[KTP]

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

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 [email protected]

[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 [email protected].

[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.

[KTP]

Oh, I misunderstood Les when he said he was using the ULS engraver to send 1.5 to 2V to the Synrad laser. I thought he was somehow using a DC value. Unless you use an oscilloscope to view the pulse stream coming from the ULS engraver you will not really be able to see what is going on with a regular multimeter. The voltage read on the meter will change with frequency and duty cycle.

Now, on the other hand, if you are getting way more power when you apply the 4.5 to 5V DC signal to the Synrad using the AA batteries, then I would tend to say that the ULS engraver for some reason is not sending the Synrad a full duty cycle signal (or 95% or so, which is what Synrad recommends) when you instruct it to engrave at full power. This is very strange though...I would think that either the ULS engraver would be broken and not sending any modulation signal or it would send the correct 0% to 95% duty cycle pulse stream as instructed. Having it send 30% duty cycle when you tell it to engraver full power is weird. Is it possible that ULS only ran the 25 watt Synrad at half power to prolong life?

[KTP]

One more thing. Buy a cheap oscilloscope on ebay if you can't borrow one from somebody. A 60mhz analog scope can be had for under $100, sometimes much less, and is a very valuable debugging aid. With the scope connected to the signal from the ULS, you will be able to see the pulses being sent as you increase the power at the engraver from 30% to 100%. If for some reason the time that the pulse is high (greater than ~2.5V) does not get larger than the time that the pulse is low (under ~0.5V) then there is a very strange problem in your electronics. Also, perhaps the digital driver buffer chip on the ULS engraver could be damaged and not sending a "high enough" high signal. If it were right on the edge, perhaps the slight increase in current draw to the chip when it goes above 30% duty cycle is causing the high level to dip below the minimum required threshold that the Synrad laser needs to see. Total wild shot guess, but maybe worth checking.

[graver1]

I was waiting for a fresh mirror so I could get a beam all the way to the table. Didnt seem to help a lot, but its a round spot now anyway. I have just enough power to turn fax paper black. I assume I would get more w/ the 5 volts direct to the tube. Is there a way to get the schematic for this? You mention some chips that could be checked. Can this board generate any sort of program w/ out using Corel draw? Wondered if my computer could be the cause of a weak signal? Still looking for magic potion. All options appreciated. Thanks very much LL.

[MacGyver]

Les, when was the last time the tube was recharged? If ULS no longer offers support for it and it hasn't been used for a while, I imagine it hasn't been recharged in quite some time, if ever.

[graver1]

I'm pretty sure the tube has never been recharged. I contacted photovac and they say they will do an inspection and repair if possible. Meanwhile I'd like to see the power on the table that I saw at the tube outlet when I applied the 4.5 volts directly. Would still like to find some sort of comparative test that would indicate the power. IE; 1 minute to burn thru a given thickness of a given material. Also, (and this is minor till I get something working), The table seems to be re set for some special set up. Locator rails are in lower left corner, and top travel of the table is about 5 inches short of the focus height. I'm using a 4 inch riser to get in range. I have the rotary attachment but have never used it. Dont think the last owner did either.
I need a good picture of what its supposed to look like at the screw slides.
Really appreciate any help Les Lyons Dallas.

[graver1]

I have another request. Is there a program I can load into Corel draw 4, that can give me a test of the system? Some of my problems can be traced to ignorance about the software. I can see art work like the old TV test pattern.
Would test for raster, vector, power, speed etc. All suggestions welcome.
My last test got an image toasted into plywood. Speed down to about 25% Power 100. Thanks very much. Les.

[niksiz]

hi,

ı have a big problem with my laser tube which is synrad which is E seires 48-2 works with 115 vac.
last ı used i burn out. when o open it ı noticed that rf transistors need to change. after change ı have checked the input voltage.on the bridge input i have calculate 5 volt ac. and output is it 5 volt dc. after that ı changed the bridge but same thing was happen.
ı noticed that there is a smps unit after the bridge(in tube).after that ı seperated the smps unit from the bridge when ı calculate the bridge again 110 volt is there.on input 110 ac on output 110 dc. I think the problem is on smps unit.

there is 2 caps on output which are 35 v 470 uf. I know that repairing smps is so hard so the question is,

what is the output voltage of this tube if it is 35. it can be esay to find new one.(

or anybody who have same, can calculate the output voltage.

any idea?

if you need photos ı can send

[MacGyver]

The AC and DC voltages should be different on either side of the bridge... you're either taking measurements wrong, or something is screwed up on the bridge.