Problems with IR Board

[jmu465]

Later in the thread you say that you powered teh board from the back-up battery... check that the back-up batter is charged. The IR board has a 5v regulator on it so it needs at least 7V to "power up" the regulator.

A dead (dying) battery sounds like a likely villian.

Originally Posted by keen101

"I broke" our board today.

It was working fine, and then all of a sudden.... nothing worked. It suddenly got quiet.



I suspected the 5V 78LO5 was bad, so I asked my dad to help me diagnose the problem. Sure enough the regulator was bad. So my dad helped me find a suitable and more robust replacement. We put in a new regulator, and now it works great again!

...My advice to anyone with a quiet board, is to check the regulator.

[ChuckDickerson]

Originally Posted by Kevin Sevcik

You could measure across pins 2 and 3 of the big whit connector with negative on 3 to check as well.

Anyone have an opinion as to if it would be advisable or not to bypass the regulator and apply a regulated 5VDC to pins 2 & 3 of the white connector to test the remainder of the board?

BTW: Our board was sitting on the anti-static envelope as well when we first powered it up. I have always done such and never knew that to be a problem. If that was the cause then I guess it was my fault. Never knew that to be a problem but I will never do it again, that's for sure. I have emailed Ben at Diversified Systems inquiring about obtaining a repair or replacement. I will post what I find out when I hear back from Ben.

Edit: Thanks Ben. It looks like you beat me to the post!

[Kevin Sevcik]

Originally Posted by DeepWater

Anyone have an opinion as to if it would be advisable or not to bypass the regulator and apply a regulated 5VDC to pins 2 & 3 of the white connector to test the remainder of the board?

BTW: Our board was sitting on the anti-static envelope as well when we first powered it up. I have always done such and never knew that to be a problem. If that was the cause then I guess it was my fault. Never knew that to be a problem but I will never do it again, that's for sure. I have emailed Ben at Diversified Systems inquiring about obtaining a repair or replacement. I will post what I find out when I hear back from Ben.

Edit: Thanks Ben. It looks like you beat me to the post!

If the 12V input were grounded somewhere I think this would be a bad idea. However, since the only ground path available to it is through a capacitor, I don't think it would make anything explode. and since your regulator's apparently dead anyways I don't know that saving it from anything matters much now unless FIRST or Divsys are planning some forensics on it.

[DonRotolo]

I completely agree: IF there really is any kind of problem, I have complete confidence that FIRST and DSI will make it right.

But, WE have to help! By that, I mean this: Unless you are posting a fact, PLEASE label it as an opinion. At the very beginning of the BaneBots issue, there was a LOT of "noise" from people speculating, guessing an just plain writing what they thought was happening, but with little basis in fact. It was not until certain engineering folks started documenting facts using the scientific method (and photographs) that we got to the "root cause" and enabled BaneBots to address it.

Again: Post facts please, not opinion. If you don't know what happened, then just post your factual observations. If you speculate, then label it as such.

Tally so far:
358: LEDs flash during learning. After, either error light or nothing
456: Totally dead, 78L05 has no output
1357: Worked, then 78L05 fried. Maybe anti-static bag?
2144: Board works, LEDs do not light
2199: Error LED lights sometimes, not "0" (learn loop) LED


FYI: Current advice is NOT to repair the board if you suspect an issue, instead report your observations (to FIRST?). The regulator is a 78L05 in the standard TO-93 package, available almost anywhere (even Radio Shack - PM me and I'll mail you one). +5 VDC can be supplie, but the PIC will fry at 5.5, VDC, so try it only if you are really certain of your power supply...

Thanks,
Don

[sayso_411]

Hmmm... thats funny because our IR board worked at first try with a Toshiba TV remote (cant tell but probably something wrong with IR board)

[Wendy Holladay]

does anyone know how to get a board, ours got lost, can you buy them, should i call first or ifi?? any help would be get

wendy holladay
mentor team 1912

[keen101]

Originally Posted by whollada

does anyone know how to get a board, ours got lost, can you buy them, should i call first or ifi?? any help would be get

wendy holladay
mentor team 1912

I'm not sure. I'd like to get a backup one as well.

I may have to start emailing diversified systems, as IFI does not seem to carry them.

[Phalanx]

We had a burning smell and got no response. We used a 9V battery.
We confirmed and doubled checked that the wiring was done correctly.
I did the wiring myself and had it doubled check by another Mentor.

We did find the the voltage regulator was lose when we first smelled it.
So we are assume the voltage regulator is fried, faulty or installed faulty.

SO if anyone knows how to get a replacement, or repair let us know.

[keen101]

you just need to somehow find a replacement 5V regulator and replace the old one.

I recommend using a solder sucker to remove the old one. as for finding a 5V L805 or equivalent... I have no idea where to find one. I just salvaged one from some old board lying around. I looked at Radio Shack, but I did not see any.

I have already fixed our board twice. It was the 5V regulator both times.

It's too bad FIRST did not design the board with a diode to prevent accidental reversed polarity.

[Phalanx]

Is there any major reason that a 7805 From Radio Shack couldn't be used as a replacement voltage regulator?
http://www.radioshack.com/product/in...rt&tab=summary

The only difference I can see that the factory LM78L05 is limited to 100mA and the 7805 from Radio Shack is 1A. Would this be a bad idea?

Thanks,
Michael

[keen101]

hmmm......... it might have been the 7805 one, that I used. I can't remember, and I don't have my board with me right now.

[Richard McClellan]

You'd have to make sure that the pins on the connector would actually fit in the holes for the regulator, but other than that, it should work from an electrical standpoint.

However, I don't know if this would be allowed by FIRST rules, so I would contact them first.

[dlotts]

Our board worked for at least 30 minutes. Then the next time we tried it appeared completely non-functional, with no LED's lighting. Maybe the ground and plus voltage got switched one time, we don't know.

We tested the voltage at the inputs, and they were correct.

Then we tested the voltage across the PIC chip at the Vdd and Vss pins. It showed a consistent 0.36 volts -- way lower than the expected 5.0V. We read the same voltage between the ground and the output of the regulator.

We de-soldered the regulator, and replaced it with a larger 7805 regulator that we had on hand, probably 1 Ampere. We used short pieces of wire so we didn't have to make the larger part fit.

Since we'll probably want to have a second one on hand at the competition, we figured we didn't have much to lose by attempting to repair it.

Then the school kicked us out and we didn't get much chance to clean up our solder and try it.

I'll let ya know how this worked out later.
MrLotts.

[RyanN]

Originally Posted by dlotts

Our board worked for at least 30 minutes. Then the next time we tried it appeared completely non-functional, with no LED's lighting. Maybe the ground and plus voltage got switched one time, we don't know.

We tested the voltage at the inputs, and they were correct.

Then we tested the voltage across the PIC chip at the Vdd and Vss pins. It showed a consistent 0.36 volts -- way lower than the expected 5.0V. We read the same voltage between the ground and the output of the regulator.

We de-soldered the regulator, and replaced it with a larger 7805 regulator that we had on hand, probably 1 Ampere. We used short pieces of wire so we didn't have to make the larger part fit.

Since we'll probably want to have a second one on hand at the competition, we figured we didn't have much to lose by attempting to repair it.

Then the school kicked us out and we didn't get much chance to clean up our solder and try it.

I'll let ya know how this worked out later.
MrLotts.

This sounds exactly what happened to us. Please tell us if you get it working. Also, I called FIRST yesterday, and they said they sent a shipment of the IR boards to Innovation First, and that they should appear some time today. Whether or not this is true, I'm going to keep on eye open for them.

[keen101]

Originally Posted by Phalanx

Is there any major reason that a 7805 From Radio Shack couldn't be used as a replacement voltage regulator?
http://www.radioshack.com/product/in...rt&tab=summary

The only difference I can see that the factory LM78L05 is limited to 100mA and the 7805 from Radio Shack is 1A. Would this be a bad idea?

Thanks,
Michael

If you can get it soldered to the board, then I think it will be fine. I think it's perfectly legal, since you aren't changing the function of the IR board. It is certainly a beefier regulator, but it should work.