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  1. bushtech

    fta Sat TV decoder: Need some ID

    Busy working on my fta Sat TV decoder. But I have come across some things that I can't identify. In the small red rectangle is two legged smd alfa 010. What is that? Then the big red rectangle has got something that looks like a 4 poster carport roof. It has got 4 leads coming up from the...
  2. bushtech

    Denon AVR 1804 amp won't switch on

    I assume the transistor being driven into saturation is good. Where do I go from here?
  3. bushtech

    Multiple batteries in a car.

    As I understand it the problem with charging multiple car batteries with one alternator is that the alternator sees the battery bank as one battery. If one battery in the bank is at a lower charge than the others this drags the average that the alternator sees down and the alternator will keep...
  4. bushtech

    Denon AVR 1804 amp won't switch on

    Thanks St Edd. Please can you tell me what the chances are that the μp is still working OK?
  5. bushtech

    Denon AVR 1804 amp won't switch on

    Shouldn't the collector be at R158's voltage of 5.16V? Don't understand what's going on here
  6. bushtech

    Denon AVR 1804 amp won't switch on

    Must say, my soldering skills have improved dramatically. Practice makes perfect I suppose. Collector to ground = -0.15V Collector to emitter = 0.65V
  7. bushtech

    Denon AVR 1804 amp won't switch on

    St. Edd Are these the readings you were expecting?
  8. bushtech

    Denon AVR 1804 amp won't switch on

    Transistor survived another ordeal Base now disconnected R158 reads 5.61V and 5.16V on it's legs
  9. bushtech

    Denon AVR 1804 amp won't switch on

    Shame poor little transistor's head must be spinning. I'll try once more to remove it, bend it's legs without breaking them and shove it back:)
  10. bushtech

    Denon AVR 1804 amp won't switch on

    What I don't understand is the voltages I get on both sides of R159. It's one leg is grounded so should be zero. And I do get virtually zero on the one leg, but how does the 0.69V on the other leg come about?
  11. bushtech

    Denon AVR 1804 amp won't switch on

    Thanks St Edd Red 3 to Red 4: Red 3 = out leg of 7805 (IC103) = 5.6V Flows to R158 incoming leg = 5.6V outgoing leg = 5.16V Which is the voltage of Red 4 Looks OK to me, what am I missing ? Must say that I'm having difficulty with readings as they jump around a lot, starting to wonder if some...
  12. bushtech

    Denon AVR 1804 amp won't switch on

    St. Edd Thanks Looking at round face of transistor the pinouts are from L to R: 1 Emitter 2 Collector 3 Base I am using this numbering as I believe it's correct Confirmed Collector is free floating Base is connected and at ground potential Emitter is at 0.68V Red 4 = 5.16V Red 5 = Here I have...
  13. bushtech

    Denon AVR 1804 amp won't switch on

    Q151 Working on the assumption that my reading of the pins as above is correct. I have now pulled the centre pin (which I hope is the collector) Readings: 1. = 0.68V 2. = 5.16V This is voltage on the board 3. = 0V (0.1mV) The pulled collector pin of the transistor reads 3.3mV if that's of...
  14. bushtech

    Nice relaxing day.

    The silence before the storm?
  15. bushtech

    Denon AVR 1804 amp won't switch on

    St. Edd My apologies. Finally found the 2SC1740 (Q151) datasheet and I've still got it wrong. Looking at round face of transistor the pinouts are from L to R: 1 Emitter 2 Collector 3 Base Must admit I was stunned by this, never imagined the base would be anywhere but in the centre. But before...
  16. bushtech

    Denon AVR 1804 amp won't switch on

    Now lifted the opposite leg So new emitter now 0V Base 5.16V Collector hole in pcb 6.3V Collector on transistor 0.13V Better?:confused:
  17. bushtech

    Denon AVR 1804 amp won't switch on

    St. Edd The lifted collector leg voltage now 5.37V Base and emitter voltages as above Just checked for continuity between base and emitter and with DMM on diode function it reads 689 So is the problem now the 5.96V on the Emitter? Ok I see the problem. I must have my collector and emitter...
  18. bushtech

    Denon AVR 1804 amp won't switch on

    Q151 voltages now: E=5.96V & B=5.48V
  19. bushtech

    Denon AVR 1804 amp won't switch on

    Whoa! back up. Just realised I was shorting out legs on Q117 OK This time I got the right resistor. And shorting out E and B I still get 0V on emitter. Will now lift collector leg of Q151 Collector leg of Q151 lifted
  20. bushtech

    Denon AVR 1804 amp won't switch on

    davenn. I wish I knew. Either that fuse was blown or I was making a stuffup of the readings. It is very tricky taking the readings on the underside of the board. Apologies. But Good Morning:D
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