Subject:
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Re: Smoking serial/charger board...!!!
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Fri, 28 Nov 1997 04:59:36 GMT
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Original-From:
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Keith R. Hacke <hacke@ns.compunetservices.AVOIDSPAMcom>
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Viewed:
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543 times
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I am having a similar problem (see notes below) - R11 is burning on the
serial/charger board. My HB had been on the shelf for a month or so, and
it may have been left on AND I had made the motor-power hack (I tapped the
center of the battery pack to supply the motors' power). This all reminded
me of the note below on a problem very much like this.
I checked the charger-to-HB cable and its correct (cable I have always used).
I think the HB was on when I first plugged in the charger. I soon started
smelling that electronic-burn smell we all hate so much!!! I quickly
disconnected every thing and noticed R11 was brown.
I checked the battery pack - its at 5V. If I try charging via the charge
jack on the HB, the charge LED glows brightly, but R14 on the HB gets very
hot in a few seconds. I also checked to be sure the HB power switch is off
position and I was not connected to the serial/charger board.
I remembered the note below of a similar problem. Oddly, I too had made
the motor power hack. But thats been in for a long time with no problem.
For good measure, I disconnected the jumper cable I had run to the HB's
motor power trace from the center of the battery pack - but no change in
symtombs.
I did not notice any hot caps, as someone else suggested a shorted cap in
response to the other posting of R11 burning.
Any ideas???? Short somewhere?? I disconnect all motors, sensors and
external connections.
Keith
> make sure you have a telephone-style and not network-style RJ11 cable.
>
> Here is how you tell if you have a telephone-style or network-style
> RJ11 cable. Hold the two ends together, metal contact side up, as if
> you were trying to plug them into each other.
>
> Then look at the wiring colors. On a telephone cable, each color
> should line up with itself on the other end.
>
> On a network cable, the colors are inverted.
>
> See the diagrams for clarification. Again, please, please, PLEASE!
> be careful about this and do not use network cables with your Handy
> Board.
>
> -Fred
>
>
> TELEPHONE STYLE WIRING
> +---------------+ +---------------+
> --------+ yellow =======+ +======= yellow +--------
> + green =======+ +======= green +
> + red =======+ +======= red +
> --------+ black =======+ +======= black +--------
> +---------------+ +---------------+
>
> NETWORK STYLE WIRING
> +---------------+ +---------------+
> --------+ yellow =======+ +======= black +--------
> + green =======+ +======= red +
> + red =======+ +======= green +
> --------+ black =======+ +======= yellow +--------
> +---------------+ +---------------+
>
>
>
>
> In your message you said:
> >
> > Well,
> >
> > Today I dig up my handyboard which was working fine with the serial/sharger
> > board and all the last time I used it a few months ago.
> >
> > After a fresh overnight NiCd charge using the onboad power connector
> > (i.e. not using the serial/charger board), I thought I would play with
> > it a bit. That's when the fun started...
> >
> > Upon plugging in the telephone cord between the handyboard and serial/charger
> > board, R11 started to turn darker and literally started smoking... By the tim • e
> > I got around to disconnecting the cord, R12 and LED14 have started to do the
> > same. I guess that R11(47 Ohms 1/2W) burnt out causing a domino effect on
> > R12(47 Ohms 1/8W)...
> >
> > My question is, does anyone know why it's doing this? Right before I shelfed
> > it couple month ago, I made the modification for using less than 9.6V motor
> > (per instruction on the handyboard homepage). But, all was working fine
> > after that (at least I thought so)... I should mention that the two motor
> > driver sockets are empty because I'm still waiting for my TI 754410 (and
> > have been for 2 months)...
> >
> > I have just replaced R11 & R12 and I thought I should ask before I try
> > again... Any clue would be appreciated... Voltage across pin 3 & 4 of the
> > modular socket on the handyboard read 10.2V. The charge rate switch was
> > at normal.
> >
> > TNX
> >
> > --Ron
> >
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Message has 1 Reply:
 | | Re: Smoking serial/charger board...!!!
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| Hi. This evidence pretty conclusively points to a power-ground short on your board. Here is why: * you are fairly certain it is not the RJ11 cable (the most common cause of blown R11's). * when applying charge pwr directly to the HB's charge jack, (...) (27 years ago, 1-Dec-97, to lugnet.robotics.handyboard)
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