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BS2 is not being detected — Parallax Forums

BS2 is not being detected

oliwicoliwic Posts: 4
edited 2012-03-23 05:59 in BASIC Stamp
HI,
My Bs2 has recently stoped being detected by the stamp editor software. both loopback and echo say yes in the identify window. i am using a brand knew 9v alkaline battery, and a newlink USB to serial adapter to connect my pc to the pcb. is it a problem with the cable, or could my bs2 have been damages, eg by esd? as i say it has worked fine in the past.
thanks

Comments

  • Martin_HMartin_H Posts: 4,051
    edited 2012-03-22 07:01
    Are you using the module in a breadboard or in the Board of Education?
  • oliwicoliwic Posts: 4
    edited 2012-03-22 09:24
    Its not the board of education but is is something similar, its the PCB that came with a book i bruoght: 123 robotics experiments for the evil genius, by Myke Predko, published by TAB electronics. here is the schematic for the bs2 circuit. sorry its not great. the pcb also has a breadboard and +/- terminals for this from the battery. I am using a newlink USB to serial adapter cable, could it be anything to do with this?
    .
    BS2 schematic.jpeg
    BS2 schematic.jpeg
    588 x 548 - 41K
  • Mike GreenMike Green Posts: 23,101
    edited 2012-03-22 09:39
    Overwhelmingly, when this sort of thing happens, there is something wrong with the power source for the BS2 or the serial connection to the PC. Check your battery connections. Check your serial cable or USB to serial adapter. Not all USB to serial adapters can program a Stamp although, if it's worked before, it should work now. The BS2 is pretty robust. It's very rare for one to fail. If you can measure the voltage between pin21 (Vdd) and pin23 (ground), it should be 5V. That would show that the power supply is ok. Loopback and echo show that part of the serial connection is working. It doesn't prove that the DTR line is working.
  • oliwicoliwic Posts: 4
    edited 2012-03-22 10:31
    Thanks for your help, I mesured 0.18 volts between pin 21 and pin 23, and also the EEPROM chip is very hot. Does this indicate a problem?
  • Martin_HMartin_H Posts: 4,051
    edited 2012-03-22 10:36
    The sounds like a short, but in the EEPOM chip. That's a bit weird but I had a capacitor fail and become a short and things stopped working and got hot, so who knows.

    Do you see any bits of metal or solder between the pins? Is the EEPOM surface mount and soldered down or a DIP in a socket? If it is in a socket you could remove it and see if the voltage between 21 and 23 returns to normal.
  • oliwicoliwic Posts: 4
    edited 2012-03-22 14:18
    I cant see any stray solder/metal, and the EEPROM is surface mount.
  • Mike GreenMike Green Posts: 23,101
    edited 2012-03-22 14:44
    It may not be the EEPROM chip. The voltage regulator sometimes comes in a similar looking package. Make sure the Vdd pin isn't shorted to something.
  • Martin_HMartin_H Posts: 4,051
    edited 2012-03-23 05:59
    Good call Mike, a short over heating the regulator makes much more sense.
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