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  1. M

    Harman Kardon 730 Help!…..

    Think you need to slow down and be a bit more systematic. OK, left channel is down. Have you tried all (or at least a few) inputs, AM, FM, AUX,,,, ! cause possible dirty function selector Have you tried the good suggestion by rickl, ie, connect ipod/iphone/ixxx to main-in ! cause power amp or...
  2. M

    Technics SH-9010 Equalizer Recap—a few questions

    Depends on the application/function of the cap. For power supply caps I'd say maybe, keep in mind that these are typically the largest (=most expensive) so there MAY be some cost cutting going on. These caps are mostly for storage so the result is increased storage. Manufacturing...
  3. M

    Pioneer SX-828 diagnostic/repair assistance needed

    If you have an issue lifting one leg of D3, D4 then removing Q9 or Q11 should remove the alternate path so you can then measure between pins 25&25. Likewise for the right channel, pull either Q10 or Q12.
  4. M

    Pioneer SX-828 diagnostic/repair assistance needed

    Can we take a look at the diode strings D3 and D4. Pix show some solder on the pins. Incircuit diode test may be misleading since alternate path through driver and output b-e junctions. Could you try the following with amp powered off/unplugged Select diode test function on mm, red probe to D3...
  5. M

    Vector Research VRX-8000 in protect

    Might be something simple like pnp output or driver short c-e. Plz measure Vdc at both pnp, npn outputs and driver b/c/e to GND Assumed you have diode tested these...
  6. M

    NAD model history?

    If you are happy with the sound of the 7225 then this is legit. Also depends on your budget but I'd think you could do better than the 7225pre, but then you loose the "NAD sound". Maybe baby steps, consider a power amp OR consider a 7250 or 7240 then you could use these standalone or plug the...
  7. M

    NAD model history?

    I've not had much luck with NADs, 3x3020, 3140, 2x3150 all refurb'd. Tones, dynamics,,, sound great but "no" sound stage. Just finished a repair on a 7125, sounds good through headphones, will test on spkrs later in the week. The 2200, 2600, 2700(?) series of power amps appear to be well...
  8. M

    Pioneer SX-828 diagnostic/repair assistance needed

    I think you mean this post. Checking that the base-emitter voltage drop (Vbe) is normal, ie, 0.5-0.7Volts. This means that a suitable current is flowing through the b-e junction. If voltages were the same would suggest a failed(short) b-e Think of the transistors b-e junction as a diode so...
  9. M

    Pioneer SX-828 Troubleshooting

    As an overview, looks like there is a low resistance path to GND in the tuner stage, this causes AWR-010 pin 2 to sag. In the hunt for more power/mA pins 4,5,6,7 are also dragged down. Downstream of pin 4 may also be the cause. Would be nice to localize problem a little. I'd be tempted to pull...
  10. M

    Pioneer SX-828 diagnostic/repair assistance needed

    Thinking that Q7 is not "fully on" which accounts for the lower current draw(missing 2mA?) Looks like the control of Q7 is suspect, ie Q1,3. I'd be inclined to replace these if not already done, KSA992, try to match Vbe and hfe. You could test resistors R17, 13, 15, 19, 21, 33 but these will be ok.
  11. M

    Pioneer SX-828 diagnostic/repair assistance needed

    Appears the high abnormal voltage is coming from the +44V rail through R29 and R31 caused by a reduced current flow, ie, 4.4mA through R29 and R31. Should be about 6.4mA, ie, missing a 2mA path. Pin 25&27 indicates current flow through D3, Pin 26 and Q7c show no volt drop probably due to small...
  12. M

    Pioneer SX-828 diagnostic/repair assistance needed

    Results from post #54 show a dc offset of +13.3V(L, pin 7) and +13.7V(R, pin 8). This would result in a horrible noise if sent to the speakers. The protection circuit is doing its job. These voltages should be less than 50mV(or so) So the question is where does the +13.3V come from? Taking one...
  13. M

    "Pop" when turning off receiver

    Zombie thread but anyway, following might be useful to someone... In their receivers, yamaha connected the tuner pointer and meter lamps to the timing cap in the protection circuit. The idea being that at power off the lamps would quickly run down any charge in the cap so the relay would be...
  14. M

    Yamaha CA-2000 With Sticky Meter

    ^^ worth trying
  15. M

    Yamaha A-1060 repair

    @clinic-audio maybe pm?
  16. M

    Yamaha CA-2000 With Sticky Meter

    There was one up in QLD/Brisbane(?) that had a failed meter, needs a replacement meter, think it was mechanically seized.
  17. M

    Vintage Gear Frustration

    Try silver polish(Silvo?) and some cotton buds, yeah it's messy but gets things clean, then rinse/lube with the contact cleaner.
  18. M

    Pioneer SX-828 diagnostic/repair assistance needed

    Thanks. I like the TTC004A/B as drivers rather than the KSC2073.
  19. M

    Pioneer SX-828 diagnostic/repair assistance needed

    Suggests either the schematic is wrong or a measurement error or both R29 and R31 are open(already measured ok). Suggest remeasure. It's a hobby so it should not run/affect your life, it's done for enjoyment. Take time away. The unit is fixable, just need to nail down the key measurement.
  20. M

    Vintage Gear Frustration

    I clean the switch "sliding saddles) by spraying some contact cleaner on the edge of some printer paper(=reasonable quality) and then run the saddle over the paper edge, ie, the paper edge acts as the track for the saddle. I'm on a tight budget and can't afford the $5k-10k for a new amp so I...
  21. M

    Pioneer SX-828 diagnostic/repair assistance needed

    Problem is the +14.4V (or abouts) on pins 25(L) and 26(R). This cascades its way through the power amp output pins 7&8 and then onto the protect circuit pins 1&3. The high voltage turns on protect Q4 which drags down the protect relay voltage so it releases. Back to +14.4V at pin 25 base of Q9...
  22. M

    Luxman R-1040 Repair Question.

    Check fuse F203, if it is blown and Q208a is failing c-e then there may be +ve voltage on the collector. Replace F203 and then pull F201, if Q207a is failing c-e short... the dbt power up. Pull F201 and F203 then dbt power up, expect very dim.
  23. M

    Luxman R-1040 Repair Question.

    208a is leaking a little(32V) or a lot(1.7V) try replacing it.
  24. M

    Looking for an Onkyo Relay - A-RV401

    Post a pix of the original showing the pinout. 12V relays are quite common, can/should increase the 5A.
  25. M

    Pioneer SX-828 diagnostic/repair assistance needed

    Yep, where as the base has the "collector" voltage 43V, prompted the wrong pinout. Verify markings on Q9 are "C2073" if it is then you will probably need to pull Q9 and put it into your chi transistor tester to verify pinout, otherwise test according to,
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