I have assembled my shiny new Peggy and have found that it will not fire up. I have gone through & checked that all compenents are properly oriented, and in the right place. I have populated about 100 LEDs randomly & have cleaned excess flux etc etc. No action, has anyone got some basic troubleshooting tips for Peggy?

Cheers,
Sc0zza

Hi Sc0zza,
Well, "it doesn't work" isn't one that I've heard before. So... not much to go on, I guess. Let's start with the big picture basic questions. Which Peggy version do you have? What power source are you using? What type of LEDs are you using? Do you have a multimeter and/or programmer to help you look for potential trouble?

Thanks,

I'm working with peggy 2. I have DMM, logic probe & arduino cable but no programmer )-: I have double checked all of the obvious trouble shooting stuff but can't find anything obvious. I'll start tracing supply to ICs etc and will post back my results. Have tried batteries and 4.5v from regulated lab supply. LEDs are a garden variety HP unit, very ordinary.

Cheers,

Sc0zza.

Okay, sounds like you're well equipped to deal with this.

It's possible that if you have some particularly dim LEDs, they would not be bright enough for you to see except in the dark-- but that's a bit of a stretch.

Let's assume that something is actually wrong. First, I'd try it with batteries, just for the sake of simplicity. Batteries in, power switch to the RIGHT, check V across the terminals of the battery box: Should be upper right of the battery box at +4.5 V with respect to the terminal on the lower left corner. (Peggy is not reverse voltage tolerant-- the chips are in sockets for a reason!)

Assuming that's good, check that you get Vcc=4.5 V with respect to GND, measuring across the two pins marked that way on the middle left of the ATmega168 (U1). If that's good, check that you get the same thing when measuring across the pins of the chip directly.

Next, check the voltage at a few of the pins to see if the chip is actually doing something: PD4 and PB3, both with respect to ground. Both of these should read intermediate values between zero and 4.5 V if everything is working correctly.

Then, a few obvious things: You *did* install all the parts, and in the correct places, right? Things aren't going to work, for example, if you didn't install the crystal and the correct two capacitors with it.

Finally, is the "Arduino cable" that you have a USB-TTL cable? If so, you might try programming the Peggy and seeing if you can get it to respond.

Let me know what you find and I might be able to help you along a little more.

Ok, here we go.

I have double checked all connections, component orientation, looked for bent pins etc etc. Voltage readings from the uc are as follows.

PC5 0
PC4 0
PC3 0
PC2 0
PC1 0
PC0 0
GND 0
AREF 4.71
VCC 4.71
PBS 0
PB4 0
PB3 0
PB2 0
PB1 0
RESET 4.71
RXD 4.71
TXD 4.71
INT0 0
INT1 0
XCK 0
VCC 4.73
GND 0
XTL1 0.7
XTL2 0.3
OC0B 0
OC0A 0
AIN1 0
CLK0 0

Also tried new batteries! Peggy just won't work for me )-: I hope it's not the uc as I will have to get a replacement sent to me here in Australia!

Cheers,

Sc0zza

Well, that doesn't sound very promising. A few more things to check... If you take the chip out, do you still see the same thing at pins RX and TX?

What is the resistance between CLK0 and GND?

Have you tried programming the chip from the arduino environment?

Also, one possible failure mechanism is that the crystal oscillator isn't oscillating. You might try looking with the logic probe, if you can, to see if anything is actually going on with the chip. (If *nothing* is going on, it may well be the fault of something besides the chip, so it's possible that even replacing the chip wouldn't solve the problem.)

Thx Windell,

0 volts at both TX and RX, open circuit between GND &and CLK0.
I'll go through everything again & check the soldering on the xtal.

Cheers,
Sc0zza.

I'm having some trouble myself, and figured I'd post here rather than starting a whole new thread. I've got a Peggy 2, running on AC power (didn't bother installing the battery box), using the diffused white LEDs (I got the Awesomeness Bundle).

Counting from the bottom, rows 1, 6, 7, 8, and 9 aren't lighting. Arduino programs install and run, although when running the firstdemo, when a diagonal line reaches the dead zone, it sort of jogs to the side and lights up horizontally before jumping the gap, as though the coordinates for those LEDs were being redirected into the last live row, if that description makes any sense.

I've checked my solder connections on the LEDs in those rows, and all the non-LED components, and don't see any problems. I also tried swapping the chips with their neighbors and got the same results, so I guess if the problem is there, it's the sockets and not the chips.

I'm pretty new to electronics, so I'm not sure how to proceed with troubleshooting from there. Are those rows govered by a particular transistor that I should try replacing? Or something?

I have a multimeter, if that helps.

thanks!

Counting from the bottom, rows 1, 6, 7, 8, and 9 aren't lighting.

First off, don't start replacing stuff left and right. That rarely solves problems.

Assuming that you were calling the bottom row is called "1" not "0", that means that the rows you are talking about correspond to rows 16-19 and 24 on the schematics and labeled rows of the display. The rows are controlled by chips U2 and U3, the 74HC154's.

Looking at which binary codes go to the 74HC154's to pick the rows, shows that the pathway from the AVR to the 74HC154's is working well-- if there were a bad line there, the codes that control rows 20-23 would also foul up. So whatever is going wrong is *after* the pins of 74HC154, specifically after the chip in the socket at location U3. So, you need to systematically check connections between the pins of the chip and where the lines are supposed to go-- specifically to the specific resistor and then to the base (middle pin) of the specific transistor for the rows in question.

So, if you look at the schematics (at the end of your instruction packet), you might notice e.g., row 18 is controlled by U3 pin 5. To find pin 5, start at the half-moon end of the chip and count counter clockwise, starting with the first pin that you see (labeled "U3_0" ) which is pin 1 of the chip. On the third page of schematics, note that row 18's signal goes to RB18, and then to Q18 which actually controls the row.

So, use your multimeter to see if you can figure out where your lines are actually connected, and see if you can find where the trouble is. One particular thing to check would be to make sure that your socket are properly seated-- I've seen cases where one or more of the socket pins got bent funny on the way into its location. If things are good, every pin of the socket sticks down below the board to protrude about the same amount.

I am having same problem, the board is not working. I have checked everything over and made sure everything has be connected properly. I have used some of the suggested tips in this post to try and figure out why its not working and now I have hit a dead end.

First off my voltage readouts are different from those Sc0zza got. With respects to GND my PD4 voltage is a constant 1.6 and PB3 is a constant 4.5. For CLK the voltage is 0 and there is no resistance. RX = 1.7 and TX = 0.5

I also I tried uploading a program to the board with a USB-TTL cable and I get an error. Arduino gives me the message " avrdude: stk500_recv(): programmer is not responding"

Any ideas why my board is not working? Is there anything else I need to do to pin point where the bug is?

Thanks for the help.

>First off my voltage readouts are different from those Sc0zza got. With respects to GND my PD4 voltage is a constant 1.6 and
>PB3 is a constant 4.5. For CLK the voltage is 0 and there is no resistance. RX = 1.7 and TX = 0.5

This isn't necessarily telling-- depending on the program that's loaded and whether or not a cable is attached, you might get a different voltages on TX, RX, PB3, and PD4. None of your values seems particularly out of place.

Whatever else may be, it remains the case that 90% of assembly issues are fundamentally soldering issues, so that's still the place to look for a problem. Since you have voltages there that are between 0 and 4.5V, it sounds like there's something actually going on in your chip-- like it's running a program. (That's good.) Since you aren't getting any LEDs to light up, you need to make sure that the other chips and transistors are working as well. Check the orientation and connections to each. PB1, PB3, and PB5 are critical connections for U4 and U5; if any of those-- or the places that they go to on those chips, that will prevent things from working. Similar connections on the left side of U1 go to U2 and U3, and from those two to the transistors.

For each of these parts, double-check the orientation, and make sure that every single pin is sticking through to the opposite side of the board and soldered with a clean joint that looks shiny and wet. Also check-- carefully-- to see if you have extra "solder bridge" connections between things that shouldn't be connected.