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Fried 2 chips in 3 days. The first, my fault, the second - ???? - Page 2 — Parallax Forums

Fried 2 chips in 3 days. The first, my fault, the second - ????

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  • W9GFOW9GFO Posts: 4,010
    edited 2009-04-18 02:12
    Michael O'Brien said...
    ...I went through your diagram and I am unable to see anything wrong with your layout. ....However I have found that the power capacitors are very important or you will see the power line harmonics higher than 3.3v causing the propeller chips to fail - but recover in a fixed circuit.

    Michael, do you mean the same chip that fails in a breadboarded circuit would function correctly when put into a PCB?

    Thanks for checking the diagram.

    Rich H
  • W9GFOW9GFO Posts: 4,010
    edited 2009-04-18 02:14
    SRLM said...
    Can you try the prop and EEPROM in another setup? Something like the PPDB or another known good board that takes DIPs.

    The only other boards I have are proto boards. I do have the two breadboards and the chip fails on both. Someday I'll get a PPDB.

    Rich H
  • W9GFOW9GFO Posts: 4,010
    edited 2009-04-18 02:19
    microcontrolled said...
    I once seemed to have a strange problem with my prop. It would run for 3 seconds and then enter a reset. It would repeat this over and over again until I had the "genius"
    idea of changing the battery. This solved the problem instantly.

    This is a dumb suggestion but check your connections going to the output devices. Sometimes you can have a problem with what is on the outside and not what is on the inside of the chip.
    Say you have a damaged resistor. Yes; it is rare but it is possible.

    I have learned the bad battery problem with the BoeBot, spent way too much time trying to solve it before changing the battery!

    The only outputs devices so far are the LEDs, if a resistor was shorted the LED would still light. I checked anyway, they are all ok.

    Rich H
  • Michael O'BrienMichael O'Brien Posts: 55
    edited 2009-04-18 02:29
    Hi, I have found that the dip chips are not harmed by an improperly capacitated power supply setup.
    Since you have proto boards, a good test will be to tie the 3.3v and gnd lines directly from the rails at the top of the board to your breadboard (disconnect all your power transistors and capacitators on the breadboard.
    The protoboard can drive a number of extra propellers and leds - no problem upto at least .5A.
    So if your protoboard is working then at least you know it is not your supply.
    Then connect pins 29 and 28 from the protoboard to your dip and reset your dip prop (see thread on daisy chaining props off one eeprom) - you will then know if it was a problem with your eeprom on the breadboard.
    /michael
  • MicrocontrolledMicrocontrolled Posts: 2,461
    edited 2009-04-18 12:22
    I have had the problem on the Boe-Bot too. Is there anything else on your breadboard that could be drawing too much current away from the chip?
    For example: if you had the rare problem of a bad capacitor it could be short circuiting your power supply and you wouldn't be getting enough current.
    There could also be a problem with one of your power rails. It could be cut or broken right after you connect it to Vss of the Propeller.
    There is always a possibility that you inserted the LED's wrong, make sure that the minus probes are in the Vss of the power rails. That is, unless they are supposed to
    pull low to activate and high to turn off. Did you write the test program yourself? It could be doing the low-for-on-high-for-off deal and you could have wired it for the other
    way around. Check under the board and make sure(if the underside is exposed)that it is not sitting on a piece of medal that is short circuiting it. It is odd that it is
    detected by the compiler and yet still does not work. This makes me suspect that the problem is coming from an external source.

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  • MicrocontrolledMicrocontrolled Posts: 2,461
    edited 2009-04-18 23:16
    Have any luck yet? (Everybody seems to have abandoned this tread this Saterday!)

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    Robots are microcontroled.
    I am microcontrolled.
  • W9GFOW9GFO Posts: 4,010
    edited 2009-04-19 02:51
    microcontrolled said...
    Have any luck yet? (Everybody seems to have abandoned this tread this Saterday!)

    I've been out all day, but no, no luck yet. At this point I expect no answer as to what happened to the chip. I am certain that it is broken because it was working in the other breadboard before switching it to the new one. Now it won't work in either breadboard. All wirings and components have been checked more times than I care to say, not one error has yet been found.

    My only guess at this point is that perhaps there was a loose power wire on the breadboard when I first tried to run it. After it didn't work I went around the breadboard making sure all wires were pushed in. I don't recall any being particularly loose but there could have been one. Would that blow a chip? I think someone indicated that it could. But still, why then would the program load? It's very perplexing. confused.gif

    I should have a new chip on Monday. If I blow that one... shocked.gif

    Rich H
  • MicrocontrolledMicrocontrolled Posts: 2,461
    edited 2009-04-19 22:13
    Well, I wish you luck then. If it still doesn't work than you know that something is wrong with your breadboard. It is a shame that you ordered a new one; I was going to offer to send you one today for free. (No one else jump on this offer, ok? smile.gif )

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Toys are microcontroled.
    Robots are microcontroled.
    I am microcontrolled.
  • W9GFOW9GFO Posts: 4,010
    edited 2009-04-19 22:53
    microcontrolled said...
    Well, I wish you luck then. If it still doesn't work than you know that something is wrong with your breadboard. It is a shame that you ordered a new one; I was going to offer to send you one today for free. (No one else jump on this offer, ok? smile.gif )

    Well... I do still need to order another one (or two - or three), I have two Propellerless breadboards now. smilewinkgrin.gif

    Rich H
  • MicrocontrolledMicrocontrolled Posts: 2,461
    edited 2009-04-19 22:59
    Unless you are like, really poor, you should order at least 2 props every time you place an order and you have none. I have three, and I also have breadboard problems with them sometimes. (I have a cheap breadboard) but I was going to just send you one to experiment with, so you could find out if the problem was with the Prop or with the board. If you need one, though, PM me and I will ship you one.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Toys are microcontroled.
    Robots are microcontroled.
    I am microcontrolled.
  • W9GFOW9GFO Posts: 4,010
    edited 2009-04-19 23:21
    Thanks for the generous offer but I will be putting in another order soon anyway. And I will order more than one!

    Rich H
  • MicrocontrolledMicrocontrolled Posts: 2,461
    edited 2009-04-19 23:24
    Thanks!! I thought I would have to abandon my idea for a Tri-prop gaming system!!
    (just kidding) smile.gif

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Toys are microcontroled.
    Robots are microcontroled.
    I am microcontrolled.
  • W9GFOW9GFO Posts: 4,010
    edited 2009-04-21 00:10
    I am pleased to report that the new chip works fine in either of the breadboards. smile.gif

    Thanks to all that helped troubleshoot.

    Rich H
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