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Main => Monitor/Video Forum => Topic started by: Rickn on October 07, 2018, 03:41:21 pm

Title: Makvision/WeiYa Vertical collapsed bootom only
Post by: Rickn on October 07, 2018, 03:41:21 pm

Like my last post I am swamped and am reaching out to help me not spend a lot of time on these odd balls.

In the past week I have taken on about 20 more board repairs and I was already had a 10 board list.

So if any one has seen this and has some insight, here is the scoop.

Chassis says Wei Ya Probably Makvion M3129DS-LGC2929D1-LG
Originally vertical colllapse, replaced the Vert output IC now good picture on top. Bottom is black and a bright Horizontal Line in the center... Complete bottom vertical foldover.

Will scope the vertical circuit next.

Any thoughts greatly appreciated... I need to catch up!

Thanks

Rick

Title: Re: Makvision/WeiYa Vertical collapsed bootom only
Post by: grantspain on October 07, 2018, 04:34:57 pm

i have c67 marked down as oddball vertical fault in my repair notes, also the safety resistor and caps on the 24v supply- although you must have 24v or there would be no vertical

Title: Re: Makvision/WeiYa Vertical collapsed bootom only
Post by: buttersoft on October 07, 2018, 07:29:23 pm

Got a schematic? Might help pick something preventing the vertical coil reversing polarity, i guess.

Title: Re: Makvision/WeiYa Vertical collapsed bootom only
Post by: Rickn on October 08, 2018, 12:41:32 pm

Thanks Grant, if you have time please check your notes.. for the life of me I cannot find C67 either on the board or the schematic..

Odd as I can locate C68.


Yes I have what appears to be the right schematic.


May have to set it aside for now.

Thanks

Ric

Title: Re: Makvision/WeiYa Vertical collapsed bootom only
Post by: grantspain on October 08, 2018, 04:25:08 pm

220nf 100v  on r107
thats if it a m3129 chassis, no idea on a m2929 chassis

Title: Re: Makvision/WeiYa Vertical collapsed bootom only
Post by: Rickn on October 08, 2018, 07:34:53 pm

Thanks Grant, the 2 boards are use different vertical IC's. I expect the cap in yours is a small tantalum cap off of pin 1 of the TDA 1675. The board I have by memory is TDA 1672..yes these puppies can cause weird issues, not usually the bottom vertical foldover. tHE 2929d1 Uses a TDA 8172.

Thanks I will plug on!