Galaga and RAM 4h

[Hawk Daddy]

When I turned it on the first time tonight, it had ram 4h on the screen.  I turned it off then back on and it worked fine.  After a little research thats an error on the video pc board, where can I find a replacement 4h chip?

Hawk

[RayB]

Check your voltages first.

[Hawk Daddy]

Voltages on what?  Now it doesn't even let me play it at all, I'm about to get fed up with this thing, and post a vid named Galaga vs.  Sledgehammer, cause I'm tired of putting money into a lemon.

Hawk

[modessitt]

Only a week and it's a lemon???

Here is what your error code means:

  RAM 4H  - RAM located on Video PC board at position 3J is bad

It's possible it IS bad.  the manual lists it as a "2114-2 ST. RAM 200NS.(1024X4)" and you should be able to get one.  Ask around, or contact some of the Galaga repair sites.

When he said to check your voltages, he mainly means your +5V as this is needed for the board to run, although they should all be proper for everything to work.

You can find out how, as well as other Galaga repair tips, here:

http://www.arcadeshop.com/galaga/galaga.htm

[Hawk Daddy]

It's 5v thats done been checked.

Hawk

[modessitt]

5.00V?  I've seen some Galaga's that don't like to run unless it's between 5.10 and 5.20.  Don't take it over 5.20, though, as Galaga's can be especially sensitive. 

Try reseating your 3J chip on your Video PC board (if it's socketed) or contact some Galaga repair sites for either a new chip, or for you to send them your board....

[Level42]

http://www.arcadechips.com/product_info.php?products_id=35

Surprise surprise it's the #2 selling item in the RAMs section.

[modessitt]

And for $1.60 a pop, it's worth buying a couple just in case you have another problem with the board and lose the new chip once it's powered up....

[Hawk Daddy]

Ok thanks, I'll order me 2 or 3 of them tomorrow and see if that fixes it.

Hawk

[Hawk Daddy]

What other ram chips would be good to pick up just incase for this thing?

Hawk

[Hawk Daddy]

Well I unplugged the chip and then replugged it and it worked fine for now.  I'll see what happens tomorrow and see if that was the problem.

Hawk

[RayB]

..........................

[SirPeale]

I think he just hit the nail on the head; I wasn't aware that this chip was socketed.  Since he reseated it, it's come back to normal operation.

Press down lightly on the rest of the socketed chips.  You may hear some crackling.  That's normal, the chip going back down into the socket.  It's called 'creep' and it results from thermal expansion and contraction.

Next, get yourself a Pink Pearl eraser (yes, it's an actual brand name, don't settle for anything less) and clean the edge connector on the PCB.  Both sides.  Go *with* the contacts, not against them, or you might peel them off.  Likely you'll see the eraser turning grey or black.  That's the crud coming off the connector.  Make sure you wipe away the eraser particulate.

Finally, check your voltage on the PCB, just behind the harness.  Adjust it to ~5.18V.