Nakamichi 580 no audio at RCAs & headphone jack

[dankik]

I don't understand. Do you have a problem with the 580 recording onto a tape or playback of a recorded tape from another deck?

1. If you playback a known good tape (either pre-recorded or from another tape deck) are both channels good and at the correct levels?
2. Do the VU meters show the same level?
3. If you record a tape on the 580 then play it back, are you saying that the R channel is lower and fluctuates?
4. In the 2nd case, when you are recording are both VU meters at the same volume level?
5. Record bias could affect the recording. Did you do anything to adjust the bias? It should not affect the playback of a good tape.

 

[gnexus]

I don't understand. Do you have a problem with the 580 recording onto a tape or playback of a recorded tape from another deck?

Sorry about last post. I thought it was clear. I should have put it in the 480 thread.

Last post was about the 480 recording issue only. It has absolutely NOTHING to do with the 580 or the playback of any recorded tapes. Playback is perfect now on both decks.

Bias levels haven't been touched yet on either deck. 480 is set at factory level. But did "tweak" all the pots on both, just to be certain no potentiometer issues, before setting them back exactly to previous positions.

580 is currently dead, as noted previously... So nothing more on the 580 recording issue until I replace the shorted logic IC.

 

[gnexus]

Referring back to the 580 in regards to your questions:

1) I'm fairly certain that I noted previously that playback is now very good to excellent on both decks. Equal playback levels (100mV - 0dB) using 400Hz test tape and equal levels on music tapes.

2) Yes. As noted above VU playback levels are now set at 0dB and 100mV using 400 Hz test tone tape.

3) No. The 580 output levels of a 400Hz test tone tape are perfectly equal and set at 0dB. The only issue on the 580 is the very slight noise on the right channel and right VU wiggling +/- 1 or 2 dB. There's also some W&F on both channels on the 580 due to the old capstan belt. But that's a different story I already am familiar with. A new belt has been ordered.

The very low recorded right output level you're referring to is ONLY on the 480. There it's -10dB to -20dB less than left channel. BAD situation!

4) This question refers to the 480 low recorded tape output. The input levels of the 333Hz test tone are exactly 0dB. Recorded tape output level for left is exactly 0dB and perfectly rock solid steady. Right output level is -10dB to -20dB and fluctuates a lot. Same thing happens with music.

5) The bias pots haven't been touched on either deck. All the bias pots on the 480 are factory set and all have basically the same position.

 

[dankik]

Have you tried a different tape type to see if the recorded low output is the same. The bias is set for each tape type so try all three with different tapes if you have them or on the same tape even if you don't. If it sounds better with different tape bias settings then maybe it needs adjusting.

 

[gnexus]

Yes. Already tried that on the 480.
Tried a different tape and EVERY combination of tape type, eq. & Dolby in/out. The left channel output varied according to tape settings, of course. But in all instances the right channel output was -10 to -20dB lower and fluctuates +/- 2 to 3dB.

Forgot to note again that right channel recorded output often also has very slight noise like crumpled paper. The output sounds similar to a badly wrinkled tape. But the tape(s) itself is fine.

 

[gnexus]

A couple of other things to note on the 480:

1) The recording levels are set the same at TP102/202 (~0.47mV). That results in 0dB (+/-0dB) playback on left channel. But right is -20dB (+/-5dB).

Maxing out VR203 gets the recorded output levels more equal. But even maxing out VR203 can't get them equal, and right VU still fluctuates +/-5dB.

2) The beginning of any recording on the left channel, lasting approx. 1 second, also varies DRAMATICALLY before stabilizing. It drops as low as -10dB before recovering.

 

[gnexus]

More 480 notes:
(Should move this all to 480 thread.)

1)Tried varying the bias level. That makes no difference.

2)Varying the record level pot VR203, even to max, makes little difference...

3)The left channel initially drops down to -10dB(+/-10dB) before recovering. But is steady. Any other fluctuations were from previous tests.

4)Playback levels on the prerecorded 400Hz test tape from the 580 is even but at -10dB or so. Not at 0dB like on the 580. Old prerecorded tapes from the 480 have VERY unequal playback levels. Right channel is at -15-20dB when left is 0dB. Most of the tapes are like that. Newer ones are slightly more even. But still way off.

I haven't yet noted the VU levels on those tapes on the 580, as VU meters weren't connected during playback.

5)I found a very cheap 480 for comparison and/or parts. It just arrived and is very clean and looks unmolested. But needs a capstan belt and ???

 

[gnexus]

This "new" "cheapo" 480 was a FANTASTIC investment!

It was completely unmolested! But was dead and missing the power cord. So immediately installed the correct power cord. Then, of course, the transport capstans were frozen solid. Had to use heat (blowtorch ) to get them off! Not easy at all without loosening the pivot pins set in plastic... While doing that one of the pressure roller pins came out of the pressure roller assy. when it flew off the pivot pin from the spring pressure! Then had to fix that... Left pivot pin was sticking way out so had to pound in back in with a sledgehammer... Right pivot was in too far. So had to pull it out slightly with a big slide hammer.

Once that was done had to replace the completely missing capstan belt with stolen one from the dead 580...

Once reassembled the control cam was in wrong position. Someone may have slightly screwed with the calibration pots. Easy enough to get stop calibrated. But play wouldn't calibrate because belt was too loose. So had to steal the control cam belt from the 580...

Now listening to tape recorded 36 years ago on the 480 from a CD. Sounds absolutely IDENTICAL to the CD! Perfect! Absolutely no detectable W&F. So the 580 capstan belt is good! That means the corrosion on one of the 580 capstan belt hubs is causing the quite bad W&F on the 580. I already scraped it clean before. So guess it needs something more severe like sandpaper.

This 480 was a straightforward repair except for the pressure roller assys. Now this deck sounds just like my 480 when new! Needs no calibrations! So now have a reference deck! Unfortunately it's silver (for now). So will need to swap out the control switches. Then it'll replace the old problematic 480.

Now need to order more belts and replace 4 button bulbs. At least the VU bulbs on this one both work.

 

[gnexus]

The replacement 480, which was originally expected to be only a parts deck. Is doing very good now

Had to steal all the new belts from the original 480. New ones for it now ordered. Also had to swap the input level slider pots (broken shafts & missing knobs) and the control buttons (now black & not silver.

The meter levels were spot on. Playback & recording levels are not perfectly even. But are 2X as good as the original deck. Don't want to touch them until I get some proper calibration tapes & M300 jig.

This 480 does have a minor power supply issue however:

The control cam oscillates rapidly upon power on. Does not really change position a lot at first. Just wiggles. Then, as power supply settles, it gets slightly out of correct position. Then that takes a power cycle or two to get it to correct stop position. The control cam is correctly calibrated. It's fine after the P/S stabilizes. But it's an annoying issue and probably not good for the motor. Haven't investigated the issue further yet as need to finish testing old tapes...

What could be the cause?

I started a new thread:

G

Thread 'Nakamichi 480 power supply issue (control cam)'

Sep 7, 2026

I bought another cheapo 480 for parts. But it was completely unmolested and turned out to be much better than mine. This 480 does have a minor power supply issue however:

The control cam oscillates very rapidly upon power on. It does not really change position at first. Just wiggles very rapidly. Then, as the power supply settles, it gets slightly out of correct position. Then that takes a power cycle or two to get it to the correct stop position. The control cam is correctly calibrated. It's fine and perfectly calibrated after the P/S stabilizes. Haven't yet checked voltages or...

• gnexus
• Replies: 53
• Forum: Tape

Dankik: I would greatly appreciate your input on what to check in the P/S. Capacitors? VR? RC4558? Please comment in new thread as this isn't a 580 issue. Thx

 

[gnexus]

The level tape I made on the 580 is way off on the 480 I just got. That 480 hasn't been touched and has very even output levels. So I'm not sure what's up with the 580. Pulling the transport makes it easier to replace the stolen belts on the 580. So will double check the tape guide height then now that I know a way to get it closer to where it should be. This is an older deck. So it only has a single one on the left.

I also didn't check the levels with an external oscillator. So must do that. The built in 400Hz levels were checked with a DMM. But it's a cheap meter and something with the levels must be quite off. Either that or 480s really don't like 580 tapes!

 

[gnexus]

Just now noticed this 580 is quite weird compared to the later ones and most Nakamichi transports.

From "Previous 580" service manual:
"The guide for the 580 is affixed to the erase head to the pressure roller assy"

No! it's not on this 580! The erase head is fixed to the head base!

The left tape guide adjustment is marked "EH- Height." But it's not connected to the actual erase head. The erase head is fixed to the moving head base backplate that controls head base stroke. So the left tape guide actually moves the tape in respect to the erase head instead of the erase head height being adjustable! Definitely not nearly as advanced as the later Nak transports!

So didn't really need to remove the head mount base... But had to remove the cassette holder anyway to fix the tape counter reset arm that wasn't installed correctly.

Also:
Now I know why tapes weren't fully erasing

In addition:
Just noticed that the plastic locking arm for the cassette case has slightly deformed over the years. It no longer holds the cassette case tightly closed. That will make it difficult to obtain proper tape alignment which doesn't vary. So transport needs further disassembling to add a spacer washer to the arm pivot before making any mechanical adjustments. At least that makes it slightly easier to replace the control motor belt...

 

[gnexus]

The washer in the locking arm really helped! Now the cassette case is perfectly closed.

Also had to sand down corrosion on the capstan motor shaft and on one of the capstan hubs. Now perfectly smooth. That and a new belt should resolve the 580 W&F issue.

This older transport is much easier to repair than the newer ones. Now just waiting on parts to get the 580 done...

 

[gnexus]

"New" 480 update:

This other 480 is amazing overall! That's even with the few minor issues it still has.

Just checked its recording capabilities:
Right channel input was basically zero!
So then cleaned the play /record switch...
Then checked again. Levels equal!
Then hit pause + record: levels were both at -20dB.
Set input levels to 0 with 330Hz test tone.
Unset pause: levels went off the scale!
Tried record again without using pause: levels stayed at 0...

Played back the recording:
levels were at -1dB! Nearly perfect!

Calibrated recording levels:
recording playback levels now perfectly set at 0dB!

 

[gnexus]

So now this other 480 is making very good and very even recordings, at least with a test tone (EDIT: recorded music sounds identical to source in both output level and quality! ). Now can hopefully use a tape from this deck for initial calibrations on the others until can get proper calibration tapes.

But input is extremely low, -20dB or less, and very distorted in pause. Sounds like pause is causing a dead transistor. What would cause pause to kill a transistor and almost fully mute the input?

Also:
Both this deck and the other take quite long to stabilize the recording levels. Prior to that the levels fluctuate dramatically. I'd assume its some capacitors in the recording circuit. But which ones could affect that?

Any comments would be greatly appreciated.

 

[gnexus]

Just found out, now that I have a decently calibrated deck, that my very old (46 yrs) frequency response tape is DEFINITELY DEFECTIVE!

The right channel is nearly gone. In addition I now can hear that magnetism from one channel has bled from left channel into right channel on a 1-2 second delay!

My understanding now is that Nakamichi tapes were made by TDK. So it's not surprising that they are of definitely lower quality than Maxell. Fortunately the Nakamichi MX metal tapes are of better quality and are equal to Maxell MX tapes - at least the single overpriced one I bought long long ago...

This one is probably better as a collectors item rather than a good one for recording.

 

[gnexus]

580 update:
Recieved a CD4001BE IC that's supposedly pin compatible with the D4001C. Be warned: It's not!
The CD4001BE fried the adjacent D4011C IC and then play or other controls only worked for a sec and then went to stop...

Had to steal a CD4011C chip from the remote receiver. Now the 580 works again, with pause light still on and disconnected mute wire. Still needs a new D4001C to fix those issues. But that chip, and all its equivalents, are discontinued. It will take a long time to find and get the correct IC. So decided just to steal the remote IC and disconnect the mute.

This deck sounds much better now after the recent transport fixes and belts from the problematic 480.

Now hopefully just needs better calibrations.

 

[dankik]

Recieved a CD4001BE IC that's supposedly pin compatible with the D4001C. Be warned: It's not!

Looking at the 580 parts list and chip function for IC404 (L diagram) and comparing the pin outs to CD4001BE (R diagram), they should be the same?
The schematic shows the logic as a logic equivalent. NOR gate = NOT AND gate. (De Morgan's equivalence)


Where did you buy your chip... maybe counterfeit if not from a distributor.
Digikey has the CD40041BE in stock for $0.76 ea.
What DC voltage to you measure between pin 7 (Vss) and pin 14 (Vdd) on your board? This chip will operate from 3V to 18V.

 

[gnexus]

Maybe you got a counterfeit chip?

No. It was TI from DigiKey. (but could be defective)

The gates are definitely equivalent. It works. But it somehow killed the PD4011. Maybe the PD4011 also got shorted and was on its last legs? Who knows... All I know is the deck mostly worked before installing the CD4001BE and it didn't play or do much afterwards.

But now don't trust the newer versions as they're the same logically, but somewhat different electrically. I don't want to waste more time and kill more chips.

The remote also (used to) work at very short distance but seems to need new LEDs. So don't want to kill that also. So I'll just get the specified part or equivalent even if costs more and takes longer to arrive.

On another note:
The deck is now VERY slow in FF &REW. That happened when IC404 got shorted. It was still that way with CD4001BE and still is now. What do you think is causing that? I'm thinking either a transistor or the RC4558. Or maybe IC404 is dragging down the power?

But what do I know. Obviously my troubleshooting skills and test equipment aren't up to what's needed ...

 

[gnexus]

On a more positive note on the 580:

The 580 playback, after latest calibrations, now sounds very good! It's almost as good as the fantastic sounding new 480!

But it still needs new belts. The W&F is much better now after smoothing out the capstan and motor hubs. But it still needs that belt. The azimuth was way off. So high frequencies are much better now. Proper calibration tapes and a better AC mV meter would likely help it get even better. But most non-audiophiles would be happy with it as it is. The transport isn't as advanced as the one on the 480. So not sure how good it can get. Didn't use it much before. So don't remember how it was previously.

Unfortunately record doesn't currently work without a good IC404. So can't test that yet...

 

[gnexus]

I can't find any other decent options for CD4001/4011ICs. Anything else is way overpriced and/or legacy compatible junk from Soviet Union!
So will need to take chance on another CD4001BE. I guess that's what it is anyway... It's from Amazon. So may be different mfr. Got both CD4001/4011. Maybe if they're both from same newer family they'll work ok... At least can actually get these. But it's a minor PITA changing them out if not working...