Blanking Issue ( itop dac )

[Lasermad]

I have itop DAC ( silver star ), it was working fine with a laser projector i just sold ..now i am trying to get it to work on another projector I just built and its driving me up the wall.

THE PROBLEM I HAVE IS NO BLANKING ! its working great apart from i cant get sodding blanking to work. I am using a viasho single 532nm laser set to + TTL Blanking ...... ( so that gives me wire with single centre core (+) and outer core either (-) or ground ?

This set up has 30k scanners ... they have two amps and each amp has two wires ... one with red line on it other no red line. So thats X+ and X- and also Y+ and Y- . K thats seems to fine , got them wired to pins as i beleive is normal .... pins 1,2,14,15 ...now i have tried variations on pins 3,16 ( intensity) and also 6,19 ( G+ & G- ) to no avail for blanking .. i just dont understand why its not blanking ... you got any clues ?

Somehting tells me i should try X- , Y- , pin 25 and pin 16 all connected together and wired back to both amps chassis ( as grounding )........... is that waayyyy off base ?

PAUL

[dave]

try this circuit, for correct differential reception.

[Lasermad]

Dave
I appreciate the thought .... but I have no background in electronics and the above doesnt mean a lot to me .
Paul

EDIT ADDITION... can anybody help translate above for me into WIRES and PINS ? ( or even explain to me what differential reception is ? is that blanking ? LOL )

[Lasermad]

Ok , finally got blanking working .. ** BUT **with an issue ! so i am still doing something wrong !

I got it working by switching to analogue , attaching centre core from blanking to pin 16 and the outer core to the metal surround of the DB25 socket . It WORKS ,i have no idea WHY but it does !

NOW FOR THE PROBELM
The output is very low ... for a 1 watt laser is kicking out less than 200mW ......

This might be giving me a clue to whats wrong overall ........ i am starting to think the itop DAC is not kicking out 5 volts ,indeed on checking it with a multimeter ( digital though ) I can only get readings of 4 volts ... i dont think this is enough to activate the viasho blanking in TTL mode whereas analogue is variable votalge .

Does any of this make sense ? are my thoughts correct ..is there major flaws in my logic ... is there other ways i can test to confirm ?

PEG

[dave]

Assuming the dac has 2.5v color channels, this is what i would try for single ended operation.

attach pin 16 to ilda ground( pin 25), run this to the shield, connect pin 3 to the center.

You wont get accurate voltage readings with a voltmeter - you really need a cro.