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marcelv

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  1. marcelv

    What is DP8? - Macintosh Analog Board

    removed one from the board to check the markings, the diode is a PH-73D the resistor next to it is 10 ohm
  2. marcelv

    Macintosh Plus R8 resistor value

    R8 is 150 Ohm
  3. marcelv

    Macintosh Plus keeps tripping RCD

    C33 and C36 are the numbers for the international board. these are the 4700 pf line filter caps
  4. marcelv

    Macintosh Plus keeps tripping RCD

    probable C33 and C36 these will be cracked after all the years of service and create a shortcut. you can remove the capacitors, you can test the mac without them,
  5. marcelv

    Mac Plus screen adjustment

    Replaced the solder on CR1 and CR5 replaced C3 (old one measured 190uF instead of 220uF) Problem still the same.
  6. marcelv

    Mac Plus screen adjustment

    Thanks for your reaction, The L3 is a coil so reversing it should have no effect, I thought also. It does have a little effect as you can see the left margin of the screen got bigger. Addes a new photo with some lines. The difference between the left and right side of the screen is >10%, it gradually changes from left to right. The magnets I put on L3 was a test following some blog about the horizontal linearity problem. The magnets are removed now. The standard things I do after opening a mac is replacing the solder on J1, J2 and J3 and inspect for further solder cracks. The flyback solder did look very good but replaced it as for ruling this out. have to check CR1 and CR5 the capacitor you mention is C3, will test it.
  7. http://32by32.com/radius-full-page-display http://www.applefritter.com/?q=node/18313
  8. marcelv

    Mac Plus screen adjustment

    Am able to influence the horizontal linearity using magnets. Put some on L3 . Still not perfect but can try other magnets or location.
  9. marcelv

    Mac Plus screen adjustment

    R1 and L3 are the components responsable for the horizontal linearity. Measured R1, 220 ohm seems ok, L3 also ok. Noticed L3 has been reversed on the board (the glue was on the R1 side) by someone previously repairing the board? After reversing L3 back the image improved somewhat
  10. marcelv

    Mac Plus screen adjustment

    C1 is replaced with a film cap 3.9uf 450vdc Ecw-fd2w395jb problem is the same before and after replacing C1 on this international analog board i have replaced CR15 and CR17 (zener 6v2) and R55 (33k)
  11. marcelv

    Mac Plus screen adjustment

    Have a mac plus here with a problem. The right side of the screen seems to be compressed. Everything on the right side is a lot smaller. Does anyone know how to fix this? Already replaced C1
  12. marcelv

    Macintosh Plus Analog Board Q12 replacement

    Maybe the following can help to understand the circuit better, is part of the powersupply schematic does anyone have the schematics for the international version of the analog board?
  13. marcelv

    Classic II beyond repair?

    The challenge you have is not the caps but the repair of the traces, the board will not work until you repair these. there are a number of traces which have the capacitor island in the middle so the connection is broken. Also for example the trace which runs between the islands of C5 and goes to U8 has to be repaired. Add the caps when yo have checked (and repaired) the traces around and under the caps.
  14. marcelv

    Macintosh Plus Analog Board Q12 replacement

    tried some other resistors, 1K5 is too much (unstable), 1K , voltages too high. 1K1 and 1K2 work this is using a BRX49, don't have other BRX4x to test. You have to regulate the 5V to get as close as possible to the desired 5V value, too high or too low => crowbar.. Still looking for a beter solution...suggestions...
  15. marcelv

    Classic II beyond repair?

    I don't think you "need" any of the caps to boot. The most important thing is to clean the board to remove alle the leaked cap fluid. c15 connects to the pins as shown in the picture
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