Hello,
I was wondering if ther were any more ideas on my CyberTig 300. There is
another post here about it. The welder is running wide open and if you change the range of it, you get the maximum amps of that range.
Innovat checked/fixed the gater board, but that may not be too accurate from what I've been told. Since Innovat didn't have the welder there to check it installed.
Let me know if there are any more ideas, I appreciate the help.
I think it was suggested by someone else, that you should pull the 2CR relay and see if your arc goes down. Have you tried that? If so, what happened?
From ...Cyber-TIG-1a.png above in area B-5, the Gater is shown. On the left side of the Gater are five connections, pins 3, 4, 5, 6 and 11. These are the current setting input connections. On top are pins 1, 2, 12. These are the current feed-back input connections. On the right are the SCR control outputs. If an output goes high, and the SCR it is connected to has a positive voltage on it, the SCR will turn on and stay on until the SCR's input voltage goes down to zero, even if the Gater's control voltage goes to zero. (See : http://en.wikipedia.org/wiki/Thyristor )
The earlier in the cycle the Gater triggers the SCR, the more current goes to the torch. If you are getting full current all of the time, it means that the SCR's are being triggered all of the time, or the SCR's have failed in a condition of a short circuit.
The fault may be in the Gater input, Gater or SCR's. Pin three of the left side pins is the input voltage for the current command. The higher the voltage on this pin the more current. If we can bring this down to zero you should get little or no welding current. Pin 3 is directly connected to the relay 2CR, which controls whether the input setting comes from the Hot Start or the Weld Current control. If you pull the 2CR relay from its socket, you disconnect the input altogether. You should verify this, and I hope others will correct me if I am wrong, but this should bring your current down. If not then either your Gater is still sending out a trigger to the SCR's or the SCR's are shorted.
If you disconnect the Gater output, the SCR's won't get the Gater triggers, so this should bring your current down. You may be able to disconnect the Gater output by removing the rectangular connector on back middle of the controller. One issue with this is that it doesn't take much to trigger an SCR, so you might need to short the SCR gate to ground, so stray voltage doesn't turn the SCR on. Area D-4 and 6 show the SCR's and the connector designation for the terminal strip on the aluminum plate (heatsink) the SCR's are mounted to. Theoretically, you can remove the rectangular connector and short terminal strip connection 12 to 13 and 14 to 15. and if you still get full welding current your SCR's are shorted. I didn't check my SCR's this way. I removed mine, and tested them with my bench power supply set to a very low current limit, so that no matter what, nothing gets damaged. I First checked for continuity with a voltmeter between the big lead and the mounting stud. If you get 0 Ohms, the SCR is shorted. Then, I seem to recall, I put +5 Volts on the threaded stud and ground to the large lead and got no current. Then I touched the small gate lead to the stud and got a current limit light (set to 50mA in this case). When I removed the gate lead the current limit stayed on until I touched the gate lead to ground. Depending on whether you have a P type or an N type SCR you may need to put +5 on the big lead and ground to the stud.
If you try any of this, please post your results. (and of course, _be careful_)
check the rec.crafts.metalworking newsgroup, and ping a guy (or look for posts by a guy) named 'iggy' (or maybe he calls himself 'ignoramus', I can't remember).
or try searching "hobart cybertig iggy" in google. he's an absolute -genius- with hobart cybertigs: rebuilds them, modifies them, redesigns and reconfigures them, rewires them, reverse-engineers them, modifies them to do other things. has a website, too (you'll "get lost in his cybertig area" for hours). I'm pretty sure he's in the upper central midwest somewhere. depth of his knowledge and abilities is simply astounding. and i'm not easily impressed. I never met the guy, but if HE can't help ya, *NOBODY* can.
his site is immense. many dozens (or possibly hundreds) of pages. but only one page, as I recall, has his e-mail link on it, it's 'somewhat hard to find'...I don't even OWN a cybertig ('yet' ;-) but I was in there for -hours-
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