LG Flatron L196WTQ monitor with bad power supply

[Ivan75]

I have an LG Flatron L196WTQ monitor with bad power supply. The fuse on this monitor is blown and one of the rectifier diodes is shorted. My problem is that I am not sure of the rating on the fuse and on the diode. The board is made in China and is rated 100-240Vac, 50/60Hz, 1.0A. Manufactured by Lien Chang. The fuse is marked “T3.15AH250V” and it is ceramic so I can not see the element. I am not sure if this is a slow blow fuse or not.
The bridge rectifier is made of four diodes. The shorted diode is marked “LT 7316 2A05”. I did a chat with Digi-Key and they could not give me a cross reference to a replacement diode.

Can someone give me advice on what fuse and diode to use? Should I replace all four diodes with common diodes used in other power supplies?

Thanks, Ivan

[PlainBill]

Re: LG Flatron L196WTQ monitor with bad power supply

I have an LG Flatron L196WTQ monitor with bad power supply. The fuse on this monitor is blown and one of the rectifier diodes is shorted. My problem is that I am not sure of the rating on the fuse and on the diode. The board is made in China and is rated 100-240Vac, 50/60Hz, 1.0A. Manufactured by Lien Chang. The fuse is marked “T3.15AH250V” and it is ceramic so I can not see the element. I am not sure if this is a slow blow fuse or not.
The bridge rectifier is made of four diodes. The shorted diode is marked “LT 7316 2A05”. I did a chat with Digi-Key and they could not give me a cross reference to a replacement diode.

Can someone give me advice on what fuse and diode to use? Should I replace all four diodes with common diodes used in other power supplies?

Thanks, Ivan

The fuse is easy - it's a Time delay 3.15A, 250 Volt. I'm not sure what H represents, but at a guess, it is for a ceramic fuse.

Googling 2A05 Datasheet gives a 2 Amp 600 Volt diode in a DO-15 package.

As an exercise to the student, you can look up the Digikey (or Mouser) part numbers and I will verify your results.

PlainBill

[Ivan75]

Re: LG Flatron L196WTQ monitor with bad power supply

I used Digi-Key and got F2485-ND (3A) for the fuse, they did not have a 3.15 amp fuse. For the diode I found P/N 2A05GDICT-ND.

Should I replace all four diodes?

Ivan

[PlainBill]

Re: LG Flatron L196WTQ monitor with bad power supply

I used Digi-Key and got F2485-ND (3A) for the fuse, they did not have a 3.15 amp fuse. For the diode I found P/N 2A05GDICT-ND.

Should I replace all four diodes?

Ivan

For the fuse, use F3585-ND.

The diode is (obviously) correct. Definitely replace all four of them. The paired diode took a lot of stress before the fuse blew.

Overall, I'd grade you a C-, but asking about replacing all the diodes raises it to a C+. (The person at Digikey who couldn't help with the diodes gets a very low F).

PlainBill

[Ivan75]

Re: LG Flatron L196WTQ monitor with bad power supply

Thanks, Your site is the best.

Ivan

[bipolar]

Re: LG Flatron L196WTQ monitor with bad power supply

Could you post a pic or look again at the PCB? I worked on an L194WT, and the board had a true bridge rectifier (D2SB60) at BR101 on the AIP-0122 rev. D, made by Lien Chang. Fuse (F101) was the same type as yours.

However, as we EE/ETs say, "What took out the fuse/bridge?"

Since this is the primary, you'll want to look at the mains cap (~100uF, 300-400V - aka, "The Big Bastard"), any power resistors, the MOSFET, and the transformer.

I haven't posted the write-up (yet) of the L194, but soon.

bipolar

[Ivan75]

Re: LG Flatron L196WTQ monitor with bad power supply

Hi bibolar, I replaced the fuse and the four diodes that make the bridge rectifier and that fixed the problem.

Ivan