Reports until 15:07, Tuesday 16 April 2024
H1 PEM (PEM)
marc.pirello@LIGO.ORG - posted 15:07, Tuesday 16 April 2024 (77217)
EX Accelerometer Conditioner Repaired

I pulled EX Accelerometer Power Conditoiner S2300070 per WP11813 to investigate a bad channel and the restult was that the input resistor had blown on that channel.  The symptom was that the channel was completely off, no LED activity on the front panel for that channel.  The current draw per channel at 24V is < 63mA, the 10 ohm resistor is rated at 1/4 watt which gives us an upper limit of 160mA current.  It could have been inrush current that blew this resistor as they have only been tested on bench and not with kepkos' higher current rating.  This is part of the low pass filter for these accelerometer channels.  I replaced the 10 ohm 1/4 watt resistor with a 5W resistor.  I will keep an eye on these, if this becomes an issue, we might consider replacing the resistors with higher wattage versions as there is space on the board for it.

Channel Order
CH1 - Cable 7 - AA7 - OPLEV-Y
CH2 - Cable 8 - AA8 - BSC9_X
CH3 - BLK_NL - U2_9 - Manifold1
CH4 - Cable 10 - AA10 - BSC9_Z
CH5 - Cable 11 - AA11 - TableX
CH6 - Cable 12 - AA12 - BSC_Floor
CH7 - Cable 13 - AA13 - Ebay_Floor
CH8 - BLK-NL - U2_11 - Manifold2
CH9 - empty - empty (ready to replace the Meggit single channel device)