RED LIGHT ERROR DENSITOMETER ON FRONTIER 350 LP1500SC

[SaymonFTL]

Hi everyone, I recently replaced the R, G, and B lasers and the LDD20 board, but when I needed to calibrate the paper, the red error light on the densitometer came on and simply won't go off, and I can't calibrate my paper. I've tried resetting it with the reset button and even turning the device off, but nothing works. Can anyone help me?



Sorry for my English.

Edited May 7 by SaymonFTL
I attached a file.

[Minilab service]

On 5/7/2026 at 8:45 PM, SaymonFTL said:

Hi everyone, I recently replaced the R, G, and B lasers and the LDD20 board, but when I needed to calibrate the paper, the red error light on the densitometer came on and simply won't go off, and I can't calibrate my paper. I've tried resetting it with the reset button and even turning the device off, but nothing works. Can anyone help me? Sorry for my English.

Hello.

Why do you use so big fonts? It is very hard to read what you wrote here. Look how I formated your text.

If I see correctly you have AD100. It is the oldest. To LP1500SC can connect newer models. Densitometer is connected to connector CTL19 on CTL20 board. There are 7 wires.
CTL19 pin 1  : +24V power supply
CTL19 pin 2 : power supply ground
CTL19 pin 3  : TX
CTL19 pin 4  : RX
CTL19 pin 5  : digital ground
CTL19 pin 7  : CTS
CTL19 pin 8  : RTS

Between printer and densitometer used not standard cable. Can't use standard COM cable there.

Check all connections. If all well, but dioesn't work then densitometer is faulty. Can use the same, or newer model ( AD200 ) .