2214-40ML: Flash from the bore, but thats it... Any hope?

[Hemlock_Mike]

Most of these lasers have a main power switch for warm up and a key switch to lase. The tube should glow bright fillament orange inside before the key is turned on.
Do you see the fillament glow? not plasma ...... This is long before the trigger pulse fires.
HMike

 

[daguin]

The fillament is the cathode. That's why the high current needed.
1. When you turn it on, does the cathode light up like an orange light bulb down inside the tube at the rear? It has to get hot like an old radio tube in order to be an electron emitter. This part is old school.
2. If it doesn't light the fillament (cathode), it might be a small break and tapping the tube gently (with the key switch OFF and power on) while rotating the head around may weld the break together restoring fillament current. Also an old school trick. Don't turn on the key while doing this, you are just trying to restore a small broken connection.

All this only if there is no fillament light.

HMike

This is the style. The tube is almost all metal with a small exposure of ceramic near the center. There is no glass or ceramic exposure at the rear. I don't know if you could see the cathode warm-up or not anyway

Peace,
dave

 

[Hemlock_Mike]

Usually, the cathode heats up enough to see it through the ceramic or " looking down the bore" . I don't recommend this unless you know the laser is disabled.
One can also monitor fillament current and see if continuity can be re-established. If the tube has loose parts this is a no-go.

HMike

 

[Dr_Evil]

Just an FYI, you can see an orange glow at the back of the tube with the key off if the filament is working.

 

[Cyparagon]

Yes, if the cathode is glowing, you would be able to tell by looking down the bore. But if there's no continuity, that seems doubtful. Maybe if you give up, you can tear open the end bell and have a look.

 

[Experimentonomen]

Or take the previous tip, shaking and hitting the tube with filament power on and see if you with a bit of luck could get the filament to weld back together.

I´d try as you have nothing to loose anyways, tho when a filament does open up its usually cause its worn out and will likely open up in another location within a few hours.

However if you decide that the tube is a total writeoff you could always put the psu for sale as there are ppl looking for ArIon psu´s.

 

[HIMNL9]

Have you considered the possibility that something put the PSU in protection mode ?

I mean, when you said that the glow last for half second, and then not reply until you power off the PSU and then on again ..... perhaps that something, in the tube or in the PSU, send a "fail" signal to the protection circuit, that cut off the power until you turn it off, resetting it ..... just an idea ..... cables, connectors, wires, all checked and ok ?

 

[diachi]

Yes, if the cathode is glowing, you would be able to tell by looking down the bore. But if there's no continuity, that seems doubtful. Maybe if you give up, you can tear open the end bell and have a look.

I like this idea, but my only concern is the existance of any BeO dust inside the tube. I doubt there would be much, but there could be some. It's not something I'd want to go near when it's in powdered form.

If you do tear it open, please post pics. I'd LOVE to see the insides of one of these!

 

[DJZ]

How are you measuring continuity of the filament? At the end of the umbilical or right at the cathode where the cables attach to the tube? I've not heard of a cathode breaking so easily, but from what you've said, the tube is mis-aligned which means it may have been dropped. Even if it doesn't sustain discharge, the start pulse alone should give a beam from the laser, if the mirrors were aligned. If you measure continuity again, try checking from either side of the filament to the cathode. It should be open. Curious to see if the filament broke off of one side and is touching the cathode.

 

[diachi]

How are you measuring continuity of the filament? At the end of the umbilical or right at the cathode where the cables attach to the tube? I've not heard of a cathode breaking so easily, but from what you've said, the tube is mis-aligned which means it may have been dropped. Even if it doesn't sustain discharge, the start pulse alone should give a beam from the laser, if the mirrors were aligned. If you measure continuity again, try checking from either side of the filament to the cathode. It should be open. Curious to see if the filament broke off of one side and is touching the cathode.

What are you on about? The filament IS the cathode. But you are right, if you haven't already it would be best to measure the continuity directly at the filament pins and not at the umbilical. I doubt that the issue would be with a broken wire, since that wire is such a high gauge. But it could be a bad connector somewhere. Or the cathode might not even be connected.

 

[DJZ]

What are you on about? The filament IS the cathode.

Well, yeah, sorta. If you consider one bell end the anode and the other bell end the cathode, then it's not. The two pins that stick out of the cathode side obviously is the connection to the filament, if you meter either pin to the end bell, there should be no continuity, if there is, that's a problem! If he is metering the filament pins and it's open, then the thing must have suffered a rather serious drop. Unless of course the hour meter is incorrect and it's a high mileage tube.

Edit- Hopefully, it's just not connected internally. I've also seen where the spade terminal lug that connects the wire to the filament pin breaks down under the high current load. When it starts to form a resistance, it can really eat up the wire and the connector itself and eventually fail completely. All that would be required, hopefully, is to replace a bit of wire and the terminal lug. It just so happens that I did this to repair a Reliant 1000M last week. I'll add a pic later if interested.

 

[ElektroFreak]

What are you on about? The filament IS the cathode. But you are right, if you haven't already it would be best to measure the continuity directly at the filament pins and not at the umbilical. I doubt that the issue would be with a broken wire, since that wire is such a high gauge. But it could be a bad connector somewhere. Or the cathode might not even be connected.

Are the umbilical wires stranded or solid? On mine the umbilical is so stiff that it seems like the wires are solid, but stranded would be far more durable.

 

[diachi]

Are the umbilical wires stranded or solid? On mine the umbilical is so stiff that it seems like the wires are solid, but stranded would be far more durable.

They are stranded IIRC. Bare in mind you have both cathode leads, each one is a doubled up high guage wire. Then you have all your other leads for the anode and starter plus whatever else. There is also the outer sheath which seems to be pretty stiff and durable even on it's own.

 

[aryntha]

I measured right at the pins/lugs at the back of the tube, essentially each side of the filament. No continuity. I'll compare this to my other 2214s and see if there is continuity there. (should be.)

 

[diachi]

I measured right at the pins/lugs at the back of the tube, essentially each side of the filament. No continuity. I'll compare this to my other 2214s and see if there is continuity there. (should be.)

I sure hope you have continuity on the other ones, otherwise you've got some pretty strange CW argons!

Looks like it's dead then if you've got no continuity ... Do the pins perhaps look oxidised?

 

[aryntha]

Un. Freaking. Believable. I just got two more 2214-40MLAM heads from Fausto, who posted them for sale in the buy/sell/trade forum this week... Took the chance, got burned AGAIN.

*BOTH* are dead.

Head #1, the "weak" one -- just click,click,clicks; never lights.

Head #2 -- Lights, but nothing but a purple discharge glow. No lasing.

Another $300 down the drain, just like that.

I don't suppose there's any hope for either of these? The newer one was serviced by Evergreen Laser 06/11/08. Could it be mirror alignment? And if so, is that at all fixable?