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Thread: Can anyone dump surface mount ROMs / MCUs?

  1. Default Can anyone dump surface mount ROMs / MCUs?

    I've got a couple of motherboards from Toshiba laptops. Some of the chips on these are surface mounted -- the font ROM (TC53257) and the keyboard controller (80C49 / 80C50). I'd like, if possible, to dump the contents of these chips, but I don't have the skill or equipment. Is there anyone who can do this?

    I can attempt to desolder the chips myself, but obviously that carries a risk that I'll damage them; so I'm equally prepared to send the complete motherboards.

  2. #2



    The Toshiba TC53257 is a 32K word x 8 Bit ROM, and is pin compatible with both the
    256K EPROM TC57256AD/ADI and the 256K OTPROM TC54256AP/AF.

    The Minipro-TL866 has the Toshiba Part Numbers in the list it can program.

    [ TOSHIBA ] 33 PCS

    TC54256AF @DIP28 TC54256AF @SOIC28 TC54256AP @DIP28 TC54256AP @SOIC28
    TC57256D @DIP28 TC57512AD @DIP28 TC57512AD @PLCC32 TC58FVB004 @TSOP40
    TC58FVB008 @TSOP40 TC58FVB016 @TSOP40 TC58FVB160 @TSOP48 TC58FVB321 @TSOP48
    TC58FVB400 @TSOP48 TC58FVB400 @SOP44 TC58FVB641 @TSOP48 TC58FVB800 @TSOP48
    TC58FVT008 @TSOP40 TC58FVT016 @TSOP40 TC58FVT160 @TSOP48 TC58FVT321 @TSOP48
    TC58FVT400 @TSOP48 TC58FVT400 @SOP44 TC58FVT641 @TSOP48 TC58FVT800 @TSOP48
    TC58FVT800 @SOP44

    If you are using Linux there is a patch for the TL866 for running in Wine under Linux:

    I've also just purchased the KEE Willem PC6.0 ver E LPT Programmer and have just finished getting it running
    in Wine on Debian 8.x & 9.x in Wine. I know it works to read a 27C512 EPROM.


    There is a product called ChipQuik carried by in Phoenix that is supposed to
    help in the SMD IC Removal. They also have the Lead Free Removal Alloy in 4.5N, 8N, 16N, and 32N. I'm not sure
    exactly what the differences are in those various products. I plan on getting over there this coming week to find
    out more information on these associated products. There are Video's on Youtube describing how to use ChipQuik.

    Another option would be to use an Arduino Mega 2560, and wire the IO to the Address & Data Lines of the EPROM
    to read the data. I've done this before on a Character Generator and used srecord in Linux to strip the PULLED UP
    BITS that needed to be masked. I documented what I did in detail and I finally located it:
    I used an Arduino Mega 2560 to read my TRS-80 Model 1's, G with Ver 1.3 ROMS, Character generator into hex bytes.
    The Arduino has PULLUP resistors enabled on the Data lines which makes the MSB (xxx11111) incorrect.

    Here is an example of the data:

    This requires each data byte to be ANDED with 0x1F to mask the PULLUP's incorrect data.

    Since I use Linux, I knew that this was a prefect job for srec_cat. srec_cat is an invaluable tool that
    can manipulate the ROM data accordingly.

    For more information in Linux, use:
    man srec-info
    man srec_cat

    The URL's of:

    give more information on the data types, and the command specifics. There are also lots of examples.

    I started by letting srec_cat & srec_info try to detect the file's data type. I knew the data was HEX bytes.

    srec_info 6670tst.rom -nh -ignore_checksums
    finds the correct data:
    Format: Needham
    Data: 0000 - 03FF

    The first four lines of data from the MCM6670.txt:

    shows the data has pullup resistors on the three MSD bits ({5..7}) and needs to be ANDED with 0x1F.

    This command will do exactly what I need:
    srec_cat infile -nh −and 0x1F −o outfile -nh -ignore_checksums -data_only

    Now the actual data is:
    00 1F 11 11 11 11 11 1F 00 1F 10 10 10 10 10 10
    00 04 04 04 04 04 04 1F 00 01 01 01 01 01 01 1F
    00 08 04 02 0F 04 02 01 00 1F 11 1B 15 1B 11 1F
    00 00 01 02 14 18 10 00 00 0E 11 11 1F 0A 0A 1B

    The first eight bytes are Character #0 and the next eight bytes are Character #1.
    This site states that the MCS-48 adapter can be used with the Willem EPROM Programmer to Program lots of the 8 Bit Microcontrollers:

    I'm using a Willem programmer, with some mods on my own, and the corresponding MSC-48 adapter.
    It handles the whole family: ROM (8048, 8049, 8050), OTP and EPROM (8748, 8749).
    It's a convenient device which also programs a wide range of EPROM's EEPROMs, Flash, Dallas (RTC's)... and serial devices: PIC's, I2C, SPI, Microwire...
    Only drawback is that you need a parallel port (farily scarcy nowadays) to connect it to your computer.
    The Documentation at tells how to read the ROM Contents on Page 11.

    And my KEE Willem PCB6.0 E LPT EPROM Programmer supports the MCS-48 Adapter required to read those Controllers. I just don't have
    the MCS-48 adapter.
    ROM (read/verify)
    P8048AH, P8049AH,P8050AH, P8042AH Vea = 12V
    P8041, P8042

    OTP (read/verify/Progam)
    P8748,P8749H,P8742H Vea = 18V

    EPROM (read/verify/Progam)
    D8748,D8749,D8742,D8741, D8742 Vea = 18V
    Let me know if I can be of more help.


    Last edited by ldkraemer; December 2nd, 2017 at 07:05 AM. Reason: Added more information

  3. Default

    I've got a Willem programmer that is able to read through-hole DIP versions of 27xxx-type ROMs and 8048-type MCUs, so that part isn't a problem. What I don't think I'd be able to do reliably is (a) get SMDs off the board with all their legs intact, and (b) make the electrical connections between the SMD and the programmer. I tried a socket adaptor on one chip I did manage to desolder; it didn't produce usable results and I ended up breaking the A8 pin off the chip trying to get a better connection. And I don't fancy my chances of soldering a surface-mount chip to a converter PCB without shorting all the pins together. That's where I need outside help.

  4. #4
    Join Date
    Jul 2009
    Central Florida


    Do you have a picture of the chip in mind? If so could you post it please. Would like to see the pin density. Also where are you? depending on the density I might be able to help out. Soldering them is easy removing can be a bear!

  5. Default

    Here's a picture of one of the boards: . I've highlighted the character ROM and the keyboard controller, which are the chips I'd like help with. The chips on the other boards are of similar pitch.

    I'm in the UK.

  6. #6
    Join Date
    Jan 2007
    Pacific Northwest, USA
    Blog Entries


    There do exist SMT test clips (Pomona has a bunch) that should eliminate the issue desoldering the chips; however they're not cheap.

  7. Default

    Even with a test clip, the chip would need to come off the board, surely? If the chip's Vcc line is still connected to the PCB, that means the programmer's going to be feeding power to the whole PCB and cause all sorts of interference.

  8. #8
    Join Date
    Jan 2007
    Pacific Northwest, USA
    Blog Entries


    Maybe, but it might be worth a shot just to see.

  9. #9


    Yes, the +5VDC could be a problem. But, to get around that, what if you used a +5.0 VDC LAB Power Supply to furnish the +5VDC, and
    then did not connect the +5VDC Pin on the IC to the EPROM Programmer. That would isolate the Programmer from the Motherboard's
    Power. Then if you found the Crystal or Resonator for the CPU, it you could unsolder those two points, and the CPU wouldn't have a Clock
    Signal to run the CPU.

    At this point an Arduino or EPROM Programmer should be able to read the IC's contents properly, assuming you can get the total pins
    minus +5VDC wired to the EPROM Programmer or Arduino Mega 2560. Sketches are available for reading IC's. I've got a couple, and
    I've used one to read my Model 1's Character Generator.

    Would you happen to have the Schematic for the Laptop Motherboards? What Model Number are they? T-5100 or T-5200?
    Maybe I can locate a Schematic if I have the Model Number.


    Last edited by ldkraemer; December 10th, 2017 at 04:52 AM.

  10. Default

    T1100+ and T1200. These ROMs aren't the BIOS ROMs though, they're the font ROMs for drawing the display, so it would be some part of the video hardware that would have to be disabled. And again, we're moving out of my area of expertise.


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