fb3 troubles please help

[badger1666]

heres the story set up my fb3 with 100mw green with one of robins drivers and my home made dual red putting out just over 400mw firstly if i set it to display a yellow sine wave its not as bright as it should be as the max drive voltage from the fb3 is only 3.5 volts so lasers not super bright second the sine will start yellow at one end and fade to orangy red the other, i seam to get this with any image with yellow in and it ??
any ideas anyone

[carmangary]

Can you adjust the gain enough on the die4drive so that at 3.5v you get the required current output? If not, maybe robin can suggest changing a component value on the board to allow that.

Not sure what your yellow level is changing. That would indicate either the green is getting dimmer or the red is getting brighter. Is there a slow-start feature on your red that would delay it? I think robins new drivers have some kind of slow start feature. You might want to see if that has anything to do with it.

Good luck.

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Edited: Said bias but meant gain.

[badger1666]

no it wont be slow start or it would start orangy red and fade to yellow it seems to be fb3 problem if it try a ttl dac it ok i could set all of the drivers at a higher currant but if i used another dac i might overdrive them isnt the fb3 suposed to put out 5v on the blanking ? as for the orangy red thing if i play that ipod video animation in yellow the orangy red bit moves all around the displayed images i just dont think the blanking voltages are very stable i think they wander as the image it displayed

[carmangary]

Weird. Do you have an oscilloscope by any chance? It would tell you what is going on.

[badger1666]

wish i had one of those about now might be able to borrow one from work tommorrow i could possibly have a gnd problem as the image was wobbling earlier today poked a bunch of wires and it stopped def somthing up laser brightness is filckring a bit with a single color circle so something weird in the blanking dept

[carmangary]

Yea, could be a connection problem. Check your wiring, soldering, etc. Also make sure your laser modules are isolated from each other so that you aren't accidently shorting a portion of the signal to ground.

[badger1666]

think i found the problem i have gnd from the laser blanking to pin 25 check this thred http://www.photonlexicon.com/forums/...ead.php?t=4207 i will test later to see what happens

[badger1666]

no that did not work all is wired up ok and made no difference
the green blanking is wandering a little my trouble is that fb3 outputs 0 to 2.5v and i need 0 to 5v for robins drivers any ideas how i can boost the blanking voltage to 0 to 5v and i cant adjust gain on drivers to compensate because the green is already set to max

[badger1666]

i did measure with multi meter i thought blanking output was analogue and a meter was ok
at the end of the day alphalite dac worked my setup well norms dac did ok
fb3 works just not very bright ouput red is putting out 200mw green 60mw they should be 420mw and 100mw i thought spending $600 was a step up not down

[Pangolin]

Hi Badger,

I think you got this problem resolved, right?

By the way, was it you who wrote to me the other day?

Bill