Flexmod P3 red light

[RGbee]

Ok, i'm really frustrated now.
I've just spent quite a while setting up the Flexmod P3 with everything as per the instructions (with interlock defeated)

Once powered up, the red diode comes on as soon as the unit is powered up, even with the interlock defeated.
Would a dead diode cause an in-complete circuit, hence the red light?

[drlava]

Hi, It's probably a simple thing. What diode are you using, what power supply, and what did you set the standby (0-bias) and gain current to?
Regards

[RGbee]

Hi, It's probably a simple thing. What diode are you using, what power supply, and what did you set the standby (0-bias) and gain current to?
Regards

Hiya,
It's a 445 diode. I've got the interlock wired correctly.
I believe the standby current is around 80mA and the gain is set to around 400mA.
The power supply i'm using is a 5vDC 5amp switched mode. The only thing i haven't done is solder the 5V pad on the flexmod. I'm hoping that's the cause and not a blown diode

[dnar]

Hiya,
It's a 445 diode. I've got the interlock wired correctly.
I believe the standby current is around 80mA and the gain is set to around 400mA.
The power supply i'm using is a 5vDC 5amp switched mode. The only thing i haven't done is solder the 5V pad on the flexmod. I'm hoping that's the cause and not a blown diode

There's your problem right there! Your 5V supply is not enough voltage!

445nm diodes have Vf of 4.2-4.5V depending on current. Your power supply needs to be at least 8 to 9 volts in my experience with the Flexmod P3. I am currently running a 12V 2.5A SMPSU and I dial the adjustment provided to 9.3V. Works a treat.

[RGbee]

There's your problem right there! Your 5V supply is not enough voltage!

445nm diodes have Vf of 4.2-4.5V depending on current. Your power supply needs to be at least 8 to 9 volts in my experience with the Flexmod P3. I am currently running a 12V 2.5A SMPSU and I dial the adjustment provided to 9.3V. Works a treat.

Thanks for the info mate. I guess i'll order a 12v
cheers
Adrian

[dnar]

Thanks for the info mate. I guess i'll order a 12v
cheers
Adrian

No worries.

BTW, I should have stated why I reduce the 12V supply adjustment to 9V. This is so the Flexmod does not generate as much heat as it does at 12V. If your running 400mA I think 12V will be just fine however.

[RGbee]

No worries.

BTW, I should have stated why I reduce the 12V supply adjustment to 9V. This is so the Flexmod does not generate as much heat as it does at 12V. If your running 400mA I think 12V will be just fine however.

I'm sure i read somewhere that 5V should be ok, as long as the '5V' pad is soldered on the FM3 (that was basically the reason for buying the 5 volt supply)

[dnar]

I'm sure i read somewhere that 5V should be ok, as long as the '5V' pad is soldered on the FM3 (that was basically the reason for buying the 5 volt supply)

I don't see how, when the maximum output voltage is VDD - 1.5 = 3.5V with a 5V supply.

You might be confused with the 5V pad you can link to the modulation pin...

Your 5V SMPSU would be ok with red diodes.

[RGbee]

I don't see how, when the maximum output voltage is VDD - 1.5 = 3.5V with a 5V supply.

You might be confused with the 5V pad you can link to the modulation pin...

Your 5V SMPSU would be ok with red diodes.

Ah, gotcha. I'll give it a go with the bench PSU tonight
Thanks dnar

[RGbee]

Ok, so tonight i set everything up with a lab PSU running at 9Volts
I set the bias at 80mA, then unshorted the modulation wires whilst power was still maintained and connected both modulation wires to a 5V SMPU. The gain was then set at 500mA.
The multimeter probes were connected to the output wires along with the diode. After powering everything back up i still get no output, despite the meter reading 0.5A. However, as soon as the probes are removedm the red light pops back on, disabling output

I'm now totally lost