[Pplug]

We just bought a synrad laser from a nice guy who stopped using it because the laser would not stop firing. Has anybody ever run into that problem?

We have an ILS engraver that was retrofitted for the synrad tube. The tube itself is 40 w and puts out a strong beam when power is applied.

I'm hoping somebody here has a little more experience than me with the synrad or engraver.

Thanks

[Laserman FLE]

RF is probably bad. If not then you have a modulation signal issue

[Pplug]

Thanks for the reply. I was playing around with the engraver today and noticed there was an LED on the motherboard right next to the connector for the laser signal. The led was blinking faintly when the laser was supposed to be emitting. I think that might lead me to believe the laser itself might have the problem.

With this synrad laser tube, where would the RF module be? and how can I fix it?

I took several pictures.

[Pplug]

I think I found it. If you look at the middle of the circuit boards there is a small board with a LM chip that happens to be a timer. The silkscreened label says, "Synrad Control Board."The RF signal from the engraver goes directly to this board. The problem is... I don't know what to check from there.

[Pplug]

Update!

I did a little troubleshooting and research on the engraver and laser control board. The engraver is putting out a variable voltage TTL signal from 0-5v. I used a multimeter and ran an alignment/test routine on the engraver. 100% power is 5v and 10% power is .5v. I also checked it while it was running a job of a large rectangle at 100% power. The meter read 5v on the sides and in the corners the voltage dropped as the beam head slowed and changed directions.

The RF control board is a different beast altogether. I couldn't see what was malfunctioning . I decided to desolder most of the connecting wires and parts so I could better see the parts and the back of the board. I didn't see anything out of the norm. I then did a little research and decided to replace the transistors and IC's on the board.

The total cost for all the replacement parts was about $35 with shipping and tax. I ordered them this morning and I'll update this thread when everything comes in.

The one part I think might have broken is the H11L2 chip. I found out that was an optoisolator. I'm thinking that if that chip goes bad it could fail in the "closed" position and make the laser fire at full bore! It's all speculation, however. I'll know more when I start replacing parts.

[Pplug]

Well, it's been a long time since I updated this thread. In that time I replaced all the ICs and checked as many caps as I could. In the end... nothing worked.

We decided to do a full retrofit instead of just purchasing a new RF laser. First we bought a 40 glass tube off eBay with a power supply and small chiller. I made some mounting rings from some scrap AL that we had around. The laser worked but we found it underpowered. It was probably the internal dap was set up for an rf laser instead of a PWM laser.

I was also having trouble with the print driver and the old programs it needed to run. We made the decision to replace the electronic controls with a Awc-608 DSP. The new DSP fit into the electronics compartment with lots of room to spare! The DSP was also able to use the existing power supplies. All the stepper motor drivers were compatible. I had to do a little bit of logic and assumption when finding the right wires for the DSP but it all worked out.

The motorized table functions great. 4th axis works by flipping a 4 pole dpdt switch to change step and dir signals from the Y axis to the A axis stepper driver. That was the best solution so the Y axis motor stays locked and won't let the Y axis wander while the x axis travels quickly.

A few odds and ends... The air assist is working and allowed me to test the laser burning through 3/4" clear pine! Almost caught the school on fire, but it was an experience. I also got the beam combiner working with the laser pointer.

For the future we are looking at purchasing an 80w laser so we can cut and engrave some denser materials.