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  1. S

    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...
  2. S

    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.
  3. S

    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.
  4. S

    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.
  5. S

    IBM 5151 Monitor

    Those are great!! My favorite is "Why is everyone else wrong ?" ;-)
  6. S

    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 &...
  7. S

    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.
  8. S

    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...
  9. S

    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...
  10. S

    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...
  11. S

    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...
  12. S

    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.
  13. S

    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
  14. S

    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...
  15. S

    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.
  16. S

    IBM 5151 Monitor

    Yep you're not kidding. I was a bit intimidated by the heatsink. I kept having to turn up the heat but with caution and fear. ;-) Around 880 degrees on the metal, but I was in and out. Use good ole wick and liquid flux (love the stuff). Then just wiggled it some while pulling slightly on it and...
  17. S

    IBM 5151 Monitor

    I'll give the IC a try. Soldering is no problem, but all the other testing you guys mentioned like the quote is out of my league. It would take some serious hand holding or experienced guys like you to do those tests. Those should probably be left with experienced CRT guys. I found some on ebay...
  18. S

    IBM 5151 Monitor

    I'm a bit confused because of a change in Pin 1 from 8.6v to now 5.2v. Checked 3 times. The first difference I can see because I forgot to solder back a few pins on those two caps. Pins: 1 = 5.2 2 = 14.4 3 = 0.3 4 = 6.4 5 = 13.9...
  19. S

    IBM 5151 Monitor

    Yes the raster does fill the screen and it does stretch out to the bottom except to about 1" from the bottom of the screen.
  20. S

    IBM 5151 Monitor

    Hugo the failure was there before the re-cap. I re-capped only because of these symptoms. I don't have a ESR meter, but ordered one.
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