Wei-Ya 429H - value of R804

QbertWPC

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R804 is open on this chassis. It was in 1 piece when I removed it from the holder, but there is no value printed on it.

If you have this chassis or a schematic for it, please measure the value of this resistor.
 

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An educated guess from similar schematics would be 140 ohms @ 20 or 25 watts.

This chassis requires operation from an isolation transformer. That resistor probably broke from being operated without an isolation transformer. Suggested to check/test the voltage regulator transistor.
 
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That resistor burned up because an isolation transformer was not used. That resistor gets EXTREMELY hot when an iso is not used and it most likely burned up because of it. Either way, the value of that resistor on the two extra 429H models I have is...(25W 140 ohms). Hope that helps...



 
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NTE # 25W115 (150 ohms) is close enough to work in your monitor. You will need to re-use the metal bracket to make the new resistor stand up.
 
Only a year late ;) Hahaha!

Of the 3 of these chassis I installed that blew up, none were isolated...dunno why I didn't. Also, how did they work for 6 months before blowing? The B+ filter capacitor also violently exploded on all 3.
 
That resistor will run very very hot if you don't use an isolation transformer. You were very lucky it lasted that long by running it without isolation. That filter capacitor probably couldn't take it either.

Test all the diodes next to the fuses for shorted or open ones. Test/check the B+ regulating transistor (it might be shorted). Naturally your main B+ filter electrolytic capacitor should get replaced if it blew up. Originally it is a 470 uf @ 200 volts, but I think it should be bumped up in value to 680 uf @ 200 volts.

BTW, I found this thread because somebody else was asking me about the model 429H and I did a search here on that model.

So far, I have found photos of the model label showing this chassis with manufacturing dates from as early as 2007 and up to February 2012.

These chassis need to be "Americanized" first before installing/using them to make them compatible with existing cabinet wiring harnesses and test equipment as I describe in this thread:

http://forum.arcadecontrols.com/index.php/topic,97584.msg1029468.html#msg1029468
 
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Hi,

So i purchased also a Wei-ya chassis 25"-29" hence i needed pincussion on my crt tube (see my topic of K71** R301 gets hot and screen squiched) I'm keeping the WG K7100 board when a perfect replacement tube pops up. meanwhile i can play!! (for 5 minutes)

The image is now straight (not yet the correct width, evening was falling so i stopped working on it yesterday)

But i noticed the same resistor mentioned above gets extremely hot. i'm running it trough the isolation transformer with 110V. What can i do? Thank you for your reply
Also on my K7100 board R301 gets hot to...

I'm form europe so we have 230Vac, so te become 110V the transformer works correct.
 
Updated wei ya 24-29" chassis. R804 runs way to hot.
desoldered it and put big ass cooled restistors 25W 100 ohm and 25W 47ohm in series to replace the original 25w. I noticed they still becoming hot, but it can resist that now. I'll replace them once with 50W resistors to decrease the temp. Now i noticed after 10 minutes that a 4K7 3W R311 resistor near the HOT is heating op to 60°C. Ill be updating that one to a 10W resistor just to keep it more cooler.
Neitherless the cheappo chassis works fine for now. After reading it is garbage i'll keep a close eye on the chassis. i noticed there is no Width coil to adjust properly. only a jumer camble for near or wide selection.

Update,
adjusted the B+ it was all the way up. When i reduced it the image became flaggy. cracked it up until that stops. (half way) R331 gets warm but not overheating. Chassis is stable now.
 
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Updated wei ya 24-29" chassis. R804 runs way to hot.
desoldered it and put big ass cooled restistors 25W 100 ohm and 25W 47ohm in series to replace the original 25w. I noticed they still becoming hot, but it can resist that now. I'll replace them once with 50W resistors to decrease the temp. Now i noticed after 10 minutes that a 4K7 3W R311 resistor near the HOT is heating op to 60°C. Ill be updating that one to a 10W resistor just to keep it more cooler.
Neitherless the cheappo chassis works fine for now. After reading it is garbage i'll keep a close eye on the chassis. i noticed there is no Width coil to adjust properly. only a jumer camble for near or wide selection.

Update,
adjusted the B+ it was all the way up. When i reduced it the image became flaggy. cracked it up until that stops. (half way) R331 gets warm but not overheating. Chassis is stable now.

Is it possible that this is why R8 04 is running so hot I just installed one on my k7000 and it's doing the same thing. Or do I have to go through and basically do what you did
 
Is it possible that this is why R8 04 is running so hot I just installed one on my k7000 and it's doing the same thing. Or do I have to go through and basically do what you did

For me it works fine for now.
Chassis is on for 1 hour without fans. i can touch the resistors and not getting burned. :) it'll cost you nothing those resistors and worth a try.

I ordered some more chassis to experiment on 21" and a 25" but a more recent build date.
 
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