Recent content by Oilmaster

  1. Oilmaster

    2017 Sansui Serial Number Database

    S-M7,922031753,internet A-M7,432033561,internet D-M7,222030867,internet B-2102 MOS VINTAGE,648100026,internet SRS-929,317050279,internet
  2. Oilmaster

    Sony 2251 and/or 2250 owners thread

    Constant current x resistance = constant voltage = zener
  3. Oilmaster

    Sony 2251 and/or 2250 owners thread

    When a (J)FET is connected like that it becomes a constant current source, combine that with a resistor and a constant voltage drop (like a zener) is created. You might think where is the resistor then? It are the regular diodes in series that have a given resistance at a given current, and thus...
  4. Oilmaster

    Sony 2251 and/or 2250 owners thread

    Indeed, as I mentioned in my thread about 1T243 devices: 1T243-xx40 = TZX11A (10.6V/500mW/1%) 1T243-xx47 = TZX7V5C (7.5V/500mW/1%) 1T243-xx49 = TZX10C (10.1V/500mW/1%) So what is the printed suffix on yours?
  5. Oilmaster

    Sony TAN 8850 amplifier

    Well, that's not entirely true: there is no global negative feedback from output to input stage There is however local negative feedback, from pre-driver stage to input stage, to keep the amp stable and at defined bandwidth. The idea behind that being that if the pre-driver stage is stable then...
  6. Oilmaster

    Relay Matsushita JR2A-DC24V-Y2 substitute?

    Measure up if the distances between the pins are the same as in the datasheet, and you are ready to order.
  7. Oilmaster

    Relay Matsushita JR2A-DC24V-Y2 substitute?

    That's why it would have been a great help to post as well the solder side of the relay at stake, but I read your remark that the board isn't directly accessible. You can see at the PCB layout that there are only 4 holes; so yes a DPST needed. But sometimes a DPDT are available at better price...
  8. Oilmaster

    Issues on Sony TA2000

    Oh that is a b**** problem to diagnose and to find out where.
  9. Oilmaster

    Issues on Sony TA2000

    I double-checked that you had the replacement transistor well positioned, and it looks they are. Since the problem is equal for both channels, and the changes are slim that the same problem happens in both channels at the same board, it makes me think of a "common mode" fault. Some resistors and...
  10. Oilmaster

    Relay Matsushita JR2A-DC24V-Y2 substitute?

    Omron G2R-2A4 for fully sealed version or Omron G2R-2A for non-sealed version You can also buy the DPDT versions of the above and cut off leg 2 and 7 Before any purchase, always check if the leg spacing of your relay is confirmed by the datasheet of the new relays...
  11. Oilmaster

    Yamaha B2 - the "why" and the "how" of a comprehensive rebuild

    The very same reasons why I pulled out of tube amps 20 years ago; an absolute money pit with no guarantees and unstable results. On top of that the tube community is flooded with hardcore subjectivitists, duly populated by folks with a lot of money and near zero technical knowledge; not the...
  12. Oilmaster

    Schematic help required

    Each secondary winding fused at 4A, hence 130VA per winding, which makes for a 260VA peak load. So a 300-400VA transformer with 2x32V to 2x34V secondaries will do as painttoad said.
  13. Oilmaster

    Sony tc-203 sd

    One on sale right now; nothing beats to have original manuals with all colors sharp and clear: https://www.ebay.com/itm/124906543188
  14. Oilmaster

    Searching for new belts for a Sony TC-FX606R

    It's a pretty packed unit. After some testing the headphone amplifier opamp turned out to be faulty and will be replaced later as well
  15. Oilmaster

    Searching for new belts for a Sony TC-FX606R

    Reinstalled and reconnected the whole tray again, and everything works mechanically perfect again, including reverse play :)
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