Diode replacement - Tilted Forum Project Discussion Community

noblejr · 11-25-2003, 08:08 AM

I'm repairing a TV my friend gave me, and I've finally identified the fried IC and ordered a replacement. There is a diode that blew up that I need to replace. It's a small diode, about half the size of a typical resistor, with a purple band and a "6" or "9" marking it. There's another character that's mostly blown off the diode that might be a "G". I'm been trying to find info online to identify diodes but have come up with nothing. Can anyone help me identify it or do you have access to schematics? It's a Zenith TVBR2522Z and the diode is D411 on the main board.

I'm planning to go by the Shack and see if I can visually match it up with something they have there.

jujueye · 11-26-2003, 12:59 PM

You will need to match this exactly, no if's or maybe's! If it passes too much or too little voltage, you could easily burn out another part of the circuit or even the tube.

Your best bet would be to spend a few minutes at a tv repair shop. You might even offer to pay for their time. just tell them what you are doing, and that you are in to amateur electronics.

Next, take a look at this:

http://www.tpub.com/neets/book7/24k.htm

Be careful!

saltfish · 11-26-2003, 09:41 PM

As a hint...

Do you know what part of the TV that the diode is from?

The primay rectification?
Flyback x-former?
channel/volume control?
etc?

-SF

alt0220bergeek · 12-01-2003, 10:04 PM

and don't forget with a diode, POLARITY IS VERY IMPORTANT!!!

the420star · 12-03-2003, 06:57 AM

yeah... dont forget which way that purple band is on when its in the circuit...polarity is key with diodes... i just felt i needed to reafirm that.

noblejr · 12-03-2003, 09:26 AM

saltfish: It is a diode that comes off the 6th pin of the vertical deflection output IC if that helps any.

saltfish · 12-03-2003, 10:09 AM

K, I'm assuming that you're talking about the #6 pin...

Is the VDOIC a la7845?

If it is, pin 6 is for +18v input. If it is pin 2, which is the 6th pin from the other side it is the output pin rated at 65V peak to peak AC.

So, d411 is the diode location, not the diode type, correct?

-SF

noblejr · 12-04-2003, 10:42 AM

It's an LA7841, #6 pin and D411 is the label on the board, not the diode. I ordered an NTE7153 to replace the IC. The #3 pin was fried (thermal protection) and a diode on the board was fried. The diode is between the #6 pin and the +Vcc as indicated in this datasheet I found. http://www.repartout.com/Datasheets/LA7841.pdf
It is not the diode between #6 and the #3 & #7 pins in the diagram, but it is in line between the #6 pin and the +Vcc.

11-25-2003, 08:08 AM	#1 (permalink)
noblejr Crazy Location: Atlanta	Diode replacement I'm repairing a TV my friend gave me, and I've finally identified the fried IC and ordered a replacement. There is a diode that blew up that I need to replace. It's a small diode, about half the size of a typical resistor, with a purple band and a "6" or "9" marking it. There's another character that's mostly blown off the diode that might be a "G". I'm been trying to find info online to identify diodes but have come up with nothing. Can anyone help me identify it or do you have access to schematics? It's a Zenith TVBR2522Z and the diode is D411 on the main board. I'm planning to go by the Shack and see if I can visually match it up with something they have there.

12-01-2003, 10:04 PM	#4 (permalink)
alt0220bergeek Psycho	and don't forget with a diode, POLARITY IS VERY IMPORTANT!!! __________________ Übergeek...

12-03-2003, 06:57 AM	#5 (permalink)
the420star Psycho Location: Cow Country, CT	yeah... dont forget which way that purple band is on when its in the circuit...polarity is key with diodes... i just felt i needed to reafirm that. __________________ No, they arnt breasts, they are personalities, because its ok to like a girl for her personalities.

11-26-2003, 12:59 PM	#2 (permalink)
jujueye alpaca lunch for the trip Location: in my computer	You will need to match this exactly, no if's or maybe's! If it passes too much or too little voltage, you could easily burn out another part of the circuit or even the tube. Your best bet would be to spend a few minutes at a tv repair shop. You might even offer to pay for their time. just tell them what you are doing, and that you are in to amateur electronics. Next, take a look at this: http://www.tpub.com/neets/book7/24k.htm Be careful!

11-26-2003, 09:41 PM	#3 (permalink)
saltfish !?!No hay pantalones!?! Location: Indian-no-place	As a hint... Do you know what part of the TV that the diode is from? The primay rectification? Flyback x-former? channel/volume control? etc? -SF

12-03-2003, 09:26 AM	#6 (permalink)
noblejr Crazy Location: Atlanta	saltfish: It is a diode that comes off the 6th pin of the vertical deflection output IC if that helps any.

12-03-2003, 10:09 AM	#7 (permalink)
saltfish !?!No hay pantalones!?! Location: Indian-no-place	K, I'm assuming that you're talking about the #6 pin... Is the VDOIC a la7845? If it is, pin 6 is for +18v input. If it is pin 2, which is the 6th pin from the other side it is the output pin rated at 65V peak to peak AC. So, d411 is the diode location, not the diode type, correct? -SF

12-04-2003, 10:42 AM	#8 (permalink)
noblejr Crazy Location: Atlanta	It's an LA7841, #6 pin and D411 is the label on the board, not the diode. I ordered an NTE7153 to replace the IC. The #3 pin was fried (thermal protection) and a diode on the board was fried. The diode is between the #6 pin and the +Vcc as indicated in this datasheet I found. http://www.repartout.com/Datasheets/LA7841.pdf It is not the diode between #6 and the #3 & #7 pins in the diagram, but it is in line between the #6 pin and the +Vcc.