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  1. Steven Tate

    MARANTZ 2230 power amp. PLEASE.help.

    https://akdatabase.com/AKview/albums/userpics/10007/Marantz%202230%20Schematic%20HiRes%20ALL.pdf
  2. Steven Tate

    Marantz 1030 Diode Question

    These are likely flyback diodes. Not sure if they are factory or not. But they are usually oriented with cathode to collector on NPN transistors and cathode to emitter on PNP transistors...
  3. Steven Tate

    2245 Boat Anchor

    You really need to find out if you are getting signal out of the switch. You could have a bad preamp or amp. The best way to tell would be to inject a sine wave into the Aux input and check for signal with a scope at the input of preamp board.
  4. Steven Tate

    2245 Boat Anchor

    Haha. I get it. But I knew exactly what I was getting when I bought it -- other than the crappy packing. I paid very little for it, knowing that the broken input select switch might be unfixable. The only setback from the packing was that the wood case was destroyed. But it was junk anyway...
  5. Steven Tate

    Marantz control cross reference spreadsheet - now searchable

    There is a link in the original post to download the spreadsheet file. If it doesn't work, let me know.
  6. Steven Tate

    2325 FM Troubleshooting Rookie Looking for FM Experts

    Good work! If you are going to continue working on FM tuners, a great piece of equipment to have on hand other than the ones you mentioned, is a parts front end that you can substitute for the one you want to rule out. If you mount it on a piece of wood and run the necessary wires to a terminal...
  7. Steven Tate

    Marantz 2325 Transistor Substitutions.

    Do you have a source for those? Mouser doesn't list KSC2683. What spec are you seeing that is closer, other than the max voltages? The two recommended subs are more robust for sure, but otherwise, pretty close in spec. From what I'm seeing, either pair should work if you can find them.
  8. Steven Tate

    My new 2245 FULLY RESTORED by former member Bob

    Talk to AK member Ocdecio. He has done a number of 240's and 250's, and seems to have them figured out.
  9. Steven Tate

    Marantz control cross reference spreadsheet - now searchable

    There are very few boards that are identical among units. Many are very similar, but there usually is a difference.
  10. Steven Tate

    First Rebuild/Restore of a Marantz 2230

    You don't need anything between the 2230 and the speakers as long as they are fairly efficient. I think most people start a rebuild with the power supply board. Nothing else can live up to its design if it doesn't have good, clean, correct power.
  11. Steven Tate

    Post Restoration Sound Difference 2245 vs 2270

    This is just one of those subjective topics. I don't hear any harshness, and use WIMA's for low value caps all over the preamp boards. But....My high frequency hearing is shot, so there may be something there that I am not hearing.
  12. Steven Tate

    Post Restoration Sound Difference 2245 vs 2270

    Heretic! :rflmao:
  13. Steven Tate

    Marantz 2238B power supply adjustment problem

    I believe the instructions for setting the PS in the service manual are incorrect. According to the instructions, you measure between J722 (+) and J724 (-). But according to the schematic, J724 is the 14V tap for the unit. Measure between chassis and J722, and see if you can adjust to 35V...
  14. Steven Tate

    My Marantz 2325 is messed up ...looking for help

    The MJE15030's should be good subs in that spot. Sounds like you have a short somewhere. Did you put mica insulators between the transistors and their mounts? Otherwise, look over all of your work with magnification if possible and look for some sign of a short or burned component on the board.
  15. Steven Tate

    Marantz 1060B Rebuild & Troubleshooting

    You might see if you can measure AC mV at the main filters during startup and after the hum goes away. There should be less than 100mV or so. I wonder if AC is leaking through during charge up, but settling down when it gets charged. If so, you might need to replace that cap. If you get...
  16. Steven Tate

    Looking for audio analyzer and have been told multiple times to go computer software route.

    I'm sure there are some very good sound cards that will give good info. The main thing you want to see is a noise floor of something around -110 db plus low THD in the signal generator.
  17. Steven Tate

    Looking for audio analyzer and have been told multiple times to go computer software route.

    The problem with software driven solutions is that they are limited by the distortion ratings of the sound card, which are usually not very good. You may get some stats, but they might not be very trustworthy.
  18. Steven Tate

    Phono "motorboating" solved(?)

    Is that across B and C?
  19. Steven Tate

    Phono "motorboating" solved(?)

    Since going down this road a few years ago, I have had one board that oscillated after changing all six transistors to KSC1815. In that case, I put the 2SC1000's back in and it worked fine. Although those transistors have a reputation for going noisy, I simply haven't experienced it. So, I...
  20. Steven Tate

    Looking for audio analyzer and have been told multiple times to go computer software route.

    Yes, I have a QA401 and use it regularly. My biggest complaint with the unit is the lack of instructions for taking audio measurements. Setting up the parameters of a test is not intuitive. But I spent a lot of time talking to a QA engineer, and with his help, I put together a little primer...
  21. Steven Tate

    Marantz Transistor/Diode/Trimmer Sub Guide

    Glad it looks helpful! Be aware that not all listed subs will work in every application. But, for the most part, they are subs that have been reported to work by someone on AK. Good luck!
  22. Steven Tate

    Marantz 2230 Signal Strength Meter - No FM indication

    No. That adjusts the muting level - the weak signal strength that will trigger the muting circuit and cut out the white noise between channels. It is not a signal attenuator.
  23. Steven Tate

    Jonstigator's 2245 rebuild

    You will get more eyes on your problem if you post a new question in the General Audio or Solid State forums. This is a Marantz forum, and probably not a lot NAD experts in here.
  24. Steven Tate

    Marantz 2230 Repair - H757 and H755

    Ahhh. Got it. The original is destroyed. I knew I had been down this road before on AK, and couldn't remember how it was settled. I looked back at my threads, and, sure enough, Tom Williams (Catrafter) suggested that the thermistor be replaced with a 1N4448 diode. If he thinks that is a good...
  25. Steven Tate

    Marantz 2230 Repair - H757 and H755

    I think we are saying the same thing. Units after serial number 38701 should not need an upgrade there. The factory built them with the upgraded design.
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