Trouble shooting a Basic Stamp

[Sprintcardriver]

I have a Basic Stamp 2 and it has stopped working. Is there a way that I can test this board and determine what the problem is? I have the bare min. of tools. I also am a beginner in electronic's.

Thanks

Don

[MrAl]

Hi Don,


A couple questions...

Are the IC's on the board plugged in or are they soldered into
place?

Do you know how to solder IC's and other electronic components?

The answers will help provide a solution.

[Sprintcardriver]

It is a basic stamp kit that I put together. The IC's are plugged in. I can solder.

Don [/img]

[MrAl]

Hi again Don,


I forgot to ask if you have a schematic, or you can get one?

The first thing to check is the power supply voltages.
With the unit turned on, measure the +5v supply (if there is one)
and any other supplies that might exist. They should be approximately
within plus or minus 5 percent of 5v (or whatever it is).

For example, a 5v supply should be 4.75v to 5.25v.
Now maybe 4.74 would still be acceptable, but 4.5 is getting marginal
and 4.0v is not good. Also, 5.5v might be ok but 6.0v is not.
Most small regulators can keep the 5v supply between 4.75 and
5.25 so if it's not that something may be wrong with the regulator
and it will have to be replaced, unless a chip is drawing too much
power and then that chip has to be replaced (voltage too low).

One of the quickest ways to test something, provided all the supplies
have been checked out as above, is to replace the IC's one at a time
with new ones. This is low tech but it works and is desirable when
there is little test equipment available. The supplies must be
checked out first because if something is wrong with them then
the new IC might blow out.

Voltage regulators can often be checked by themselves with all
the chips pulled out, or taken off the board, if you suspect the
voltage regulator.

If there is an external supply instead, then you would default to
replacing the chips one at a time. You can feel to see if one
is too hot first too.


These are just some general troubleshooting tips that can be used
for any device usually, however it's good to have a schematic
first so you know what to check and what it should be. So first
if you can get a schematic that would help a lot.

[VernGraner]

I have a Basic Stamp 2 and it has stopped working. Is there a way that I can test this board and determine what the problem is?

You said this is one that you "put together". I would guess this means you built the Basic Stamp II OEM kit shown here:

Basic Stamp II OEM

If thats the case, you're in luck as most of the individual components are socketed and that makes for a quick swap out when you discover the bad part.

As for it "no longer" working, this would suggest that it *did* work at one time and then it ceased to work. Can you tell us under what circumstances it failed? Were you working with it at the time?

Also, we would need to know the symptoms of the failure. For example, is it no longer responding to the IDE when you try to "identify" the chip? Or, is it a circumstance where the stamp receives the code but it not longer operates as expected?

A LOT more detail would help us to help you. In the meantime, a good place to go for support is the Parallax Forums. Parallax employees are there answering questions such as this.

Hope that helps!

Vern

[Sprintcardriver]

VernGraner, you are correct that is the kit.

It was working last week when I was checking motor controls. Tried to use it last night and it was not located by the IDE. Hooked another of my stamps and that one was found. I am using a 9 pin serial cable.

I am using a 9volt battery to supply the stamp.

I am still learning here, so what more info would you need?

Thanks

Don

ps.
As far as the Parallax employees, their support, (or lack thereof) is what caused me to put away all my robotic equipment a few years back.

pss. And this is what drives a noob like me crazy.. I just plugged the stamp in again to check the LM940CT and got voltage. Plugged in the serial cable and the stamp was located and works!!!! ugh!! Why me.. lol!

[VernGraner]

It was working last week when I was checking motor controls. Tried to use it last night and it was not located by the IDE.

A question: when you say you were "checking motor controls", does this mean you were trying to drive a motor from one of the pins on the Basic Stamp itself?

If so, this could have "killed' the chip as the Basic Stamp (or most any other micro controller for that matter) is not designed to drive a motor without some type of high-current buffer (like the ULN2803a) and some back EMF protection (like a clamping diode across the motor coil).

As for troubleshooting, one thing you could try would be possible if you have more than one BSII- OEM board. You could "swap" the PIC 16C57 and see if that brings your OEM board back to life. If it does, you can order a replacement chip from Parallax here.

As far as the Parallax employees, their support, (or lack thereof) is what caused me to put away all my robotic equipment a few years back.

Wow! Thats the first time I've heard that! In my experience, Parallax folks will bend over backwards to help in any way they can. Sorry you had a bad experience back then, but you might want to revist the forums and see if things are better now.

Vern

[MrAl]

VernGraner, you are correct that is the kit.

It was working last week when I was checking motor controls. Tried to use it last night and it was not located by the IDE. Hooked another of my stamps and that one was found. I am using a 9 pin serial cable.

I am using a 9volt battery to supply the stamp.

I am still learning here, so what more info would you need?

Thanks

Don

ps.
As far as the Parallax employees, their support, (or lack thereof) is what caused me to put away all my robotic equipment a few years back.

pss. And this is what drives a noob like me crazy.. I just plugged the stamp in again to check the LM940CT and got voltage. Plugged in the serial cable and the stamp was located and works!!!! ugh!! Why me.. lol!

Hi again Don,

I am happy to hear that you got it working again. From what you
are saying it sounds now like you simply had a bad connection
somewhere and plugging and unplugging might have cleaned
the contacts making it work again. That'a great.
If it happens again you may want to check the connectors to
see if they look solid and clean. I seldom have to replace a connector,
but have had to clean them many times over the years so my first
guess is that they were just a little dirty or even not pushed in all
the way.
Good luck with it in the future too.

Just a side note here, but when i buy parts like IC chips i usually buy
at least two at the same time, in case something unforseeable goes
wrong in the future i always have a spare in the parts drawers.
Dont know how 'critical' this device is in your daily life however,
but i hate waiting for parts to come in, even if it's two days (he he).