2220B - yet another tuner issue

Discussion in 'Marantz Audio' started by Uncle Bambi, Dec 26, 2017.

  1. Uncle Bambi

    Uncle Bambi Funky Tut Subscriber

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    Checked R223 and R243 with one leg lifted - .993k and .994 respectively. They're good. Pulled H204 to test, but decided to just replace with a KSC1845. Voltage is up on the emitter, much closer to the listed 2.7:

    H204
    E - 2.64v
    C - 9.3v
    B - 3.27v

    I re-swept the mute trimmer, ans still no stereo light.
     

     

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  2. rBuckner

    rBuckner Luv 2 Restore Subscriber

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    Well, that looks much better. The 1845 has a typical frequency spec of 110MHz and the old 2SC829 is 230MHz, but I think that is at unity gain. It's operating at 10.7MHz but may be doing enough gain to have the signal cut down, bringing back to being too low again. Just not sure. I'd be putting a scope on it and comparing it to another working unit here, making it easy. Bring it on by to AZ!

    I do have some old donor boards and can harvest an old C829 or two for you if you like, just for the postage (which is to go to AK as a donation). Just PM me with an address if you want.
     
  3. Uncle Bambi

    Uncle Bambi Funky Tut Subscriber

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    If only I were closer to AZ!

    I have several transistors on-hand, if you might know a more suitable replacement candidate? I could always put the original back as well, as it didn`t seem to fix the problem. If you think it would be a useful step, I will be happy to take you up on your generous offer. PM inbound....
     
    Last edited: Dec 30, 2017
  4. Uncle Bambi

    Uncle Bambi Funky Tut Subscriber

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    Re-checking H302 and H303:

    H302
    E - 0v
    C - 3.28v
    B -0v

    H303
    E - 0v
    C - .04v
    B - .63v

    So, it looks like H303 is turned on and blocking the stereo light from being lit. H303 gets fed by pin 8 & 9. Pin 8 is at 0v, which is forced mono operation. Pin 8 gets fed by the Phase Comp, which I can't check. The input of the phase compensator is pin 11, which is at 2.20v, but should be 5.3v...... but pin 11 gets its input from Pin 3, which is at an acceptable 5.2v. The only other thing I see that could be the problem is the 19khz divider, but I cannot check that.

    That's all I got, and I'm confused by it . :) Could the HA1156 be the culprit? Either that, or maybe this thing just needs an alignment and I'm SOL.

    Would it be safe to jumper pin 8 to pin 9 as a test to see if the stereo light illuminates?
     
    Last edited: Dec 30, 2017
  5. rBuckner

    rBuckner Luv 2 Restore Subscriber

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    Let's get that C829 installed and see where we are. I wouldn't jumper those pins, it's not safe. If all else fails, Chrismarantz is up in Martinez, less than an hour away from you, without traffic issues of course!

    My sister in law and hubby lived for years in SR, can't recall the developments' names though. Last one was on Ginger Lane I think and was near Doherty but that's a heck of a long road as I recall. Beautiful area. I was over the hill in Alameda for my first 36 years of life.
     
  6. Uncle Bambi

    Uncle Bambi Funky Tut Subscriber

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    Ok - I'll wait for the 829's and we'll see what's what. I'm just not seeing what is keeping pin 8 at 0v...... The thing that is puzzling me is that Pin 3 is 5.3v, and is directly connected through a capacitor to pin 11 which is at 2.20v. So, that little .047uf film capacitor at C302 is dropping 3v?

    Martinez is not far at all - I'll drop Chrismarantz a PM and see if he's inclined to get involved with this mess. :)

    San Ramon has grown quite a bit since I moved here in 1987.... from a population of 20k to over 70k. Crazy. It is a beautiful area, but it is getting too crowded for me..... :)
     
    Last edited: Dec 30, 2017

     

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  7. vrobec

    vrobec New Member

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    Watching this interesting discussion. :) I have the same stereo issue on my Marantz 2216.
     
  8. Uncle Bambi

    Uncle Bambi Funky Tut Subscriber

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    Your replacement C829's arrived safe and sound, and I was able to replace my replacement 1845 with one of yours. Sadly, no stereo lock. :(

    Here are the readings from your replacement 829:

    H204
    E - 2.59v
    C - 9.53v
    B - 3.25v

    Better than the original, just about the same as the 1845. But no stereo lock, and HA1156 pin 8 still reads near zero (.04v)

    Any ideas? At this point I'd pay to have it aligned, but wouldn't know anyone local to take it to.
     
  9. Uncle Bambi

    Uncle Bambi Funky Tut Subscriber

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    Oh - and just to reiterate....... with the DVM on pin J208, I get 0.61v. Tuning in and out of stations and/or turning the muting threshold trimmer R253 trimmer has no effect on this reading - it stays steady at 0.61v. If I depress the Muting button, the voltage changes from 0.61v to 0.63v, and there is no change in that reading if I sweep the trimmer from side to side.
     
  10. Uncle Bambi

    Uncle Bambi Funky Tut Subscriber

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    Anyone have any other ideas, or am I SOL?
     
  11. Beamer302

    Beamer302 AK Subscriber Subscriber

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    You might want to try another board .
     

     

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  12. Uncle Bambi

    Uncle Bambi Funky Tut Subscriber

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    So - looking at this POS again, I see a resistor on pin 6 that is on the schematic as 100 Ohms, but when I measure it it is at 10 Ohms. When I check the color code, it confirms that this resistor is 10 Ohms (brown, black, black). Since the voltage on pin 6 should be 1v and mine is at 10v, this has got me wondering if that resistor might have something to do with the problem. Then I do some more searching and come up with this AK post from way back:

    http://audiokarma.org/forums/index.php?threads/marantz-2220b-tuner-problems.192331/

    So, now I'm wondering if my HA1156 chip is toast, and/or I need to change that resistor.....
     
  13. Northwinds

    Northwinds Huh? Turn what down? Subscriber

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    What happened to catcrafter? Seems like he was blown out of this thread and also seems to be the most qualified to help you?
     
  14. Uncle Bambi

    Uncle Bambi Funky Tut Subscriber

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    Dunno.... I took all of his suggestions, and posted my results. I was really happy to have him lending a hand, and was looking forward to his continued support and diagnosis, but he never came back. Maybe busy with his own stuff? He's certainly more than welcome to help out - I'd absolutely LOVE to hear what he thinks about this.....
     
    Last edited: Jan 14, 2018
  15. rBuckner

    rBuckner Luv 2 Restore Subscriber

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    I looked up what you found and figured that it is R311. I had pictures of a 2220B's insides and zoomed in on that part and it's 100 ohms. I'd start by replacing it with a 100 ohms but I bet your 1156 chip is toast. Maybe someone switched it after using a wrong value bulb to make it brighter. There were factory mistakes that made it out the door though, I've seen it.
     
  16. Uncle Bambi

    Uncle Bambi Funky Tut Subscriber

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    Yeah, I forgot to specify, R311. Any chance your donor board has a H1156 on it? :)

    Apparently, the HA1156 is available on the auction site, as well as direct from China and Taiwan. Also, nte801 is supposed to be an equivalent replacement. I'll try changing out R311 tomorrow to see if that fixes anything. If not, I suppose I can always ground pin 6 and see if the light comes on. If it does, that would prove that the IC is the issue, no?
     
    Last edited: Jan 15, 2018

     

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  17. rBuckner

    rBuckner Luv 2 Restore Subscriber

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    I wouldn't let an HA1156 go if I had one, sorry! I need them once in awhile myself. I have used NTE tuner chip replacements before and all have been fine. Those chips can't be subbed by something else because they are so unique is my reasoning. So either they got a bunch of old ones long ago or have gotten the info to have them made. Who knows?

    Grounding that pin will check the path from the pin to the lamp but not the IC's function. Given that the audio doesn't seem to you to be in stereo I'd bet the lamp will light up if you ground pin 6. That would put more current through the lamp than it's supposed to have so try it by removing the 10 ohm resistor and leaving the end of R311 up on the 100 ohm replacement that is by the IC and ground that.

    Here's something worth a shot: In the alignment instructions there's a step (page 6, section 9, item 8) where you use a voltmeter and adjust a transformer slug for 0 volts which is the discriminator. It's the equivalent to tuning off of any stations (and nothing hooked to the antenna terminals) and centering a center tune meter on higher models. If it's way off that may kill the stereo. Way off would be like 0.1 volts DC or more. Don't use a metal screwdriver though! Customize something plastic or hardwood like maybe a kabob skewer. That is if you don't have an alignment tool kit... Don't mess with the pink adjustment without a distortion analyzer.
     
  18. catrafter

    catrafter Marantz Specialist Subscriber

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    I'm still reading...
    It's hard to decipher what has or hasn't been tested.
    I only have the schematic from a non-Dolby 2220B so take the references with a grain of salt.
    When the signal strength is high enough for stereo operation H209 will turn and it's collector and J209 will go to nearly zero volts. This 'ground' at J209 is sent though a bunch of switch contacts to J308, which should turn OFF H303. With H303 OFF, HA1156 pin 8 should rise to about 3V enabling it to decode stereo if it finds the proper pilot signal.
    You can safely ground pin 6 to see if the lamp comes on, this will only tell you if the path from pin 6 through the mono switches, the lamp and the lamp power source are OK.
    PM sent on HA1156 source.

    Tom
     
  19. Uncle Bambi

    Uncle Bambi Funky Tut Subscriber

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    OK - I didn't have a 100 Ohm resistor on-hand, so used a 150 Ohm instead. No stereo lock. Swept the muting trimmer and R304, with no change. Grounding Pin 6 gets me a dim (because of the 150 ohm resistor) stereo light, so the path is good.

    Checking J208, I now see 0v. According to my notes it was at 0.625vdc, so something has changed. Pin 6 is still 10v, and Pin 8 is near 0v.

    Measuring H209:
    E = 0v
    C = 7.19v Mono voltages present
    B = 0v

    Measuring H303:
    E = 0v
    C = 0.62v
    B = 0v

    Is it our best collective guess that the 1156 might be bad? If so, I'll order one or two.
     
    Last edited: Jan 15, 2018
  20. Uncle Bambi

    Uncle Bambi Funky Tut Subscriber

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    I checked both sides of R237 as described, and both ends read at or near 0v (0.001v), so I didn't try turning the slug.
     

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