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Looks like you’re more on top of this than I am! Yes– do what the diagram says, not what I say. ;)
If you can’t fix it with a screwdriver, then we can send you a new wooden block to go there. You could also glue a piece of wider wood (or metal, maybe a coin?) there to bridge the gap.
(And, thanks for noticing!)In general, it’s a bad idea to re-solder connections unless you have a specific reason to do so. We’ve seen quite a few boards destroyed by unnecessary re-soldering.
You can use your multimeter (with the Bulbdial unplugged) to check the resistance between the different lines. Look at the circuit diagram, and make sure that (for example) the resistance from pin 16 of the chip to control line LED10 is 68 ohms, and that the resistance from pin 15 to LED 8 is 24 ohms. Also make sure that there is high resistance between any two of the signal lines that go to the red board.Yup, that sure looks like it misses! The wood is bit far to the left, and the servo horn is bend the other way a little bit.
If you very slightly loosen the two phillips-head screws on the top, you may be able to move the wooden piece over so that it makes a clean contact. Could you give that a try?There should not be any negative voltage anywhere. So, you may not be measuring what you think you’re measuring. And in any case, there is not a DC voltage that can be measured there; it’s an oscillating signal that you can view with an oscilloscope, but the “DC voltage” that you measure will depend upon several factors including the type of meter that you use.
All of the red LEDs are connected to the LED10 line. So, check that line carefully, both at resistor R10 on the main (blue) circuit board, and its connections on the red ring. Make sure that it’s not accidentally connected (electrically) to something that it shouldn’t be, and that there is actually a connection from R10 to the ring.Which EggBot version are you using?
Please see this discussion:
http://forum.evilmadscientist.com/discussion/320/medium-power-transistor-questionThe Principles of Operation guide (available on the kit’s documentation page: http://wiki.evilmadscientist.com/555 ), walks through how the 555 works in detail, and says what every component does. Without this detailed guide, you’ll likely find the schematic alone nearly useless for debugging.
Figure 1, the block diagram, shows the major parts of the 555 and how they are connected. Look further in for what constitutes each of those parts, and where their outputs are. Can you see a change in the output of the threshold comparator when you change the voltage on the threshold pin? Can you see a change in the output of the value of the trigger comparator when you change the voltage on the trigger pin? By asking these sorts of questions, you can narrow down exactly what parts of the circuit are working, and which are not. If you can’t get the LED to flash, then it sounds like the final output (at pin 3) is not working– but is it just the output circuit that is damaged (or not connected), or something before it?Kid3471,
Once again, please read the documentation. You can test the board at every single intersection between the components, to determine exactly where the error or errors are occurring.If you are not sure that the solder adhered, then you should probably test that first, before trying to hook it up.Hmm. Could well be a hardware issue. I’d ask you to contact us by e-mail, but you already did, so we’ll follow up there.
Thank you again. (And, damn you forum software!)
On the pins that haven’t soldered well, is there solder stuck to those pins already, or is there just bare flux? If there is solder there on one of the pins, try heating the pin for a few seconds, to see if the existing solder melts. You can check (for example) with the tip of a hobby knife or wire, to see if the solder is molten. If there is no solder wet to the pins, but just flux, you might consider scraping at the flux on the pins with a hobby knife to expose some metal. Make sure to hold your soldering iron against both the plated hole on the circuit board and against the pin of the component. Make sure the plated rings on the circuit board around the component pins are still in place. Excessive heating or pressure can damage the board and cause these to delaminate.
Once you finish soldering, I’d advise first testing with a standard test circuit, such as the LED blinker. If you can’t get that to work, double-check your soldering. If things still aren’t working, please read the documentation for the kit, which is extensive, and available here: http://wiki.evilmadscientist.com/555
Using that documentation, you should be able to trace through the entire circuit to figure out exactly what is and is not working, assuming that you have a voltage source and a multimeter.
Thanks! Fixed!
Hi Alex,
Please try the new version uploaded here:Sorry to hear about the trouble, and glad that you’ve got it up and (mostly) working.
Can you say what the “wrong” software was?Since the WCB is losing position control, you should definitely stop and work without a brush until you’ve got that resolved. We have a long guide to troubleshooting WCB issues, up here: http://wiki.evilmadscientist.com/WaterColorBot_TroubleshootingYou may have, for example, extra slack in the cord that is getting caught somewhere, or (if a WCB v 1.0) need to adjust the motor current. If you can which version you have, and what things you’ve checked (on the troubleshooting list), we can help further point you in the right direction.
