Good Day,
This is my first post after reading your posts for several years. With all of the knowledgeable members here and the previous threads I've read regarding the subject of tube repair, I thought I'd seek some advice.
Laser: ULS-25PS, mfr 1996
Tube: Synrad G48-2 mfr. 1996
Power out: 13 watts at aperture
Power Supply: 28.2
RF Driver III, rev C
One of the driver boards in this tube was really cooked; read that LOTS of carbon, two lands burned and two caps no longer identifiable.
C7 1000pf mica coupling cap CARBON ONLY
C4 100 uf/50v VERY CHARRED
The lead from coax matching line to tube feed-tru VAPORIZED.
This older board uses a MRF-148 MOSFET driving a pair of MRF-174 devices in parallel. With the DVM I had handy, I found no shorts, but the meter did not develop enough voltage for me to test the devices. If they are bad, they appear to be available via RF Parts.
Synrad did supply me with two pdf manuals, one each for the F & G series 48-2 tubes in my two lasers. The gentleman I spoke to who helped me was in the marketing department. Considering the cost of replacement tubes, I would like to repair this RF driver board if I possibly can.
Tools on hand:
dual trace 60 mHz scope
thru line rf wattmeters
dummy loads
laser power meter
analog and digital voltmeters
rf driver III schematic
Unfortunately, this ULS-25PS also suffers from a faulty 'u-step' board in the 'stepper motor control box'. I am testing this laser now with a 'u-step' board from the second laser. This is, however, a topic for a later post and thread which might include "Chinese DSP controller". :-)
Does anyone with experience have suggestions that might aid me recovering this now no longer supported 'rf driver board' for a G series 48-2 Synrad tube?
Thanks in advance and it's nice to have an excuse to post and introduce myself.
Regards,
Donn
South Kingstown, RI