Barco LCN-42 No Power

[budm]

Re: Barco LCN-42 No Power

It looks like the VCC is generated from that sub circuits board with multi pins, not sure yet.

[Jasgriff]

Re: Barco LCN-42 No Power

I have replaced the resistor and nothing went bang.

I retested the voltage on the pin that you asked and its 8.53v thin 6.2v on pin 6 VCC.

Do you think this smps was also controlling the 24v supply?

[Jasgriff]

Re: Barco LCN-42 No Power

Do you think I am going to need to de-solder that secondary board to see what's going on underneath it?

I have found the part numbers of the 2 transistors that the 8.53v's comes from.

A1020 & C2655

[budm]

Re: Barco LCN-42 No Power

I beleive the SMPS IC for the 24dc power supply section is on that board, but let me verify the traces for sure that the VCC is generated fromm that board first, by thw way, how about that 18 Ohms reading on that ZENER, is it really 18 Ohms when you measure across that ZENER?

[Jasgriff]

Re: Barco LCN-42 No Power

The Zener on its own is 511 Ohms with the Negative probe on the black strip and 11.9K when I reverse the probes.

Just re checked everything on that pin 6 and its connected to j33 and c207.

[budm]

Re: Barco LCN-42 No Power

Ok that is OK. I will look at the latest picture tonight to see what is going on.

[Jasgriff]

Re: Barco LCN-42 No Power

Ok cheers Budm.

I have ordered some 1 pin connectors and some 24v 20 watt bulbs to make up some leads for adding load to some of the pins when the 24v circuit is back up and running.

[budm]

Re: Barco LCN-42 No Power

Get 10watts if you can just want to start with lighter load first.

[Jasgriff]

Re: Barco LCN-42 No Power

I decided to take off the sub board today to see if it was the cause of the problem.

There are 3 ic's on it.....

L4981AD

http://www.st.com/internet/com/TECHN...CD00000085.pdf

L6598D

http://www.alldatasheet.com/datashee...ICS/L6598.html

I'm really struggling to get the model off the 3rd ic though.

[Jasgriff]

Re: Barco LCN-42 No Power

Pics of the Sub Board.

[budm]

Re: Barco LCN-42 No Power

It looks like pin #4 (Count from the left) on picture #3 is where the VCC is generated. Do you have a chance to find out what those three ICs are? One of them must be for the PFC circuits.

[Jasgriff]

Re: Barco LCN-42 No Power

I decided to take off the sub board today to see if it was the cause of the problem.

There are 3 ic's on it.....

L4981AD

http://www.st.com/internet/com/TECHN...CD00000085.pdf

L6598D

http://www.alldatasheet.com/datashee...ICS/L6598.html

I'm really struggling to get the model off the 3rd ic though.

I can find those 2 but the one in the middle is more difficult it looks like 103AIW but the alldatasheet data for that number tells me that it cant be that number.

That pin does however connect to either pin 4 or pin 8 of that Ic

[retiredcaps]

Re: Barco LCN-42 No Power

Put your Fluke 177 in capacitance mode

Of course I meant Fluke 175.

[selldoor]

Re: Barco LCN-42 No Power

Well here's an amazing coincidence - cant see that it will be any help but:
https://www.badcaps.net/forum/showth...170#post229170

Vizio VX37LHDTV10A
I have some numbers, but I'm not sure which one is the actual part number.
On the top is 103AIW
Second row is ST EK726

[Jasgriff]

Re: Barco LCN-42 No Power

Lol that is a massive coincidence!

[budm]

Re: Barco LCN-42 No Power

If I can solve yours then I may be able to solve the Vizio or vice versa. I think some one is playing tricks on me.

[Jasgriff]

Re: Barco LCN-42 No Power

lol why is someone playing tricks on you? I don't know any tricks

I did a search on the net for this chip and on ebay it lists another model number for this chip.

http://www.alldatasheet.com/datashee.../TSM103AI.html

This is the datasheet for the equivalent IC.

I can get this sub board back in and take some measurements now we have pictures of it? looking at these ic's that are on here its dealing with AC is that right?

[selldoor]

Re: Barco LCN-42 No Power

I have emailed ST.com to ask what a replacement would be but doubt if I'll get a reply

[Jasgriff]

Re: Barco LCN-42 No Power

http://www.ebay.co.uk/itm/TSM103AIW-...-/300499454773

Isn't that the replacement?

[selldoor]

Re: Barco LCN-42 No Power

Probably/possibly I googled lots and couldnt find it -tried substituting some numbers
ie your 1 may have been a 2 after a couple of pints and the W an H N etc and having
accidentally booked several flights on EK726 and EK545 sent the email 5 minutes before
your post 137