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Chinese Chassis , need help.
lilshawn:
carefully cut the top of the sleeving and remove the top (it's just a round disk of plastic) and see if the metal can itself is domed, or it's just the plastic. I have seen some of those with bubbly looking tops, but it's just the plastic.
the strange part you took photos of is an induction coil. it's just wire wrapped around a ferrite core. it does look like it had a bad solder joint that went hot and burned off. it can happen especially if you have a bad capacitor on the same line. the inductor filters the little bit of ripple out of the power and converts it to magnetism... if the capacitor on the line is dead...all kinds of ripple needs to be filtered...the core cant handle all the magnetism and produces heat. i've seen them get so hot they catch fire.
your video looks like you have a vertical deflection issue it could be something around that 20 pin IC chip. i'd replace the electrolytic capacitors around that IC. i'd also change out the little yellow one next to the IC it's a "tantalum" capacitor. I just replace it with regular electrolytic...those tantalum caps are notorious for going sketchy. that cap should have a couple numbers printed on it like
22
25
this means 22uF and 25 volts.
likewise
4.7
35
means 4.7uF 35 volts.
I just replace it with the same uF value and the same voltage or higher (50 volts is fine)
abispac:
--- Quote from: lilshawn on March 21, 2020, 12:08:19 am ---carefully cut the top of the sleeving and remove the top (it's just a round disk of plastic) and see if the metal can itself is domed, or it's just the plastic. I have seen some of those with bubbly looking tops, but it's just the plastic.
the strange part you took photos of is an induction coil. it's just wire wrapped around a ferrite core. it does look like it had a bad solder joint that went hot and burned off. it can happen especially if you have a bad capacitor on the same line. the inductor filters the little bit of ripple out of the power and converts it to magnetism... if the capacitor on the line is dead...all kinds of ripple needs to be filtered...the core cant handle all the magnetism and produces heat. i've seen them get so hot they catch fire.
your video looks like you have a vertical deflection issue it could be something around that 20 pin IC chip. i'd replace the electrolytic capacitors around that IC. i'd also change out the little yellow one next to the IC it's a "tantalum" capacitor. I just replace it with regular electrolytic...those tantalum caps are notorious for going sketchy. that cap should have a couple numbers printed on it like
22
25
this means 22uF and 25 volts.
likewise
4.7
35
means 4.7uF 35 volts.
I just replace it with the same uF value and the same voltage or higher (50 volts is fine)
--- End quote ---
thanks ill post results.
abispac:
do you have an advice on what to look at chasis number 2 which is dead, beside the bubble big capacitor? the coil things were from chassis number one which it turned on. Thanks for the help.
lilshawn:
--- Quote from: abispac on March 21, 2020, 11:00:05 pm ---do you have an advice on what to look at chasis number 2 which is dead, beside the bubble big capacitor? the coil things were from chassis number one which it turned on. Thanks for the help.
--- End quote ---
check the 2 glass fuses near where the power goes in. it could be that one or both are no good. they don't look completely fried...but could have broken due to vibration.
if nothing looks obviously wrong, without a schematic for them...it's going to be tough to figure out what the issue is. you could just randomly start replacing things (called "shotgunning") and hope for the best. knowing nothing, other than it doesn't work... maybe a blown horizontal output transistor. maybe a fault in the main B+... could just be old dried out capacitors... hard to say. it might be impossible to find information.
is there any indication of a part number or model or manufacturer or anything on the outside or back side of the chassis? maybe a sticker or something on the heatsinking around the flyback transformer...I don't see any Identifying marks or numbers in any of the photos you posted so far.
if you can't find anything you'd basically have to resort to reverse engineering how the chassis is SUPPOSED to work...then test it to find out what isn't working. Something that is going to be very difficult to do unless you know what to look for and expect.
abispac:
--- Quote from: lilshawn on March 21, 2020, 12:08:19 am ---carefully cut the top of the sleeving and remove the top (it's just a round disk of plastic) and see if the metal can itself is domed, or it's just the plastic. I have seen some of those with bubbly looking tops, but it's just the plastic.
the strange part you took photos of is an induction coil. it's just wire wrapped around a ferrite core. it does look like it had a bad solder joint that went hot and burned off. it can happen especially if you have a bad capacitor on the same line. the inductor filters the little bit of ripple out of the power and converts it to magnetism... if the capacitor on the line is dead...all kinds of ripple needs to be filtered...the core cant handle all the magnetism and produces heat. i've seen them get so hot they catch fire.
your video looks like you have a vertical deflection issue it could be something around that 20 pin IC chip. i'd replace the electrolytic capacitors around that IC. i'd also change out the little yellow one next to the IC it's a "tantalum" capacitor. I just replace it with regular electrolytic...those tantalum caps are notorious for going sketchy. that cap should have a couple numbers printed on it like
22
25
this means 22uF and 25 volts.
likewise
4.7
35
means 4.7uF 35 volts.
I just replace it with the same uF value and the same voltage or higher (50 volts is fine)
--- End quote ---
you were right, big cap looks good, now, the yellow cap has a marc of c225, what would be the equal to a regular cap? thanks for the help