[blacka013]

I bought one of these supercarts, Rev B (no case) off eBay with a 27c64 eprom in it and it didn't work. Having read through the posts above, I have removed R2 (6.8K) and soldered in a link from the bottom of R2 to earth. This now works with 2764 eproms.

 

Can you tell me what is the largest rom image size that can be used as I can't get 16K images to run?

 

Regards

[BillC]

On 1/23/2020 at 10:55 AM, blacka013 said:

I bought one of these supercarts, Rev B (no case) off eBay with a 27c64 eprom in it and it didn't work. Having read through the posts above, I have removed R2 (6.8K) and soldered in a link from the bottom of R2 to earth. This now works with 2764 eproms.

 

Can you tell me what is the largest rom image size that can be used as I can't get 16K images to run?

 

Regards

2764 EPROMs are only 8K bytes, a 27128 would be required for 16K.

[Wilheim]

I can make you a reproducción pcb with the game installed on it. If you are interested, please let me know.

[+Nezgar]

The PCB pictured earlier in the thread is a 23256 mask ROM, which is 32KB.

 

I previously got a 16KB supercart converted to use a 27c128 EPROM to replace a dead mask ROM with some help from the folks here. Maybe your PCB is the same to compare with?

 

https://atariage.com/forums/topic/271777-bad-necromancer-xegs-cart-fixable/