DK Log Book Started January 2026 ------------------------------------- The most recent entries appear first in this log book. ----------------------------------------------------------------- DATE: -Jan-2026 Topic(s): ----------------------------------------------------------------- DATE: 20-Jan-2026 Topic(s): DK SN #13 back to Dan Returned DK SN #13 back to Dan. It is a normal standard Final Form DK board for Rev A. Spacer height for the heatsink on DK SN #13 was 0.229" - 0.230" and the fit looked good, i.e > 1 mil < 3 mils So far it looks like 4 or 5 spacer heights would work fine for most of the boards. Custom spacers may end up being an OK way to do this long term. ----------------------------------------------------------------- DATE: 19-Jan-2026 Topic(s): DK SN #13 SMD Pad Repair Work to repair and get DK SN #13 into final form. SN #13 was used in October 2025 while I was away as a test board where the normal secondary side terminators were removed and replaced with different lower value terminators. The secondary side terminators were removed from only the odd numbered channels (in the 1:16 dialect). Folks did not have the proper tools to remove these resistors and one of the pads for R783 a Ch #11 terminator was pulled off of the board along with its trace that ran over to a via that made the connection to both the transformer secondary terminal and to the run over to the ADC Input pins. I was able to repair this pad, i.e. make a connection down through the associated small via with a single straind of wire from the center conductor of the RG-178 coax cable. That strong but very small diameter silver plated steel wire works well for feeding through these vias. It took ethanol on the via to get the wire through - probably to clean out flux ----------------------------------------------------------------- DATE: 16-Jan-2026 Topic(s): Felix P-Cal, Rev A to B changes, MSU meeting times DK #39 only its channel #1 has been modified to match DK Drw #62 for P-Cal operation and a full set of measurements taken with 1 usec long Positive voltage source pulses to see what P-Cal signals look like in both standard PMT channel and in the modified P-Cal channel. See the "readme" file in DK web directory ..../Characterization/Felix_P_Cal_Signal_Study/ Waiting for Nathan to look things over and decide, are we going to make special P-Cal boards or put P-Cal signals into standard PMT Channels ? If we do make special modified P-Cal channels then I want to change DK Drw to include a 75 to 100 Ohm resistor in series with the input signal to give the ADC input a little more protection. Current we are using a jumper between pins 1- 2- 5 of the pads where the Input Transformer was. Such a series resistor can go between 1 -2 and a jumpre between 2 -5. I added one more PMT Input Circuit idea to the Rev A to Rev B changes document - use "isolation" resistors between the input transformer secondary and the start of the diferential trace run over to the ADC's input pins. Waiting to hear from Nathan about the current changes document. I think that the Dan S. meetings are at 2PM Monday and 1:30 PM on Friday. ----------------------------------------------------------------- DATE: 9-Jan-2026 Topic(s): Release Changes, Meeting, Cold Test Meeting with Jeanne, Dan, and Nathan. Nathan lists on the board what we should focus on. My first job is to collect Positive P-Cal type signals in a standard normal DK PMT Channel and then after that work on making SN #39 into a Felix P-Cal board. Release my current version of Rev A to Rev B changes. Dan S. has gotten us a refrigerator and a board was in it over night to get fully cold. The only test so far was that the board started up OK. I do not know how cold the inside of the refriderator and the board were. ----------------------------------------------------------------- DATE: 8-Jan-2026 Topic(s): DK SN# 33, 35, 39 Ran DKs 33, 35, 39 through my engineering power supply checks and the OM-Init, Waveform-Stats, and Pulser_Display scripts. Return SN 33 & 35 to Dan as Spares for the string and/or to be used for measurements and tests at MSU. SN #33 took 0.230 0.231 spacers and SN #35 also took 0.230 0.231 spacers that were filed down by about 2 mils. I kept SN #39 as it is to become the first Felix P-Cal board. From the engineering power supply check of SN: 31, 33, 35, 39 Check or Disco-Kraken Board Rotor SW ----------------------------------------- Adjust Position SN #31 SN #33 SN #35 SN #39 Target -------- -------- -------- -------- -------- -------- Choke mV 70.1 70.0 71.4 70.4 P.S. mA 98.2 98.0 99.4 98.6 Leak mV <100 <100 <100 <100 1. V 5.010 4.993 5.019 5.001 2. V 1.0056 1.0054 1.0059 1.0047 1.006 3. mV 3.95 3.92 3.99 4.04 4. V 1.0627 1.0628 1.0622 1.0621 1.062 5. mV 11.42 11.72 11.40 11.53 6. V 1.2013 1.2006 1.2010 1.2005 1.201 7. mV 1.85 1.92 1.82 1.90 8. V 1.8060 1.8055 1.8060 1.8058 1.806 9. mV 7.31 7.49 7.13 7.42 10. V 2.502 2.502 2.503 2.502 2.502 11. mV 2.12 1.87 1.99 2.00 12. V 3.303 3.303 3.303 3.302 3.302 13. mV 5.84 5.76 6.06 5.79 14. V 3.328 3.328 3.329 3.323 15. V 0.5955 0.5950 0.5933 0.5953 16. V 0.5927 0.5949 0.5954 0.5947 Base 807 813 805 864 Line 757 763 750 812 Base Line is the aprox min and max pedestal values on a given board. See the log book entry from 28:30-Nov-2025 for a description of each of these measurements. ----------------------------------------------------------------- DATE: 6-Jan-2026 Topic(s): Work on DK SN# 33, 35, 39 DK SN# 33 one of its ceramic capacitors across the TRACO input pins C1657 0.47 uFd 250V had been mechanically smashed to bits. The pcb pads were still OK and I had a replacement from the parts purchased to make the External TRACO test board. ----------------------------------------------------------------- DATE: 5-Jan-2026 Topic(s): Return DK SN# 31 Start 33, 35, 39 I finished: Pedestal resistor swap, Bond heatsink, TRACO noise mitigation, and Added 220 Ohm terminators on DK SN# 31. It passed: OM_Init, Waveform-Stats, and 16 Ch Pulser Display tests and I trimmed and measured its power supplies. Returned SN# 31 to Dan so that he can have 6 cards to ship this week, i.e. the 4th batch of 5 boards and this SN# 31. 6 boards lets him replace SN #27 - the victim of their Shake not-really-a-test. Dan passed to me SN# 39 so now I start SN# 33, 35, 39 as a batch. ----------------------------------------------------------------- DATE: 4-Jan-2026 Topic(s): Working on DK SN# 31, 33, 35 Pedestal Offset Resistor Swap DK SN #31 was missing its C1476 100 nFd 25 V XR7 From the pad's solder blobs it looks like it was never installed. The Harwin mounting screws and the heatsink screws by the PMT ADC were not tight on DK SN3 31 - they were not even screwed in the whole way, i.e. 2 mm short of being fully screwed in, even thought some one went ahead and installed the heatsink- shield on DK SN# 31. The spacers for the heatsink-shield on DK SN# 31 needed to be 0.240" i.e. about 7 or 8 mils longer than normal.