Electronics > Beginners
repairing crt tv, start with recapping
2takt:
i didnt see the country flags :) i life near kaiserslautern rheinland-pfalz.
i think i will stay away with my oscilloscope from the tv. i will train me on lower volt equitment first! and i have no isolation transformer
i will search for some spare caps, when i find something i will post it. so the only things that are importent is V uF and ESR. i will search for this over 100°C caps. i already read that i can go a little higher with V.
deflection grid, what is this in german? i think the picture was square befor i started working on it but i didnt look for it.. so i will get the leaking cap new and then we will see.
befor the pictures i cleaned the board with a vacuum, no liquids. the caps are a bit apart and there are other caps in between with no marks. the color looked the same(the small one had more gung so the colour was darker). on the underside of the pcb i found some black stuff(cap juice?)
i found other caps with "colored" legs but there was nothing to see if something had leaked.
i thought the same about the flicker, maybe it was this way. but it got away after 10mins and i used the program list of the tv, this shouldnt be an interlaced screen?!
yes the service manual tells me the points, i searched the schematics but couldnt find them. i think i have to look again. the system voltage should be in the psu area?
2takt:
for the smal one:
https://www.ebay.de/itm/1-pc-NICHICON-Elko-Low-ESR-43mOhm-UPW1J102MHD-1000uF-63V-16x31-5mm-RM7-5-NEW/233128281101?hash=item364787440d:g:aKIAAOSwxp9W6Fft
for the psu cap:
https://www.ebay.de/itm/2-x-330-F-330uF-400V-105-Snap-In-RM10-Elko-Kondensa-Samwha-Elko-SnapIn-2pcs/152860959292?hash=item239739223c:g:jB8AAOSwItFc1xBy
this one doesnt say low esr. i found a datasheet, there is also no mention for low esr. its also smaller then mine 22mm to 31mm
http://www.samwha.com/electric/product/list_pdf2/HE.pdf
can i use these 2 caps for spare?
Gyro:
--- Quote from: 2takt on September 13, 2019, 05:23:41 pm ---i think i will stay away with my oscilloscope from the tv. i will train me on lower volt equitment first! and i have no isolation transformer
--- End quote ---
Good plan! Stay far away from the TV with your scope - a handheld DMM should be all you need for a CRT TV.
--- Quote from: 2takt on September 13, 2019, 05:23:41 pm ---I thought the same about the flicker, maybe it was this way. but it got away after 10mins and i used the program list of the tv, this shouldnt be an interlaced screen?!
yes the service manual tells me the points, i searched the schematics but couldnt find them. i think i have to look again. the system voltage should be in the psu area?
--- End quote ---
I would be surprised if the TV suddenly switched to non-interlaced when the program list is up, I think it will probably always be interlaced.
Regarding the 148V measurement. Looking at your partial schematic in reply #28, it is the signal named 'USYS', the only place I can see it is on Pin 8 of the line output transformer, LLO1 (makes sense as it is the regulated HT line feeding the line output stage). The LOPT isn't the safest place to measure it though, you should be able to find it in the PSU area (not on the partial schematic photo).
2takt:
ok this helps me. i have added the rest of the schematics. would DP56 be a good measure point?
i should measure from the underside? because its near the line output transformer
Gyro:
I don't know if you have safe access to the underside of the PCB when it is operating. If so, then CP54 looks like the biggest target. Harder to mis-identify.
Please don't do it if not confident in your ability.
The safest way, after checking that the capacitor is discharged, is to solder on a pair of wires and attach these to your meter probes (and insulate) before powering the TV. Your hands are then free.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version