Author Topic: Help repairing/replacing this Wei-Ya chassis (Read 3099 times)

ahofle · « **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 · « **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 · « **Reply #2 on:** March 23, 2020, 07:28:49 pm »

Thanks Ken I will take a look at that.

ahofle · « **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 · « **Reply #4 on:** March 23, 2020, 10:19:56 pm »

Why isn't the yoke plugged in?

ahofle · « **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 · « **Reply #6 on:** March 25, 2020, 08:24:08 am »

Electrohome G07 may be compatible with that tube.

grantspain · « **Reply #7 on:** March 25, 2020, 09:14:12 am »

is there not a code on the flyback

Ken Layton · « **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 · « **Reply #9 on:** March 25, 2020, 01:10:10 pm »

Quote from: Ken Layton on March 25, 2020, 12:32:54 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 · « **Reply #10 on:** March 26, 2020, 01:30:45 am »

Quote from: Ken Layton 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?

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 · « **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 · « **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 · « **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 · « **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?

ahofle · « **Reply #15 on:** February 22, 2023, 11:25:13 pm »

Hello all, it's been a while and would like to try and get this thing repaired/replaced, but have not had any luck after a few tries. Does anyone recommend someone that can repair a chassis like this? I assume they would need to have a tube with similar measurements to test it. Any help would be appreciated...I don't want to get rid of this perfectly good arcade monitor.

buttersoft · « **Reply #16 on:** February 23, 2023, 06:17:46 am »

If you can't find a replacement flyback, a new chassis is going to be the best bet.

lilshawn · « **Reply #17 on:** February 23, 2023, 12:54:14 pm »

a CP-808 flyback will probably work. not sure 100% since that one is a CP-808-2 but the "-2" could denote a revision or something.

ahofle · « **Reply #18 on:** February 25, 2023, 04:04:47 pm »

Quote from: buttersoft on February 23, 2023, 06:17:46 am

If you can't find a replacement flyback, a new chassis is going to be the best bet.

I was thinking the same but I have no idea where to find one. All the junk on Ali Express doesn't seem like it would match (most don't even list specs). Any idea where to find one?

buttersoft · « **Reply #19 on:** February 25, 2023, 07:24:44 pm »

Quote from: ahofle on February 25, 2023, 04:04:47 pm

I was thinking the same but I have no idea where to find one. All the junk on Ali Express doesn't seem like it would match (most don't even list specs). Any idea where to find one?

Well, you could ask the sellers on Aliexpress about compatibility, but...

IDK, really. There are lots of facebook groups, forums and classifieds. monitors certainly crop up on those. Where are you located? You could even try to grab a same-size CRT TV and RGB mod it.

grantspain · « **Reply #20 on:** February 26, 2023, 01:51:39 am »

or you could convert the yoke to low impedance and therefore have the choice of many chassis that will match

buttersoft · « **Reply #21 on:** February 26, 2023, 04:29:09 am »

Quote from: grantspain on February 26, 2023, 01:51:39 am

or you could convert the yoke to low impedance and therefore have the choice of many chassis that will match

Oh, yeah, that

hah.

Basically your vertical windings are in series right now, and you can rewire them in parallel and get a low resistance yoke. Each coil is just under 30ohms in this case, so instead of 30+30 you have (30x30)/(30+30) = just under 15 ohms. The green and yellow wires are the ones you want to desolder from the neck. I'd make sure to measure with a multimeter before ordering the new chassis though, just to check things seem ok.

ahofle · « **Reply #22 on:** March 02, 2023, 11:26:11 pm »

Hmm that sounds like something I could really screw up hhaha. Any good guides out there? I can't even find a low impedance chassis at this point...

grantspain · « **Reply #23 on:** March 03, 2023, 05:06:52 am »

Quote from: ahofle on March 02, 2023, 11:26:11 pm

Hmm that sounds like something I could really screw up hhaha. Any good guides out there? I can't even find a low impedance chassis at this point...

youtube has a few vids on this, its very easy
your tube has pretty standard wells gardner connectors, other makes have the same
what is your power input to the chassis and do you have an isolation transformer fitted

ahofle · « **Reply #24 on:** March 07, 2023, 12:30:56 am »

This one has a standard 2 prong 120v power plug, no Isolation Transformer (it is for a PC/MAME setup).
I'll look at some videos, but even if I do it where do I find a decent low impedance chassis?


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