Wei ya 826 collapse

BobsterD

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I have a Wei Ya 826 that has verticle collapse, can't seem to find out any issues. Anyone have this problem before?
 
I would replace the El caps

And vertical ic at the same time

And confirm You have 24's at the vcc

Going to the ic. Or at the diode

In front of the ic is a good place to check

If you like before ordering any parts.
 
Do you have a part number for the vertical IC?
 
Do you have a part number for the vertical IC?

Location, Ic401. Use the number on it for a placement number.

And some heatsink paste. To replace the old paste, bad caps will make

The ic run hotter and shorten its life, because it's a high current component

Needs to keep cool, for best results restoring the vertical circuit.

Sometimes it with short and open the 24'v supply from flyback

Check it out
 
Sorry, I'm new to these chassis, can you tell me whereabouts IC401 is?
 
Ok, I *believe* the IC the screw pointing is correct. There's no markings indicating it though

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The ic on the heatsink

With to much paste on it.

You could reuse it, if needed

It needs just a small amount

On the ic. La7840

That's a good number you came up with

And if you got 24's on the diode and if

You could measure the 3 watt resistor

That looks overheated.

You see which one I'm talking about

Lift one end and measure the ohms across

The resistor should replace it to.

All the color bands are missing it's been

Running to hot.

Because to much B+ or bad El caps

Check it out.
 
Update: recapped chassis and replaced vertical deflection ic, no help.
 
Never to late to confirm you have the your vertical Voltage

Mention a few times

It's not uncommon to kill the voltage to the ic when it fails.


Does the ic get warm at all.

Does That chassis have a service switch?

To set RGB tracking? It does open the vertical drive when setting

RGB adjustments.
 
Sorry, I need more handholding. How to do confirm vertical voltage.

There is a Physical switch on the bottom, near the center.
 
Sorry, I need more handholding. How to do confirm vertical voltage.

There is a Physical switch on the bottom, near the center.

It's ok to switch when running, could be a sync polarity

If not that and no bad contacts or connection then Need Number on ic

Google that number

See data sheet. It will show the pin out and Vcc

Most common 25-27vs dc

Or probe the diode I talked in front of ic for the voltage

or any of the pins on the ic..

Does vertical heat sink get warm after a while or at all?


Anytime you have no vertical deflection you need to turn down the

Black level or screen pot, so not to burn a line on tube during troubleshooting

While testing voltage on ic. Or over 15 minutes

And when you think vertical is working then turn it up

And check, to much time with brightness up with cause burn
 
So I probed in front of pin 6 which should be fed by D401. I have 24v before the diode but not after so I pulled it but it passes the diode test.

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I also pulled r336 and it reads open out of circuit so I think this is the culprit. The schematic says 1w 4.3 so I assume this is 4.3 ohm. I'll try to find a replacement.
 
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So I replaced r336 and have +24v to pin 6 now. Still collapsed though. I'm starting to think this chassis is beyond help.
 
So I replaced r336 and have +24v to pin 6 now. Still collapsed though. I'm starting to think this chassis is beyond help.


it's not a good design but can be a replacement

Chassis not one you depend on long term.

Measuring the yoke is always a option in some cases.

To fine a close chassis compatible to yoke and tube neck board

If you would like to find another chassis,

With the schematic we should be able to find a fix,

Hopefully you have the correct vertical ic

After a few minutes does the ic feel warm?

Now that it has voltage to it.

With the resistor open then the ic was shorted

So that should have fix your vertical collapse

Luk
 
Yeah, I may swap the original IC back if I get bored. This tube is also weak so I'm mostly working on it for experience and challenge. It's getting to they point where I have almost as much money in this as a new Wei-ya chassis so this may end up as a parts donor.
 
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