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c-4 preamp

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    Yamaha C-4, circuit board diagram for the Function Board, good scan required.

    Might anyone have a Yamaha C-4 service manual or at least a circuit board diagram for the Function Board? I already have the ones available from HiFi Engine etc and unfortunately they're close to illegible for reading some of the capacitor references. Very hard to confidently/easily recap...
    • Hifibythekg
    • Thread
    • c-4 c-4 preamp function board service manual yamaha
    • Replies: 6
    • Forum: Yamaha
  2. H

    Yamaha C-4. Capacitor types on the main board.

    Hello.. Does anyone have a list (BOM?) for replacement of capacitor types ('low ESR,' or 'good for power supply' designations is what I'm really after) on the Yamaha C-4’s main board? (The ‘Function C Board NA 07149.’) Could probably buy all Nichicon FG or Panasonic FC but would be grateful...
    • Hifibythekg
    • Thread
    • c-4 c-4 preamp capacitor nichicon capacitor range nichicon fine gold nichicon muse panasonic yamaha yamaha c-4
    • Replies: 33
    • Forum: Yamaha
  3. H

    Reed relay test. Yamaha C-4 preamp.

    Can a reed relay be tested in situ? If so, how does one do this? The reed relay in question is a RL6442 - H132 (location RY301) in a Yamaha C4 preamp.
  4. H

    Yamaha C4 - zener diode WZ130 - Power C Board

    Is the correct replacement for a WZ130 located at D503 and D504 on the Power C Board this? ONSEMI 1N4148TA Small Signal Diode, Single, 100 V, 200 mA, 1 V, 4 ns, 4 A https://uk.farnell.com/on-semiconductor/1n4148ta/diode-ultrafast-300ma-100v-do/dp/2322485?CMP=i-bf9f-00001000
    • Hifibythekg
    • Thread
    • c-4 preamp yamaha zener diode
    • Replies: 34
    • Forum: Yamaha
  5. H

    Dual JFET- 2SK100 - Yamaha

    Can anyone tell me how, or direct me to a page, that explains how to test a dual jfet? I want to test the 2SK100’s I have in my Yamaha C4 and A1 with a DMM. Apparently, if they’re working well, they’re interchangeable. However, I have issues in one channel in each amp and confirming their...
  6. H

    Varistor VDT 1212 Yamaha C4

    Just want to check whether this photo shows a VD 1212 varistor, next to its printed symbol on the pcb, facing the WRONG way? It’s currently residing in a Yamaha C4 preamp on the Function Board. Also, what’s the best way to test these components out of circuit.. a DMM or a cheap transistor...
  7. H

    Yamaha wafer switch disassembly limits - C4 preamp

    When disassembling these to thoroughly clean them.. can one remove the circular contact that sits on the black plastic centre piece with twelve studs? Is it ok to bend up the copper contacts to remove everything for cleaning and then bend them back afterwards for retensioning? Or should a more...
    • Hifibythekg
    • Thread
    • c-4 preamp input selector phono ground wafer switch yamaha
    • Replies: 21
    • Forum: Yamaha
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