Which 50k are you referring to?
Nakamichi 580 no audio at RCAs & headphone jack
- Thread starter gnexus
- Start date
My bad! It's 10k...
Was thinking of the sliders on the 480. Still obsessed with them since can't find them without buying another parts deck...
Now attempting to troubleshoot the no erasure issue:
Received order of 0.1 ohm resistors specified in SM. Put one in series with erase head at CN-1(1). Get 0Hz ocillator and no current. But oscillation must be happening because it records. ???
Maybe I'm doing it wrong?
Edit: Actually it's NOT recording anymore! Great!
Received order of 0.1 ohm resistors specified in SM. Put one in series with erase head at CN-1(1). Get 0Hz ocillator and no current. But oscillation must be happening because it records. ???
Maybe I'm doing it wrong?
Edit: Actually it's NOT recording anymore! Great!
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It's a miracle! 
Actually resolved the recording issue on first try!
It was a dead 945 transistor(Q301).
But does it now FULLY erase?
Edit: Yes!
So it wasn't actually an "erasure" issue it was a "not recording at all" issue...
Good! This deck is nearly done now!
Only problem left is the right channel distortion at higher output levels (both headphone and line out).
Actually resolved the recording issue on first try!
It was a dead 945 transistor(Q301).
But does it now FULLY erase?
Edit: Yes!
So it wasn't actually an "erasure" issue it was a "not recording at all" issue...
Good! This deck is nearly done now!
Only problem left is the right channel distortion at higher output levels (both headphone and line out).
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@dankik
So now only need to eliminate the right channel distortion at high output levels and this deck will finally be done except cosmetics...
It's on both headphone and line out. Only noticeable at +70% output level although might be present at lower levels. Only right channel.
Any ideas and/or comments on what to check?
So now only need to eliminate the right channel distortion at high output levels and this deck will finally be done except cosmetics...
It's on both headphone and line out. Only noticeable at +70% output level although might be present at lower levels. Only right channel.
Any ideas and/or comments on what to check?
It's not a recording issue.
This is playback from a known good audiophile quality tape of a CD which was recorded long ago...
ONLY on 580.
"Almost" certain! But will double check that now. Never know these days the way things go here
Edit:
DEFINITELY ONLY on 580!
It's on both headphone and line out. Only noticeable at +70% output level although might be present at lower levels. Only right channel has distortion.
Edit:
To me it looks like ONLY IC302 could be the cause because it's only thing before line out that could be the cause of the distortion - unless it's coming from even earlier location like playback circuit or Dolby circuit.
Really BADLY need a scope!
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Another miracle!
Wow! Fixed on first try again!
This baby is finally DONE!
(Except for cosmetics... it still looks like crap...Top has rust. Front panel has heat damage. It also has a damaged knob... )
Edit:
I suppose i also should calibrate EX recording levels and bias...
But hey, I've never ever even had any cheap crappy tapes like that! So just bought some cheapo blank tapes from Amazon with a clear shell. Will convert one to a mirror tape and use the other for testing and calibration. Will it sound like crap? Or can a Nakamichi make even a no name crappy Chinese tape sound good?
Wow! Fixed on first try again!
This baby is finally DONE!
(Except for cosmetics... it still looks like crap...
Top has rust. Front panel has heat damage. It also has a damaged knob... )Edit:
I suppose i also should calibrate EX recording levels and bias...
But hey, I've never ever even had any cheap crappy tapes like that! So just bought some cheapo blank tapes from Amazon with a clear shell. Will convert one to a mirror tape and use the other for testing and calibration. Will it sound like crap? Or can a Nakamichi make even a no name crappy Chinese tape sound good?
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Now recording to PC from the 580:
A very rare 1980 Japanese audiophile LP pressing of "Pink Floyd - The Wall." This Nakamichi ZX metal tape was recorded on the 480 when it was brand new. The LP was also brand new, and it was pressed from very high quality virgin vinyl. But, of course, there's a still an occasional few tiny pops to let you know you're actually listening to an LP
I'm going to convert this file to highest quality FLAC. Is it possible to upload a sample here to allow people to understand the full quality of ancient Nakamichi tape decks?
Of course I know most people here will already be familiar with their high quality. But maybe not with an audiophile LP on genuine ZX metal tape.
A very rare 1980 Japanese audiophile LP pressing of "Pink Floyd - The Wall." This Nakamichi ZX metal tape was recorded on the 480 when it was brand new. The LP was also brand new, and it was pressed from very high quality virgin vinyl. But, of course, there's a still an occasional few tiny pops to let you know you're actually listening to an LP
I'm going to convert this file to highest quality FLAC. Is it possible to upload a sample here to allow people to understand the full quality of ancient Nakamichi tape decks?
Of course I know most people here will already be familiar with their high quality. But maybe not with an audiophile LP on genuine ZX metal tape.
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I was about to go absolutely insane this morning because, after recording an album last night none of the buttons worked on this deck when powered on!
Then moved it to workbench. Now it works again!
Maybe it's now so comfortable on the workbench that it never wants to leave...
Then moved it to workbench. Now it works again!
Maybe it's now so comfortable on the workbench that it never wants to leave...
@dankik
Line-In is exactly -1dB low on left channel.
0dB on right. -1dB on left.
Both input voltages are identical at the RCAs (181mV). That's from a 400Hz test tone from computer. It happens both on that and with 330Hz test tone from tuner.
That's with the balance pot centered. The SM has nothing on a way to adjust line input levels or balance because they're supposed to be the same and then adjusted with the input pots.
The meters are calibrated to exactly 0dB at 100mV.
The test tone is calibrated to exactly 0dB at 100mV.
It's a minor annoyance for now. But need a way to obtain equal levels with the balance pot centered. That will obviously require adding or changing the value of a resistor on one of the inputs to get them equal.
Line-In is exactly -1dB low on left channel.
0dB on right. -1dB on left.
Both input voltages are identical at the RCAs (181mV). That's from a 400Hz test tone from computer. It happens both on that and with 330Hz test tone from tuner.
That's with the balance pot centered. The SM has nothing on a way to adjust line input levels or balance because they're supposed to be the same and then adjusted with the input pots.
The meters are calibrated to exactly 0dB at 100mV.
The test tone is calibrated to exactly 0dB at 100mV.
It's a minor annoyance for now. But need a way to obtain equal levels with the balance pot centered. That will obviously require adding or changing the value of a resistor on one of the inputs to get them equal.
Done that already as previous calibration step. The playback levels are perfectly set. That's not the issue. It's the input levels that are very slightly off balance. Just noticed also that it's slightly different balance at other frequencies.
I'm not sure if it's even bothering with because it's only 1dB difference. But it's annoying because I never experienced that before on the 480. (Suppose that's because it has TWO input level controls and no balance pot)
Now have bias correctly calibrated for SX tape. A couple of crappy normal bias tapes should arrive later today to do the EX bias calibrations.
Just recorded a song from Steely Dan -Aja SACD on the 580. It sounds EXACTLY like the SACD to my ears!
But then I noticed Dolby was off. So need to record it again for further testing...Also sounds fantastic with Dolby on!
I probably shouldn't mess with it more except EX recording levels & bias.
I don't want to press my luck!
That was scary this morning, but think it was just because the remote unit was disconnected and the deck didn't reset until power cycled.
I probably shouldn't mess with it more except EX recording levels & bias.
I don't want to press my luck!
That was scary this morning, but think it was just because the remote unit was disconnected and the deck didn't reset until power cycled.