My Nakamichi RX 202

[reubensm]

Just coming out of mechanic's place. The transformer gas gone. But if alone the transmitter I would hv been safe. But its more to it as the power transmission at +12v is not happening. Its hovering around 3.5. So there is something more which has gone short. Now need to find out what else gone wrong.

Honestly that's relieving news. Powersupplies are the easiest to fix in cassette decks. Looks like you may have lost a couple of regulator ICs and filter caps, in the process. Again, not serious but just needs some time to be spent with it. Try to source OEM parts (this is the difficult aspect of repairs). Rewinding the transformer should be used only as a last resort. If using a substitute, ensure that you use a high quality one.

 

[jayants]

Honestly that's relieving news. Powersupplies are the easiest to fix in cassette decks. Looks like you may have lost a couple of regulator ICs and filter caps, in the process. Again, not serious but just needs some time to be spent with it. Try to source OEM parts (this is the difficult aspect of repairs). Rewinding the transformer should be used only as a last resort. If using a substitute, ensure that you use a high quality one.

Thanks Reuben.

But its serious I guess.There was no fuse in the transformer or it would have saved my Deck.Now the issue is something has gione short inside the DECK as normally 120V would have been converted into 12V and distributed in the circuit but unfortunately beacuse of my mistake 240 V got converted into 24 v and got distributed inside in the process making few things short as except the led light inside nothing is working.The rewind/ff counter and the channel indicators which displays bright red colours are now too weak.

So my MAN FRIDAY is not working hard trying out to figure out where it has gone short.Am crestfallen to say the least.

 

[reubensm]

Hey, but you need to look closely. Naks come with regulated powersupplies, so in effect, if there's a surge, the regulators will either regulate or blow out. Only if these fail to contain the surge, will the rest of the circuitry be effected. I suggest you show the deck to a trained technician. To start with, take a close look at the board and look for indication of physical damage. Only then proceed to test.

 

[Selvin]

+1 to Reubensm Statement...

I just gone through few Nakamichi Service manuals. In all cases Nakamichi used single Input Transformer with single primary multiple tap and multiple isolated secondary windings for different voltage.

In general (99.9%) if the transformer gone with overvoltage means the primary winding become open. Once the primary open you never get output in all secondaries and the system will be in dead.

Also in your case if you used the deck with 220V tap the chance of failure of the transformer is less. Because most transformers withstand + / - 10% voltage tolerance. If some part of the deck is functioning means some part of power supply is healthy and implies the transformer is healthy. Most possibilities is some of the voltage regulator circuit may faulty and need to be find and fix.

Keep update here... we do our best to fix.. good luck.

 

[jayants]

Thanks a lot for all ur support guys. One good news is that one IC which got short has been detected and once its removed from the circuit the 12v gets restored. Now need to change the IC and see whether its working perfectly or there r some more faults. Lets see.

 

[reubensm]

Yes, you are on track. Don't worry it will be back to normal.

Before changing this particular IC, please run a check on the others as well. After a complete check on the semiconductors of the powersupply unit, you will get a clear idea as to what all has gone out. Replace all the faulty components together. If you replace only this faulty IC which you have detected (assuming you've not checked the rest), there is a possibility that the replacement may blow again when you turn it on (if something else is causing it to blow).

Try to use good quality components as its for a NAK after all.

But the lesson learn for all of us is never to mess around with the voltage settings.

 

[jayants]

Yes, you are on track. Don't worry it will be back to normal.

Before changing this particular IC, please run a check on the others as well. After a complete check on the semiconductors of the powersupply unit, you will get a clear idea as to what all has gone out. Replace all the faulty components together. If you replace only this faulty IC which you have detected (assuming you've not checked the rest), there is a possibility that the replacement may blow again when you turn it on (if something else is causing it to blow).

Try to use good quality components as its for a NAK after all.

But the lesson learn for all of us is never to mess around with the voltage settings.

Than Reuben!!

My Deck is in the hands of one of the best Technicians (if not the best) in Calcutta. He is a hugely respected gentleman in the audiophile segment and I know him for over 2 decades now (though we lost touch in between). I have full faith and trust in him and am updating you all with whatever information am receiving from him.As I am a ZERO Technical guy I have practically no knowledge once the machine is opened up.Am sure he has done all the necessary checkings.


Lesson Learnt - Never ever remove the Step Down Plug from the power source or one can repeat the same SLIP what I did of putting the power directly in the spike buster.

A very very special thanks to all of u guys for the great great support u all r providing in sharing my grief.Thank u so so much all of u.Pls keep the inputs coming.

 

[reubensm]

Good going Jayant, please keep the updates coming.

More than the curiosity of knowing what's happening with the diagnosis and fix, we're waiting in anticipation to hear the news that your Nak is singing again. All of us out here, in this lovely forum, are the guys who keep the flags of legends like Nakamichi, Garrard, Technics, etc, flying and it is of extreme importance that we do so, as it is only then will our future generations get to hear what real true Hi-Fi sounded like.

 

[jayants]

Good going Jayant, please keep the updates coming.

More than the curiosity of knowing what's happening with the diagnosis and fix, we're waiting in anticipation to hear the news that your Nak is singing again. All of us out here, in this lovely forum, are the guys who keep the flags of legends like Nakamichi, Garrard, Technics, etc, flying and it is of extreme importance that we do so, as it is only then will our future generations get to hear what real true Hi-Fi sounded like.

Absolutely!!!!

 

[jayants]

The update is my 7812 Regulator is gone which has affected the IC.

 

[reubensm]

what's the update on this deck? eager to know if its up and running now.

 

[rpm]

Wow, what a beauty.....best wishes

 

[jayants]

what's the update on this deck? eager to know if its up and running now.

Hi,

Brought my Deck repaired and was working fine for 2 days but suddenly a problem started today.

When I clik thee play button it doesnt play and instead the play and pause button together keeps blinking in tandem with the stop button.The cassette tray gets locked while all the lights are on and after sometime it opens.

What can be the reason for this problem?

 

[jayants]

Hi,

Brought my Deck repaired and was working fine for 2 days but suddenly a problem started today.

When I clik thee play button it doesnt play and instead the play and pause button together keeps blinking in tandem with the stop button.The cassette tray gets locked while all the lights are on and after sometime it opens.

What can be the reason for this problem?

Any inputs please?

 

[jayants]

No inputs??
Quite surprising.

Anyone can tell me please whether there is something to do with the Motor or the Transporter?

 

[greenhorn]

we are not psychic you know

for such obscure problems, a look at the deck is needed usually, unless one has a lot of experience with similar decks

 

[reubensm]

Hi,

Brought my Deck repaired and was working fine for 2 days but suddenly a problem started today.

When I clik thee play button it doesnt play and instead the play and pause button together keeps blinking in tandem with the stop button.The cassette tray gets locked while all the lights are on and after sometime it opens.

What can be the reason for this problem?

Sorry, just saw this post. It is difficult to diagnose such issues on NAKs as many of us have not experienced more than one NAK model. FM IndiNakDoc appears to be very knowledgeable in this area, hence it would make sense to take his advise. In my opinion, without examining or trouble shooting, looks like you may have anything from sensor to semiconductor failure. The mechanism is servo controlled and hence would need a close look.

 

[jayants]

Seems bad times with my RX202 is finally over.After having a tough time for the last few weeks (changing the transformer due to wrong usage of volts) and then followed by the HEADBLOCK not coming down properly............now it seems everything is perfectly fine!!


The loading gear which was malfunctioning has finally been taken care of by araldite and now its absolutely smooth.But there was a sound issue and then it was discovered that the azimuth alignment went haywire,was hence balanced and now its running absolutely smooth.


My sincere thanks to Ram (from USA) for the great inputs,Rahul (a dear Nak enthusiast from this forum) for all his support and finally my man Fiday (the great Mechanic) from Calcutta for fixing this issue.


Here is the Youtube link as how my RX202 is now playing : https://www.youtube.com/watch?v=KGelpjHHUB8&feature=youtu.be