Chromatography Forum

I have a Waters 2487 dual absorbance detector that starts up fine (every option is OK on the startup diognostics) but after it warms up for 5 minutes, it seems to just restart and proceeds with the startup and warmup again. Can anyone help with this problem?

My first guess would be that a cooling fan is not functioning and the unit overheats after a while.

Second guess would be that the lamp is dying.

it might be worthwhile replacing the onboard battery on the cpu pcb, this is a standard cr2032 battery, if this does not fix the problem then you could check the 5v supply on the low voltage psu, i think there is an adjustment on there for the 5v supply, if not it will be a replacement low voltage psu required. if my memory is correct the detector will give a lamp error if the optic bench overheats due to a fan failure

Hi,

When the 2487 powers up and then cycles power that is a LVPS issue. You need to adjust the 5VDC on the PSU.

I have the same problem can you give instruction on how to adjust the power supply?

Adjusting it usually doesnt help. You almost always need to replace that power supply when it goes. It is a fairly easy thing to do.

On the 2487 there are two power supplies, the one furthest to the left is the main and the one to the right of that is the lamp power supply. On the main power supply (left) towards the back and top of the board there is a pot resistor (adjustable resistor) that is plastic with a screw head on it. Using a plasitc screw driver turn the pot clockwise about a quarter a turn. Turn the detector back on and it will boot, you might need to adjust the contrast of the screen because it will be darker from the adjustment. Basically what you did is increase the voltage to the rest of the components.

Why it break is over time this pot drifts and one you start the detector up more components turn on (grating moves, filter wheel moves) drawing more power to the point where the it draws too much and reboots itself in a continuous loop. This trick only works a few times it it keeps happening more than likely the power supply needs to be replaced.

Adjusted power supply to 5.05 volts (if I am remembering correctly) and the problem was solved.

Thank You

Hi,

anything over a value of 5.1 or even 5.2Vdc should work perfectly. At 5.05Vdc the value can drift lower.
You'll get away with adjusting the voltage upwards a few times and then you'll have to replace the LVPS. But it should be good for another while.

I have a Waters 2487 dual absorbance detector that starts up fine (every option is OK on the startup diognostics) but after it warms up for 5 minutes, it seems to just restart and proceeds with the startup and warmup again. Can anyone help with this problem?

I know this thread is a little old but what was the resolution to this problem? I am having the exact same problem. I hope someone has notification enabled.

Thanks,
DWFlickner

Your problem is to do with the LVPS. You need to adjust the 5Vdc to 5.2Vdc or replace the PSU if this doesn't rectify the issue.

@bmo37

Thanks, a quarter turn was enough for me. Problem fixed for now.

Cheers

Just a heads up.

don't blindly adjusted the voltage, you need to use a multimeter and adjust to value. Because if you go to far you will damage the LVPS and will need it replaced. Also note that the LVPS when adjusted is classed as a temporary fix as this is an indication that the LVPS is abot to fail. What timeframe I'm not sure. It could last for another year or two days.

Regards,
Bull76.

Your problem is to do with the LVPS. You need to adjust the 5Vdc to 5.2Vdc or replace the PSU if this doesn't rectify the issue.

I have the same start up issue with my 2487 detector, I did quarter turn clockwise as the post mentioned but did not fix the problem. my question is

1. the one I adjusted is a blue 3-leg resistor with a mental head on it. it is labeled as R12 on the power supply board. Is this the one that I should turn 1/4 turn?

2. where to measure that 5Vdc? I have multi-meter so I just want to check what is the voltage now.

3. in case this temporary method does not work, what piece I should replace? I saw there are answers of LVPS (low volt power supply) and PSU (power supply unit?), which one is the correct answer?

reply will be highly appreciated

Hi,

Been away from the repair end for quiet a while. PSU & LVPS are reference to the same part. When I adjusted the Voltage usually measured on the output side of the unit. Then adjusted to 5.1 to 5.2. Wouldn't go any higher than that. Blindly turning the pot a 1/4 of a turn will tell you nothing and could damage the LVPS.
If the fan is blocked or covered in dust then this can have the same affect. Need to ensure the air path from front to back is clear.