Epilog problem

[Radu Bogdan]

Hello
In the first place, please excuse my bad english.
I work with an Epilog Laser 75W but I have some questions about this machine. In the first place I have problems with the laser tube coolers. Two coolers don't want to work, after some tests I discovered that on the connection cables (from source to coolers) is inserted a diode. The question is : what type is this diode and why is necesary ?
Thank you

[Dave Jones]

Can you read a number on the diodes? I'm just guessing, but it might be a zener diode to drop the voltage to the correct amount. Or if it's mounted on the heat sink, maybe it's a temperature sensor?

[Radu Bogdan]

The diode is a low power zenner at 24 v , the coolers are at 24v/0.33A and seems to be serial conected, the source is 24V, I can't understand, maybe is a protection for the electrical shocks tha can appear at startup ?

[Dave Fifield]

Why second guess the Epilog design engineering team when you can get on the phone and call them directly? I suggest you give the Epilog Laser Support Team (http://www.epiloglaser.com/tech_support.htm) a call on Tuesday Radu. Let us know how you get on.

Dave F.

[Radu Bogdan]

Thank you for your suggestion but I can't contact the technical staff from Epilog because Ii will put the service guys from Romania in a difficult situation. In fact the problem is with the service, they ask Epilog about everything and I get an answer in minimum 3 days. When they changed 2 coolers I waited for 3 weeks !. I can't work in this rhytm, and that's why I need these informations.
I don't know if all Epilog owners have the same luck, but this is the situation.

[Dave Fifield]

I see your problem. Well, you might get lucky here - at least one of the Epilog HQ support people (or their boss...not sure who now) reads this forum, so you may have instigated a direct line to them yourself already!

Putting on my electronics engineering hat, I have to say that putting a 24V zener diode in series with a device is not a good way to regulate the voltage to it. It's much more normal to use a zener diode in parallel with a device and use a dropper resistor in series. Can you draw the schematic of that part of the circuit for us to take a look at? Are the other coolers (the ones that work OK) wired differently to the two that don't work? What are the cooler devices - are they fans or are they Peltier devices? If they are fans, then it's just feasible that they are 24V fans being run on a 48V rail using zeners to drop 24V in series - this is a non-ideal situation, since DC fans can take large currents at turn-on time, potentially harming the series zener diodes. If they are Peltier devices, then it's highly unlikely that the diode is a low-power zener in series with the DC feed - Peltier devices take quite a bit of current, so this method of dropping voltage isn't going to work.

Good luck, hope you get it fixed up and working soon - get me some more info and I'll see if I can come up with an answer for you - my Epilog laser is only 45W and is air cooled, so not much help there, sorry.

Cheers for now,
Dave F.

[Peck Sidara]

Dear Radu,

Reading thru the postings, I am assuming you have a Helix machine. If at any point you feel your technical inquires are not being handled in a timely manner, please contact Epilog tech support directly at tech at epiloglaser dot com. Forward the serial number of the machine and we'll get the necessary components sent out to repair your machine.

For international customers, we typically require the customers to contact their local sales rep, whom in your case is Mariomatic Trade. Domestic/US customers contact us directly.

Instead of trouble-shooting the exact electronics, we will build a replacement fan assembly and send this complete so there is no need to solder in diodes and such. Replacement will be easy and there will be instructions on replacing the part.

Let us know if you have any further questions and we'll go from there.

I would also like to thank members of sawmillcreek for getting involved and assisting with this issue.

Regards,
Peck Sidara
Epilog Tech Support

[Radu Bogdan]

Thank you everyone who answere trying to help me. I ordered the components. Next days I will post some photos of my work.
Have a nice day