Triac testing / readings ?

Thread Starter

DarthVolta

Joined Jan 27, 2015
447
I took a triac out of circuit to measure it, and followed this guide, http://www.tonyvanroon.com/oldwebsite/gadgets/triactst.htm, the 1st section
My DMM output on resistance is high on the red lead, so I follow the guide, get 93 Ohms both ways, then without touching any metal myself, I get to step 8b and get 93 Ohm again ?? Not OL ?

Here's the triac out of my hotair station, everything else checks out so far, yet it started cutting out for the 1st time the other day.
http://download.maritex.com.pl/pdfs/sc/BTA16-600B.pdf

So I built this Triac/thyristor tester, and I swear I soldered it right, and the LED and diodes are right, visually, mentally, verbally, and not a zener symbol, etc. I built it basically like the actual schematic looks, not the other pic.
http://translate.google.com/translate?hl=el&ie=UTF8&prev=_t&rurl=translate.google.com&sl=es&tl=en&twu=1&u=http://www.soloelectronica.net/thyristor_and_triac_tester.html

TRIAC TESTER.jpg

Yet when I jumpered the left switch SW2, the RED LED went on, and if I jumpered the right side- SW3, the GREEN went on, which is the opposite of the Spanish as far as I can tell. And I checked everything too many times, went away for a while, etc.

Then just now I turned it on with SW2 jumpered 1st, IDK if that matters. I'm only using 19Vpp@60Hz from a SDG2042X. They are 600V rated triac's. They both started flickering, and then they both stayed on. So is it fried or what ?


I have other Triac's somewhere, I better compare them. Oh and with my component tester, see if it can read them, IDR.

The 1 thing i haven't done yet, is try the whole 858d station with the isolation trans, and variac. It might start again. The control board works alone, the heater element reads 15ohm or 30ohms, (IDR). The fan still runs.
 
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Thread Starter

DarthVolta

Joined Jan 27, 2015
447
Hmm I tried the bag of new Triac's, and they also turned on both lights with no switches pressed. I looked at it on the scope, looks pretty normal to me, nothing crazy.

They are rated for a lot lower current tho, so I can't really use them anyways. I need a power meter.

I can try the snubber from the circuit. I can try with a step-down trans. as well
 
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Thread Starter

DarthVolta

Joined Jan 27, 2015
447
I tried with 4.7k alone, then 47R +100nF and still no luck on new triac's. What should my input voltage be ? When it's low enough, it works more like a tester. I used a 19VAC trans but that's too much for those parts, and it lights both. Soon I'll have to get my new scope software running on PC, then I could upload the real images.....nice.

I think the 858d triac is fine, and the whole thing is fine , and it was the house voltages, maybe this wiring is not new. But why didn't it come back on ?? That's a lot of programing, because there's nothing analog for it on the circuit.

But I better try testing the 0V crossing point opto-coupler, the AC side. And the handle sensor, IDK what is in there yet, whatever model I have.

In the handle, "Senor" to GND reads 0.7R, IDK if that's normal or not, I guess it's like the single wire thermo-couple type. and "Handle" to GND is open, I guess a magnetic switch ?. The heater reads 21R.

I've checked all elec.caps, 1 of the 470uF/50V is borderline or over, I should replace it with a 100V cap. The other non-ceramic caps are good.

The BJT's are good. So there could be an intermittent problem, with the op-amp, MCU, or EEPROM, that is soldered/addressed to 000b.


I'd test main's AC stuff a lot more, if I had proper cables, switches, setup on a plank of wood, wire outlet boxes. etc, something solid, not 120V wires loose on my desk. I'll have to make a AC breadboard real soon, I have all the parts I need. Then I can just plug that into the current-limiter/variac/isolation trans, ....as needed.
 
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