konrad

Thanks for your input. The resistor has been removed completely from the pcb and the colours are red/yellow/silver/gold. The silver is just that as it shines whereas grey is a matt colour. Grey would give a reading of mega ohms. I have tried to photograph the resistor but the macro is struggling to pick up the focus and colour. I did test it in both directions although this should not make any difference to a resistor and this is undoubtedly a resistor. The only possible explanation is that the silver turns out to be grey but I have seen grey on other risistors and it looks nothing like the silver colour on this resistor. The meter is what it is and I don't have the resource to guage its accuracy so I have to believe what it is telling me. regards, Konrad

Hi, Don't know if this is the correct place to ask my question but it seems the most logical looking at the options available. I have been writing and receiving feedback on an issue relating to an Acer monitor that I am trying to repair. The few components I have managed to test with my multi meter have all checked out OK but for one resistor on the power pcb. This particular resistor has a value of just 0.24 ohms according to the colour coding on it. It is reading 0.7 ohms. As the resistor has a tolerance of just 5% plus or minus I would judge that it is faulty and needs replacing. This is where I need your help. Trying to source a resistor with this value is proving almost impossible. I have found them for sale but in bulk orders only (50+). Does anybody know where I can get hold of a 0.24 ohm resistor (just one)? regards, Konrad :confused:

Hi PN, Yes the fuse is OK. I found another fuse lurking in the midst of the cluttered pcb but that is OK too. I take your point about the checking of resistors whilst still on the pcb. I have checked other resistors in situ as the legs are exposed component side up and they check out regarding the values indicated by the colour rings. That's what made me suspect the one that did not give the correct value. I haven't taken any of the capacitors off the board yet as I am still awaiting the capacitance meter from China. I read somewhere recently that pcb's from monitors are not serviceable items. Perhaps some of the components are not readily available and therefore make repair impossible. I will however continue to replace any suspect components that are easy to source and see if it fixes the problem. I remember once having a TV controller become defective and the man at the outlet said that he did not repair such items so I had to purchase a new one for £34. I took the opportunity to compare like for like when I was able to get into the two pcb's and found the fault within minutes. A faulty ceramic resonator, cost 14 pence. So much for the 'we don't fix these' attitude. regards, Konrad

Thanks PN, While I am waiting the arrival of the capacitance meter I have been checking the various resistors with my multimeter and I have found at least one that is not giving the correct reading according to the colour coding on it. Another possible fault has been found on one of the blue (capacitors ?) at least that is what I think they are. On the photo previously posted of the main pcb they are shown with what looks like cream blobs on them. I don't know if this is leakage but considering they are identical in appearance they exhibit different readings when tested with the ohm setting on my meter. Having discharged each I then connected the multimeter to charge them and watched the reading. On one it basically started at 0 and then steadily climbed to infinity (good ?). The other just stayed at 0, no increase in charge (bad?). This descrepancy indicates a fault I think. Incidentally these blue capacitors are located either side of a transformer. What do you reckon about what I have found and do you think that these results are significant? regards, Konrad:confused2:

Trying out the upload facility Hello PN, Thank you for the infr on uploading photo's. I hope this effort works. If it does you may be interested in the layout of the pcb from my Acer P191W monitor. It shows the layout quite clearly of the capacitors and other components that you have mentioned in your previous replies. I was wondering if it would be possible to check the continuity (using a multimeter) of the illumination lamp and its inverter/s that you mentioned without stripping off the metal tape and delving deeper into the screen. It would be nice to rule out these particular components, likewise with the transformer/s. I would imagine that if a component is blown their would be no continuity, is that right? Forgive my ignorance. Once again thanks for the info on uploading. Hope it is attached accordingly. regards, Konrad

Hello PN, The weak link(s) in the chain could be anything. From my time working on motor vehicles I always begin with the most simple component, usually the cheapest and then move on to more complicated and usually more expensive items. A process of elimination. You just have to decide when to stop because the cost outweighs the item being repaired, but then monitors are not cheap. My time is free and labour charges are outlandish these days. I just hate throwing stuff away that can obviously be repaired. One other thing. How exactly do you upload pictures to the threads? I have searched without success to find a solution. It's always helpful to look at pictures when describing a problem. regards, Konrad:wink:

Hello PN, The power supply for the monitor is direct from the mains. Knowing the risk involved and taking adequate precautions is the key. I appreciate your concern about the danger when working with mains voltage and I do understand that the capacitor in question may still hold a lethal charge. I would be very surprised if the voltage is anything other than mains ac (240V) although the capacitor is rated at 450V. With this margin of performance capability its odds on that this component will still be serviceable so I shouldn't have to remove it from the board or do anything with it. With the other capacitors running on a low DC voltage the potential for injury is very much reduced provided that they are shorted out when removed from the board prior to testing. Regarding the meter, I have sent for a capacitance meter on e-bay having watched a clip on U-tube. The model used in the clip was a Newcason XC6013L and will be sent from China including postage for just under £14. Result. My next purchase will be some desolder equipment to help in removing the capacitors from the pcb. Thanks once again for the advice. Will post again when the meter arrives from China. regards, Konrad:)

Many thanks for the information and excellent photos. Fortunately I had already got this far using much the same method. Some of the connectors are very tight and its tempting to just pull on the wires instead of the block they are in. Resist this at all costs, I did but the needle nose pliars I used slipped and I now have a very nice devils pinch on one of my fingers. No pain no gain. The capacitors are not showing the bulge I was expecting to see, but comparing them to new ones they do exhibit some deformation looking at them under a magnifying glass. Of course what I really want to do is to take them of the board and test them using a capacitance meter but this could prove to be an expensive way of proceeding as I would have to buy a meter just for this one off job. I have looked at the capacitors in the Maplin catalogue and all are available very cheaply other than the 100 micro Farad 450 V capacitor. This one is not listed. It is very much physically larger than all the other capacitors. If anyone knows where I can get one please do so via this thread. My problem is that the screen just went dead, not on for a few seconds and then dead. Without changing multi components I thought it would be a wise thing just to look at the capacitors as these are relatively cheap to buy and easy to install. Anyway all I have to do now is change them and see what happens. My thanks to everybody for the input so far. I will hopefully come back soon with a success story to tell providing everything goes back together. The reverse process should be easier. LOL. Konrad:)

Thanks PN, I have opened up the monitor using a plastic spreader, used for spreading filler. This did not damage the casing. I wonder if anyone can advise me on how to test the capacitors on the power board whilst they are in situ, using a multimeter. Konrad

Hi, My Acer P191W monitor died the other day and I believe that it may be possible to repair the power board by replacing blown capacitors. My problem is that I cannot get into the monitor. I have removed the base stand and one other screw from the bottom of the monitor but have no idea how to separate the back from the front of the monitor. My hunch is that it snaps together around its edges. Can anyone please advise me if their is a way of separating the casing without damaging it? regards, Konrad

I know this forum is used for introductions. Hi. Now can anybody help me? for whatever reason I just can't find how you post a new thread. I've sat here for ages just trying to find the correct link but life is too short. It has to be easy, so how do you do it????????????????????? If you reply to this thread please be kind and be very specific. Thanks, Konrad