partyanimallighting
- Oct 22, 2012
- 330
- Joined
- Oct 22, 2012
- Messages
- 330
Hi all, I have a 1/2 watt RGB laser that was purchased quite a few years ago and it was DOA. Because of this, and a lack of spare time to fiddle, it's been packed up in it's flight case all this time and I basically was using the flight case as a trolley/workbench for other units being repaired.
Anyway......I decided to take a stab at it to see if it could be repaired. The layout is pretty basic, there's a rear panel PCB that handles POWER IN, RED, GREEN and BLUE INTENSITY, X x Y SCANNING WIDTH, ILDA INPUT, KEY LOCK and INTERLOCK. This PCB receives 24VDC from one of three AC/DC power supplies, another outputs 5VDC to each of the laser drivers and the last outputs 18VDC to the X / Y scanner motors. All the power supplies are functional but....the 5VDC power supply is not outputting sufficient voltage to the diodes. When it's connected directly to 120VAC, it powers up fine, but it's 120VAC input if fed from a small voltage control PCB that is connected to the rear panel PCB.
Here's the thing, when the 5VDC power supply is NOT connected to this control PCB, the 120VAC output from the PCB is fine. Once the power supply is connected to the control PCB, the voltage drops down to 1.5VAC so the power supply does not power up the diodes. I gave the control PCB a basic look through and I'm not seeing anything untoward with my untrained eyes. I also removed the relay that controls the 120VAC feed and tested this off the PCB and it's fine, clicking and continuity is there. i then connected the 5VDC power supply directly to a separate feed and all the diode PCB's are receiving proper voltage so it's definitely an issue with either the voltage control PCB or the rear panel PCB that feeds 24VDC to this control PCB.
The RED diode is also working fine but the GREEN and BLUE are not functioning so I swapped out connectors on the driver PCB's and the RED diode is working fine on all of the other PCB's so I'm assuming that the GREEN and BLUE diodes have died so I was also wondering if laser diodes will naturally fade or die over time, even if not in use.
Here are some pix. One of them has the relay removed. I'd really appreciate some assistance with this!!
Anyway......I decided to take a stab at it to see if it could be repaired. The layout is pretty basic, there's a rear panel PCB that handles POWER IN, RED, GREEN and BLUE INTENSITY, X x Y SCANNING WIDTH, ILDA INPUT, KEY LOCK and INTERLOCK. This PCB receives 24VDC from one of three AC/DC power supplies, another outputs 5VDC to each of the laser drivers and the last outputs 18VDC to the X / Y scanner motors. All the power supplies are functional but....the 5VDC power supply is not outputting sufficient voltage to the diodes. When it's connected directly to 120VAC, it powers up fine, but it's 120VAC input if fed from a small voltage control PCB that is connected to the rear panel PCB.
Here's the thing, when the 5VDC power supply is NOT connected to this control PCB, the 120VAC output from the PCB is fine. Once the power supply is connected to the control PCB, the voltage drops down to 1.5VAC so the power supply does not power up the diodes. I gave the control PCB a basic look through and I'm not seeing anything untoward with my untrained eyes. I also removed the relay that controls the 120VAC feed and tested this off the PCB and it's fine, clicking and continuity is there. i then connected the 5VDC power supply directly to a separate feed and all the diode PCB's are receiving proper voltage so it's definitely an issue with either the voltage control PCB or the rear panel PCB that feeds 24VDC to this control PCB.
The RED diode is also working fine but the GREEN and BLUE are not functioning so I swapped out connectors on the driver PCB's and the RED diode is working fine on all of the other PCB's so I'm assuming that the GREEN and BLUE diodes have died so I was also wondering if laser diodes will naturally fade or die over time, even if not in use.
Here are some pix. One of them has the relay removed. I'd really appreciate some assistance with this!!