Wednesday, October 2, 2019

Lucky HD647180

We previously dumped some HD647180 and TeamEurope asked if we could do a few more.

The new chips are in obscure gambling machines of which little is known other than a little work on Lucky 74. The boards don't even work, but we hope that a successful ROM extraction could be used to learn more about them.

However, these were in the more obscure SDIP90 package. To truly appreciate their massive size, here'ss one with a DIP40.

We've numbered these C050 to C053. They are the same size as a Motorola 68K, but have a 0.07" pitch instead of 0.1". SDIP90 seems rather uncommon and I wonder if there are any other chips that use this package.

Unfortunately, while we both BP Microsystems and Xeltek make SDIP adapters, we've only seen them to 64 pins.

So TeamEurope helped design an SDIP90 to 27C256 EPROM adapter so that we could use a commodity device programmer. Originally we thought we'd have to solder each chip in, but somehow managed to find an SDIP90 socket.

We proceeded to decap a sample SDIP90 part to try to reduce the following risks:

  1. Organic film over chip can be difficult to remove
  2. Some QFN parts have a wire bonding defect (see previous post)
  3. The SDIP adapter was untested
Early testing also revealed the sample was received protected. Interestingly, it had a similar sticker residue (the sticker itself was gone) to the target chips.

Here's some of an organic layer that wasn't fully removed. It must at least be partially removed to expose the security fuse and allow applying a mask to protect the EPROM. We're not sure what its made out of, but its possibly silicone. Its very chemically resistant but is relatively soft and, if the bond pads are strong, can be removed mechanically by gently tugging on it. More chemical treatment seems to soften it more, so is a delicate balance between prolonged acid exposure (weakens material but can weaken pads) and mechanical force applied to the wires. On the sample we used a mix of white fuming nitric acid (WFNA) and H2SO4 at a relatively low temperature based on some previous notes. This seemed to work pretty well and the sample was processed successfully.

No bonding defects were found.

We applied a UV mask like done previously and cleared the security bit. Fortunately the adapter worked we we successfully dumped the sample! Unfortunately, there are no strings in it, so we really aren't sure what it is.

Anyway, the process was then repeated to successfully dump C051 to C053! Sample strings from Lucky 21-D / C051:

000011d0  13 e1 c1 23 23 10 dc cd  08 06 c9 18 43 52 45 44 |...##.......CRED|
000011e0  49 54 20 49 4e 00 18 43  52 45 44 49 54 20 4f 55 |IT IN..CREDIT OU|
000011f0  54 00 18 43 52 45 44 49  54 20 25 00 18 25 00 18 |T..CREDIT %..%..|
00001200  54 4f 54 41 4c 20 42 45  54 00 18 54 4f 54 41 4c |TOTAL BET..TOTAL|
00001210  20 57 49 4e 00 18 57 49  4e 20 25 00 18 25 00 18 | WIN..WIN %..%..|
00001220  50 4c 41 59 20 43 4f 55  4e 54 00 18 25 53 45 54 |PLAY COUNT..%SET|
00001230  20 43 4f 55 4e 54 00 18  50 4f 57 45 52 20 4f 4e | COUNT..POWER ON|
00001240  20 43 4f 55 4e 54 00 10  50 55 53 48 20 53 54 41 | COUNT..PUSH STA|
00001250  52 54 20 53 57 20 46 4f  52 20 51 55 49 54 00 20 |RT SW FOR QUIT. |

However, you may have noticed we omitted C050 (Lucky 25). We were having some issues removing the organic layer and so did a little more H2SO4 acid soak at a relatively low temperature. While this was fine in testing, it resulted in corrosion on C050 pads. We switched to pure WFNA for C051 to C053, which results in more package wear but, when done properly, is gentler on the actual die. We're looking into options to repair the pads. This would be pretty straightforward with a FIB, but unfortunately don't have access to one. There are also some alternatives under investigation.

Special thanks to TeamEurope for both supplying the chips and designing the adapter board! Finally, stay tuned for AT89C51 glitching post!

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