#garfield Logs

Feb 13 2020

12:01 AM rue_mohr: playing with an ethernet transformer
01:05 AM zhanx: rue_mohr, got the job
01:05 AM zhanx: for satellite stuff
01:32 AM rue_bed: oh good
01:32 AM rue_bed: zhanx, so, you can afford to get fiber internet then
01:32 AM rue_bed: and just stay online
01:32 AM rue_bed: ...
01:32 AM zhanx: yep
04:53 AM polprog: rue_mohr: good morning, yeah, the one to write to the flash
04:55 AM polprog: whats the offset at 20mhz frequency in your transformer from?
05:26 AM polprog: I wonder if I could use the ethernet transformer for a DC DC converter...
06:02 AM polprog: crt discharged...
06:02 AM polprog: no flash though
06:28 AM polprog: https://twitter.com/polprogpl/status/1227930349394702336?s=19
06:28 AM polprog: still faulty
06:28 AM polprog: any ideas what could be the failure?
08:16 AM rue_bed: polprog, the 74hc04 is a 4ns delay
08:17 AM rue_bed: polprog, it might be an HV shutdown, they have a thing to prevent them generating xrays
08:17 AM rue_bed: lots of times with crts the HV transformer fails, the insulation breaks down
08:18 AM rue_bed: even in the day finding replacement flybacks was really hard
08:18 AM rue_bed: polprog, so, I need to find you the bit file that makes the fpga into a programmer for the eeprom
08:19 AM rue_bed: not sure what that was called
08:26 AM polprog: yes
08:26 AM polprog: also, looks like replacing suspicious joints helps
08:27 AM polprog: after i resoldered the flyback it went for 2 mins without collapse
09:00 AM polprog: hmm, first power up - horizontal collapse, second power up works fine!
09:00 AM polprog: should i put the cover back on..
09:17 AM polprog: still doesnt work
09:18 AM rue_mohr: oh hi
09:19 AM rue_mohr: horizontal problems are bad, cause the horiz is usually run from the flyback
09:19 AM rue_mohr: unless *ONLY* the horiz collapses, which means solder joint
09:19 AM polprog: intermittent horizontal collapse
09:20 AM polprog: the noise is concerning me
09:20 AM rue_mohr: the horiz is tied to the flyback
09:20 AM rue_mohr: thats why multisync was a mess for crts
09:21 AM rue_mohr: the noise must be arcing
09:21 AM polprog: back on the shelf it goes. i need to get my hands dirty on the bathroom seals
09:21 AM polprog: but its good to know whats wrong
09:21 AM rue_mohr: if you can slap it and have it come back, its a bad joint
09:21 AM polprog: let me try..
09:22 AM rue_mohr: if it goes out after it warms up, its a conductor
09:22 AM rue_mohr: if it wont work right untill it warms up, its a capacitor
09:23 AM polprog: so i guess its the former
09:28 AM polprog: when the back cover was off it would work right
09:28 AM polprog: i had it running on the bios screen of the test PC for a good 10 mins or so
09:28 AM polprog: must be a bad joint i missed..
09:28 AM polprog: fuck
09:28 AM rue_mohr: k
09:38 AM polprog: https://www.youtube.com/watch?v=rXehidxXlPA
09:38 AM polprog: it was fine when the chassis was off
09:39 AM polprog: the vertical driver will be one of the heatsinked transistors, right?
12:47 PM polprog: https://polprog.net/rozne1/ircjunk/nokiacrt/
07:07 PM rue_mohr: yup
07:07 PM rue_mohr: its vert problem now?