Gunslinger 260 problem?

I bought a usedGunslinger and it's not behaving the way I expected. I'm a rank
amateur
but the 250X we used in class was a lot easier to use.
I'm using 75/25 mix, .035 solid wire, and input power, gas flow, ground, etc.
are all
good. It just doesn't short circuit weld smoothly, no matter what settings I
use. It
spatters, arcs, drips, you name it.
When I measure the voltage at the gun (trigger pulled, not welding) I see 39.9
volts at
all settings. While welding (it's really pretty tough to read a volt meter
while welding
at arms length with no helmet) the voltage jumps all over the place.
The local Airgas guy (who's never seen a Gunslinger) says the open torch voltage
should
track the meter. Is this true in general or is it a Miller thing?
Reply to
jimg
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Sounds like you have a bad circuit. Gunslingers are really tough machines, but any machine can blow a circuit. Find your local welding repair shop and ask them to diagnose it.
Reply to
Ernie Leimkuhler
My local Airgas place is 50 miles away and has never even seen a Panasonic. 250 miles to Portland, where they atleast admit such a thing exists.
As an Electrical Engineer, I'm game to figure it out myself, if I can get an answer to the open torch voltage tracking the adjustment question? Can I put a small load on the torch (say a few amps) to make it reflect the setting? I'm just trying to get a head start on the workweek.
Reply to
jimgnospam
answer to the
The open circuit voltage at the torch head should track the power supply setting. It should be the same voltage as at the machine terminals. Why wouldn't it be? There's nothing but a copper cable between them. The only possible way the voltage could differ here would be due to a high resistance, probably a poor connection, or maybe a nearly broken welding cable. But if that were the case, the torch reading would be lower than the reading at the machine.
If the torch head voltage is high, then the power supply voltage must be high, and if it can't be adjusted by the front panel control, that means the voltage regulating circuitry in the power supply is very likely fried.
MIG power supplies are constant voltage supplies. That means they have a voltage regulator in them. That regulator's voltage set point is adjustable by a panel mounted control over a range of about 16 volts to maybe 33 volts. Now it is possible that the regulator needs a load on it in order to function. That's kind of rare these days, but it is possible. A load that draws a few amps should be sufficient to test that theory. An ordinary 100 watt light bulb would do as a test load.
Gary
Reply to
Gary Coffman
I had already started looking for the parts to hookup a 100W bulb. I'm measuring the voltage at the feed rollers, and it's 39.9 regardless of adjustment. I'll see what the load does...thanks.
The circuit board looks pretty low-tech, so I'm thinking I should be able to figure out how it works.
Reply to
jimgnospam
good. It just doesn't short circuit weld smoothly, no matter what settings I use. It spatters, arcs, drips, you name it.
Reply to
Keith Marshall
Zilch control. With a 150W floodlight, it actually increases to 40.5v across the whole range. I guess I should test the potentiometer before I start reverse engineering the board...
250 miles to
answer to the
Reply to
jimgnospam
The Gunslinger can be changed by swapping the cable connection points. The gun is + right now, which I think is right...
On Mon, 05 Apr 2004 02:20:11 GMT, "Keith Marshall"
wrote:
Reply to
jimgnospam
The gun is + right now, which I think is right... >etc. are all
Reply to
Keith Marshall
I have an Oscilloscope, but I haven't pulled out the big gun yet. My manual includes a schematic, but it doesn't include the control board, which is pretty much everything but the transfromer and a few SCRs. I've verified the control knobs work reasonably at the board connection, but I guess I'll wait to make contact with Panasonic tomorrow.
My meter can indicate AC components which it didn't.
I've already downloaded all the datasheets for the components used on the board, so if I can't buy/borrow/steal a schematic, I guess I'll start tracing etch. The board appears to be mostly linear components, which on one hand can be pretty straight-forward, but on the other, can include downright diabolical designs ;-)
On Mon, 05 Apr 2004 03:16:06 GMT, "Keith Marshall"
wrote:
Reply to
jimgnospam
250 miles to
answer to the
Looks like a perfect time for a data logging scope or voltmeter. Put at the inside (if possible) connection to the cable or just to the posts. Then log the tip end trying to do controlled loading.
Just a thought. Maybe you have a DRANTZ logger. Hum. I suspect the earlier comment - high impedance (1.0 ohm not .001 ohm) at the binding post or in the gun. Maybe the cable itself (one or the other) was twisted so much that strands broke. Try a physical feel down the cable for discontinuity. TDR anyone ? :-)
Martin
Reply to
Martin H. Eastburn
...lots of good answers. The Gunslinger 260 is a multiprocess machine (all models?). I'm wondering if you've overlooked the obvious and have it in constant current mode (CC) or else the switch/circuit that changes modes is bad?
Reply to
Zorro
I'll check the switch. It's two pole, and maybe the "logic" pole is bad.
It turns out that the torch voltage is only proper while an arc is drawn, so all the measurements so far are irrelevant. I'm taking the whole thing into town tomorrow where an Airgas guy will meet me to see if it's just my imagination...
Reply to
jimgnospam

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