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Nakamichi cr-4e service?

T

TrevorBarten

Well-Known Member
I bought a nakamichi cr-4e second hand and was planning on using it as my personal cassette deck but I noticed that recording with this deck doesn't net that great of a result. Everything I record with it sounds like it's missing several small pieces throughout the recording if that makes sense. Could this just be caused by the cassettes I am using? (Work fine with other way cassette recorders). Or does the nakamichi need service? And if so, how should I go about servicing it?
 
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I sent my CR-4a to Willy Herman.
It takes some time and money, but I sent a deck most people might toss into the dumpster and Willy restored the performance to factory new.

Initially I did try 2 different local technicians, but neither had the knowledge nor the specialized equipment to repair the deck.

Frankly, before Willy restored it, I had no idea just how good a Nakamichi deck can sound, but I'm a believer now.
Willy also tests the deck and provides a printout of the results.
 
analoge4ever said:
I sent my CR-4a to Willy Herman.
It takes some time and money, but I sent a deck most people might toss into the dumpster and Willy restored the performance to factory new.

Initially I did try 2 different local technicians, but neither had the knowledge nor the specialized equipment to repair the deck.

Frankly, before Willy restored it, I had no idea just how good a Nakamichi deck can sound, but I'm a believer now.
Willy also tests the deck and provides a printout of the results.
Click to expand...
That's fantastic but I'd like to do it myself. Even if the results might honestly not be as good it would be a great learning process. Also I don't think you should toss a nakamichi cr-4e in any condition :).
 
You need several pieces of specialized test equipment, several test tapes and a tape path gauge if you expect to improve the sound quality of your CR-4. Basically start on page 1 of the service manual and follow the calibration instructions.
 
tapetech said:
You need several pieces of specialized test equipment, several test tapes and a tape path gauge if you expect to improve the sound quality of your CR-4. Basically start on page 1 of the service manual and follow the calibration instructions.
Click to expand...
I already have a signal generator and an oscilloscope and know how to use them, would I need anything else? I don't have test tapes, should I buy those or can I make one myself? And if I can make one how would that work if my deck is not correctly calibrated? And what is a tape path gauge ?
 
You will need an AC millivolt meter made specifically for measuring audio levels. Needs to have bandwidth of 200KHz. Your DMM will only measure AC voltage up to 1KHz at best. Also need a wow/flutter/speed analyzer.

Also need test tapes. You can't make them yourself. Need: Dolby level tape, head height tape, azimuth tape. speed tape, mirror tape and torque tape.

Need an M300 gauge or a good copy like the WHS-300 made by Willi Herman. The gauge is for aligning the tape guides and heads.
 
tapetech said:
You will need an AC millivolt meter made specifically for measuring audio levels. Needs to have bandwidth of 200KHz. Your DMM will only measure AC voltage up to 1KHz at best. Also need a wow/flutter/speed analyzer.

Also need test tapes. You can't make them yourself. Need: Dolby level tape, head height tape, azimuth tape. speed tape, mirror tape and torque tape.

Need an M300 gauge or a good copy like the WHS-300 made by Willi Herman. The gauge is for aligning the tape guides and heads.
Click to expand...

wouldn't I be able to do the wow flutter and speed measurements with my oscilloscope ? Atleast the speed one should be doable. And ok thanks for the help so far.
 
No, you can't measure wow/flutter with a scope. You can measure absolute speed and speed drift with the counter in your DMM (if your DMM has a counter.)
 
For w&f, you need a device that can do analysis of the signal over some time. The scope will only take a snapshot of the signal. There is some fairly cheap software that can be used for this though, within the limits of the sound card accuracy. There is really no way around getting test tapes and a gauge though. That's several hundreds of dollars. Up to you to decide if that's worth it. I contacted Willy Herman a few months ago, and he was not taking any new work at the time to work through his backlog. You can try to see if that's changed. All the few remaining reputable techs are swamped.
 
TrevorBarten said:
it would be a great learning process.
Click to expand...

It would be a learning process that would likely end in tears. The CR-4 is a very high performance, high value deck, not something to be used as a trainer.

I am not saying that you can't do this yourself, but it does require a stiff investment, a lot of commitment, effort, and time, before you are in a state where you can tackle a CR-4. (And that's an easy one, as high-end decks go.)
 
WernerO said:
It would be a learning process that would likely end in tears. The CR-4 is a very high performance, high value deck, not something to be used as a trainer.

I am not saying that you can't do this yourself, but it does require a stiff investment, a lot of commitment, effort, and time, before you are in a state where you can tackle a CR-4. (And that's an easy one, as high-end decks go.)
Click to expand...
I very much doubt it would be that difficult. I already have ample experience with other audio equipment. And obviously I have worked on other cassette decks before but I always just set those up via ear and only really did measuring for recording/playback levels and channel balance. I just figured that since I wanted to use this one as my personal machine I might as well try to get it running as well as possible. Also idk about high value. I paid 150 euros and I think market is probably around 250-300. That's not cheap but also not what I would call 'high value'.
 
Big Ben said:
For w&f, you need a device that can do analysis of the signal over some time. The scope will only take a snapshot of the signal. There is some fairly cheap software that can be used for this though, within the limits of the sound card accuracy. There is really no way around getting test tapes and a gauge though. That's several hundreds of dollars. Up to you to decide if that's worth it. I contacted Willy Herman a few months ago, and he was not taking any new work at the time to work through his backlog. You can try to see if that's changed. All the few remaining reputable techs are swamped.
Click to expand...
I work on cassette decks quite often for general service so having calibration equipment to be able to do a full calibration would not hurt at all. That is indeed something I overlooked for the wow and flutter measurements thank you.
 
TrevorBarten said:
I have worked on other cassette decks before but I always just set those up via ear and only really did measuring for recording/playback levels and channel balance.
Click to expand...

I am sorry but that is not exactly confidence inspiring. Again, you are probably perfectly capable of learning how to serice a CR-4, but if I were you I would invest in the correct tools and alignment tapes (and not just any tapes, many for sale now are crap), and I would train on something like a CR-1/2 or BX-100/125/150/1/2.

What you need:
-full track Dolby level tape
-full track azimuth tape
-full track playback frequency response tape (ideally)
-speed + wow&flutter tape
-track alignment tape (ideally)
-torque cassette
-mirror cassette

And if you want to check/align the tape guide you will also need an M300 gauge.

For HW I use a two-channel digital scope, a DVM (correct up to 1kHz), and a PC with MOTU M2 running AudioTester and WFGUI software.

You can find some of my projects here http://audiochrome.blogspot.com/2019/05/restoring-nakamichi-bx-300e-cassette.html

I paid 150 euros and I think market is probably around 250-300. That's not cheap but also not what I would call 'high value'.
Click to expand...

With high-value I meant that this model belongs to the absolute top. There are not too many of them, so the value of a well-serviced one in excellent shape only can appreciate.

As for the market: unserviced they go 250 to 300+ here, serviced 500 to 600.
 
You can get a full set of usable for “ your personal use “ tapes on ebay from Hans Peter Roth, $65. I compared them to my professional tapes, and they're adequate. Nak T-100 software is $25 at the Microsoft store. You just need to calibrate a quality sound card.
 
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