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  1. Ylli

    Denon DRA-545RD

    Is there +19 volts on the 'hot' end of R658? C647 should charge through R658 until it reaches the turn on voltage of the Zener diode ZD601. That should only take a few ms. Something must be holding it to 7.9 volts during the in-op time. BTW, looks like you got more test equipment than I do...
  2. Ylli

    Denon DRA-545RD

    We are definitely in the right area. If we look at R658, one end connects to C647 that you just measured. The other end should be at about 19 volts per the schematic. Check that. I'm thinking C647 is leaky. If you can lift that out of the circuit, you could check it with an ohmmeter. You...
  3. Ylli

    Denon DRA-545RD

    "TR615 collector 3.6 V cold and 0.65 V warm." So are you saying that TR615 collector is at 3.6 volts after turn on and stays there until the unit starts to work after the warm up time, then dropping to 0.65v? During the turn on delay, can you measure the voltage at the positive end of C647?
  4. Ylli

    Denon DRA-545RD

    I was typing when you posted your last.... Be sure you are looking at the right transistors as shown in the schematic snipped I posted. If the numbering is different (based on the differences between the -R vs -RD) we may be confusing ourselves.
  5. Ylli

    Denon DRA-545RD

    Both the collector of TR616 and the collector of TR614 are wrong. At initial power up, C647 will begin to charge through R658. While it is charging, the base of TR615 will remain low and the collector will stay high. A high on the collector of TR615/base of TR616 will hold the collector of...
  6. Ylli

    Denon DRA-545RD

    Sounds like progress. Missing +5 volts would certainly prevent the unit from coming on. (I thought we had measured the output of IC605 earlier) Not sure what the 'Hold' does, but I bet it also could prevent the unit from coming on. Let's measure the volt at the cathode of D604 and the...
  7. Ylli

    Denon DRA-545RD

    It looks like the 'D' in the model number means the receiver can receive 'Data'. Have been unable to find a service manual for the 'RD'.
  8. Ylli

    Denon DRA-545RD

    Don't give up! One other technique you can try. I really think the processor is not properly asserting the 'P.ON/OFF' signal and it may be thermally related. Grab a can of freeze spray, and after the unit has been on and working for a bit, try using the freeze spray around the processor and...
  9. Ylli

    Denon DRA-545RD

    Sorry for the delay, dog demanded a walk... With TR612 installed and the unit operating, you see 2.5 volts on the P.ON/OFF line, and with TR612 removed, you see only 1.4 volts? 2.5 volts is what I would expect. Strange, but let's continue. Do a good physical inspection of the area around...
  10. Ylli

    Denon DRA-545RD

    That P.ON/OFF signal comes from the processor IC701 pin 27. It is likely an open collector output, and it does have a pull up on it. It appears to feed two loads - it turns on the +/- 16 volt regulators, and it turns on power to the receiver circuitry via TR612 & TR611. There are three...
  11. Ylli

    Denon DRA-545RD

    TR415 Collector ,04 volts (Ground) TR416 Collector +49 volts ^^I assume these are after the unit starts working. Looks like the 'on' command is not being generated or is not making it to the base of TR415. Find the end of R420 that is *not* connected to the TR415 base and measure it's...
  12. Ylli

    Denon DRA-545RD

    OK, first let's be sure the on/off command is making it to this regulator segment. Measure the voltage at the base of TR415 - it should be near +0.6 volts immediately when turning unit on. Collector of TR415 should go to ground when unit is turned on. Collector of TR416 should go to about +40...
  13. Ylli

    Denon DRA-545RD

    Going to need to get in there with a voltmeter. Being very careful to not short between any components/traces..... From a cold start, check the voltage at the input of IC605 - should be about +18 volts. Check voltage at the output of IC605 - should be about +6.0 volts. Check the rail voltages...
  14. Ylli

    Denon DRA-545RD

    Describe what you mean by "3 minutes before it turns on". Do you mean it takes 3 minutes for the display to light up, or that it takes 3 minutes for the speaker protect relay to engage (enables audio output)?
  15. Ylli

    Denon DRA-545RD

    https://www.hifiengine.com/manual_library/denon/dra-545r.shtml You do have to register at the site, but there is no spam or other.
  16. Ylli

    LM338K Availability

    Always had acceptable service from Newegg. Alternately, you could always go with an LM317 and an external pass transistor.
  17. Ylli

    LM338K Availability

    If it were me, I'd go here: https://www.newegg.com/Product/Product.aspx?Item=9SIA6RP36W3643&nm_mc=KNC-GoogleAdwords&cm_mmc=KNC-GoogleAdwords-_-EC%20-%20Sensors%20%26%20Transducers-_-GENERIC-_-9SIA6RP36W3643&ignorebbr=1&source=region
  18. Ylli

    What component is this? And where can I get one?

    Yeah, looks like a simple stretched dual bead. Just jumper the top left connection to the top right, and the bottom left to the bottom right. See if it works.
  19. Ylli

    Lead acid battery

    Yes.
  20. Ylli

    Lead acid battery

    If it will be left on charge continuously, set your voltage limit to 6.75 - 6.90 volts. If it is going to be used regularly, recharge to 7.2 - 7.5 volts and hold it there for a couple hours - then remove the charging source.. or, you can recharge at the higher current rate until the battery...
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