Hello,
I am from sweden and i have reasently bought a GCC L-25 whith a J48-2S tube from 2002 installed. I am cutting hobbythings out of 4mm HDF sheets. After about 5-10 minutes cutting att 100% power its slowly start losing power and after 60 minutes it cuts only aboute 3mm. If i start at the same spot where i ended cut after a hour it cuts throu nice again. Could it be that the CO2 need to be refilled or can it be a heating problem somewhere? I have been in contact whith GCC and get a tip to check the caps on the RF-boards but they seams to be ok, i mesured the 1000pF caps to 1480pF on my Fluke whithout desolder them, they must have bin changed before because there was burnmark on the inside off the lid. I have tryed to lowering the voltage to the tube from 32.16 to 30.00 at full power but it didnt seems to make any change. The ripple on the Dc voltage is aboute 14mVAC. I have read aboute the important tuning of the RF-card and the caps that tends to blow on this forum, some says that is possible to damage the card if you drive them whith wrong voltage? Does higer voltage make higer laserpower? Is someone sitting on a tuningmanual for the RF-card or som other things i can test/mesure? Synrad says that the tube probably needs a full service but thats out of my budget right now and thats all help i got from them so far. I have a 100MHz osilloscope and i can make a device to provide the right tickle and PWM signals if its nesecery to test the laser.
/Greetings from Sweden