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Recent content by stangman517

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    IBM 5151 Monitor

    LOL. Ok I started from R404 touched a leg of C403 - continuity, but with the probe on the same leg of R404 I touch either leg on C404 no continuity. I shouldn't get anything from the earth leg right? If I'm seeing the schematic right one leg of R404 goes to earth as is one leg on C404. I'm not...
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    IBM 5151 Monitor

    Sorry been very busy lately and haven't had the time to get back to you. Hopefully very soon I can get back to this.
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    IBM 5151 Monitor

    Do you mean test continuity? I'll re-read these posts. Yes, sorry for the mistype. Do you mean cut a leg on those resistors to the right of imaginary vertical line between pin 2 and pin 12 or one or two? If I counted that's 8 resistors.
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    IBM 5151 Monitor

    Hello everyone. Ok just replaced C403 and C404 with 15uF 50v NP Polyfilm caps and the same. I crossed my fingers too. Thank you very much for your help with this old guy - the 5151. I'll consider any other ideas.
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    IBM 5151 Monitor

    Those are great!! My favorite is "Why is everyone else wrong ?" ;-)
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    IBM 5151 Monitor

    I will replace C403 and C404 after checking R404 if that's suggested. I admit I'm as green as it comes and newbie when it comes to popping the hood of a monitor, but not to computers, ICs and soldering and many other exposures. I've retired 33 years IT (half my life), first 13 years were PC &...
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    IBM 5151 Monitor

    Another quick note; if it's an adjustment/fix someone green can do I will most willing to attempt it with your suggested tweak.
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    IBM 5151 Monitor

    If you guys can recommend a scope (that's a good one) but it's not too high I will consider buying one. Please first educate me on the next step if the readings I get are way off. What's the necessary repair? Then an approximate of the cost + a scope. I do like having the 5151 but $600...
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    IBM 5151 Monitor

    Being the neophyte/ green guy here I'm not sure what capacitors you guys are referring to so I made a guess. I replaced a neck board cap C204 with a 50v 1uF, and following a wire from the DC resistance resister on the yoke to the board I double checked the cap next to the connector: C408 10v...
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    IBM 5151 Monitor

    This makes much more sense to the layperson. If that resistor on the yoke is R403 no wonder I couldn't find it. I was looking on the pcb. Its resistance = 4.2ohms. I also saw the number 1 and 2 on the white piece of plastic. NOW it makes sense. ;-) Pin 2 = 14.47v Pin 5 = 13.92v If waveforms...
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    IBM 5151 Monitor

    Some confusion here for me. The first confusion is "First, check this suply voltage" part. I don't know where I'm supposed to put the probes to get a measurement. Measuring pin 2 = .877v, measuring pin 5 = 13.92v. These were obtained without a PC connected to the monitor; don't if this...
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    IBM 5151 Monitor

    I received the new TDA1170 ICs. Installed ok. A bit tricky getting the pins lined up in the holes. Sorry to say no change. I really appreciate your efforts from all of you! It's been educational for me.
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    Tantalum Capacitor

    I measured using my VM and the value was 0.016nF. I looked up kemet k5m 470 ceraramic capacitor and it (item on Digikey) came back with https://www.digikey.com/en/products/detail/kemet/C322C473M5U5TA/818149
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    Tantalum Capacitor

    Can someone please tell me the value of this capacitor. I'm guessing a 47uF or 4.7uF or 0.47uF??? ;-) I'm not a whiz at this. Searched the internet for help but I haven't found anything beneficial in my goal: how to determine the markings on these caps. Some were helpful but none that looks...
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    IBM 5151 Monitor

    I just realized something m7. I am wrong about saying these VR pots were two legs. I apologize! I did not see the middle leg behind the two outer legs in the back. So my mistake. Hope you accept my apology.
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