Synrad 50 watt laser

[KTP]

I repaired a bad board on a Synrad 48-5 50watt laser and now it is putting out 62.5 watts!

I had to replace one of the MRF150 microwave transistors...a pain to desolder/solder and I was a bit worried about the amount of heat I had to use to get the solder to flow. Two of the transistor flat tabs are mounted directly to the thick (2 oz?) copper board.

Now that I have two working 50 watt rf excited co2 lasers it is probably time to get back to building my laser engraver. :-)

If any of you come across a dead or low power 48 series Synrad laser, contact me if you want debugging tips. I learned a lot from repairing these two.

[graver1]

Hi;
Not sure how the contact part works here. I have a synrad 25 w laser that need help.
How do we connect? Les Lyons

[MacGyver]

KTP, good job on getting the board up and running... I wish I knew where you were getting a hold of these lasers (PM would be great... don't want EVERYONE bum-rushing the marketplace and leaving me high and dry ), as I would love to get my hands on a fairly powerful RF-based one. I think 60W would qualify, and I don't think I would have any problems fixing it.

When it comes to soldering to thick board, consider heating the entire board in the oven at the lowest setting first. Let the board sit in for 10-15 minutes to get up to temp. This won't hurt the components, but it will bring the mass of copper up to a reasonable temp, allowing for a much shorter solder time on the large tabs.

[KTP]

Hey Les,

So what is the model # of your Synrad (it makes a big difference as they had a major change in design of electronics after the F or G series I believe).

What is wrong with it? Just plain dead, low output, half output (this would indicate one of the two rf drivers is not working), or what?

Mac: I got those 2 Synrads off ebay on a very scary buy-it now deal that I snapped up 5 seconds after it was posted. I got really worried because after I mailed the seller a cashier's check he got banned from ebay for some reason. Fortunately he shipped everything perfectly, and even offered to throw in a 1996 Neslab chiller which I refused (it was in Boston and I am in Seattle, shipping would have been like $500).

[graver1]

My laser is a ULS 25 PS, The tube has this info. Synrad 206-403-6100
APR 29 95
MOD. F48-2-1153/2045
115 VAC.
Test does not work at all. Running a program will produce a small beam from the laser opening to the first mirror. (Will burn 1/8 dia hole in tape) Nothing beyond that. The first mirror is from a piece of photo equip. but does not get warm or burn. I was told it would cut 1/4 plastic, but very slow. ULS says they will not repair this tube. Havnt contacted Synrad yet. Not sure it will be worth repairing. Looking for cheap way out. Thanks very much. Les Lyons.

[KTP]

Last time I checked, Synrad would recharge the 25 watt lasers for about $700 if they didn't need any other type of electronics repair. The problem will be that yours is an F series, which uses their older electronics. They might want to upgrade the electronics to the current version, which would cost you many bucks (think $2000 or more).

I would call them and ask how much it would be to check out the laser and quote you on a recharge, telling them it is an F series tube. If it is more than $1000, I would start looking on ebay for a used tube with a 25+ watt output. They go for $1200 to $1800 used depending on condition. Or you can sell the engraver to me and I will cram in the 35 watt ULS laser I have and be quite happy

[graver1]

KTP:
OK , you have given me some options. I'd really like to make this work if I can.
I will keep you offer to buy open though. Thanks very much. LL

[graver1]

KTP:
Synrad says very obsolete and they cant /wont help. I'm waiting for a reply from Access lasers, who seem to be able to do something.
I need to find out how to check the power supply w/ out doing any more harm to me or the machine. I'll search the files here I guess.
Might be close to giving up and starting over. LL.

[SkipW]

graver,

You might contact Photovac Laser in Ohio. They repaired an older Synrad tube for my brother's ULS laser. www.photovaclaser.com

From their website:

Remanufactured Laser Systems
Our inventory consists of numerous previously owned units, which we have dismantled and refurbished to "like-new" condition. We have several styles and types ready to go for immediate installation. Our lists are constantly updated and our database is networked nationwide.

We invite you to contact us at: Ph: 614-875-3300 or 888-Fix-Tube

[graver1]

KTP
You mentioned being interested in my dead ULS 35 w laser. I havnt found a replacement tube and hacking in something else will be a "Bridge too far". I sent all the numbers before. What could we do?. I'm in Dallas TX. Thanks Les Lyons.
This is a 25 watt. Not 35. My email is llyons@flash.net

[graver1]

After some more inspections, I have the following situation.
Removed the laser and found the control signal plug. Used a battery pack of used AAs and fired the machine up. Plugging in the 4.5 volts or so gives me a pretty hot beam. Instant fire on wood. About 5-7 seconds to burn thru 1/4 plexiglas. Does not touch metal at all. When we were testing through the control board, setting the power at the machine panel, we got a beam starting at about 4% ( Very light)increasing to about 30%.( burns wood). No increase beyond that. Measuring the voltage at the control plug w/ a voltmeter, 4% was less than .5 volt, 30% was about 1.5 -2 volts. This was using a program w/ mostly a raster cut. No voltage increase above 30%. I assume from this that I have a problem on the supply side. I'd like to know what power I have even when the voltage is 4.5. I expect I have 2 problems. Is there some combination of time and material that can estimate the power w/ in 10 % or so. Any suggestions about what to look at for the voltage problem? All my machine info has been posted here. All help appreciated. I'm hopeful I can keep this after all. Email llyons@flash.net.

[MacGyver]

The signal is not voltage-based, it's logic level-based. In other words, when you applied 4.5V, you were at a high logic level, at 0.5V you were at a low logic level... there are only these two levels (on and off). Depending upon the type of logic circuits they used, your typical low-level will be about 0.0-2.3V, and high will be about 2.7-5.0V.

The signal is pulse width modulated (PWM), so a standard meter will read the average value. A 30% duty cycle amounts to 1.5V (for a 5V signal), matching up with what your meter read.