Differences

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--- pmt [2024/12/30 12:27] – created reno
+++ pmt [2025/12/18 12:11] (current) – reno
@@ Line 8: / Line 8: @@
 {{ :pictures:high_speed_amp_testing.png?400 |}}
+====== Disassembly ======
+<hidden ===== Removing the PMT Tube with Filter wheel 3 (Mk4 and selective Mk3)=====>
+  - Remove the coax cable (1)
+  - Remove the db9 connector (2) {{:brewer_main:20251208_102212.jpg?600|}}
+  - Remove the db9 connectors (1 & 2)
+  - Carefully remove the thermister from the PMT (3)
+  - Remove the 10-32 socket head screws (4,5,6,7) {{:brewer_main:media_6_.jpg?600|}}
+  - Carefully slide the entire PMT tube out (Note the orientation when you put the PMT back in later)
+</hidden>
+<hidden ===== Removing the PMT Core =====>
+  - With the PMT standing up, remove the top cap (Note: It is a very fine thread, carefully remove the lid as there are electronics right under it.){{:brewer_main:20251209_131536.jpg?600|}}
+  - Remove the two 4-40 socket head screws {{:brewer_main:20251209_073639.jpg?600|}}
+  - Move the PCB board (High Speed Amp) out of the way and Loosen (do not remove) the 3 (1,2,3) 4-40 socket head screws (about 3 turns){{:brewer_main:20251209_073559.jpg?600|}}
+  - unscrew the threaded plate and carefully remove the PMT core {{::20251209_073438.jpg?600|}}
+  - un-solder the resistor off the post
+    - Tip 1: Due to the old solder, it maybe a good idea to add a little bit of new solder then remove it.
+    - Tip 2: You don't need to completely remove all the solder, once most the solder is gone, use a pair of plyers to move the coiled up resistor off the post
+    - Tip 3: there may be a bit of silicone on it, make sure you remove the silicone first {{:brewer_main:20251209_072620.jpg?600|}}
+  - Put on a pair of gloves!
+  - Remove the PMT's shield to expose the PMT core{{::20251209_072719.jpg?600|}}
+  - Slowly wiggle out the old PMT core {{:brewer_main:20251209_072743.jpg?600|}}
+</hidden>
+<hidden ===== Notes for Reinstalling The PMT ===== >
+  - When reinstalling the "new" PMT core note the keyed section of the PMT socket {{:brewer_main:20251209_072803.jpg?600|}}
+  - Once the PMT core and PMT shield is reinstalled, ensure the resistor is soldered back onto the post. This is very important otherwise it will not measure/count well! Add some silicone to it to protect it from shorting it with anything else
+  - All the threads on the PMT are fine threads, be very careful and not cross thread anything
+  - Repeat the steps backwards to reinstall everything.
+  - In step 10, you do not need to thread it until it is tight, the 3 screws will keep it tight from letting it spin. Spin the thread so that the coax cable and db9 is in the correct orientation.
+  - After re-installation, in sure you seal the instrument up with fresh desiccant. It may take a couple of days for the PMT to settle down on the counts and dark counts after being opened up. In more humid location, this may take longer.
+</hidden>