Laser pointer discussion. Read/write reviews of laser pointers and laser pointer companies. Learn about all types of laser pointers and lasers





Welcome to Laser Pointer Forums! If you are looking for a laser pointer or want to compare different laser pointer companies, you may want to check out the LPF Laser Pointer Company Database. The link will open in a new window for your convenience.








Green Laser Pointers by Category Blue Laser Pointers by Category Red Laser Pointers by Category
Yellow Laser Pointers by Category Violet Laser Pointers by Category Orange Laser Pointers by Category
Top Laser Pointers by Power - 1 Watt+ Top Laser Pointers by Power - 500mW+ Top Laser Pointers by Power - 250mW+
Laser Pointer Database High Power Laser Pointers Laser Pointer Diodes
Laser Technology Laser Pointer Parts Lasers by Wavelength
Top 10 Laser Pointer Companies Laser Pointer Company Database Visible Beam Laser Pointers


One laser store meets all your needs

























Go Back   Laser Pointer Forums - Discuss Laser Pointers > Lasers > Tutorials, Help & Repairs



LPF List of Laser Pointer Companies (link opens new window)



Reply
 
LinkBack Thread Tools Display Modes
Old 09-10-2008, 10:44 PM #1
GooeyGus's Avatar
Class 3B Laser
 
Join Date: Mar 2008
Posts: 2,673
Rep Power: 970
GooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond repute
Send a message via AIM to GooeyGus Send a message via MSN to GooeyGus
GooeyGus GooeyGus is offline
Class 3B Laser
GooeyGus's Avatar
 
Join Date: Mar 2008
Posts: 2,673
Rep Power: 970
GooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond repute
Send a message via AIM to GooeyGus Send a message via MSN to GooeyGus
Default Capacitor question

Ok, so as some of you may know I'm trying to track down a short in the PSU of one of my Argon lasers.

SOOO... I have it narrowed down to a capacitor that is acting funny. Normally when I tested resistance across all the other capacitors, it started with a fairly low resistance which got higher as the meter pumped electricity into it. But this one is being a bit weird. When I try to test resistance across the capacitor in question, I get nothing. Not 'nothing' as in 0ohm, but nothing as in the meter sees it as an open circuit.

So my question is: While my meter see's this as an open circuit, the meter only uses MAYBE 6v when measuring resistance. This capacitor normally sees upwards of 150VAC (basically straight from the wall). Could an 'open circuit' at 6v actually be a short at 150V? Is this a typical failure mode of capacitors?

I'm not sure what kind of caps they are, but here is a picture for reference. The cap in question is the white one right in front, which you can see all the information on.





Thanks!!
GG



GooeyGus is offline   Reply With Quote







LPF List of Laser Pointer Companies (link opens new window)







Old 09-10-2008, 11:22 PM #2
rkcstr's Avatar
Class 3R Laser
 
Join Date: Dec 2007
Posts: 1,368
Rep Power: 142
rkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond repute
rkcstr rkcstr is offline
Class 3R Laser
rkcstr's Avatar
 
Join Date: Dec 2007
Posts: 1,368
Rep Power: 142
rkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond repute
Default Re: Capacitor question

I can't really tell in the picture (I don't think I see any), but is the top popped up at all on the "bad" cap? *That's typical for a failed electrolytic capacitor.
__________________
Laser drivers and Test Loads - rkcstr.com

Enter discount code "LPF" during checkout to save 10% off of the regular prices!
rkcstr is offline   Reply With Quote
Old 09-10-2008, 11:29 PM #3
MarioMaster's Avatar
Class 3B Laser
 
Join Date: Jul 2007
Location: Allentown, PA
Posts: 3,621
Rep Power: 346
MarioMaster has a reputation beyond reputeMarioMaster has a reputation beyond reputeMarioMaster has a reputation beyond reputeMarioMaster has a reputation beyond reputeMarioMaster has a reputation beyond reputeMarioMaster has a reputation beyond reputeMarioMaster has a reputation beyond reputeMarioMaster has a reputation beyond reputeMarioMaster has a reputation beyond reputeMarioMaster has a reputation beyond reputeMarioMaster has a reputation beyond repute
Send a message via AIM to MarioMaster
MarioMaster MarioMaster is offline
Class 3B Laser
MarioMaster's Avatar
 
Join Date: Jul 2007
Location: Allentown, PA
Posts: 3,621
Rep Power: 346
MarioMaster has a reputation beyond reputeMarioMaster has a reputation beyond reputeMarioMaster has a reputation beyond reputeMarioMaster has a reputation beyond reputeMarioMaster has a reputation beyond reputeMarioMaster has a reputation beyond reputeMarioMaster has a reputation beyond reputeMarioMaster has a reputation beyond reputeMarioMaster has a reputation beyond reputeMarioMaster has a reputation beyond reputeMarioMaster has a reputation beyond repute
Send a message via AIM to MarioMaster
Default Re: Capacitor question

i don't think you should be getting an open reading - but the only true way to tell if it has failed or not is to test it with a meter that can measure capacitance (I've already used mine to diagnose my friend's central air conditioning system - the fan would stop working when hot because the fan's run capacitor went bad)
__________________
ILT 5500KR krypton only air cooled ion 100mW 647.1nm | ILT 5500AR argon only air cooled ion >300mW multiline
Omnichrome 643 air cooled Ar/Kr ion 10mW 676.4nm 647.1nm 568.2nm 488nm 476.2nm (high hours)
Spectra Physics 127 >30mW 632.8nm HeNe | Uniphase 1.5mW 543.5nm GreeNe
Coherent Innova 90 argon ion water cooled ??W (got plasma, alignment in progress)
Coherent 60W 830nm water cooled diode brick | Shenhui Laser 40W 10600nm water cooled CO2

(9:03:50 PM) Picasso: the best guys i saw ever at burning man was two dudes dressed as all green army men shooting pants at naked guys
MarioMaster is offline   Reply With Quote
Old 09-11-2008, 01:44 AM #4
GooeyGus's Avatar
Class 3B Laser
 
Join Date: Mar 2008
Posts: 2,673
Rep Power: 970
GooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond repute
Send a message via AIM to GooeyGus Send a message via MSN to GooeyGus
GooeyGus GooeyGus is offline
Class 3B Laser
GooeyGus's Avatar
 
Join Date: Mar 2008
Posts: 2,673
Rep Power: 970
GooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond repute
Send a message via AIM to GooeyGus Send a message via MSN to GooeyGus
Default Re: Capacitor question

I'll try to test capacitance, but doesn't it need to complete a circuit to do that? I'll try to wire it in parallel with a 9v battery and see if any voltage even makes it through.

And another question, does anyone know where I can get another capacitor which is the same size? Or do you think that would be pretty hard to find?
GooeyGus is offline   Reply With Quote
Old 09-11-2008, 02:03 AM #5
Hemlock_Mike's Avatar
Class 4 Laser
 
Join Date: Jan 2007
Location: North Iowa
Posts: 6,184
Rep Power: 4058
Hemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond repute
Hemlock_Mike Hemlock_Mike is online now
Class 4 Laser
Hemlock_Mike's Avatar
 
Join Date: Jan 2007
Location: North Iowa
Posts: 6,184
Rep Power: 4058
Hemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond repute
Default Re: Capacitor question

If it measures different than the others, it is a starting point. I presume it is in the primary circuit as we discussed. A diode and the power line may tell you something but it appears open but at 9 volts ....... Hard to tell what that would do to the circuit.
DigiKey may have something similar.

Mike
__________________
It's a dog's life
Hemlock_Mike is online now   Reply With Quote
Old 09-11-2008, 02:41 AM #6
rkcstr's Avatar
Class 3R Laser
 
Join Date: Dec 2007
Posts: 1,368
Rep Power: 142
rkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond repute
rkcstr rkcstr is offline
Class 3R Laser
rkcstr's Avatar
 
Join Date: Dec 2007
Posts: 1,368
Rep Power: 142
rkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond repute
Default Re: Capacitor question

At Mouser.com:

http://www.mouser.com/Search/Product...C8RNIBxw%3d%3d

Or, this place has em cheaper, but they also have $20 min. order:

http://www.apexjr.com/capacitorsR.html


Either way, make sure they'll fit in place of the old ones.


Also, most capacitance meters you just measure across the cap... but most have an upper limit of range somewhere around 100uf, I think.
__________________
Laser drivers and Test Loads - rkcstr.com

Enter discount code "LPF" during checkout to save 10% off of the regular prices!
rkcstr is offline   Reply With Quote
Old 09-11-2008, 02:55 AM #7
Class 1 Laser
 
Join Date: Jul 2008
Posts: 67
Rep Power: 10
Hodad is on a distinguished road
Hodad Hodad is offline
Class 1 Laser
 
Join Date: Jul 2008
Posts: 67
Rep Power: 10
Hodad is on a distinguished road
Default Re: Capacitor question

I believe that cap is a type of HV ceramic cap, with a very low capacitance. You won't be able to read anything but an "open circuit" with a meter set to resistance because it will charge too fast for the meter to pick it up.

Your idea with the 9v battery might work, if you removed the cap from the circuit, though you would have to charge it with the battery, then connect the cap to your meter set to a low DC voltage range - you might briefly see the voltage go up then quickly back down.
Hodad is offline   Reply With Quote
Old 09-11-2008, 02:56 AM #8
GooeyGus's Avatar
Class 3B Laser
 
Join Date: Mar 2008
Posts: 2,673
Rep Power: 970
GooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond repute
Send a message via AIM to GooeyGus Send a message via MSN to GooeyGus
GooeyGus GooeyGus is offline
Class 3B Laser
GooeyGus's Avatar
 
Join Date: Mar 2008
Posts: 2,673
Rep Power: 970
GooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond repute
Send a message via AIM to GooeyGus Send a message via MSN to GooeyGus
Default Re: Capacitor question

Quote:
Originally Posted by rkcstr
At Mouser.com:

http://www.mouser.com/Search/Product...C8RNIBxw%3d%3d

Or, this place has em cheaper, but they also have $20 min. order:

http://www.apexjr.com/capacitorsR.html


Either way, make sure they'll fit in place of the old ones.


Also, most capacitance meters you just measure across the cap... but most have an upper limit of range somewhere around 100uf, I think.
Rkcstr, thanks for the link! Unfortunately I'm looking for a match to the white 'box style' ones.

Mike, do you know how EXACT the match needs to be for these caps? Yes they are on the line side, and I think the cap in question is the second or 3rd component on the AC side, so it takes the brunt of it! I found these, which appear to have the same ratings. It sure is hard to find these kind of caps rated for AC.... Here's a link, think these would be ok?

http://cgi.ebay.com/Y2-Film-SAFETY-C...ayphotohosting
GooeyGus is offline   Reply With Quote
Old 09-11-2008, 03:01 AM #9
GooeyGus's Avatar
Class 3B Laser
 
Join Date: Mar 2008
Posts: 2,673
Rep Power: 970
GooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond repute
Send a message via AIM to GooeyGus Send a message via MSN to GooeyGus
GooeyGus GooeyGus is offline
Class 3B Laser
GooeyGus's Avatar
 
Join Date: Mar 2008
Posts: 2,673
Rep Power: 970
GooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond repute
Send a message via AIM to GooeyGus Send a message via MSN to GooeyGus
Default Re: Capacitor question

Quote:
Originally Posted by Hodad
I believe that cap is a type of HV ceramic cap, with a very low capacitance. *You won't be able to read anything but an "open circuit" with a meter set to resistance because it will charge too fast for the meter to pick it up. *

Your idea with the 9v battery might work, if you removed the cap from the circuit, though you would have to charge it with the battery, then connect the cap to your meter set to a low DC voltage range - you might briefly see the voltage go up then quickly back down.
Hodad, there are several of these types of caps on the board, and they all give me a measurement except for this one

I've done some looking around, and they are poly film capacitors. Used for high rate pulsing or line filtering (like in switching power supplies, such as this). This one is meadium sized compared to the other white 'box-style' capacitors. Even the bigger and smaller (and even ones with the same ratings) still give me a measurement
GooeyGus is offline   Reply With Quote
Old 09-11-2008, 03:03 AM #10
Class 3R Laser
 
Join Date: Aug 2007
Posts: 1,880
Rep Power: 21
BlueFusion is just really niceBlueFusion is just really niceBlueFusion is just really niceBlueFusion is just really nice
Send a message via MSN to BlueFusion
BlueFusion BlueFusion is offline
Class 3R Laser
 
Join Date: Aug 2007
Posts: 1,880
Rep Power: 21
BlueFusion is just really niceBlueFusion is just really niceBlueFusion is just really niceBlueFusion is just really nice
Send a message via MSN to BlueFusion
Default Re: Capacitor question

Those ones look perfect. Good luck
For future reference, caps usually need the exact same capacitance (uF or mFd) rating, and equivalent or higher voltage rating.
BlueFusion is offline   Reply With Quote
Old 09-11-2008, 03:41 AM #11
GooeyGus's Avatar
Class 3B Laser
 
Join Date: Mar 2008
Posts: 2,673
Rep Power: 970
GooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond repute
Send a message via AIM to GooeyGus Send a message via MSN to GooeyGus
GooeyGus GooeyGus is offline
Class 3B Laser
GooeyGus's Avatar
 
Join Date: Mar 2008
Posts: 2,673
Rep Power: 970
GooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond repute
Send a message via AIM to GooeyGus Send a message via MSN to GooeyGus
Default Re: Capacitor question

I think I've found something a bit more interesting than a cap that measures funky. Maybe Mike can chime in on this one as well... But I had a chance to measure the main rectifiers which are bolted and heat-sinked to the huge metal heat sink in the power supply. On one of them, I am measuring a 'short' across it, but I dont know if it's supposed to be that way or what. I tried putting the DMM leads both ways in case I just had them on wrong, but it registers 1ohm or less either way. I'm guessing it shouldn't be like this... but who knows. Laser builders are pretty wacky. Here is a picture of what I'm talking about, it is the diode on the RIGHT (CR4), just to the left of the little LED. The one on the LEFT, measures 50+Ohm.





EDIT: In the picture it looks like theres a piece of *something* that could be shorting two pins of Q8 together, but it's just a little piece of debris that I dropped in there on accident. Forgot to clear it for the pictures *:P
GooeyGus is offline   Reply With Quote
Old 09-11-2008, 04:54 AM #12
Hemlock_Mike's Avatar
Class 4 Laser
 
Join Date: Jan 2007
Location: North Iowa
Posts: 6,184
Rep Power: 4058
Hemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond repute
Hemlock_Mike Hemlock_Mike is online now
Class 4 Laser
Hemlock_Mike's Avatar
 
Join Date: Jan 2007
Location: North Iowa
Posts: 6,184
Rep Power: 4058
Hemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond repute
Default Re: Capacitor question

That part of the PS looks like mine. I wonder why only two diodes. You need 4 for full wave rectification and the voltage rating on the caps isn't enough for a voltage doubler circuit. The 1 ohm reading is unusual since most diodes don't read that low with an ohmeter. Those diodes are big enough to be in the main supply -- looks hard to remove to check out of circuit. Also look for a short in the circuit connected to the diode.

Too late for me here. Niteall -------

Mike
__________________
It's a dog's life
Hemlock_Mike is online now   Reply With Quote
Old 09-11-2008, 05:04 AM #13
GooeyGus's Avatar
Class 3B Laser
 
Join Date: Mar 2008
Posts: 2,673
Rep Power: 970
GooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond repute
Send a message via AIM to GooeyGus Send a message via MSN to GooeyGus
GooeyGus GooeyGus is offline
Class 3B Laser
GooeyGus's Avatar
 
Join Date: Mar 2008
Posts: 2,673
Rep Power: 970
GooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond repute
Send a message via AIM to GooeyGus Send a message via MSN to GooeyGus
Default Re: Capacitor question

Quote:
Originally Posted by Hemlock Mike
That part of the PS looks like mine. *I wonder why only two diodes. *You need 4 for full wave rectification and the voltage rating on the caps isn't enough for a voltage doubler circuit. *The 1 ohm reading is unusual since most diodes don't read that low with an ohmeter. *Those diodes are big enough to be in the main supply -- looks hard to remove to check out of circuit. *Also look for a short in the circuit connected to the diode.

Too late for me here. *Niteall -------

Mike
there are two more diodes behind that big toroid ring, just cant see them in the picture :-[

the other diode, which has the EXACT same model number, reads above 50 ohm. It wouldn't be too hard to remove to test. And by the 'circuit connected to the diode' do you just mean the components before/after the diode?
GooeyGus is offline   Reply With Quote
Old 09-11-2008, 02:38 PM #14
rkcstr's Avatar
Class 3R Laser
 
Join Date: Dec 2007
Posts: 1,368
Rep Power: 142
rkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond repute
rkcstr rkcstr is offline
Class 3R Laser
rkcstr's Avatar
 
Join Date: Dec 2007
Posts: 1,368
Rep Power: 142
rkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond reputerkcstr has a reputation beyond repute
Default Re: Capacitor question

Sorry, I thought you were talking about the large electrolytic caps earlier *:-[

Now I see you were talking about the smaller ones. *Those actually are what I believe are caps across the AC in, I think they're for noise supression. *I doubt they'd go bad, and you probably have a different problem... which I see you're talking about now.

As for the diodes (or transistors), they should only pass current in one direction, so if you measure low resistance in both directions, something's up... BUT, that is for OUT of circuit since there may be something else shorting it in the circuit. *If you suspect one, it would be best to remove it to test, though it looks like that may be difficult.

Though, I'm not sure the rectifiers going bad is very common... ?
__________________
Laser drivers and Test Loads - rkcstr.com

Enter discount code "LPF" during checkout to save 10% off of the regular prices!
rkcstr is offline   Reply With Quote
Old 09-11-2008, 05:14 PM #15
laserguys
Guest
 
Posts: n/a
laserguys
Guest
 
Posts: n/a
Default Re: Capacitor question

I think you found your problem..
If all the similar diodes measure the same except the CR4....
then I'd bet the CR4 diode is gone (shorted out).
Take it out and test it on the bench.
  Reply With Quote
Old 09-11-2008, 10:02 PM #16
GooeyGus's Avatar
Class 3B Laser
 
Join Date: Mar 2008
Posts: 2,673
Rep Power: 970
GooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond repute
Send a message via AIM to GooeyGus Send a message via MSN to GooeyGus
GooeyGus GooeyGus is offline
Class 3B Laser
GooeyGus's Avatar
 
Join Date: Mar 2008
Posts: 2,673
Rep Power: 970
GooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond reputeGooeyGus has a reputation beyond repute
Send a message via AIM to GooeyGus Send a message via MSN to GooeyGus
Default Re: Capacitor question

I'll order a new diode (god knows it will be easier to find than those white caps!!) ASAP and swap it in. It really isn't too hard to get out of there, its just bolted on a heat sink with some dielectric grease *

Oh, and I know it was posted above but I just want to make sure.... These rectifier diodes should only pass current in one direction, right? If so, I'll just pull it out tonight and give it a test on a simple circuit to see what I get.
GooeyGus is offline   Reply With Quote
Reply





Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On











Loading








Green Laser Pointers by Category Blue Laser Pointers by Category Red Laser Pointers by Category
Yellow Laser Pointers by Category Violet Laser Pointers by Category Orange Laser Pointers by Category
Top Laser Pointers by Power - 1 Watt+ Top Laser Pointers by Power - 500mW+ Top Laser Pointers by Power - 250mW+
Laser Pointer Database High Power Laser Pointers Laser Pointer Diodes






Privacy Policy | Advertising Disclaimer | Terms of Use


 


All times are GMT. The time now is 02:55 AM.


Powered by: vBulletin
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO
Privacy Policy | Advertising Disclaimer | Terms of Use
Copyright (C) 2017 Laser Pointer Forums, LLC