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poppie

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Item "A" I believe is a transformer the numbers on the side are as follow TPW-E901 JSI 0746.
This item rattles when I shake the board lightly, is this suppose to do this? Also at "B" The board
says 18volts for output, I am only getting 9 volts, Would letter "A" be the problem? Also would
anyone now what numbers represent? The board came out of a Gateway HD2200 monitor.
Thank you all.
 

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If you are confident in your soldering/desoldering skills, you might remove the TWP numbered part from the board, and check the leads for continuity or short circuits.
However, there is also another possible cause for the 18V/9V discrepancy. It may be that one of the blue ceramic parts ...MOVs ... has failed ... or is not performing at 100% .... due to an electrical surge or lightning strike.

Are you able to read the lettering on any of the possible MOV .... blue ceramic disks ... in the vicinity of the A lettered part?
 
A is a high frequency transformer.

B is a Y1 rated RF suppression capacitor.
 
Hero999 I am sorry for the place of the arrow from letter B it should be pointing at the white output connector. The blue mov that I can read is as follows B 103K 1KV. How do I check the leads for continuity or short circuits? I am new at circuit board works. I do have general knowledge of electrical.
Thanks
 
those aren't MOV's, they're capacitors. when you measure the voltage, is the power supply connected in the monitor? these power supplies require a signal from the main board of the monitor to turn on. when not turned on, all you will get is the standby supply voltage of 3 or 5V. if you're measuring 9V on a pin that should be 18V, either something connected to the supply is shorted, or you have a bad filter cap in the power supply. normally shorted devices will drop the output to close to 0V, so the most likely problem here is a bad electrolytic cap (the aluminum cans with the plastic labels on them). the best way to find out which one is bad is with an ESR (effective series resistance) meter. it's very common for them to dry out (they contain an electrolyte liquid soaked into a paper substrate). the heat generated by a power supply will dry them out in a very short time, especially if the monitor is left on (even in standby state) all the time.
 
This item rattles when I shake the board lightly, is this suppose to do this?
I doubt it is the transfomer rattling. More likely it is the ferrite beads B801, B802 & B803 that are rattling.


says 18volts for output, I am only getting 9 volts,
I agree with unclejed613 that it is probably a bad electrolytic cap. Turn the PCB over and see what caps connect to the +18V trace. If you do find one bad electrolytic cap replace them all. They are all the same vintage and the shipping is the same for 10 caps as it is for one. Get 105C, low ESR caps designed for switching power supplies.
 
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The power board that poppie shows must belong to a gateway lcd 22" or something alike. I just got one like that out of a monitor Gateway 22", that when turned on would light briefly when the pc starts and then nothing. So far I checked the high frecuency transformer and it's not working... I would prefer to obtain a new board just like this one, but Gateway only offers full equipment. Does anyone knows where to get one power board? Otherwise, where can I get the high frecuency transformer?
 
The power board that poppie shows must belong to a gateway lcd 22" or something alike. I just got one like that out of a monitor Gateway 22", that when turned on would light briefly when the pc starts and then nothing. So far I checked the high frecuency transformer and it's not working... I would prefer to obtain a new board just like this one, but Gateway only offers full equipment. Does anyone knows where to get one power board? Otherwise, where can I get the high frecuency transformer?

if it comes on for a short time, then there's nothing wrong with the transformer. most likely suspects as usual are the electrolytic caps. definitely replace the one near the blue block shaped capacitor on the bottom left corner in the picture shown above, as well as the ones near the heat sinks on the mid-right. the switching transformers rarely go bad. usually when they do they blow up the switching transistor (or sometimes a 5-pin chip) on the heat sink at the bottom of the picture as well as completely blacken the line fuse. you could also have a bad lamp. the processor poweres up the lamps during start up and if the lamp current isn't right shuts off the inverters (the two smaller transformers in the picture above). gateways also have a nasty habit of getting the wires between the inverters and the lamps pinched between pieces of sheet metal, and leakage current through the insulation at the pinch point will shut the monitor down.

the easy way to see if the switching supply is coming on is to put an oscope probe near the switching transformer and look for the switching noise on the scope.
 
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P852-P855 Connectors

Hey all,

Sorry to dig up an old topic, but I just wondering if anyone knew the correct orientation of the Red/White & Blue/Grey (times 2) power cables that came off the LCD Display and plugged into the power board we are talking about.
The tech at my work that pulled this apart, didn't know the orientation. Just replaced the caps, and dont want this things blowing in my face.

Thanks for your help.

Edit- If I didnt explain the connectors well enough, you can look at the picture at the top, its the 4 white connectors on the very top of the picture.

TIA
 
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Also at "B" The board says 18volts for output, I am only getting 9 volts, Would letter "A" be the problem?

Take a look at the spec label - it shows the outputs as being +5V and +10V -- not +18V. Are you sure that the PCB isn't marked +1ØV -- and that it only looks like +18V??
 
usually, when the board is in place, the relative length of the wires at the board is a clue. also whatever order they come off the panel is usually the order in which they plug in. this keeps them from crossing over in a limited amount of space between the panel and the shield cover that some TVs (or monitors) have. if the cables cross over, they can get pinched. and cause a short.
Hey all,

Sorry to dig up an old topic, but I just wondering if anyone knew the correct orientation of the Red/White & Blue/Grey (times 2) power cables that came off the LCD Display and plugged into the power board we are talking about.
The tech at my work that pulled this apart, didn't know the orientation. Just replaced the caps, and dont want this things blowing in my face.

Thanks for your help.

Edit- If I didnt explain the connectors well enough, you can look at the picture at the top, its the 4 white connectors on the very top of the picture.

TIA
 
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