Problems with IR Board

[Mark McLeod]

The logic of the board appears to have it step through the learning sequence even if it isn't really learning anything, as evidenced by the learning sequence continuing even with the error LED blinking. It seems to have to recognize a valid carrier signal and will flash the error light on special protocols it cannot handle.

Anyone else learn anything interesting about their IR board?

I'm pretty sure we received a defective board, but until my sack full of remotes can be tested with another board and we find at least one to be effective can we prove it. I've tried it with remotes from more than a dozen manufacturers, and tried it with and without cycling the power after completing a learning sequence. The LEDs flash during learning, but afterwards not even the error light blinks. Ben from Diversified Systems has been helping and said they'd found a bunch of remotes that wouldn't work. e.g., wrong frequency, cable protocol.

Responses vary from:
--Immediately getting an error light (JVC--tv, Toshiba--dvd, Viewsonic--projector, Infocus--cameras, JQA--projector, Tascam--dvd, Tandberg)

--Uneventful stepping through the learning sequence, but no acknowledgment afterwards (Panasonic universal--vcr/dvd/tv,Pioneer--plasma,Barco--projector, Samsung--dvd/vcr/tv, Sharp universal--hdtv)

--No response whatsoever (old Sherwood--stereo)

[Gdeaver]

Sony IR codes where popular with the hobby robotics crowd several years ago. You might want to try several of them.

[ChuckDickerson]

We received ours today and hooked it up tonight but it seems totally dead. We tried a benchtop power supply set to ~13 VDC and a standard 9V battery. No LEDs did anything at all no matter what we did. We checked the power at the board and even connected power directly to the 1&2 (Vin) and 3&4 (GND) input pins on the 10 pin header directly via micro clips to eliminate any issues with the ribbon cable. Is it possible we just got a bad board? Anyone else have this problem? Any ideas how to fix or further test it? Anyone know how we would go about getting a replacement?

[Kevin Sevcik]

DeepWater,

It's entirely likely you've gotten a bad board, but have you checked the voltage out of the voltage regulator while the board has power? If you measure across C4 with negative on the pad closest to the ribbon cable, you should get 5V. You could measure across pins 2 and 3 of the big whit connector with negative on 3 to check as well. Beyond that, I'm not sure what it could be.

[ChuckDickerson]

DeepWater,

It's entirely likely you've gotten a bad board, but have you checked the voltage out of the voltage regulator while the board has power? If you measure across C4 with negative on the pad closest to the ribbon cable, you should get 5V. You could measure across pins 2 and 3 of the big whit connector with negative on 3 to check as well. Beyond that, I'm not sure what it could be.

Good idea Kevin! The board is up at the shop tonight but I will check the 5V output ASAP tomorrow.

[T3_1565]

We haven't tried ours yet, but perhaps your broke in shippment?? Also, what if they were meant to work (ok so its a long shot) does anyone have their's working perfectly???

I'm going to try ours tomorrow!

[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.

[MrForbes]

What voltage were you sending to the board when it fried the regulator?

[keen101]

If your question was directed at me, then here's my answer...



I was using a 7.2v back-up battery.

Doesn't seem very likely that that would fry it.

Static electricity? I was being careful in regards of using it in a static free environment.

My dad said maybe it was half (over) heated when they assembled the board. But, he even had doubts about that. He seems about as bewildered as I am.

[ChuckDickerson]

Yep, that's the problem. The voltage regulator is dead. 9V battery in, nothing out. So, should I:

a) Try to repair it? Implications: We may make it worse!, Is it even legal to do this before build season or even at all?, What voltage regulator should I replace it with and where to get it?

or

b) Get it replaced? Implications: Where do we get a new board?

[Bharat Nain]

It looks like there are a few issues with this. I would HIGHLY recommend letting FIRST know about this ASAP. This way they can hopefully figure out a solution and check to see if there is a pattern with the problems. We are yet to get ours...

[MrForbes]

I was using a 7.2v back-up battery.

Doesn't seem very likely that that would fry it.

Not from overvoltage, at least!

Thanks for the reply....I wonder what's going on....

[T3_1565]

my thoughts IT'S PART OF THE HINT!!!!!! Quick somebody find something out on 5v regulators!!! (:p)

In all seriousiness though We are going to try this

[keen101]

Yes, it does seem strange that almost everyone who has a problem with the board is an issue with the 5v regulator.

Perhaps a design flaw. I shall e-mail someone from FIRST teams, to take a look at this page.

...as for options... I say try and fix it. Mostly because It could be cheaper than shipping it off to FIRST to get fixed. and also because I have no idea where you can get a new one at this time. Maybe try e-mailing IFIROBOTICS.com (http://ifirobotics.com). Besides, you'll probably have access to order a new one from ifirobotics later.

We used something like a L809h. Maybe not a perfect match, but it fixed the board, so I'm not complaining. So, you should probably try and get an L805, otherwise improvise.

Usually I would not recommend trying to fix electronics from FIRST (ie. camera board), but in this case... I have no idea if there any kind of warranty that could be void. I would assume there is no warranty. That's the problem with releasing cool electronics as a game hint. You virtually have no knowledge about the device.

[Kevin Sevcik]

EDIT: Disregard the next paragraph...

I'm thinking this might be an oversight in the circuit design. The 78L05 series of regulators are rated for 100mA max output current. And the IR manual claims the circuit draws 100mA when an LED is on. Granted, that's a transient draw and the things are rated for occasional current peaks above that, but if it's been derated from overheating during the soldering process, then it could be marginal.

Of course, something could have just been shorted while you were testing it or something. At any rate, you should be able to find a 78L05 regulator of some brand at a local electronics shop that actualy carries things like resistors and caps and such. If you can find a 7805 or 78M05 regulator in a TO-220 package it'd probably be hardier, but you'd have to really try to jam it in to the same footprint, and heaven knows if any of this will be legal come kickoff.

EDIT: Whoops! I must have misread the IR manual, current draw is certainly not close to 100mA....

[Mark McLeod]

IFI isn't in the production or supply loop on this IR board yet.

For technical assistance I'd talk to Ben Wrightsman at Diversified Systems Inc. the manufacturers of the board.

For a replacement we'll probably have to go through FIRST.
I have a message in to FIRST and will let you know what I discover.

So far the reported failures are quite small in regards to the 1500+ boards produced, so I'm hopeful it's a less than 1% failure rate. Ben told me they sampled boards coming off the production line and the samples all passed, but not every board was tested due to the time constraints of the Christmas rush. :)

P.S. Based on keen101's experience it does sound as though teams should run these for some time to make sure they catch any marginal failures early.

[keen101]

as far as how mine died... It shall probably always be a mystery.

Maybe something shorted, but I think overheating is more likely. I had been playing with it for over an hour. Enough time to overheat?

Besides... I didn't think anything could short out on an anti-static bag. Who knows, maybe my finger slipped and shorted something. seems dubious though.

[MrForbes]

beeing over 40, I had to take a picture of the part to be able to read the writing on it!

[Alan Anderson]

Besides... I didn't think anything could short out on an anti-static bag.

That turns out not to be the case.

An "anti-static bag" is conductive. It protects against static electricity building up on the bag itself and then zapping something inside it. But exactly because it is conductive, putting a device on top of it is almost like putting a device on a piece of metal. Even if it doesn't short itself out just by sitting there, you can very easily zap it by touching it and having the current flow through the bag to ground.

[keen101]

:eek: oh. ...So it probably was me.


Thanks for the info. I did not know that.

I shall be more careful in the future.

[Elgin Clock]

That turns out not to be the case.

An "anti-static bag" is conductive. It protects against static electricity building up on the bag itself and then zapping something inside it. But exactly because it is conductive, putting a device on top of it is almost like putting a device on a piece of metal. Even if it doesn't short itself out just by sitting there, you can very easily zap it by touching it and having the current flow through the bag to ground.

I would think that FIRST would have put a warning on the datasheet announcing something like this if it were something they expected us to be handling a lot. Not every team has a trained electonics Mentor, and something like this could indeed be looked over if you weren't trained in how to handle circuit boards.

I'm even hesitant in testing this, or doing anything with it till we get the full aspect of what it's used for, but maybe that's just because I've broken a ton of FIRST related parts from the kit in the past and it's my forced cautious nature taking over me now. :rolleyes: :ahh:

[billbo911]

I'm thinking this might be an oversight in the circuit design. The 78L05 series of regulators are rated for 100mA max output current. And the IR manual claims the circuit draws 100mA when an LED is on.

I can't say I agree with this. Here is a quote from the IR board users manual: When a single LED is on, the current should increase to approximately 19 mA.

It also says:
With a single LED on, the power consumption will increase to approximately 228mW.
Which at 12vdc: (228mW/12vdc) = 19mA.
So at least they agree. My guess is that it is not a design flaw, but more likely a user error. (Sorry, I don't mean to point fingers.) I believe it is more likely the board shorted on something, whether it was one of the output wires or the back board. Either way, replacing the regulator "should" resolve the issue.
So far, I have only read about 2 or 3 boards failing, each time it appears to be the regulator. I'm not ready to jump to any conclusions yet. Let's see if a more consistent pattern develops.

[MrForbes]

the board runs at 5 volts, not 12 volts, so 228 / 5 = 46 mA

I put an ohmmeter on a handy anti-static bag, it said infinite resistance....but it's not a very good ohmmeter.

I found the wrappings for the IR board, the same ohmmeter says infinite.

Maybe I'll have to fire up my old Fluke nixie DMM, or go out to the shop and get my old 77....

[www.divsys.com]

As an fyi the Part is
NATIONAL SEMICONDUCTOR
LM78L05ACZ-TO92 IC
VOLTAGE REGULATOR Package TO-92

***I would highly advise not to modify/rework and part of this board before contacting FIRST***

We are working with the group at FIRST and will advise.

thanks,
BMW

[ChuckDickerson]

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!

[Team 562]

Team 562 has no problems with the IR board. In fact, everything has worked smoothly. We trained it to recognize a Sanyo remote control and also hooked it up to a 2004 controller's digital inputs just to see if we could recognize the boards output. It worked fine. I assume there will be a field element that will transmit 4 different codes for some reason and the robot will need to detect the different codes and perform actions based on the different signals?

[www.divsys.com]

That turns out not to be the case.

An "anti-static bag" is conductive. It protects against static electricity building up on the bag itself and then zapping something inside it. But exactly because it is conductive, putting a device on top of it is almost like putting a device on a piece of metal. Even if it doesn't short itself out just by sitting there, you can very easily zap it by touching it and having the current flow through the bag to ground.



Incorrect, the bags are a faraday cage protection. Static shielding bags protect against static charge from both inside and outside. You could only harm a part by inducing static charge to it once removed from the bag.

As far as powering the part while on the bag that would be a bad idea. The aluminum layer sandwiched between the two poly layers could possibly cause an issue if the parts leads dug into the bag. We have seen failures caused by this.

BMW

[T3_1565]

Incorrect, the bags are a faraday cage protection. Static shielding bags protect against static charge from both inside and outside. You could only harm a part by inducing static charge to it once removed from the bag.

BMW

Good to know, I will know place my board back on the package lol.

Our board has been working fine since we got it (and still works fine thankfully) How long did you guys work with it, as I have only had it on for 15 minutes at a time. then I come back on here and post interesting things I have found (like the double remote problem!)

[Kevin Sevcik]

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.

[Elgin Clock]

***I would highly advise not to modify/rework and part of this board before contacting FIRST***

/me Can just see the invisible writing on the typical electronics field wall.
"Opening this case (ie: playing with the components of the board) voids all warranty"
Oops. :o :yikes: LOL

Thanks for keeping in contact with all of us about some problems/concerns raised with the board Ben. I'm guessing we are the "guinea pigs" for this board, so heavy use probably can (and will) find something that representative testing of the boards off the assembly line unfortunately would not.
It's just the way it is.


Welcome to the wonderful (and most times hectic) world of being a first sponsor/supplier. :)
Good luck in the next 4 months keeping your sanity. LOL ;)

[Daniel Bathgate]

I can not make our board work either. I have tried hooking it up to a 9 volt battery and a benchtop power supply set to 9 volts, and have verified that there are 5 volts across C4 and the pins 2 and 3 on the white connector. However, nothing happens when I connect power. If I hold down the "learn" button and connect the battery, none of the LEDs light.

I've paranoidly double checked the polarity every time I've connected it, and since I have been fairly careful, I doubt static has damaged it (though that is always a possibility.) I seem to attract problems sometimes...

---[More fiddling with the edit window still open]---

Aha! Our board DOES work. Just not the LEDs. I checked across the contacts of the LEDs with my trusty voltmeter after entering the setup sequence, and low and behold CMD0 had 5 volts across it. So I tried going through the whole learning sequence, then held my voltmeter to the connector and saw a voltage jump whenever I pressed the button. It works! Either all of the LEDs are bad, or could it be the LEDs are wired backwards? According to the voltmeter, the positive leads (for all but ERROR) are the ones towards the outside, which is the side of the LED that has the little notch and the larger piece of metal internally. If I'm reading the Wikipedia page correctly, it seems they should be the other way around.

That's something I could fix myself, but following BMW's recommendation I won't attempt it. Good to know ours works except for that though!

[Daniel Bathgate]

And about keen101's board:

I put an ohmmeter on a handy anti-static bag, it said infinite resistance....but it's not a very good ohmmeter.

Did the same with my Fluke, and also got infinite resistance. But if I jammed the leads just right into some of the holes the board had poked in transit, the resistance dropped to about an ohm. So if the board got pushed into the bag while it was on, it very well could have shorted out.

[Daniel_LaFleur]

beeing over 40, I had to take a picture of the part to be able to read the writing on it!

Looking at your picture, the part is made by National Semiconductor (thats the funky looking 'N' as the first letter) .

A quick search found a data sheet here ( http://www.national.com/ds/LM/LM78L05.pdf )

While they are ESD sensitive devices, they tend to be rather robust so a little handling should not hurt them very much.

There are a number of things that these little guys dont like:
1: Input power and ground reversed. So watch your polarity when applying power.
2: Voltage on the output being driven higher than the input voltage. This typically only happends with some sort of inductive kick, but ...
3: Applying more than 35 Volts at the input. Some power supplies (especially older ones) may spike when turning on. Check your power supply with an o'scope to see if it spikes (DMMs don't read fast enough).

They can be bought here http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=LM78L05ACZNS-ND

[ChuckDickerson]

For what its worth, I contacted Ben at Diversified Systems and asked about testing the board by bypassing the 5 volt regulator and just powering the board via a regulated 5VDC supply connected to pins 2 and 3 of the white connector. He replied that the PIC will smoke at 5.5 volts but it would be a good test of the functionality of the rest of the board to try it at 5VDC. So we broke down and tried it. Same results, nothing seemed to happen at least with the on board LEDs. Ben indicated that Diversified Systems is working with FIRST to determine how best to resolve the problems so I suspect we will all be getting an email blast from FIRST sooner or later on how to repair/replace/order the IR receiver boards. I guess all we can do for now is wait and see.

Ben and Diversified Systems: Thank you again very much for your support of FRC and the very generous donation. We are all looking forward to learning exactly what it is we are supposed to do with these IR boards!

[ShortBang]

so we finnaly got our board today, but all that would light up was the error LED. we followed the directiond word for word, holding the button before powering up, and letting go after more that 2 sec., and had the Error LED do the instructed Flash once or twice, but never had the 0 LED flash to signal the learning loop.

We also had the board sitting on the anti static bag at one point, but seeing how the error LED light, i doubt we fried it.

Does anybody know if this is a board problem or a user problem?

[billbo911]

the board runs at 5 volts, not 12 volts, so 228 / 5 = 46 mA....

I was quoting the values directly from the users guide provided by FIRST. I agree the circuit past the regulator is run off 5 vdc, but the board it's self is powered by >7.2 vdc to 10 vdc. In the users guide it says that it "assumes" the board is powered by 12 vdc.
Either way, the load drawn by circuit when one LED is on should not exceed the ability of the regulator to power the circuit without failing.

If there is a problem with the circuit, FIRST will find it, maybe with the help of some of us, (Remember the Bane-Bot trannies from last year?) and suggest, provide or publish the solution.

[www.divsys.com]

It appears only <10 of the total qty have had any concerns. I would hold tight to see what is done for any resolution. All of the boards were powered prior to packaging, programming was reserved for teams per the instructions.

BMW

[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

[Ed Sparks]

Looking at your picture, the part is made by National Semiconductor (thats the funky looking 'N' as the first letter) .

A quick search found a data sheet here ( http://www.national.com/ds/LM/LM78L05.pdf )

While they are ESD sensitive devices, they tend to be rather robust so a little handling should not hurt them very much.

There are a number of things that these little guys dont like:
1: Input power and ground reversed. So watch your polarity when applying power.
2: Voltage on the output being driven higher than the input voltage. This typically only happends with some sort of inductive kick, but ...
3: Applying more than 35 Volts at the input. Some power supplies (especially older ones) may spike when turning on. Check your power supply with an o'scope to see if it spikes (DMMs don't read fast enough).

They can be bought here http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=LM78L05ACZNS-ND

Hmmm.....

Says in the data sheet that these regulators have short circuit and thermal protection built in. In other words, given that the power source is within spec, you should not be able to destroy them (no matter what the load). Maybe some were accidently powered up with reverse polarity at some point. I'm leaning toward the explanations in Daniel's list.

[GaryVoshol]

If anyone is going to modify/fix this board, wouldn't the work have to be done AFTER kickoff?

[nautica]

Our team successfully trained the chip today.
All we did was follow the instructions about pressing the buttons.
We were able to light up the LEDs using channel buttons (1-4) on a universal TV remote.

Tally so far:
358: LEDs flash during learning. After, either error light or nothing
456: Totally dead, 78L05 has no output
846: LEDs flash during learning and afterwards when controlled by remote.
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

[keen101]

Heh. Maybe people should start using the numbers that Don supplied as error numbers.


for example: I had a "1357 error" on Wed. :D


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

............

Then again... maybe not. I don't know if it would help or not. :)

[Mark McLeod]

Please focus this thread on issues with the board only.
Can be failures, potential ways to kill the board, or just interesting unreported behavior, such as, getting the LEDs into a chase sequence.:)
Let's assume most of the boards operate normally, and we're looking for that 1%.

I added a thread with a poll where we can report that our boards are working great!

Please don't repeat the talley if you haven't added your team to it. Otherwise it just takes up space.
We're looking for added value.

I'd like to avoid a 1500 post chatty thread of who's board works.

[BanksKid]

no offense but did it ever occur to you guys fiddeling with your board hookup that the ribbon cable is the key to successfull opperation????(ie not frying the board)/it is definatly bad about the faulty voltage regulators....i have no idea about our board.

[Aren_Hill]

Ours was functioning perfectly fine responding as per the pdf guidelines, then some magic smoke came out of the 5v regulator and it now smells funny (this is a mechanical persons diagnosis). So BMW any advice?

[Tom Bottiglieri]

I feel like this is controlled chaos.

[DonRotolo]

I feel like this is controlled chaos.
Controlled?

Regarding 78L05 regulators: They are indeed short circuit protected, but that's only against a heavy short. Draw 150 mA from it for a bit of time and the magic smoke will come out quite easily. Short does not equal Overload. A 78L05 is not overload protected.

Don

[Mark McLeod]

An update...

FIRST exchanged our IR board and the new one works with all the remotes listed in my first post that passed the learning stage.


They drove all the way to my house to drop it off. Incredible service :ahh:
Thanks Andrea and Kate !!!
(door-to-door service not available in all areas :) )

I did try a Sony based on Gdeaver's suggestion, but the model I had was rejected by the error LED. But if at first your remote doesn't succeed, try, try another one.

[Tom Bottiglieri]

I feel like this is controlled chaos.



FIRST exchanged our IR board and the new one works with all the remotes listed in my first post that passed the learning stage.

I guess I was wrong. No cool broken supplies for an engineering project this season.

[Daniel_LaFleur]

Hmmm.....

Says in the data sheet that these regulators have short circuit and thermal protection built in. In other words, given that the power source is within spec, you should not be able to destroy them (no matter what the load). Maybe some were accidently powered up with reverse polarity at some point. I'm leaning toward the explanations in Daniel's list.

Thanks.

The short circuit protection in this chip is a current limiter circuit. That said, the chip wont survive prolonged usage at max current (>140mA).

The Thermal protection is also a short term stopgap measure. The output current is driven by a FET which as it heats up provides lower current. This will slow down the heating process but will still fail if the chip is allowed to continously run at high current.

I've never really had issues with a National Semiconductor chip. They tend to be much more robust that some of the other knock off chips. Makes me wonder if something else on the board is drawing too much current.

[keen101]

Is this going to be a problem when running off our robots on 12 v batteries, and probably at max current for long periods of time?


Will one of those auto-resetting breaker fuses protect this?

[Aren_Hill]

Any advice on what to do if we've fried the 5v regulator?
Should we replace it, or wait for more info from DIVSYS

[Daniel Bathgate]

Update: We reversed the LEDs on our board (with FIRST's blessing), and now it works great. Hopefully backwards LEDs was a fluke limited to our board.

[DonRotolo]

Tally so far:
358: LEDs flash during learning. After, either error light or nothing. Replacement board works fine.
456: Totally dead, 78L05 has no output
1357: Worked, then 78L05 fried. Maybe anti-static bag?
1625: Fried regulator??
2144: Board works, LEDs do not light. Reversed LEDS (with FIRST's blessing) and all is well.
2199: Error LED lights sometimes, not "0" (learn loop) LED

Aren_Hill: So far the advice has been to inform FIRST and NOT to replace it yourself.
Please elaborate: What makes you think the regulator is fried??

Don

[Daniel_LaFleur]

Is this going to be a problem when running off our robots on 12 v batteries, and probably at max current for long periods of time?


Will one of those auto-resetting breaker fuses protect this?

If the boards were designed correctly (and as of now I have no data to support otherwise) then the regulator should not be running anywhere near max current, and therefore should be fine.

The 12V from the battery is well within the specifications for input power for the chip (36V max, 7-15V nominal).

Unfortunately the auto reseting breakers will not protect this device as the smallest of the auto resetting breakers are 20 amps and the board is speced for 100mA max normal usage and 140 mA catastrophic current.

Again, as of now, we've only heard of a few failures. Lets take tallies of whats failed and why. At this point we should still be in information gathering mode and not jumping to any conclusions.

[Aren_Hill]

We visually saw smoke rise from it. and the board appears melted by the back of the 3 pins of the regulator. and after that it doesn't work, so my diagnosis is the regulator fried

[DonRotolo]

Pretty conclusive...

[billbo911]

We visually saw smoke rise from it. and the board appears melted by the back of the 3 pins of the regulator. and after that it doesn't work, so my diagnosis is the regulator fried

FYI, All electronic components use smoke and mirrors. If you let out the smoke, they're broke. If you break the mirrors,.....darn, no rhyme.:o

You get the picture.

[Chris_Elston]

1501 IR board works great out of the box.

[Jim E]

Speculation:

Hmmm. Having not seen the board yet, It does appear a problem exists with the 5V regulator load.

One could measure the resistance between the output pin of the regulator to ground to determine if a short is there before power is applied.

Look the board over closely before applying power. Use a magnifying glass or microscope. Make sure the solder connections are good and sound. A good lead-free solder connection will appear slightly grainy. Any connection a dull, bumpy gray is suspect. Also check to make sure the pins are actually making contact to the pads. Sometimes it looks good, but oxidation or lack of flux will cause an open connection.

Lead-free (RoHs) solder does require higher temps in the reflow oven. Many companies are scrambling to overcome this obstacle. If the part is not designed for RoHs solder techniques, it may not survive. National Semiconductor's new stock has been RoHs compliant for years.

Hopefully, the problem is not in the PCB traces themselves. A short in adjacent traces will be impossible to repair if it occurs in internal PCB layers.

[Richard McClellan]

1501 IR board works great out of the box.
Hmm....I don't quite understand how you are powering your IR board. Is the power coming from one of the IO ports on the Vex controller? The power output is only 5V, so does the IR board still work when the minimum required input voltage is 7V?

[billbo911]

Hmm....I don't quite understand how you are powering your IR board. Is the power coming from one of the IO ports on the Vex controller? The power output is only 5V, so does the IR board still work when the minimum required input voltage is 7V?

Vex controllers are quite similar to the FRC RC. The Vcc voltage out on the Analog in and Digital in/out connectors is +5vdc. The Vcc voltage on the PWM connectors is the same voltage as the backup battery on the RC and the main battery on Vex, both being +7.2vdc.

[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)
:confused:

[Richard McClellan]

Vex controllers are quite similar to the FRC RC. The Vcc voltage out on the Analog in and Digital in/out connectors is +5vdc. The Vcc voltage on the PWM connectors is the same voltage as the backup battery on the RC and the main battery on Vex, both being +7.2vdc.

Well that's good to know. I can't see exactly where the power is coming from by looking at the picture. It really still looks like they're coming from the Analog/Digital IO ports, but I guess they could be from the motor ports.

Chris_Elston, where are the power leads connected?

[Chris_Elston]

Chris_Elston, where are the power leads connected?

I had the power on the PWM servo power 7.2 volts on the VEX as spec'd, but then I decided to try it on the I/O side as you see in the pictures. There is only 5V on that side of the VEX controller. So the IR board works at 5volts....dog gone it...the cat's out of the bag....I didn't move the wires when I took the picture....

I have logged in feet the signal degrading factor using 5 volts, verses 7.2 volts. It's about 0.37 times factor.

[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]

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/index.jsp?summary=summary&techSpecs=techSpecs&currentTab=summary&cp=&custRatings=custRatings&features=features&accessories=accessories&productId=2062599&support=support&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. :D 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]

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]

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/index.jsp?summary=summary&techSpecs=techSpecs&currentTab=summary&cp=&custRatings=custRatings&features=features&accessories=accessories&productId=2062599&support=support&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.

[Deacon Blues]

Has anyone been succesful in getting a replacement board? Ours does not work, and when we took it to our lead electrical mentor, he pointed out several "dirty" solders on the board. We went to our local Radioshack to purchased every 5v reg that Radioshack had, but they were all too big.

Does anyone have a better source for a 5v reg? Is there a quicker way to get a replacement part?

[keen101]

http://www.chiefdelphi.com/forums/showthread.php?t=61650&highlight=keen101

For ours I just found an old 78L05 on some old broken piece of equipment here at school. I salvaged it from that. The board was up and running again in less than a min.

[C64Hero]

After Mr. Lotts and I tried replacing the regulator, we left it alone for a while.

Today, I tried testing our board again, and we got some jumping sparks from the pins of the regulator. This sort of thing didnt seem to happen with the original regulator. Im pretty sure its because the replacement one has to be lifted up off of the board, and attached with a few wires (since its beefier). After that, we imediatly shut it off, disconected the power... and backed away slowly.

Our team leader is suggesting we abandon this messed up board, and get a brand new one.

[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.


"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.

[jmu465]

I like a mail order shop called Jameco. $0.72 each. So Buy some spares...



http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=902291&pa=902291PS

http://www.jameco.com/Jameco/Products/ProdDS/902291.pdf



..... We went to our local Radioshack to purchased every 5v reg that Radioshack had, but they were all too big.

Does anyone have a better source for a 5v reg? Is there a quicker way to get a replacement part?