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  1. Tha fios agaibh

    Digital piano won't power ON

    On second thought, some of those esr readings are a bit high.
  2. Tha fios agaibh

    Digital piano won't power ON

    You need to pull the 10uf cap that reads 196uf and test it out of circuit. Everything else looks ok to me, including the transistor you thought you fried.
  3. Tha fios agaibh

    New diy'er

    Welcome Frederick, Great to get your son learning new things and perhaps even greater that he likes the same music as you. lol. You are talking about a mosfet transistor, not a transmitter. Download the spec sheet for that mosfet and compare the values to the substitute part to see if its...
  4. Tha fios agaibh

    Digital piano won't power ON

    Yes, but there's got to more to the precise rating. 5 or 6v, I can see. But 6.3v? Perhaps they are high precision at that voltage? Do they have other non-standard ratings like 16.3v or 25.6v?
  5. Tha fios agaibh

    Denon AVR-1912 E2/EA

    There is the possibility that pin 8 of op amp IC800:B (p114) has internally shorted. I'd try removing it and temporarily power up to check if your +7v is restored. Also make sure you check caps C823 and C807 with your esr meter.
  6. Tha fios agaibh

    Denon AVR-1912 E2/EA

    Michael, If I remember correctly, your problem was the 7v supply to ic801 was only 3.5v. Either something downstream of D800 is overloading the supply, or the ps is unable to deliver the required current. There are several approaches to finding the culprit, I like to use an isolation method to...
  7. Tha fios agaibh

    Denon AVR-1912 E2/EA

    Perfect Vf readings for most silicon diodes. I trust they had almost infinite readings (open) when reverse biased?
  8. Tha fios agaibh

    Digital piano won't power ON

    Maybe so, but why? Why wouldn't circuit designers just go with a 10v standard voltage rating?
  9. Tha fios agaibh

    Denon AVR-1912 E2/EA

    Yes, exactly like a map reference. In this case, G10 points to cn14 at bottom of page 111. It'd be nice if they'd just give you the page # 'eh? Sorry, I meant to check + and - power supply rail once you get Humpty Dumpty back together and powered up.
  10. Tha fios agaibh

    Denon AVR-1912 E2/EA

    It's good that you caught your mistake Michael. You need eyes like a hawk to catch every detail. You might be out £2, but now you can experiment on the bench with your new box of zeners. :) Back to diodes D800 and D801 feeding your 7v supply, make sure to check the negative side (D801) also...
  11. Tha fios agaibh

    Denon AVR-1912 E2/EA

    Just took a quick glance at the print and it shows D800 as a 1n4007 (i know you already know this but I'm not totally up to speed here with all your tinkering) which is not a zener. It appears to just drop. the voltage by Its forward voltage. which is what, .7v? So, I would install a 1n4007...
  12. Tha fios agaibh

    Digital piano won't power ON

    When in doubt, pull them out. It's seeing it as a diode because theres one parallel to it. I got to say though, I'm confused by the specialty voltage rating of 6.3v. I've never heard/seen such thing. Usually their rated at 10v, 16v, 25v....etc. It appears your 1000uf cap is fine.
  13. Tha fios agaibh

    Denon AVR-1912 E2/EA

    I can't pull up your print right now but the symbol is similar to a conventional switching diode except the black line for cathode looks like a z. The annode is the arrow part that I think of as a sideways "A" and the line part almost looks like a "K" (cathode). The difference with zeners is...
  14. Tha fios agaibh

    DVR 620 Ejects tape and powers off

    I will say that some will fault if the mechanism is overloaded (binding) or if a belt is slipping. It's very likely your belts are worn out due to age.
  15. Tha fios agaibh

    DVR 620 Ejects tape and powers off

    Or, don't put a tape in it.
  16. Tha fios agaibh

    Digital piano won't power ON

    I don't know I just googled it. Try Mouser. They are also a good source. You can usually esr test caps in circuit but I like to pull them and also check with a capacitance meter.
  17. Tha fios agaibh

    Digital piano won't power ON

    Here's a source but I'd wait to order until you know all the components you may need. https://www.digikey.com/product-detail/en/panasonic-electronic-components/MA2Q73800L/MA2Q73800LCT-ND/267207
  18. Tha fios agaibh

    Digital piano won't power ON

    Ah thanks. I was thinking the upstream board left of Q8 was called 1000unit or something. I could still use some clarification of how it would impact the diode. I'm thinking maybe the absence of sufficient capacitance caused the inductor to spike back to the diode instead or resonating through...
  19. Tha fios agaibh

    Denon AVR-1912 E2/EA

    Orange shold be anode and the black represents the kathode side. Your meter should verify this. Btw, you never mentioned what its forward voltage was. You tested it in with your dvm in diode test mode didn't you?
  20. Tha fios agaibh

    Pioneer SA-505 clicking

    So crop it, resize it, or lower the resolution in just about any photo editor.
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