With great difficulty, we repair our Patron-donated HP 115BR divider and clock, an instrument that was once used to synchronize all of the world's atomic clocks. It requires a bit of a fight, but in the end, we are rewarded with the most steampunk atomic clock ever!
HP 115BR Playlist: https://www.youtube.com/playlist?list=PL-_93BVApb5-_7sWRxQ0on8vNy7_H-zxS
Link to the HP 115BR Manual: https://bama.edebris.com/download/hp/115br/HP_115BR_frequency_divider_and_clock_op_service_manual_1967.pdf
Stuff that supports the channel:
- Support us on Patreon: https://www.patreon.com/curiousmarc
- Amazon links for the tools I use in the lab: https://www.curiousmarc.com/amazon-links
- Channel merch on Fourthwall: https://curiousmarc-shop.fourthwall.com
- Legacy channel merch on Teespring (I don't have everything transferred to Fourthwall yet): https://teespring.com/stores/curiousmarcs-store
"Elevator Music" Credit: Crinoline Dreams by Kevin MacLeod
Our lovely sponsors
- PCBWay: fast turn PCBs, https://www.pcbway.com
- Electro-Rent: https://www.electrorent.com
- Keysight: test instruments: https://www.keysight.com
- Samtec: connectors: https://www.samtec.com
- R&D Microwaves: https://rdmicrowaves.com
Get more technical info on the companion site: https://www.curiousmarc.com
Contact info: https://www.youtube.com/curiousmarc/about
00:00 Recap of Part 1
01:45 Reverting to the original configuration
04:43 Schematics explanation
07:41 First regenerative divider
10:40 Magic "endless" phase shifter
12:46 Second divider not working
14:48 Debugging the divider
16:57 Tripler transistor weird fault
19:25 Our loopy circuit is cursed!
20:30 Second fault in the mixer?
23:20 It must be the transistor
24:10 It must be the tuning circuit
29:00 Maybe a biasing fault?
32:21 We got it, it's working
33:35 60 Hz reference repair
35:58 It's all repaired!
37:13 Atomic time, baby!