avatar: Basan
3 posts
Replied to Basan's post on April 15th, 2018

Dear Don

We have at the Ministry of Science & Technology, Beckman Coulter LS6500 Liquid Scintillation Counter, serial No.7071463 delivered to Ministry of science and technology in Baghdad / Iraq in 2009.

Now, we are experiencing a major problem which is not accepting any calibration, and always ends up with the message (unsuccessful calibration) or when trying to read a vial ends with the message (error).

Any suggestion on how to repair it or some troubleshooting, or any advice will be most appreciated

The last Calibration done on the 22nd of April 2010, where the left gain was 2807 and the right gain was 2561.

Left Offset was 800 and the right Offset was 754

Yours sincerely

Basman Rassam

Subject: Mr.Basman Rassam

Answer to your questions:

Are you getting zero counts for everything? NO.

There are two LEDs on the board, for the Left and Right supplies. Do both light up when you try counting? YES

When I look at the status LEDs on the Coincidence/Analog board (right side) do DS2 and DS4 light up when you try counting? YES

Can I actually count samples and get count data? YES and I get the message INVALID SAMPLE COUNT when no vial in the rack , which suppose to skip and when there is a vial, I get very high readings for C14 and 3H and Background.

May be a problem with the internal Cesium137 standard installed in the counter. Or PMs, I am back with the answer to whether or not I can just count samples without trying to calibrate the counter.

Yes I can count samples but not real.

How to check the internal Cesium137 standard installed in the counter?

Sample count error

My 137Cesium source may have come loose in its spring, There is a limited amount of troubleshooting that a user can do without a Service Diagnostic Card which all service engineers carry but I believe that a service visit is required.