Re: Identification help
Well I'm sad to say this story doesn't have a happy ending. I replace all six transistors and the two current measuring resistors. I tested the coil triggers with my scope and the four that hadn't shorted worked fine, but the two that were burnt were being pulled to ground constantly. So I'm not sure if the coils shorting damaged the control circuits or the control circuits failed causing the transistors to activate until they burnt out. Kind of a chicken and egg problem I'd love to check, but sadly it doesn't matter because..
You would think...
CraigParton
Member
Last Activity: 01-26-2018, 07:28 PM
Joined: 02-29-2012
Location: Sevierville, TN
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Re: Identification help
These are the MOSFETs I ended up ordering. They didn't have any IGBTs in the voltage range I needed. But the ones I ordered were made by ON semiconductor and the voltage and current specs are correct. Fingers crossed.
[url]http://www.digikey.com/product-detail/en/ATP404-TL-H/869-1087-1-ND/2165565[/url]Re: Identification help<br /> <br /...rrect. FingersLeave a comment:
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Re: Identification help
The model does use coil-on-plug ignition. It uses one transistor to drive each coil. By looking at the board I'm assuming the two low ohm resistors are supplying ground to three transistors each, used either for current measurement or current limitation. Regardless they are fried so I'm changing them as well.
I'm also replacing #3 and #4 coils because they are shorted and that's what fried the two transistors. I'm replacing all six as a safety measure. Fords of this model are know for this problem. The reason I'm trying to fix the board is...Leave a comment:
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Re: Identification help
I believe that might be it! The 100A drain current is plenty for that application and 60V is what I would expect for source to drain voltage. Correct package too. Even if that isn't the exact part I believe it would be an excellent substitute.
I really appreciate your help.. thank you so much! I'll let you know how the repair goes once I get those in.Leave a comment:
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Re: Identification help
Sure no problem. The second pic shows the six transistors I'm replacing outlined in red. I removed the two melted ones already. The blue outlines are two large resistors (.5 - 1 ohm) that I removed because they were badly melted. I was able to find those pretty easily, they were stamped with WSR-2....Leave a comment:
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Identification help
I need a little help identifying a transistor. I'm repairing a 2005 Ford Escape powertrain control module that has damaged ignition coil driver transistors. I'm not sure if they are MOSFETs or IGBTs. I believe they are manufactured by ON semiconductor because there's an ON surrounded by a circle in the corner. It is a TO-252 (DPAK) package. I searched for the numbers online and found nothing. Here are the identifying marks as they're layed out on the transistor:
401 ON (ON is circled)
55
03 GM
The circuit controlled is an ignition... -
Re: Samsung LN40A650A1F, no backlight
IT LIVES!! I removed and tested CI221 and it was perfect. Infinite resistance and .447 uF. I was able to get a 15V zener from a local TV shop. Replaced it and the TV lit up and worked like new!
Thanks you guys so much!! Without the schematic and operational theory I would have never been able to fix this. You guys rock!...Leave a comment:
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Re: Samsung LN40A650A1F, no backlight
I'll check that in the morning. I forgot to bring my capacitance meter home with me. I'll also need to hunt down a 15V zener somewhere. The only electronics supply store I have nearby is Radioshack and they definitely aren't what they used to be.Leave a comment:
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Re: Samsung LN40A650A1F, no backlight
I wish there was an easier way to check QI101 & QI102. I'm having a very difficult time removing these SMD components. They seem to be glued to the board.
I was able to test C1221 in circuit as long as I kept my meter leads reverse biased again D1224. It tested infinite on the 20 Megaohm scale.Leave a comment:
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Re: Samsung LN40A650A1F, no backlight
Thanks for the thorough explanation budm, it will take a few reads to decipher that due to my limited knowledge but I'll read it until I get it completely. I finally was able to get ZI101 off the board (no I don't have a soldering station) and it was indeed the cause of the short. Tested 9 ohms in both directions. Can I use a normal replacement 15v zener or do I need to try to find a surface mounted one?
edit: OK, wow that was a great explanation. The circuit is a LOT less cryptic now. I'll take the cap out and test it. I do have...Last edited by CraigParton; 03-01-2012, 11:25 PM.Leave a comment:
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Re: Samsung LN40A650A1F, no backlight
Sorry, should have specified. Its the 198Leave a comment:
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Re: Samsung LN40A650A1F, no backlight
Sorry I should have specified which scope I was using. It's an automotive scope/scan tool. Its a Snapon MODIS. It's handheld 4 channel scope and the entire case is plastic. No exposed metal. I checked the voltage rating and it's rated at 400V AC/DC. The highest voltage I've seen on this supply (except the HVT) is 380V. Close but just inside the limit.
But I may not even need to test it live. Not that I could, most everything I need to test is on the bottom of the board. I checked between the gate and source of QI201 and the resistance...Leave a comment:
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Re: Samsung LN40A650A1F, no backlight
One question on that isolation transformer: The scope I'm using is battery operated and doesn't plug into the wall at all. Will I still need that?Leave a comment:
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Re: Samsung LN40A650A1F, no backlight
Scenic I found a service manual for the european version of this tv on a similar site. I had to manually dump the text into google translator to figure out how to register and download. No schematic for the power board in that manual, but I really don't need it now do I?
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Re: Samsung LN40A650A1F, no backlight
Now I see what blew the fuse. When the MOSFETs shorted it gave diodes DI221 & DI223 a straight path from ground to power. I did notice the solder trace on one of those had been hot. I forgot to mention that I tested the larger power diodes DI221, DI222, DI223, and DI224 with one leg unsoldered and they tested fine with the diode test funtion on my multimeter. I'm wondering if they're failing under power.
So from what I can see (with my limited knowledge) it appears that UI101 uses the AOUT and BOUT terminals to control the...Leave a comment:
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Re: Samsung LN40A650A1F, no backlight
Lemme just say, you are THE MAN! Thank you so much. That's going to help tremendously. I'll check it this afternoon and post results.Leave a comment:
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Re: Samsung LN40A650A1F, no backlight
Thank you for the schematic I'm trying to decipher it and understand what's going on. I'll try to diagram the circuit tomorrow and trace it back to the ic. Any tips on identifying those small smd components?Leave a comment:
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Re: Samsung LN40A650A1F, no backlight
Thanks for the info Budm! The marking on that small surface mount resistor connected to the gate of the mosfet is 3002. Would that be 30,000 ohms? Also is the small diode is marked WL. Is it a regular diode or a zener and do I need to test it live? Can I use the scope to check the gate of the MOSFET to see if it's being controlled? If so what should the waveform look like?Leave a comment:
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Re: Samsung LN40A650A1F, no backlight
Here are the pics. Sorry I should have done this in the first post......Leave a comment:
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Samsung LN40A650A1F, no backlight
Hello everyone! I'm a little new to TV repair and I was looking for a little help with this Samsung LCD TV. It will power up (red LED goes out) and you hear the startup sound as well as sound from the HDMI input I had connected to it. But the LCD screen stays dark. I opened it and noticed a blown 3.15A fuse on the power supply board (BN44-00198A). It wasn't the main fuse (obviously) but after looking over the board a bit I saw it protected the control circuitry for the high voltage transformer that powers the inverter board.
After a little testing I found two MOSFET transistors...
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