Formation Z, Chip ID help.

darthbob1425

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After a year or so out I have finally escaped back to the garage to try and fix up my collection.

I have come across a Jaleco Formation Z board. Overall its looks in good nick apart from a chip smack in the middle of the PCB at 6J. Its a 24 pin chip but the ID has been scrubbed.

Is this a custom chip or not? If it is can anyone point me in the right direction to get hold of one.

Cheers in advance.
 
Never heard of it so I looked it up out of interest. KLOV says it was released by Williams as Aeroboto. May be worth looking at their manual. Layout may not be the same but you may be able to back into the part.

As to the scrubbed off top. I was under the impression some vendors did that to make replication, or perhaps non-Certified repair center work, harder. It may just be something common.
 
AEROBOTO Chip Id

Thanks Brent for the alt board name. I don't know how I missed it on klov.

I've looked at a pic on Crazy Kong and it is the same board and layout. You can see the details on the chip but not clear enough to read.

Has anyone got an aeroboto board who can ID the chip at J6??

Thanks

Rob
 
Sorry. I just found this thread. The Aeroboto manuals I've found on line don't have schematics. I'll see if I can read the chip on my board when I get home tonight.

If I forget, please PM me. I think the heat is frying my brain or I'm getting senile or both :dead1:.

ken
 
They didn't scratch it off, but it was black magic markered. I tried soaking it off with rubbing alcohol. As near as I can make out the numbers on it are: m54821p

The m is iffy as is the 5 but the others are pretty solid. A quick google search didn't turn up a part to match the number.

ken
 
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here is a possibility (54821/74821)
http://www.alldatasheet.com/datasheet-pdf/pdf/143967/PERICOM/PI74FCT821T.html
check pin count and position of supply voltages/ground pin to start with

Also
Possible manufacturers: Mitsubishi Electric (M54821P), or Kenwood (M 54821 P)

Possible datasheet sources
http://www.eca.de/html/M5/M54821P.html
http://www.ecadata.de/ddv/mysuchddv.php?ECA_KEY=M54821P

The 74hct821 sounds like a good possibility. I am not sure why they would need a frequency divider. But on my board pin 3 has been clipped. It looks like it was done intentionally. There is just a solder pad on the board with no piece of leg stuck in it and the solder looks original. It is very hard to rework a chip to look like wave solder. Especially the way most operators solder...:D

ken
 
1. test the voltage between pins 16 (+ve) and 2 (gnd) - if it is a steady 5v then it is prob if it is the frequency divider part

2. test the voltage between pins 24 (+ve) and 12 (gnd) - if it is a steady 5v then it is prob if it is the bus latch part .
it makes sense as a bus latch

testing the bus latch - watch pin 1 and test the outputs at pins 14-23.
- when pin 1 goes HIGH, the outputs should go high impedance (the output pin voltage readings in this state depends on what else is connected to the output pins)
- when pin 1 goes LOW, you should get various diff LOW/HIGH states as the game works

thats all i can come up with for now
 
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