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1
Projects, Designs, and Technical Stuff / Re: Corrosion on DIP pins
« Last post by Alex Eisenhut on Today at 02:56:33 am »

I have seen DRAMs fail as well - you can also check a few of the vintage folks (Adrian's basement, 8-bit guy, etc.) comment this as well.

Micron Tech 4164s in the 64 are almost certain to fail. I don't know much about MOSTEK DRAMs.
2
General Technical Chat / Re: Is LinkedIn worth keeping?
« Last post by floobydust on Today at 02:56:21 am »
I mention it because it's funny and shows how social media is so overrated and plastic in a way.
On LinkedIn people showboat- their exaggerated number of connections, their social standing, the fame they are following. I got requests from strangers all over the world and no, I have no idea who you are and I don't pad my number of connections. Some HR person frowns about it, IDK.
My generation cares about merit, not image so I have few connections but each is highly skilled, not fake... is Kardashian Test Equipment Co. on there lol. OK she is.  :palm:
3
General Technical Chat / Re: Relay trigger when voltage above 13v
« Last post by SmallCog on Today at 02:51:17 am »
Sounds, in function, similar to what a traditional dual battery controller would do.

These are sometimes referred to as voltage sensing relays or VSR's

Even if your project is not for this purpose, you may find some useful information in magazine articles for similar projects - it's certainly been a topic covered in our local magazines here and likely will have in others

eg: https://www.siliconchip.com.au/Issue/2019/July/Dual+Battery+Isolator+for+4WD%2C+RVs%2C+Caravans%2C+etc

or this: https://www.siliconchip.com.au/Issue/2020/December/Dual+Battery+Lifesaver

Someone may be able to lend you a copy of their issue of this magazine if required :-)
4
General Technical Chat / Re: Relay trigger when voltage above 13v
« Last post by Ian.M on Today at 02:44:07 am »
TL431, driving the base of a PNP transistor to switch the supply to the relay.  You'll need appropriate base resistors, an anti-parallel diode across the relay coil, and possibly a high value feedback resistor from the collector of the PNP to the TL431 REF pin to add a little hysteresis.  Make the feedback resistor much lower, and once triggered it will latch on, till you momentarily either remove the supply, or ground the REF pin.
5
I would check the VFD's getter has not gone white due to air ingress in the tube.
A '518 output short to another or to ground would heat up the IC and possibly damage it. Look for any solder bridges or just beep it out checking continuity. You can do this with the display in, also ohmmeter the pins to ground, look for shorts.
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Repair / Re: Mig welder wire feeder controller board not working
« Last post by xavier60 on Today at 02:25:24 am »
A little off topic but wire feed related. Since repairing a no wire feed problem with my brother's WIA 250i, it now will stop feeding if an arc doesn't strike within a second of pulling the trigger. Seems to be a feature that has been activated somehow, but no mention of it in the manual. Not a problem in practice.
7
Beginners / Re: 555 driver and Transformer questions
« Last post by DanMann on Today at 02:24:23 am »
to confirm, I attempting to use this power supply for its original intended purpose.

I do not want to replace the power supply as it passes all checks I  am looking to maintain as much of the original parts as possible, such as the vacuum tube rectifier.

I am trying to replace the mechanical vibrator (interrupter) which is the weak link and is shown in the purple box in the diagram I posted in my previous post. 










 
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How does this look to you?

I added a plastic washer under that screw on mine.
9
I recently wrote a simple piece of code that could be helpful to others. Note that the code here needs a little customization to be used. I posted a generic version of it to facilitate such customization. Pretty self explanatory, however, please ask questions if needed. Hopefully it helps.
Best
AL

Code: [Select]

//set pins
const int pinOne = 2; //
const int pinTwo = 3; //
.
.
.
const int pinN = n; // define as many pins needed for as many input signals needed to be validated

//variables
double currentMillis; //the current time in milliseconds (begins count at power on)
unsigned long lastDebounceTime;  //  (miliseconds) the last time the signals were checked
unsigned long debounceDelay;    // (miliseconds) the debounce time

//arrays
#define numSignals N //define array
// INDEX..............................[0].......[1].........[N]............
const int signalPins[numSignals] = {pinOne, pinTwo, pinN,...}; //include  as many pins declared
boolean signalValidation[numSignals]; //validation output (1=valid)
boolean signalState[numSignals];        // current state of the signal
boolean lastSignalState[numSignals];    // previous state of the signal
int highSignalValidationCounter[numSignals]; // signal counter for valid high signals
int lowSignalValidationCounter[numSignals]; // signal counter for valid low signals

void setup() { //system variables initial set values
  lastDebounceTime = 0;
  debounceDelay = 10;//change to suit sensitivity needs
  //arrays initial set values
  for (int i = 0; i < numSignals ; i++) {
    signalValidation[i] = 0; //validation output (1=valid)
    signalState[i] = 0;      // current state of the button
    lastSignalState[i] = 0;  // previous state of the button
    highSignalValidationCounter[i] = 0; // signal counter for valid open or close signals
    lowSignalValidationCounter[i] = 0; // signal counter for valid open or close signals
  }
}

  void loop() {
    currentMillis = millis(); //get the current millis at the beginning of the loop
    signalVal (); //validates input signals
  }

10
I recently wrote a simple piece of code that could be helpful to others. Note that the code here needs a little customization to be used. I posted a generic version of it to facilitate such customization. Pretty self explanatory, however, please ask questions if needed. Hopefully it helps.
Best
AL

Code: [Select]

//set pins
const int pinOne = 2; //
const int pinTwo = 3; //
.
.
.
const int pinN = n; // define as many pins needed for as many input signals needed to be validated

//variables
double currentMillis; //the current time in milliseconds (begins count at power on)
unsigned long lastDebounceTime;  //  (miliseconds) the last time the signals were checked
unsigned long debounceDelay;    // (miliseconds) the debounce time

//arrays
#define numSignals N //define array
// INDEX..............................[0].......[1].........[N]............
const int signalPins[numSignals] = {pinOne, pinTwo, pinN,...}; //include  as many pins declared
boolean signalValidation[numSignals]; //validation output (1=valid)
boolean signalState[numSignals];        // current state of the signal
boolean lastSignalState[numSignals];    // previous state of the signal
int highSignalValidationCounter[numSignals]; // signal counter for valid high signals
int lowSignalValidationCounter[numSignals]; // signal counter for valid low signals

void setup() { //system variables initial set values
  lastDebounceTime = 0;
  debounceDelay = 10;//change to suit sensitivity needs
  //arrays initial set values
  for (int i = 0; i < numSignals ; i++) {
    signalValidation[i] = 0; //validation output (1=valid)
    signalState[i] = 0;      // current state of the button
    lastSignalState[i] = 0;  // previous state of the button
    highSignalValidationCounter[i] = 0; // signal counter for valid open or close signals
    lowSignalValidationCounter[i] = 0; // signal counter for valid open or close signals
  }
}

  void loop() {
    currentMillis = millis(); //get the current millis at the beginning of the loop
    signalVal (); //validates input signals
  }

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