Inside an Version F Synrad Series 48 Laser :o

[Chris Hohmann]

Well after seeing how everyone was able to work on the later versions of Synrad series 48 lasers we decided to open up our version F to see what we could do to get it working....

Yeah dont think we will touch this one :(

Cheers

Chris

[Richard Rumancik]

Did Synrad give you any documentation? I forget what the symptoms were that you were experiencing. You should look closely at all the boards and see if you detect any burning or overheating as that may be a clue to the problem. Also look for bulging or discolored caps etc. Many of the Synrads use 2 RF boards and if one fails the output drops by 50% but I think you said you had nothing. If it went from 100% to nothing I'd look at other possibilities first before the RF boards. If you can borrow a Synrad controller from somewhere you might be able to do some bench testing. Have you checked the power supply output thoroughly? I'd try a few things before giving up . . .

[AL Ursich]

IF you still want to play..... If the Laser just quit than I would suspect that the Full Wave Rectifier shown in the picture below that I copied from your picture. That is the Single Most Common Failure mostly due to HEAT... Note the Rectifier has a piece of heat conductive mylar or plastic between the body of the big rectangular block and the frame of the power supply. I dismiss the RF as in a open part only because of 2 RF Sections as posted above...

Here is one of the many you tube videos that shows you how easy it is to test a Full Wave Rectifier. He finds one JUST LIKE YOURS bad on the board that he is testing in the video. http://www.youtube.com/watch?v=11JPy4t36oo

I am Retired Navy Fire Control Tech Chief (E-7), 20 years of fixing electronics. Then 8 years with Sony, 4 making Picture Tubes in San Diego the last 2 in the Electronic Calibration Lab. While in the lab I overhauled close to 400 Power Supplies removing the Heat Conductive Mylar as it dried out over time and let heat build up in the Rectifier until failure. I replaced the Rectifier with a slightly heavier duty version and used a Heat Conductive White Paste for much better Heat Dissipation. The Power Supplies were used in banks of zones to age the picture tube gun. I started this in 1995... Showing my age... When we still bought Picture Tubes... My last 4 at Sony was fixing stuff at the Philly Service Center like TiVO, Play Station 2, and many other products....

So that is why my first indicator of what could be the "Common Fail Part" in that laser... would be the Full Wave Rectifier.... All it takes is ONE of the 4 Diodes to be either Shorted or OPEN... MY guess is OPEN since you did not mention a blown fuse.. Diodes fail one of 2 ways.... Short as they Melt Together inside.... OR BLOW like a FUSE and are open....

Now for the Meter.... A Digital Multimeter is the best device to do this test. Sony also sent me to Fluke Calibration School and I maintained about 500 Multimeter's for Calibration at Sony in San Diego.... SO when you turn the Multi meter to the Diode Test Mode with the leads NOT touching. The leads are actually producing a voltage.... Zero to about 2 Volts over and over... in a Ramp. When you touch the leads together you will make the meter BEEP as in you shorted the 2 volts together. This is also a Continuity Tester some people use. Now when you touch the 2 leads to a diode the ramp of zero to 2 volts happens. When the Meter "Detects a DIODE JUNCTION by the +- .6 as in Point 6 Volts... or .599 that tells you that the diode is GOOD. IF you reverse the leads to the same contacts you should see OL or a OPEN as the Polarity of the Zero to 2 volts is important.... It only detects the junction in one direction in the other direction it will see a open or no gate. Now if you do this test and the Diode Junction is SHORTED as many times they ARE... The Meter will BEEP in BOTH Directions. It's just like crossing the leads.

This guy did a great job of showing you a BAD Diode... THAT Reading was something like 1.8.... And that was a indication of a BAD JUNCTION.... GOOD JOB !!!!

YOUR Rectifier also has some Capacitors on the leads that I believe are just for Noise Suppression. They should not effect the test. Since a Transformer can sometimes power of send power to a Full Wave Rectifier you may get funny readings as you read into the coil of the transformer. Un Soldering the Rectifier would be required to test.

IF I were a Gambling MAN.... I would just replace the Full Wave Rectifier ensuring you get the polarity correct... And look into Dielectric Grease or Heat Sync Compound... The Mylar sheet may be the ACTUAL REASON for this FAILURE... NOTE the Position of the Rectifier ALL by it's LONESOME.... TO let is Dissipate the heat....

OK... Second Look edit.... The Green Components could also be a Varistor as they look similar to a Capacitor used on Power Supply Circuits but have a different job...

https://en.wikipedia.org/wiki/Varistor

The Varistor is wired to the SCREW of the Rectifier and hence GROUNDED on one end... SO I retract the thinking it is a Capacitor... More Likely a Varistor. The Varistor' JOB is to act as a Protection Device and if the voltage gets above a point the device turns ON and SHORTS that Voltage to the SCREW or GROUND..... When it does.... IT GIVES UP IT's LIFE.... It Explodes.... THIS is the same Component in a common 115 volt AC Power Strip.... IT has 2 Varistor's to Ground one on the HOT Leg and one on the Neutral Leg. IF Lightning Strikes the Power Line, this component would SHORT that Lightning to GROUND is a Spectacular Fire Storm.... Giving up it's life... The Varistor's in the Photo look OK so I would expect that they will look like a Capacitor or a OPEN to the Diode Test and you should have a Successful Test without removing the Varistor. Now if one is Shorted... YOU will see it in the test....


So in my opinion.... It's ALL About the Full Wave Rectifier...... In all my Sony Troubleshooting and even NAVY Days.... THIS is the Single most common failure.... And in this case.... HEAT RELATED.... Get this running... I would install a 4 inch cooling fan on the outside of the laser case near this spot...
Good Luck,

AL

EVERY Electronic Device has a "Most Likely to Fail" part... With Play Station 2's.... It was the Laser Optic... That reads the disk... And 9 times out of 10... Cigarette Smoke or the TAR gets on the outside of the optic.... The 2's had a cooling fan that pulled air past the optic... Then INSERT a what I call the "Eye Lash" CD Cleaning Disk with SQUIRT Bottle.... And like a car Windshield... A Smashed BUG and Wipers.... Classic Fail.... On the Play Station 2 if the unit smelled like SMOKE... you knew.... Sony Home Phones... A little 6 pin Optical Coupler for the Ringer Circuit.... Lightning ZAP.... Shorts the part..... Phone now DEAD and shorts out all other phones in the house until you un plug it.... The list can GO ON....

Darn.... I miss fixing stuff... That is why I have over 7000 posts on the CarveWright Forum giving some fix it advice...

[Dan Hintz]

Darn.... I miss fixing stuff...

I'm with ya on this one... I don't get nearly as much bench time as I used to, and it sucks. There's something pretty exciting about tracking down a problem, finding it, and resolving the issue. And none of it involves boxing it up and sending it back to the manufacturer.

[Philip Tarnawskyj]

hello you lot, this is the same tube i have but the newer one. Does any one happen to know of a decent 48-2 series tube going cheap?

[Dan Hintz]

hello you lot, this is the same tube i have but the newer one. Does any one happen to know of a decent 48-2 series tube going cheap?

Philip,

Try not to post the same question multiple times. I already posted in the other thread you brought back, but eBay and laser resellers will be your best bet.

[Dave Sheldrake]

Fantastic info Al, stored away for when I'm stuck next :)

great stuff

cheers

Dave

[Chuck Stone]

hello you lot, this is the same tube i have but the newer one. Does any one happen to know of a decent 48-2 series tube going cheap?

I didn't see the other thread yet, but last time I checked, laserresale had a couple.
Define 'cheap' ?