Decapping Chips


I wanted to get into decapping back in 2004 when my friend took this die shot of a Channel F ROM through a biological microscope, but was put off by the difficulty. Then I got all fired up about the work done at Visual 6502, and really got inspired by John McMaster's blog. I picked up a relatively inexpensive microscope and a camera adapter, and quickly found out that you need to automate the process of taking all those pictures. So I built an X-Y table from some aluminum stock and two PIC Design linear slides (unlabeled, maybe PB08-10?) that uses two linear actuator stepper motors (Haydon 26363-12) to position the dice under the microscope, then wrote code to control it using a PIC 16F88 microcontroller, using some Sainsmart MD430 stepper motor controllers. I added a 3rd stepper to control the focus; you pan to 3 of the 4 corners and manually focus at each, then the microcontroller calculates the focus while you pan around and moves the stage up and down accordingly. I wired the PIC to the shutter release of a digital camera, and began producing hundreds of pics. When I attempted to stich them into a large panorama, I discovered that that's even more work! Many of the tools seem to have steep learning curves, and the ones that are easier to use seem to have problems with this type of panorama. Microsoft's ICE, for example, looked like it was going to work well, but it keeps doing some kind of color/exposure compensation that pretty much ruins the resulting panorama. [Fix: export as layered Photoshop] And its preview of the panorama looks very good, but the resulting image has geometry issues. I wrote some Python scripts for GIMP to crop images, adjust for uneven lighting, and position the tiles on a large canvas, but they require a lot of manual work. I think my next step will be to use GIMP to crop and adjust lighting, have a custom program position the tiles, then create a project file for ICE with the position info and let it create the final composite.

Update 9/8/2016

Here's my latest setup: I was given a very nice motorized XY table and wanted to control it with trapezoidal velocity profiles, so I bought a KAE PIC-STEP IC. It has direction and step outputs for one stepper motor, as well as limit inputs and general purpose outputs. Since I don't need to drive all 3 axes at the same time, I multiplex the step output to the 3 stepper controllers. I wrote a new control program in C and talk to the chip via an old laptop's serial port. I have a manual tip/tilt stage and a manual rotation stage to level and square up the die before taking pics. I now use Fiji to composite the pics.

Most recent die shots on blog


Texas Instrument Calculator die shots

TMS-1100 MCU die shots

TMS-1000 MCU die shots

TMS-1040: Tomy Break Up

Simon game custom chip and TMS-1000 die shots

TMS-0950: TI-1200 die shots

TMS-0970: Comp IV, Code Name: Sector, Wiz-A-Tron, TI-1250, TI-1270 and Little Professor 76 die shots

TMS-0980: Stop Thief, TI-30, TI Programmer, TI Business Analyst I and Electronic Detective die shots

TMS-1400: Split Second, Bank Shot, Total Control 4, Dark Tower, Astro, Entex Jackpot, Master Merlin and Entex Color Football die shots

TMS-1500: TI-57 die shot

TMS-1980: DataMan die shot

TMS-1990: Little Professor 1978 and TI-1000 die shots

TP-0456: Little Professor 1982 and TI-55-II die shots

TP-0320: TI Business Analyst-II die shot

TMS-1025: I/O expander

TMC-0270: SpellingB and Mr Challenger

Speak & Spell

Speak & Spell Compact

Speak & Read

Touch & Tell

TSI Speech+ talking calculator

SN76477 sound generator IC

COP400 Family: Entex Space Invader, Milton Bradley Lightfight, Funtronics Jacks, Coleco Head to Head Basketball

COPS I MM5799: Mattel Basketball, Hockey and Soccer, National Semiconductor Quiz Kid Racer and Quiz Kid Speller

NEC uCOM4 Family: Fabulous Fred

Motorola MC6805: Milton Bradley Milton

GI PIC 1650A and 1655A: Tandy Baseball, Tandy Basketball, Tiger Rocket Pinball

GI AY-3-8800-1: Unisonic Champion

MN1400: Computer Perfection

Tiger and Konami handheld games (Sharp MCUs)

Mattel Battlestar Galactica Space Alert

6809E CPU die shots

55516 CVSD IC die shots

Williams Special Chip die shots

the Microvision LCD controller

Apple ][ keyboard encoder

Soundblaster CT1741 80C52

Soundblaster CT1341 80C51

Fairchild 3851 (after removing top metal layer with acid) HD View 15000x15000

Fairchild 3851 (after removing top metal layer with acid) JPG 5000x5000

Video chip from Grandstand (PAL Channel F) - EX9111A HD View 12000x12000

Video chip from Grandstand (PAL Channel F) - EX9111A JPG 4000x4000

31290 PSU ROM from cart 3 HD View 16000x8000

31290 PSU ROM from cart 3 JPG 4000x2000

3870 dumps

National Semiconductor DM7880 BCD-to-7-segment decoder/driver


Things I'm working on


Creative Commons License
Except where otherwise noted, content on this site is licensed under a Creative Commons Attribution 3.0 Unported License.

back to Special Chip Info page

back to Blitter Info page

back to Williams Info page

back to Arcade Game Info page

back to Home page