#avr Logs

Feb 13 2020

01:26 AM rue_bed: I'm using my scope to test out a whole whack of circuits
01:32 AM rue_bed: was playing with ethernet transformers today
02:49 AM rue_bed: there ARE online web designers for filters
06:28 AM polprog: https://twitter.com/polprogpl/status/1227930349394702336?s=19
06:29 AM polprog: what could the issue be?
06:29 AM Thrashbarg: dry joints
07:03 AM Fuchikoma: Go over the solder joints with an iron, some flux and fresh lead-based solder and it'll fix it up
07:04 AM Fuchikoma: If th ejoints look like shit, they *are* shit.
12:22 PM nuxil: most of the ones i came across online. did handle the Q factor poorly, a lot of them thinks you can just cascase filters without taking the Q factor into account for different stages and a lot do just one pole or is just for passives ones. designing filters is not as easy as one thinks it is. when you dive into it you see its a can of worms as davie jones would have put it :)
12:23 PM nuxil: *dave
12:25 PM nuxil: polprog, did you manage to resurrect it?
12:29 PM polprog: nuxil: no, but im close
12:29 PM * nuxil sees polprog is laying on the floor in spasms after thouching high voltage in his old crt monitor :p
12:30 PM polprog: i think i forgot to reflow the horizotal driver transistor
12:30 PM polprog: nah
12:30 PM polprog: i discharge it everytime
12:30 PM polprog: provided, it hasnt sparked yet
12:30 PM polprog: but the screwdriver touches the anode
12:30 PM nuxil: have it on. tap around gently on the board with plastic hammer
12:31 PM polprog: it works fine when the board is out of the chassis
12:31 PM polprog: ie the back cover is off
12:31 PM polprog: but the problems come back when the cover is back on again
12:32 PM nuxil: em. that makes no sense. its all plastic anyway right ?
12:32 PM polprog: ive reflown the power supply section joints and the flyback, and that made it work fine when its naked
12:32 PM nuxil: is the cover pushing on some cables ?
12:32 PM polprog: no, it makes perfect sense. The cover must be stressing the pcb in a way that the transistor looses contact
12:32 PM polprog: it also goes out after several secs so must be heat contraction
12:33 PM polprog: without the cover it displayed fine for more than 10 mins (i shut it off later to let it discharge, waited about 15 mins, shorted the anode cap and put the cover back on, and then the fault came back)
12:33 PM nuxil: oh. cover pushes on the backside of the pcb?
12:34 PM nuxil: oh i see in picture
12:34 PM polprog: yeah its a bit crooked when you put it on, you need to twist it about 10deg to make it fit...
12:36 PM nuxil: so possible a craced pcb trace under a soldermask :p, if redoing the solderjoints didnt help.
12:36 PM polprog: yeah
12:36 PM polprog: i hope that when i reflow the transistor it will help
12:41 PM nuxil: also, try spend a few min finding the service manual. a good service manual will tell you where to look based of failures/symtoms. it will save you alot of time instead of going blindly into it
12:46 PM polprog: there isnt any
12:46 PM polprog: there arent even instruction manuals for that
12:46 PM polprog: zilch. I only found specs on CNET
12:46 PM polprog: https://polprog.net/rozne1/ircjunk/nokiacrt/
12:46 PM polprog: the model number is in there on a photo
12:46 PM polprog: i even tried the FCC ID :P
12:46 PM polprog: https://polprog.net/rozne1/ircjunk/nokiacrt/model.png
12:47 PM nuxil: hmm.. maybe they only know how to make manuals for cellphones :p
12:48 PM polprog: haha
12:48 PM polprog: no user servicable parts inside! perkele!
12:49 PM nuxil: i think i only seen a nokia monitor a few times in my life. rare stuff here.
12:49 PM polprog: arent you finnish?
12:49 PM nuxil: no
12:49 PM polprog: wait..
12:49 PM nuxil: no im no :p
12:50 PM nuxil: from the motherland land of avr :p
12:50 PM polprog: you and nohit have so similar nicks i mix you two non stop
12:50 PM polprog: so where are you from?
12:51 PM nuxil: i told you :=)
12:52 PM polprog: ah
12:52 PM polprog: i see
12:53 PM nuxil: lol :)
11:54 PM day__ is now known as day