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Author Topic: Help repairing/replacing this Wei-Ya chassis  (Read 560 times)

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ahofle

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Help repairing/replacing this Wei-Ya chassis
« on: March 22, 2020, 06:47:55 pm »
Hello all,
I'm hoping there are still some CRT studs still around here that can help.
I have a Samsung monitor with a Wei-Ya chassis whose flyback that has started arcing (silicon has not helped). Before this everything seemed to worked perfectly. I've included pics of the yoke resistance specs and measurements seem to confirm them. I have tried a couple of those wei-ya 'universal chassis' replacements with the same resistance/impedance values but haven't had much luck there. I don't know how to find just a replacement flyback that will fit (pic included of the pin pattern too). Any advice or assistance on getting this monitor back up and running would be appreciated.

Ken Layton

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Re: Help repairing/replacing this Wei-Ya chassis
« Reply #1 on: March 22, 2020, 10:38:41 pm »
In your main picture, I'm not seeing the black ground wire from spring that is supposed to be stretched across the lower part of the tube.

Without that grounding spring and ground wire, arcing will happen as the high voltage electricity is looking for somewhere to go.

ahofle

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Re: Help repairing/replacing this Wei-Ya chassis
« Reply #2 on: March 23, 2020, 07:28:49 pm »
Thanks Ken I will take a look at that.

ahofle

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Re: Help repairing/replacing this Wei-Ya chassis
« Reply #3 on: March 23, 2020, 08:13:41 pm »
It's actually connected to the neckboard...here's a better picture. Do I need to add a grounding wire from the chassis to the metal frame? I don't think it ever had one of those but what do I know.

Ken Layton

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Re: Help repairing/replacing this Wei-Ya chassis
« Reply #4 on: March 23, 2020, 10:19:56 pm »
Why isn't the yoke plugged in?

ahofle

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Re: Help repairing/replacing this Wei-Ya chassis
« Reply #5 on: March 24, 2020, 09:54:52 pm »
I pulled it out to take the measurements in the pics. The flyback is sparking all over so no point in plugging anything back in yet.

princess prin prin

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Re: Help repairing/replacing this Wei-Ya chassis
« Reply #6 on: March 25, 2020, 08:24:08 am »
Electrohome G07 may be compatible with that tube.

grantspain

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Re: Help repairing/replacing this Wei-Ya chassis
« Reply #7 on: March 25, 2020, 09:14:12 am »
is there not a code on the flyback

Ken Layton

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Re: Help repairing/replacing this Wei-Ya chassis
« Reply #8 on: March 25, 2020, 12:32:54 pm »
There must be a label on the flyback with part numbers.

Could be a possibility the B+ voltage is too high and the safety shutdown circuit isn't working.

Is there cracks in the flyback?

princess prin prin

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Re: Help repairing/replacing this Wei-Ya chassis
« Reply #9 on: March 25, 2020, 01:10:10 pm »
Could be a possibility the B+ voltage is too high and the safety shutdown circuit isn't working.

This POS chassis doesn't even have a shutdown circuit. The shutdown pin (9) of the HA11235 is not used!

https://www.arcade-museum.com/manuals-monitors/Weiya%202820HR%20lower%20half.pdf

ahofle

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Re: Help repairing/replacing this Wei-Ya chassis
« Reply #10 on: March 26, 2020, 01:30:45 am »
There must be a label on the flyback with part numbers.

Could be a possibility the B+ voltage is too high and the safety shutdown circuit isn't working.

Is there cracks in the flyback?

I don't see any obvious cracks other than the singe marks where the arc'ing occurred. I will try and get more pics of the flyback this weekend.  I've already desoldered the damn flyback twice attempting to replace with one from a Wei-Ya universal chassis which just made a weird whistling sound every couple seconds. I am thinking of trying more grounding like you suggested. This is an 8liners monitor that was shipped out way back when they were selling 19" CGA monitors and I kept it around as a spare...it is clearly a used frankenstein monitor. I am good with ditching the entire chassis and flyback, just need to find a replacement. Are the recent Wei-Ya universal chassis pretty much all junk?


grantspain

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Re: Help repairing/replacing this Wei-Ya chassis
« Reply #11 on: March 26, 2020, 02:36:00 am »
the issue is matching the correct yoke, you have a high impedance yoke on your tube so your chassis must match
the problem with many of the weiya chassis is that they are clones made in china and therefore the flyback may or may not be different and the circuit layout slightly different
i work on a lot of chassis and every single weiya/clone of this design that i have ever had come in for repair the flyback is bad

if you do an online search you will find a matching new chassis-yoke specs, tube size,power input type and neck pinout are all considerations when purchasing a replacement chassis

ahofle

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Re: Help repairing/replacing this Wei-Ya chassis
« Reply #12 on: March 28, 2020, 12:15:44 pm »
Where does one even buy replacement chassis these days? I can't seem to find anything as all the old places are gone.

grantspain

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Re: Help repairing/replacing this Wei-Ya chassis
« Reply #13 on: March 28, 2020, 12:56:39 pm »
aliexpress and ebay
timeharvest sell on aliexpress and there is a u.s based seller on ebay

ahofle

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Re: Help repairing/replacing this Wei-Ya chassis
« Reply #14 on: March 28, 2020, 03:37:07 pm »
Added a bunch of grounding, but same thing (arc'ing' flyback). I took off the bad flyback and took pics of it -- also took pics of the chassis without flyback. If anyone has a replacement flyback in mind I would really appreciate any links. Or even a replacement chassis. I saw some more of the high impedance wei-ya chassis on aliexpress...is that my best bet?