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  1. patrick_l

    Marantz SR-50L receiver power supply problem

    Here is schematics of circuits where are both voltages used (+12V and -12V):
  2. patrick_l

    Marantz SR-50L receiver power supply problem

    I've been trying for days to figure out what is wrong with this receiver. When it is switched on, everything appears ok. Speaker relay engages. But there is no sound at all! Tried different inputs, and it can't be heard anything, not even a static noise, nothing. Tried headphones, also nothing...
  3. patrick_l

    Sony STR-GX79ES strange protection problem

    I'm happy to say it is solved :). After I tested transistors, decided that I should solder them back where they were, and also to put boards back to their place. As I figured out, only option left is to check every possible connection there to see if somewhere I have cold solder or loss of...
  4. patrick_l

    Sony STR-GX79ES strange protection problem

    Because protection IC got me thinking in completely another direction than I should according to voltages I measured at it's pins. I didn't realize I have so big offset at the end stage when I thought about problem in the first place. Because, voltages suggested that AC off detected. I wasn't...
  5. patrick_l

    Sony STR-GX79ES strange protection problem

    Day 4th, and problem not solved, yet. In my last post, I mentioned regulators, so that was first thing to do today, to check if they are ok. My DMM show they are perfectly fine, so it's not the problem in this case. Next I tried to see if problem will go away if I disconnect some of the boards...
  6. patrick_l

    Sony STR-GX79ES strange protection problem

    Well, day 3, and struggle continues. This time I wanted to be sure I don't have bad output transistors, so I desoldered them and tested individually by using Peak DCA55 semiconductor component analyser. Every single one is ok. Also noticed not so well solder on two of them. Soldered them again...
  7. patrick_l

    Sony STR-GX79ES strange protection problem

    I've been trying for two days already to figure out what is going on with this receiver that all from a sudden went to protection mode. Before that it was ok, played ok, and after switching it off, after about 10 days of not using it, tried to switch it on, but, surprisingly, it went to...
  8. patrick_l

    Kenwood KT-980F problem

    Also checked all parts around voltage regulator, didn't find anything bad. Service manual is very complex. Starting to lose hope...
  9. patrick_l

    Kenwood KT-980F problem

    Got this tuner few days ago, but it is not working. Tuner does not respond to any command. On display i have number 1888, "tuning mode" and also numbers from 1 to 5 that would indicate signal, but don't have bars for signal at all. Checked power supply unit, and concluded i don't have 5V...
  10. patrick_l

    Onkyo Integra A-8250 question

    Contacted seller about those caps, and he told me to try it...Later I got tempted to see if this plastic sleeve was placed over another one, but seems that it isn't. But, top of the capacitors are different, so I completely doubt that Rubycon would use different kind of cans for same series of...
  11. patrick_l

    Onkyo Integra A-8250 question

    Unfortunately, I don't have variable power supply, so I can't test voltage rating of that caps. My ESR meter don't check voltage rating, just capacitance and ESR. Shipping costs of reputable suppliers for my country are way too much, much more than price of parts is, so ebay looks like only...
  12. patrick_l

    Onkyo Integra A-8250 question

    Got this item few months ago, but it's not working ok. I can hear both channel working, but one seems to have big distortions, that is more noticeable if i crank the volume up. So what I found inside is that one of two filter capacitors leaked so much, that it can be seen on bottom plate of...
  13. patrick_l

    Troubleshooting CD Players

    Thank you for advice. Pity I didn't have chance to try that, because buyer didn't complain about problem I mentioned to him. It was not a big deal for him, options I explained as problematic ones. But for sure I will know in the future what to do.
  14. patrick_l

    Troubleshooting CD Players

    Onkyo CR-L5 have problem. Read any disc without problems, plays half of tracks of every cd without any error, but last tracks on cd fail to read. For example, if CD have 16 tracks, and I want to hear number 16 first, it won't read it. But if I press play, number 1 start really fast and I could...
  15. patrick_l

    Yamaha RX-397 DC protection?

    Thank you very much. I've been testing it since repairing, no problems whatsoever. Amazing sound, and I am really satisfied. Quality phono section! Also noticed, that unit doesn't warm up at all :). Tested idling current, and everything is perfect by specification. I totally recommend this...
  16. patrick_l

    Yamaha RX-397 DC protection?

    I know it sound strange, but I managed to enter diagnostic mode, in which protection is disabled, exactly for the reason of troubleshooting, and I wrote in that mode I can actually switch speaker relays on/off, and it works, but microprocessor interpreted it wrong, because of shorted zener diode...
  17. patrick_l

    Yamaha RX-397 DC protection?

    Good news! After intervention, receiver works as it should. Before I even saw replies here, I was thinking about exactly the same thing, to check supply voltages, especially +5S, since it feeds that zener diodes, that are connected to pin 90 (PRV) and pin 91 (PRD). Before, when I discovered that...
  18. patrick_l

    Yamaha RX-397 DC protection?

    Few days ago, i've been trying to repair this receiver I bought in non-working order. The thing is when you try to switch on, power relay clicks, CD/DVD appear on the display, and that lasts for about 3 seconds, and device shuts itself off. Already got service manual, and tried to enter...
  19. patrick_l

    Sony TA-700es

    I would first apply DeOxit on speaker selector. If that doesn't do the trick, I'm affraid it is relay problem. It is possible due to age, that relay contacts become oxidized. If relay is easy to access, and to remove plastic cover, i would use extra fine sand paper, and also apply DeOxit. That...
  20. patrick_l

    Vintage receiver choice

    When I have read that you want more warmth/presence, I am surprised that you didn't consider good old German made brands, such as Grundig, especially FineArts series, Telefunken, Wega? Price is much much lower then anything mentioned, but sound is very warm. The same goes about speakers. I would...
  21. patrick_l

    When your vintage collection becomes worthless.

    I think that value of vintage hi-fi gear may only be higher in the future. As long as there are quality replacement components to maintain old stuff, it will live forever. Standards change, that is true, and some great formats haven't survived, unfortunatelly, such as minidisc, vhs etc. Soon the...
  22. patrick_l

    Marantz PM-32 with new replacement transistors

    Wanted to share my short story about repairing Marantz PM-32 integrated amplifier. I got it in non-working condition in very good shape, and noticed burned fuse that was on the back of the amp, taped with transparent tape. I realized that fuse someone took out of the amp, and logically amp would...
  23. patrick_l

    Help me choose between a few amps

    Onkyo A8500 is Onkyo Integra (higher class of brand), and it would be the best choice among others in that list. But if you want stronger bass, Kenwood of that era is so strong you would need to adjust bass regulation in minus :). I noticed that Kenwood could have problems with switches...
  24. patrick_l

    Troubleshooting CD Players

    Few days ago I have discovered something very interesting about troubleshooting CD-players. I have finally decided to try to repair JVC XL-V174 CD-player. Most of the discs wouldn't spin at all, and only few would spin little bit, but there were no TOC. It couldn't read any disc. First thing I...
  25. patrick_l

    Sansui A-60 question

    I just need to tell you my story, about buying A-80 Sansui :). In the flea market they asked for 25 euro. It was very suspicious, especially when I took amp in my hands, I could clearly hear something inside, like broken plastics or so. Wondered what might be wrong with it, but they refused to...
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