Opinion on Dying Epilog - tube or motherboard

[Bruce Clumpner]

I'm looking to the collective mind for opinions on what's happening to my mini. I'm working out of the house/shop now so I have not had the chance to contacted support with this latest issue while I can sit over the machine. So I thought I'd poll the members before I start digging into my wallet.

My mini-18 35 has been losing power slowly over the last year or so. It's a used machine and when I bought it I was cutting 3/16" plex all day at 6-speed and 100-power. Now I'm down to 3 speed and can't cut longer than 20 minutes without it shutting down. I'm seeing a cycling or rhythmic pulsing in the power as it starts to cut a sheet. The glow of cutting the backing paper fades between bright and nothing in about a 1 second cycle. There is also small uncut bridges left one the first couple of pieces at a regular interval.

I just replaced the I-rail on my x-axis and when talking with Epilog, ran the 75-dpi test on a piece of aluminum. The result showed the tear-drop shape of the "dot" which support says is an indicator of the tube going. So that's something definite.

I'm also concerned with the system shutting down. It seems to be a heat issue, but last night was not too warm and it only lasted 20 minutes of vector cutting. But it can run all day in raster mode.

So my question to the forum is... from your collective experience, are these symptoms of a tube failure, the motherboard or both? How painful will this fix be?

Thanks in advance Oh Great Laser Collective!

[Joe Pelonio]

Those were the exact same symptoms I had when my first tube went out.

[Steve Clarkson]

I'm worried my tube is going too......what's the 75 dpi test?

[Bruce Clumpner]

Steve,

The 75DPI test is to run a full black square on a piece of Anodized aluminum at 75dpi, this results is a square of dots as the machine can't fill the square at that resolution. It shows if the laser is running straight ( which is why I replaced my I-beam) and how "coherent" the laser pulse is. My laser showed a "tail" on the dots toward the end of the square (right side) and tech said that was an indication of some sort on the condition of the tube.

[Bruce Clumpner]

Thought I'd share the response from Epilog support...

After describing the symptoms and how the laser is cutting, they confirmed that it was the tube. The reasoning behind it was that there may be a short in the tube circuitry, drawing too much power and degrading the beam quality. This was causing the power supplie(s) to overheat which resulted in the whole system shutting down (instead of just loosing the beam and having the head continuing to move). Now to open the purse-strings for the big hit.

Got to love their quick turn-around though... The two options Epilog offered were, to pay a core deposit, they ship the replacement almost that day and you return the bad tube to get your credit back. The other option is to return the bad tube first, for a $200 discount and no deposit, and they will ship the replacement as soon as they receive the shipment confirmation. There is only a day difference between their shipment on the two options, so I chose to take the discount for the longer wait.

Can't wait to get back to full power.... This running at 3 speed was killing me!

[Steve Clarkson]

Bruce,

Thanks for explaining the 75DPI test..........I put it on my "To Do" list, but never got around to doing it........before my laser DIED!!!!!!!

My new laser tube should be shipped out tomorrow. :(

[Bruce Clumpner]

Just received my "new" tube and dropped it in last night. Unfortunately I didn't have time to re-align everything before it got too late. I'm looking forward to the increase in speed and reliability! Wish me luck.

[Martin Boekers]

This is one of those posts which is good to bookmark so it's easy to find when you need a refresher for tube test.

[Amos De Pasquale]

Allow me to share odd "fault"; my machine(not Epilog) was doing something similar, so I realigned the mirrors just in case, still the same, got a new tube, still the same???, went check the alignment, and by chance found that the actual mirror was loose in the holder, the holder itself was firm, but the mirror was loose in its socket, tightened mirror in its socket, realigned and all was ok?!!!
The other thing I learnt was that cleaning not only the mirrors, but the output hole on the tube was important, didn't realize that until looking through the mirrors I saw a cloudy milky colour?! Amos

[Bruce Clumpner]

OMG Not sure why I didn't do this earlier (beside the $1,500 Hit!) I aligned and ran all weekend with the new tube.. since this was a used machine I didn't know what to expect in improvement.. When I got the machine I was cutting 3/16" plex at 6-speed and worked its way down to 3-speed as it died... This weekend got it up to 12-speed... I could just sit and watch this thing cut.

thanks everyone for your input.