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  1. dorke

    How to ground unwanted AC from a metal case?

    I looked at the "lcd_enable" code ,it doesn't look right. The state of the "E" signal should be normally low unless you are actually accessing the LCD. For writhing, it is the falling edge of "E" that does the writing. Should be like this: void lcd_enable() { output_low(rs); //is...
  2. dorke

    How to ground unwanted AC from a metal case?

    About the AN7805, Looking at the datasheet (look at the notes on the bottom of each table on almost every page.), You actually don't use the correct values and you should use Ci of 0.33uF and Co of 0.1uF if possible solder them directly on the regulator side you can do it on the bottom of the...
  3. dorke

    How to ground unwanted AC from a metal case?

    Making a Faraday cage doesn't require grounding at all. Surrounding some volume with a closed metallic surface is enough. How good a ground is the (-) of the wall wart is doubtful anyways. Is the side of the TruePunch grounded? The first thing to do is identify the cause for the blown...
  4. dorke

    How to ground unwanted AC from a metal case?

    About the measurments: Please check all the LCD pins. If you have a scope do it with a scope as well , when the μC is accessing the LCD. Look for under-over shots on all the "interface" LCD lines. Did you write the code for the LCD yourself? Can it be you are creating a momentary conflict...
  5. dorke

    Hot air rework tool

    I have the Saike 8858 for about 2 years . I'm not using it on a daily basis, very pleased with it.
  6. dorke

    How to ground unwanted AC from a metal case?

    A lot more info is needed. Could you please show a diagram of your circuit and some pictures(of the wall-wart as well)? What is the ambient temperature of the LCD? Can you measure the voltages AC/DC on the LCD pins? I assume there is a μC in it. What is the physical distance (wire...
  7. dorke

    Looking for Service Manual of AEG LAVAMAT 981 SENSOTRONIC Washing machine

    Schematics or Diagrams are welcome as well. A similar model could help as well. Thanks
  8. dorke

    Old School and stuck on component ID

    Old school? Look at it as the same numerical, no-color code for 3 and 4 digit codes. There are some more codes , here is a nice site including a calculator and video. Another issue is the SMD resistors sizes/wattage. In general ,for ceramic caps SMD is a head-hack,the parts are not marked...
  9. dorke

    Tektronix 465 Not B Service Manual

    Hi Donald, Here you go, 291 pages the full service manual. Good luck, if you need detailed repair help,we are here;)
  10. dorke

    2 motors pushing an object. 1 motor goes bad... other keeps going... object breaks???

    A simple test to check if your p.s is floating : Check the voltage between the (+) and the chassis(at a good connection point) of your PS . if there is 12V it isn't floating.
  11. dorke

    HP3478A Bench DMM... Good for a beginner starting out?

    Welcome to EP. I think this 6 digits precision DMM is an overkill for a hobbyist. I would buy a handheld (much more useful)DMM . A Fluke like the 15/17/77 etc. Here is a used Fluke 115 for less then 70$. Needs cleaning ,but if it is fully functional it is a good buy, it is true RMS. DMM
  12. dorke

    Phono Pre Amp

    Welcom to EP Malcolm. Here is a schematic of the A1(seems to be various mks.) Is it like the one you have? There is the connector CN6(phono PSU) with ±28V, Looks like inserting a phono board requires some mods, read the remarks on the schematic.
  13. dorke

    MAX1747 circuit montage

    Do you know how a charge pump works? It utilizes diodes and capacitors, learn about it here. In the datasheet you attached there is an explanation regarding all your questions , all you need to do is read it ...
  14. dorke

    Clean square waves using a 555 timer?

    My camera has lost it's zooming ability(Old Canon S5). The logo looks like this:
  15. dorke

    Using 2 Sevent Segment to display only 0-15 decimal

    Hop , you have a huge heart, I love you man!
  16. dorke

    Clean square waves using a 555 timer?

    No ,it isn't TI, it is different.
  17. dorke

    Clean square waves using a 555 timer?

    Sure, I found this photo on the web,tried to enhance the logo.
  18. dorke

    18 pin DIL IC SH69P 20C 1217.E 018DU N6SNY-3-3

    It is the first one . A 4bit OTP μC. Here at company site.
  19. dorke

    Using 2 Sevent Segment to display only 0-15 decimal

    Here is a more detailed block diagram. You can use a single 7447 ,if you do , you should replace the "MSB 7447" with logic to show 0 and 1.
  20. dorke

    Clean square waves using a 555 timer?

    The 555 I used isn't a CMOS one it is labeled NE555and is bipolar. The manufacture logo isn't a famous known one.
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