Viasho 1W 532 PSU question?

[greenalien]

Just in case I gave the wrong impression earlier, I haven't had a problem with my Viasho 1W green module and PSU so far; the inside of the PSU is somewhat different from that shown in the photos, i.e. 2 resistors where the photos show 4.
Now it's installed in the projector, it seems to modulate fine, so I'm happy to 'leave well alone' and keep using it. Time will tell...

[greenalien]

Resurrecting an old post - my Viasho 1w green, bought as part of the group buy a couple of years ago has now done 70 hours. As I have a show tomorrow, I was checking the projector over, and noticed that the brightness of the green was slowly reducing, by about 50% over half an hour. (no problem with the red or blue). Turning the projector off for an hour returned the green to its original brightness. This makes me think it's got some sort of cooling problem, but the fan is running OK and the case doesn't seem to be getting warm. As a precaution, I'm going to turn down the power knob on the PSU, but I don't have time to tear the projector apart to investigate further until next week.
Any thoughts / advice would be welcome!

[smogthemog]

Mine now does exactly this as I noticed a shift in white balance at the last UKLEM after it had been used for a while. It was the green that had gone low power.

[flecom]

hrmm, good to know, how are you guys checking the diode current with a multimeter? like where do you measure it (between what points)?

[rfourt]

hrmm, good to know, how are you guys checking the diode current with a multimeter? like where do you measure it (between what points)?

Same here.-.. how would i go about checking the correct current for my diode.

I have a 1.7W from VIasho also.
funny part is that i have never been able to get it over 1.6, but i thought that its better that it is not overpowered. Although now im starting to think its an overpowered 1.0 that cant reach 1.7.

Any idea how to check this?

Thnx.

[flecom]

I have a 1W doing 1.6~1.7W so I am worried its over-current

[smogthemog]

Please read Rob (Stanwax's) post as he tells you how to check the current.

[flecom]

These are 4x 0.33 ohm resistors in parallel so their combined resistance is 0.825 ohms. Calculating the current using the voltages I was getting on my meter across these confimed that the front panel meter was way out.

dont suppose you remember the vdrop to amps on those resistors?

[rfourt]

I have a 1W doing 1.6~1.7W so I am worried its over-current

damn,..
going to check that diode current as soon as im down at the workshop next time.

Flecom, could you check yours also if possible.? would be interesting to see if we can get similar readings, then i guess i paid alot more then i wanted for my Viasho.

The head hasnt more then about 70hours on it but who would i contact if this is the case. I bought the laser from Lasershowparts(Dave) but perhaps contact Viasho directly?

[greenalien]

Well, I did Saturday's show with just red and blue lasers - the green was still there, but so faint as to be almost invisible. My projector's going to be dismantled in the next couple of days, and once the green module is on the bench, I'll run some tests. Not happy.