Search results

  1. K

    Are PICs still being used

    I use PICs extensively too. I cut my teeth on 'em. Check out the enhanced mid-range line, they have some nice features over the older midrange parts.
  2. K

    How to work vintage O-Scope

    From what I can see in the manual that calibration sine wave is from the mains power, so it's 60 or 50 hertz depending on where you are.
  3. K

    How to work vintage O-Scope

    Those are mounting clamps and screws. I found a datasheet for the 5UP1 CRT that scope uses: http://frank.pocnet.net/sheets/137/5/5UP1.pdf It uses electrostatic focusing and deflection, so there is no yoke. To adjust the tilt, you'll have to rotate the entire CRT. Start by grounding the probe...
  4. K

    Designing DC motor with 8051 and transisors

    Circuit 1 uses all NPN transistors while circuit B uses two PNP and two NPNs. Since the H bridge needs the opposite "corners" (Q1/Q4 and Q2/Q3) to be switched on or off at a given time the bases need to be wired differently if you're using all NPNs vs. the PNP/NPN combination.
  5. K

    How to work vintage O-Scope

    This is normal for square waves on an analog scope, since in a square wave the signal transitions from the "high" to the "low" and back so fast the beam literally jumps from one position to the next so fast it doesn't get a chance to illuminate the path in between. You could add a simple...
  6. K

    How to work vintage O-Scope

    Ok, I'll do the best that I can. I don't know what all those things mean on your scope either. :) Starting at the top left in your controls pic, the first knob appears to select two scales of voltage ranges marked 1.5MC and 4.5MC. I'm not sure what those mean or what "MC" stands for, but it...
  7. K

    How to work vintage O-Scope

    Astigmatism adjustment is to get the spot circular. If the spot is elliptical in shape, it needs astigmatism adjustment. You should be able to do it "by eye". You'll need to get the spot to stop sweeping so it stays stationary. Possibly the sync/H sel knob on the right has a setting that'll...
  8. K

    AT25128 Mass Erase / Write Lock

    If you have an I/O pin available,tie WP to it and use it to write-disable the chip when it isn't being written to.
  9. K

    AT25128 Mass Erase / Write Lock

    A quick glance at the datasheet doesn't seem to indicate any opcodes that do a bulk erase of the chip. Barring some faulty code that is writing 64-byte pages of FF to the entire chip, two things that come to mind are: (1) do you have decoupling capacitors in the circuit, near the EEPROM as as...
  10. K

    How to work vintage O-Scope

    Well, start by reading the manual and getting familiar with how the controls work, what they do, etc. Do you have a known signal source to connect to it so you can test the calibration? Looks like the trace is tilted in your pic. Usually the CRT has to be rotated to correct this. There's...
  11. K

    GameBoy Pocket

    The rectangular part to the left of the CPU chip (with the 4.1943 markings) is either a crystal or resonator that clocks (controls the speed/timing) of the CPU.
  12. K

    Jog Wheel Problems- Very Finicky- Repair, Replace, Clean??

    If you can't find a suitable replacement encoder it may be possible to disassemble and repair the existing one. First of all, check and make sure the solder connections to the encoder are good. It could be as simple as a bad solder joint causing your problem and the encoder itself is fine. If...
  13. K

    A little help with voltage regulator basics: Line Regulation

    "Line regulation" specifies how much the output voltage will vary when the input ("line") voltage varies. "Load regulation" specifies how much the output voltage will vary when the load current varies.
  14. K

    Joke components/circuits

    I know electronic geeks can have a great sense of humor, so there's a thread to show it off. Post your favorite joke components/circuits/concepts here. That is, things that don't (normally) exist but are funny to think/talk about. For example: a dark-emitting diode, or for those who have...
  15. K

    Hi, I have a Sony Bravia TV with an amplifier connected to the RCA outs ...

    Check in the audio menu. If your amp/receiver has a remote, why not mute that instead?
  16. K

    GameBoy Pocket

    Does that say DC/DC to the left of that little board on the bottom left corner, next to where it says "U5"? It's probably a DC/DC converter, also known as a boost converter. It converts the ~3V coming from the AA batteries to a higher voltage to power the gameboy. The round thing at the...
  17. K

    LED's turning on if hand crosses area.

    You don't want both a pull-up and a pull-down resistor on the same input since then they'll act as a voltage divider and you'll end up with some voltage in between high and low on the input and your circuit will draw more current and behave unpredictably. You don't need 10k resistors to limit...
  18. K

    LED's turning on if hand crosses area.

    Sounds like you have floating inputs. They are high impedance, so electric fields from your body can trigger the inputs, if they aren't connected to either the power rail or ground, when the switch controlling the input is open. Digital inputs should always be connected to either high...
  19. K

    circuit components

    Each device is marked on the schematic with either a value or a part number. So, for example (looking at a few parts on the left side as an example), you need a 100 ohm resistor, 1K resistor, 2.2K resistor, 100uf 16v electrolytic capacitor, C557B PNP transistor, a couple 4000-series ICs, the IR...
  20. K

    Raspberry Pi V. Arduino

    In short, Raspberry Pi has a more powerful processor that runs Linux. Arduino uses a simple microcontroller that is programmed in C or Assembly. Similar in principle, but they have different capabilities and applications.
Top