Synrad swaperoony

[rszemeti]

So I have two Synrad lasers,

one a J48-2SW ... I assume 25W device, with a pair of RF board containing a single MRF150 ... one of these boards is broken, FET missing, output cap missing, etc. but the tube itself is believed to be good.

The other is a similar, older, G48-2 25W tube, physically identical, but has two RF modules containing a pair of MRF174's .. this tube has been in use for a while and is now so low output that its struggling to cut 1mm card at snail pace ...

I was wondering if I could swap the RF modules out of the G48 device into the J48-2SW ... the PSU I have obviously drives them fine ... and the tubes look physically identical, the J48 even has the correct threaded holes to mount the boards ... just a bit concerned whether stuff more RF power into the J48 tube will be OK?

[rszemeti]

Well, scratch that.

I fired up the "weak but two good RF drives" tube, it pulled 13.5A, showing both drivers are alive ... it is weaker than expected. A slight burn on cardboard that becomes non existent after about 30 seconds CW, the tube is close to dead.

The second tube, I fired up with one good RF unit, no output ... the tube needs a re-gas.

At this point, my options are flog them on eBay as is ... or talk one of the regas guys into doing a deal on both units where repair the RF drive on the other tube so ship both units with good RF and I get one good one back.

Or I think I still have the gas mixer block off the big Trumpf I used to run ... and a have a very good Varian vacuum pump ...

[dar303]

Hi,

I have a supposedly good (at least gas-wise) 25W that blew one of the FETs, the previous owner then changed the FET but it blew again when he turned it to full power so he suspected some tuning was off. I´m probably not ever getting around to fixing it so I´m open for trades. Where are you located? I´m in Sweden.

[rszemeti]

Hi,

I have a supposedly good (at least gas-wise) 25W that blew one of the FETs, the previous owner then changed the FET but it blew again when he turned it to full power so he suspected some tuning was off. I´m probably not ever getting around to fixing it so I´m open for trades. Where are you located? I´m in Sweden.

That could be interesting, I am in the UK ... UPS works fine between the two ...

[rszemeti]

Hi,

I have a supposedly good (at least gas-wise) 25W that blew one of the FETs, the previous owner then changed the FET but it blew again when he turned it to full power so he suspected some tuning was off. I´m probably not ever getting around to fixing it so I´m open for trades. Where are you located? I´m in Sweden.

Just as a quick question, does yours produce roughly half power with one drive stage running? With one of the drive stages blown it *should* produce some output afaik, if the gas is good. The one I have with a blown stage was supposed to be a good tube too, but ...

[dar303]

Just as a quick question, does yours produce roughly half power with one drive stage running? With one of the drive stages blown it *should* produce some output afaik, if the gas is good. The one I have with a blown stage was supposed to be a good tube too, but ...

I can test it when I find the PSU that came with it!
I have a few 48-1's too in the same box, I sniped them for 100USD on eBay back in the days, pulls from medical equipment it seems since they have the auto power sensor accessory.

[rszemeti]

I can test it when I find the PSU that came with it!
I have a few 48-1's too in the same box, I sniped them for 100USD on eBay back in the days, pulls from medical equipment it seems since they have the auto power sensor accessory.

Yeah, I got this 48-2 with the dead RF drive the same way, I kept it thinking when the tube in this eventually gives out, I always have the other one to swap the bits into. I don't remember if I ever tested it before hiding it on a shelf. The machine (an ancient Universal Laser I picked up on eBay with a dead stepper drive) doesn't get a lot of use, mainly laser cutting gaskets for random old motorbikes I am tinkering with, but it would be nice to have it working.

[rszemeti]

So after a bit of messing about swapping RF modules around, I managed to get about 8W out of the spare tube. I think, if I fixed the driver that has the blown MRF150 in it, it would be a bi better, as I don't think the earlier revision drivers do quite so well. Anyway, it's back on the machine and seems to make a reasonable impression of something that works so that will do for now.

The other option is a 70W "Laserscope" 532nm system that I think I could just about squeeze into the space under the machine on the trolley .. but I suspect I would be better off flogging the 532nm system and buying another CO2 tube ...

[mixedgas]

The matching and tuning cap for the RF load on most of the RF excited aluminum tube lasers is (well used to be) under the fill port in the laser head, so to tune it properly you have to let the tube up to air. It is RF, and the load does need to be impedance matched. They should be close, but not perfect when exchanged.

The Laser tube is a nickel plated aluminum extrusion.

Steve