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1
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.
2
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.
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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
  }

5
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
  }

6
Repair / Re: Mig welder wire feeder controller board not working
« Last post by coppercone2 on Today at 02:19:01 am »
I imagine  the degree of porosity added by some oil would require x-ray to find, it must be very minor.

Not that I care, but you know, boeing might be using mig welders for airframe repair or something

But I do have the mentality that a non professional will benefit from the best possible conditions because the work you put out without it being basically a trade job might be so marginal in some cases that the extra steps keep it barely in line. If I can get some extra help from essentially a passive system I will take it, I just don't have the time and inclination to always do a practice bead and stuff that a pro would get paid to do
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I measured via visual and electrical methods, so there is no doubt about my measurements.
Pleaae publish your measuremenets.
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...
   it's the same story as my Chinese made trailer, it will almost meet the stated load but there is NO safety margin.

There's a Chinese EE located near me, running a transformer rewinding business. He's from Shanghai. Many years ago, he told me that
Chinese electronics are made to a price, and they will only just meet spec. (if at all).

He went on to say that, unlike US or EU equipment, Chinese-brand equipment will not have any overload capability, not even
short-term overload.
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Test Equipment / Re: Agilent 54845A Failing all trigger self tests
« Last post by MarkL on Today at 02:13:53 am »
I've been following your progress on this thread, but I can't really add much since I don't have this scope.

However, I will point out that the Agilent 16533A and 16534A scope cards for their logic analyzer line (which I do have) uses the same Logic Trigger 1FJ9-0002 ASIC or 1821-4786 carrier board, and the same Time Base 1SE6-0056 ASIC.  Other scopes from that era also use this chip set.  I'm sure HPAK re-used this design as much as they could.

I think you're right that the Logic Trigger carrier card replaced the ASIC at some point for unknown reasons.  The 16533A/16534A cards also exhibit this change in their lineage as well.  I have some of both types and the behavior and specifications are identical.  However, I don't think the 1821-4786 carrier card is a complete drop-in for the 1FJ9-0002 ASIC because there are other changes in that area on the 16533A/16534A cards between the two versions.

I'm just pointing this out since these cards might be a possible source for ASIC replacements, if you should determine you need one.

I don't want to send you on a wild goose chase since you are working on a completely different device, but I can also say the scope cards have a history of bad resistors, either completely open or wrongly high value.  I've had a couple of bad termination resistors, one of which was on a clock line which caused multiple errors during self-test.

I've also bad resistors on the output setting pins of local voltage regulators that caused the wrong voltage to be output.  In one instance, it was on a regulator used to supply ECL termination networks on the card, again causing multiple and seemingly unrelated self-tests to fail.
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Repair / Re: Mig welder wire feeder controller board not working
« Last post by TERRA Operative on Today at 02:11:50 am »
Yeah, basic, non critical MIG welding on mild steel is pretty forgiving. I never really understood why some people end up with no penetration on their bird-poop welds....

TIG does need a clean surface, but there are welders that provide cleaning settings (AC balance IIRC?) especially for aluminium alloys etc, but nothing beats a pre-cleaned surface.
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