Morning input alignment work: better IR alignment to POP_X and LSC-POP

L.Dartez, S. Dwyer, M. Nakano

Continuing from alog 91450, I started using awg to raster the im4 alignment to find the IR beam on the ISCT1 REFL camera on Friday. This effort was paused at the end of the day without finding the beam. This morning, Masayuki and Sheila noticed that the AS AIR camera had a beam but it was off-center. They walked it back using PR2 and IM4 and adjusted PR3 and the BS to compensate. 

When I got in to the control room I adjusted IM4 further to center the beam on ASC-POP_A. ASC-POP_B is still off center but we're choosing to prefer that POP_A stays centered for now.

Later this morning, Masayuki and I decided to see if we could find a PR2 + PR3 + PM1 alignment that 1.) maximizes LSC-POP, 2.) maintains the beam centered on ASC-POP_X, and 3.) maintains the beam center on the ISCT1 REFL camera. Starting from the nominal position (e.g. the position it was already in before we started) we moved PR2 in each direction. Each trial move's procedure was as follows: 1.) move PR2, 2.) compensate with PR3 to recenter ISCT1 REFL camera, 3.) adjust PM1 to center onto POP_X, 4.) observe/record the LSC POP counts.

We currently have roughly 3.4 counts on ASC-POP_X NSUM and 2.7 counts on LSC POP with POP_X centered within about 0.15 and 0.1 counts for PIT and YAW, respectively.

The slider values for PM1 are in PM1_sliders.png and the sliders for PR2,PR3, and IM4 are in IFO_sliders.png.

This new alignment configuration should better position us for the arm peak taking place this week, since we can confirm that we have red beam down to the ISCT1 table and on POP_X. The next intermediate step here will be to lock PRMI...

Masayuki and I aligned PRM. We aren't able to lock PRMI yet since there is no light on LSC POPAIR 18 right now.

Sliders for PRM are in PRM_sliders.png.

I briefly misaligned the PRM and BS to check the actuation range of the RMs with the DC centering loops engaged to make sure that we aren't at risk of railing them. All looks good.

DAS Interrogators settings

Wanda V., Reinhardt R. 

On Friday (08/07) we connected both fibres which measure the arms to the Febus interrogator, with the X arm on Ch1 and the Y arm on Ch2. This frees up the Sintela interrogator for Reinhardts experiments. 

The Febus interrogator is now measuring at 2500 Hz with a downsample factor of 10 before saving, coming to a recorded sampling rate of 250 Hz. The gauge length was 6m. In case there is a crash or the measurement needs to be restarted, the pipleline to load is LIGO_20260807_DS_SR_Writer_both250hz_v2. Filesize is ca 50 MB/min/channel

Monday August 10th: 
We measured at 10 m gaugelength over the weekend and it was changed to 6m at 11:00 am (PST) on Monday. 

The filesize is roughly 100 MB/min for the 6m gaugelength (so 200 MB/min for both channels) and roughly 60 MB/min per channel for 10m GL. If this measurement should be restarted, the pipeline is LIGO_20260807_DS_SR_Writer_both250hz_v3. 

In principle, the interrogator can now run "as is" through IR1, but we are still free to change any of the settings. 

Well Pump Failure

On the morning of Monday, 8/3 I noticed that the well tank was quite low. Given the sporadic re-routing of well water supply to CEBEX this was not immediately concerning. Because the well tank can call for the pump to run, it sometimes calls but never satisfies because of the possible configuration of valves at MY. This confuses the FMCS logic, and will cause it to no longer function as designed. That said, when I attempted to manually command the well pump remotely, it alarmed out. At that point, Eric, Bubba and Richard did some lite electrical troubleshooting. The most obvious issue at the time was that the IR contactor refused to pull in despite the cabinet being in hand and being told to run.

At this point, I called Ohmco to see if they were able to shift their schedule around to put eyes on the well cabinet ASAP. They arrived within ~2 hours and began their troubleshooting. After hours of poking around, their assessment was that the soft start motor control was likely faulty. Unfortunately, despite the soft start readout being largely shielded from the sun, it was not operable so no apparent faults could be documented.

A soft start (P/N ATS480D88Y) was ordered on Monday and arrived Friday. Ohmco arrived that day, swapped the motor control's, set the appropriate parameters according to our pump HP and we verified rotation. This fixed the issue and operation of the wellhead returned to normal.

A second, identical soft start motor control has been ordered and is expected to arrive today. This will serve as a backup in the event this issue arises again. It will be clearly labeled and stored in the carpenter shop.

B. Gateley E. Otterman R. McCarthy T. Guidry 

Mon Day Ops Transition

TITLE: 08/10 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    SEI_ENV state: EARTHQUAKE
    Wind: 7mph Gusts, 4mph 3min avg
    Primary useism: 0.58 μm/s
    Secondary useism: 0.09 μm/s 
QUICK SUMMARY:

NOTE:  Both Ops work stations had troubles logging in  (I could enter my username, but then the computer would freeze...for both computers).  So I'm back here at cdsws27.  It worked, but it was a little slow.

We had a M7.4 earthquake in Bogota (sort of in between Cali/Medellin/Bogota) that rolled in here about 2hrs ago.  Looks like this has mainly tripped mostly LVEA HAMs.  Picket Fence is lighting up in yellow also.

Oh and Rattlesnake Mountain finally returns (after missing quite a bit last week due to a smoky week).  AQI for Richland (closest sensor on AirNow) is at a YELLOW 71.  Only active fire in Benton Franklin counties is far away up near Kahlotus (Nunamaker Road Fire with 20k+ acres.

Also, the GWANW (Gravitational Wave Astronomy North West) meeting will be hosted here at LHO today and tomorrow.

Post NOTE:  Looks like BOTH ops workstations have now moved to the password for the login, so I will try to move back there.

Friday Ops shift report.

TITLE: 08/07 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:
Dust levels for H1:PEM-CS_DUST_LAB1_300NM_PCF is climbing up to 70,000 counts today. I imagine that the Dust level is goign to continues to rise with the wind this weekend. 

Input Alignment team has a PLAN, which is a simple matter of just walking the mirrors.  

Output  Arm team has been looking for MAXIMUM_POWER through their straws in HAM7, Note: Removed yellow View Port cover and left a guillotine in place on HAM6  & Misaliging SR2 & SR3.  

VAC team reports:  "Cryo Traps are open to the Beam Tubes." &  "The Corner station is still isolated from the Beam tubes." 

End Station Y had it's PCAL Integrating sphere returned today after it was stolen for some lab measurements last night. 

LOG:

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
14:53	FAC	Kim	LVEA	n	Technical cleaning.	15:35
15:30	VAC	Jordan	LVEA	n	Taking pics of GV6 status	16:00
17:12	SQZ	Sheila & Ryan S	LVEA	YES	Power measurements In HAM7	19:42
18:29	VAC	Jordan & Mitchel	LVEA	y/n	opening ION pumps in the LVEA	19:14
19:49	PCAL	Tony, Cory	PCalLab, EY	YES	Taking Ey's PCAL Sphere back to EY's Laser Enclosure.	21:05
20:01	FAC	Tyler +1	EY	-	Wellhead work	22:01
20:24	CDS	Marc, Caroline	CER	-	Swapping ISC power supply	21:04
20:26	PEM	Carlos, Shrey, Miranda	Overpass	-	Seismometer tests	22:26
20:37	VAC	Jordan	LVEA	-	Opening/closing GVs	22:25
21:08	SQZ	Sheila & Ryan	LVEA HAM7	YES	Power Budget measurments & Beam Profiling	23:08
22:09	CDS	Dave	CER	N	Looking at the accelerometer.... Specifically Not Touching it	22:25
22:35	CDS	Dave Miranda	CER	N	Checking on more accelerometer chassis cabling	23:15
22:43	VAC	Jordan	LVEA HAM6	yes	Isolating turbo pumps, and turning on the ION pump in HAM6	22:54

PCAL Receiver Spheres Romoved from End Stations!

Both End Stations had their  PCAL Reciever modules pillaged for Integrating spheres. They were taken to the lab and measured against PS4 on the lab bench for the first time in..... at least 4 years. 
Preliminary Results found here: PSEYRX
And Here: PSEXRX.

Set up notes:
python pcalRRSO4_measure.py \
    -DN1 PSEXRX \   <-Power Sensor  from EX's Receiver side.
    -DV1 8018023 \  <- This KVM is getting the signal that we usually get a temperature signal from.
    -DN2 PS4 \ <---- this is nominal 
    -DV2 8002111 \ < - nominal
    -DT2 1421891 \ <-nominal 
    -a yes \
    -x \
    -log 'PSEXRX_PS4 PSEXRX front track PS4 on the rear track' \

These measurements were ran without a temperature measurement as they do not have an AD590 to read from. But rather the script just assumes the temperatures for both spheres are the same and just used PS4 temperature sensor.
I used the PS5 Kit to set them up (Satelite box, cable, & accessories.) plugged in exactly the way I'd set up PS5.
Read the Voltage off of what would normally be the temperature KVM as it is nominally plugged in. The reason for this is because I was surprised to see that the KVM that we would normally get temperature signals from PS5 with would change voltage readings when the Sphere was exposed to Laser light....  I Also noted that this Temperature KVM had a Higher voltage reading that the normal KVM we would use to read the voltage from PS5 . Infact the normal Voltage KVM is half of the voltage read by the Temperature KVM. So I chose that one for a better signal to noise ratio. Is this the correct value. I'm not sure yet. but we will find out.

I ran this over night running multiple measurments. 


Another  Note: The PCAL Laser Chassis at End X has been showing a Red LED that is not normally red and Labeled "I limit" or "l limit" either way. The First time I saw it was right after a power outage so i thought it was just a weird one off sort of situation. I just powered the laser Off and back on again and the LED went away.
But I saw it had happened again yesterday, and power cycling the Chassis did NOT resolve it. I checked the MEDM screen and saw that  H1:CAL-PCALX_LASERDIODECURRENT was jumping around 9.7-10.0 Amps. So I simply changed the voltage a little and brought the voltage back up and it resolved the issue. l limit was no longer lit. Checking on it today and it seems to still be functioning normally now.

All spheres are now back in their Nominal configuartion.... bolted to the IFO.

HAM7 power budget repeat

Ryan S, Sheila

In summary, after removal of the A:L2 apperture stop we still see about 4% extra losses in HAM7.  We searched for the rejected beam from SFI1 in both directions with lights out, IR card, and viewer.  To explain a few % loss we should expect to have 10-20urad in this beam, which should be visible with lights out an a viewer.  We also noticed that the beam is off in yaw at the location where we had an iris after ZM1.  

Since Ryan and Camilla aligned the beam onto the SQZT7 PD yesterday, we are noting the power on that PD here after each measurement so we can use that to account for fluctuations in power out of the OPO.  

• out of OPO 1.354mW std 0.5uW PD 1.26-1.154 max-min, repeat in same location 1.340mW std 0.57uW PD: 1.26-1.154 max-min
• after ZM4: 1.209mW std 11.5uW  PD 1.233-1.12  
  • PD ratio: 98%  power dropped during measurement
  • power meter ratio:  89%(1st meas) or 90% (2nd meas)
• after BL1: 1.265 mW std 2uW  PD 1.241-1.14
• before BM1 (SFI1 return): 1.268 mW std 582nW  PD  1.23-1.11
• Remembered to start turning lights off
• before ZM1: 1.342 mW std 688nW  PD 1.24-1.11
• after AP1 before SF1 (on the way to FC): 1.316 mW std 680nW  PD 1.235- 1.08
• before BM1: 1.267 mW std 831nW
• on SQZT7: 1.191 mW std 5uW PD: 1.2032 much quieter with curtain up  (9.5% loss where we expect 4%)

From the control room, we dithered ZM2 + ZM3 and tried to reduce the fluctuations in the SQZT7 IR PD, we were able to recover a 4% of power this way, with fairly small adjustments (+9urad ZM2 P, +19 urad ZM2 yaw, 5 urad ZM3 yaw).  

One more round of power measurements: 

• out of OPO: 1.334 mW std 480nW  PD 1.248
• on SQZT7: 1.217 mW std 2.8uW (8.8% total loss)
• before BM1: 1.265 mW std 600nW  PD 1.25 (5% losses from 2 passes of SFI1)
• after BL1: 1.272 mW std 1.6uW  PD 1.25 (no loss from B:L2 apperture stop)
• after ZM1: 1.307 mw (not perfectly centered)  PD 1.25 (2% loss from 1 pass of SFI1)
• on SQZt7: 1.227 mW std 900nW  PD 1.25 (8% total loss)

 

New input alignment settings for IM1, IM2, and IM3

K. Kawabe, E. Capote, L. Dartez

This log covers work that started yesterday. We set out to scan the IM1 pointing to see if we could find evidence of clipping and to potentially identify a preferred input pointing configuration. We applied a dither to the IM1 and IM3 suspensions to use IM4_trans and the ISS second loop QPDs as sensors. This test was laborious because each new IM1 pointing mis-centered the beam on both QPDs. Keita pointed out that we can use IM2 and IM3 to center the beam on the IM4_trans and ISS second loop QPDs, respectively. Moreover, by centering the beam on IM4_trans and the ISS second loop QPDs, we get the beam for free on the POP QPDs (even though it is not centered there). To support the argument that we can arrive on a pointing now that will be relevant once we open the arms, we note that the QPD NSUM levels for the IM4_trans, ISS second loop, REFL WFS A and B QPDs are all consistent with what we had in O4 at 2W. The NSUM levels of the POP QPDs is consistent with what we had in O4 at 2W straight shot (PRC misaligned) as well. During this test we paid particular attention to avoid moving the input alignment to a spot that would have the RMs near their actuation range to keep the beam centered on the REFL QPDs.


For each IM1 pointing trial we did the following: 

1. Move IM1 alignment to new trial position
2. Walk the alignment of IM2 and IM3 to center the beam onto IM4_trans QPD and the ISS Second Loop QPD (within about 0.04 in PIT and YAW). I used IM2 to center the beam onto IM4_trans and IM3 to center it onto the ISS Second Loop QPD.
3. Check that the beam hasn't fallen off of the REFL PDs or the POP PDs and that the NSUM, PIT, and YAW signal values are at roughly the same values as they were before the IM1 adjustment.
4. Run the DC centering loops to center the beam on the REFL PDs and ensure that the RMs are not close to their actuation range. 
5. Measure the transfer function from the IM1 and IM3 DAMP banks to the IM4_trans and ISS second loop QPD SUM channels while injecting an 8Hz excitation into the IM1 and IM3 SUS TEST banks. 

The IM1 trials we tried are as follows:

Nominal position (the IM1 position when we began): 524.2 / -386.6 (P/Y)

Trial 1 (pink): (+30 uRad Yaw): 524.2 / -356.6 (P/Y)
Trial 2 (brown): (-50 uRad Yaw): 524.2 / -436.6 (P/Y)
Trial 3 (green): (-10 uRad Yaw): 524.2 / -396.6 (P/Y)
Trial 4 (blue): (+40 uRad PIT): 564.2 / -386.6 (P/Y)
Trial 5 (red): (-40 uRad  PIT): 484.2 / -386.6 (P/Y)

The five trials for this test were split across two days. And the excitation amplitude was not necessarily constant across all 5 measurements. This made it difficult to compare today's measurements against yesterday's. In any case, we think that the position at Trial 4 is the best one so far in that it shows the lowest coherence between the dither at IM1/IM3 and the IM4 trans QPD. We do not know or think it is unilaterally the best position, but we think it is better than it was before we started this. We won't know more until we have the arms. 

The new slider values for IM1, IM2, and IM3 are in IM_alignment_sliders.png. A screenshot of the TFs we took is at blueisgood.png. The colors of the traces correspond to the color next to each trial listed above. The blue trace has the best coherence for most of the measured transfer functions (and for all of the IM4_trans measurements). The DTT template we used can be found at ~keita.kawabe/IM1_moves_IM4_trans_ISS_QPD.xml.

Opening Cryotraps and Ion Pumps to Corner Volume

Per WP 13497

I opened IP1/2/3/4 to the corner volume at 18:38 UTC / 11:38 PDT

GV8 Soft closed  at 20:47 UTC / 13:47 PDT

GV7 opened at 21:20 UTC / 14:20 PDT

GV5 opened at 21:48 UTC / 14:48 PDT

Both GV5 & GV7 opened between 45-50 psi, and the holding pressure is set to 55 psi.

GV6 and GV8 will remain soft closed to isolate the beamtubes. CP1 and CP2 are now open to the corner volume to assist with the water pumping, water is still the dominant gas after ~22 days of pumping, see corner RGA scans in alog 91446

Corner pressure is decreasing as expected.

PR3 moved to O4 slider (not OSEM), next we need IM4 scan

I've moved PR3 back to latter half of O4 based on the slider, not OSEM.

Assuming that the ITMX angle is good and the beam deflection angle through the BS is the same as before, the plan to get ready for the arm peeking is as follows.

Find a good IM4 angle where the ITMX reflection comes back to ISCT1 camera (Louis is working on it).

Once that's found, align PRM, refine PRM and IM4 alignment to have a good PRX flash.

After that we might have to walk the beam on PR2 without touching ITMX and PR3. Unless there's a convenient script to do that, you'll move IM4 a bit, change PR2 so that ITMX retro reflects, and change PRM to recover PRX.

By iterating, you'll eventually settle on the beam position on PR2 that will give you an ok signal on LSC or ASC (hopefully both) POP sensors in HAM1. 

Also work on the ISCT1 alignment for the ALS beam, but this will be on Monday.

CER Kepco Power Supplies

WP13495

The following supplies were replaced in the CER Mezanine.

Kepco Power Supply in VDD-C6 Rack, Left Slot U31-29, ISC-R3&R5 +24V
Old S12001945
New S12001992

Kepco Power Supply in VDD-C6 Rack, Right Slot U31-29, ISC-R3&R5 -24V
Old S1201946
New S1201947

The negative supply was oscillating between 22V and 21V when measured before replacing, possibly due to failed fan.  New supplies were adjusted to +/-24V at the racks.

Caroline C, Marc P.

To the operators: What to do when JAC lost lock and JACK_LOCK cannot lock it because WFS went crazy.

This morning JAC lost lock due to temperature drift (temperature control was on) and at the same time WFS went crazy. After that JACK_LOCK guardian couldn't lock it, just kept scanning without success because the alignment was very much off.

When this happens, what you should do is:

• Move JAC_LOCK to DOWN.
• Open JAC_WFS_MASTER medm screen and clear history for DOF1_P and DOF1_Y.  JAC_WFS_crazy.png
• From that screen, open JM1 screen and you'll see that the LOCK_P and/or LOCK_Y output are big, like (JAC_WFS_crazy_JM1.png). Click "Lock Filters" and clear the history of P and Y.
• Move JAC_LOCK to LOCKED.

For the lockloss and WFS behavior see jac_lockloss.png.

 JAC lock voltage was drifting lower and lower, which meant that you must have cooled JAC down, but the temperature servo was heating it more. Ultimately we need a temperature servo to keep the lock PZT voltage constant rather than keeping the temperature sensed by the thermistor.

After the lock voltage alredy hit the bottom rail, it took about a minute for JAC to completely lose it. During this time, JAC_L error increased as the JAC slowly became off-resonant, and of course the same signal is seen by all WFS segments. Since WFS centering is not perfect, this increased WFS P and Y signal. JAC ASC tried to counter this by twisting JM1 and the PZT mirror without success.

Finally the WFS was turned off but mirrors were already heavily misaligned at that point. 

Corner RGA Scans - August 7 2026

RGA scans were collected for the corner volume using the new PrismaPro RGA. This RGA tree had been rebuilt and baked at high temp for 2+ weeks. Scan info below, raw data files will be posted to the DCC at T2600329.

RGA Model: Pfeiffer Prisma Pro

EM Voltage: 1200V

Dwell Time: 1s, 0-100 AMU, 10 pts/AMU

Valve States: GV5 & GV7 closed, FC2 & FC4 closed (Relay Tube removed & FCB-1 section common with corner)

Pumping: 3x 2000 l/s Turbo pumps, 1x 500 l/s turbopump (HAM6)

RGA filament has been on since 7/22 after RGA tree bakeout

Corner Pressure (8/7/26): 3.2E-7 Torr (PT120B)

Corner Pressure (7/27/26): 5.3E-7 Torr (PT120B)

Comparison plot showing partial pressure decrease after an additional ~10 days of pumping with turbo. Corner started high vacuum pumping on July 16th 2026 (22 days of pumping with turbopumps only)

DAQ CRC error trend over past 6 months

Dave, Erik, Claude

Claude AI wrote a python script to plot the H1 DAQ CRC rates for the past 6 months for all frontend and both DAQ legs (see attached). This plot only shows when an individual DAQ leg recorded a CRC error from the front end. The times there were CRCs on both legs were usually due to model restarts and not spontaneous errors, so these have been removed from the plot.

The vertial lines align with Tuesdays and possible maintenance activities.

General first thoughts are: over the long term the CRCs are fairly randomly distributed over front ends and DAQ legs; in the past week they have been concentrated on the 0leg and the two frontends iscey, seib1.

DAS system, tap testing to calibrate distances along fiber

Jenne, Wanda, Shoshana, Gizem

We started very early this morning to beat the heat, and performed 'tap tests' at various points along the length of the arms to identify positions along the length of the fiber (according to DAS) with GPS positions (according to Wanda's phone).

Spreadsheet attachment is information about where along the fiber Shoshana and Gizem identified our tapping in the data, and associated time stamps.  I've also copied the spreadsheet data to a google sheet, so that we can add to it.  

We tried to do more dense taps on the 'inside of the vertex' side of the arms, where the fiber actually is.  This required some walking out in the sand along the arms, so we had sun hats and knee-high boots and plenty of water.   We also did a few taps along the road during our drive back, to get some more coarse information along the length of the arms.  At the Xend station, there were too many tumbleweeds for us to walk along the inside-vertex side of the arm, so there at EX we did our more dense taps along the road side, with the exception of the EX vault location. 

In the attached photos, you can see some examples of our tap test method.  Gerardo provided us with a scrap piece of steel that we used as a strike plate.  We also borrowed a sledgehammer from the mechanical / vacuum parts lab.  For most of the Yarm, we only did 3 heavy strikes and Gizem and Shoshana chose the strongest signal from that as our time.  Once we were on the road-side of Yarm, and then for all of Xarm, we added some light tapping that seems to have helped identify which distance bin (called a "channel" in DAS terminology) we were closest to.  The photos are also labeled with X/Yarm, and position number, which corresponds to the position numbers in the google sheet - I tried to capture features in the photo to help identify where exactly the strike plate was.

Wanda has added to the google sheet the GPS locations that she identified while we were at each tap point.

The last photo shows our used (but can be used again in the future!) strike plate. 

I have attached some screenshots which show what the referenced path looks like for the x-arm. Further, it demonstrates how the optical metres of the fibre are now referenced to a certain co-ordinate. With this, we can now correlate any events that we detect to a physical location. In this software, a straight line is drawn between two referenced points. 
In picture 1, the whole arm is shown. 
In picture 2, it is zoomed in on the area around the corner station, showing the limitations in our technique as it is relatively rough considering we know the fibre is curving at this point. 
In picture 3, we see how hovering over the waterfall plot will produce a red point in the refenced fibre showing the location of this channel. 

And here are some more pictures of the georeferencing.

Seal Replacement on GV6 Air Cylinder

Travis, Gerardo, Jordan

During the closing of GV6 back in May, we noticed that there was some blow-by in the pneumatic system when trying to hard close the valve, see alog 90093. 

We were able to hard close the valve eventually but as preventative maintenance we wanted to replace the air cylinder seals, similar to GV7.

Prior to disassembly we measured the locations of the reed switches from the top surface of the bottom plate to the bottom surface of the reed switches:

Bottom Switch: 1 1/8"

Top Switch: 49 1/4"

We then disassembled the air cylinder and replaced the seals following procedure/notes collected during the GV7 repair. During cleaning of the old grease on the piston head, we noticed there were two burrs on the top of the piston, we did not notice any damage to the inside of the cylinder, but as a precaution we used a small flat file to remove the burrs. We also chased the threads on the four threaded rods with a die to aid with reinstallation. After cleaning and inspection of the cylinder tube, we found no issues or damage so we decided to continue to use that cylinder and keep the new one as a spare.

No other issues encountered, we removed the old seals, cleaned the grooves, added copious amounts of the supplied grease to the o-rings, seals and the inside of the air cylinder, and then re-assembled the cylinder tube. Pictures posted below and a final procedure is in progress and will be posted to the DCC.

We did not get a chance to cycle the valve after the seal replacement, so we will continue tomorrow with cycling the valve.