Nakamichi RX-202 problem

[nicolas25]

Good day everyone.2 days ago i bought a Nakamichi RX-202 tape deck with problems. Upon hitting the play button, it plays about 3 seconds (Side A) then stops and the door automatically opens and engages the auto reverse and the door closes again. it tries to play in side B but nothing happens then it opens again and engages the auto reverse. it stops there. also FF and REW do the same. i changed the idler tire, i changed the belts, i cleaned the cam motor but still have the same problem. any ideas? thanks

 

[JFRACE]

Sounds like a sensor to me.

 

[nakmandan]

Could be the sensor but more likely is the new idler tire is slipping or the reel motor is dead spotting. New tires often have a slippery mold release compound on them that prevents good engagement. Just lightly scuff the outside drive surface of the tire and clean with alcohol before installing. Reel motor dead spotting is sometimes hard to see and a lot of people dismiss this as a cause because FF/REW work just fine with plenty of power. But on Nakamichi decks for sure, it's easy to see if the idler tire is slipping by just pressing FF without a tape and grab the take up reel with your fingers. It should not be easy to stop the reel and it should have plenty of torque. If it slips easily then your tire is bad or not prepared correctly.

Reel motor dead spotting can be hard to diagnose because fast wind usually is strong so people dismiss this as a cause. What most people don't realize is that in play mode, the reel motor voltage drops SIGNIFICANTLY, to as little as 2.8 volts, from the much higher 6-9 volts of fast wind. What this means is that in play mode, it doesn't take much to stop the slowly turning reel motor. Any compromise in the brush/commutator relationship inside the slowly turning motor is enough to stop it. You rarely see this problem on other transports that use reel clutches because the motor spins fast enough in play mode that weak areas of the commutator are quickly passed before it has a chance to stop. The remedy for this is either recondition the motor or replace it. A quick temporary fix is to leave the tape in FF without a tape for a few hours. This can sometimes clean off the dirt/oxidation on the commutator so it can work again. But as I said, this is a temporary fix and doesn't always work.

 

[Adaboy5]

I had the same symptoms with my RX-202. I changed the belts, idler tire, cleaned and same problem. After watching a few you tube videos over again I decided to go at the reel motor I had nothing to loose. It fixed the problem removing the motor and cleaning the brushes and small drop of oil on the spindle. Happy camper here!!! Also adjusting the Udar there are arrows on three gears under the slide mechanism. I lined all three up and followed the adjustment instructions in the service manual, worked like a charm!! Hope you get it sorted out.

 

[Jiggz]

Had the same problem with my RX202. After reading much from this forum, I decided to change the main drive belt. In fact, I even ordered tire for the idler and a belt for the reverse function. But come to find out, my unit has geared reverse function and eject function. So all I needed is the main drive belt. Just to repeat, this is originally owned by me and bought it back in the late 80's. It was working perfectly until about two years ago wherein it would play for about a second or two and then reverse then stops. Changing the drive belt fixed this problem. However, after testing with a pre-recorded tape, no sound is coming out of the unit. The output level indicator lights stays at the bottom led light and no sign of output signal even with the slider adjustment to the max level.
So I tried doing some recording and the record level lights were working in accordance with the slider adjustment. However, when I played it back, there was no sound coming out of the unit nor there was any indication of output signal from the output LED light levels even with the slider at max position. Could this be a bad R/P head? Any insight is truly appreciated. Sorry to hijack this thread but it seems the problem have similarities.

 

[perryinva]

No, the head is fine. There is small relay that is required to switch the electronics to the head from record mode to play mode. The original relays often fail and there is a standard sealed solid state relay that replaces it. Takes about 5 minutes to do.

 

[Jiggz]

Thanks. You are absolutely correct there's a small relay that controls the R/P head. I did not even have to replaced it but just cleaned it with very fine sand paper and it was working again, perfectly. Thank you again for your help.

 

[perryinva]

Those relay contacts are actually plated so they are lower resistance and supposed to prevent oxidation, just not for 40 years, LOL. Hopefully you didn’t sand through the coating. If you find the same problem in a few months, the solid state relay is like $3 on Mouser. I’ve got 2 202s here for service. I just replace them whether they work or not. I'll post the part number when I do the next one.

 

[Jiggz]

To sand the contact points without dismounting it from the board requires a pointed tweezers and 1/8~1/4 strip of 1000 grit sand paper about an inch long. Meaning the force used is only the clamping force of the contacts in its de-energized state. But it's always nice to have a spare. If you can just provide a link or part number at Mouser, It surely be appreciated. Thank you again.

 

[perryinva]

Here you go. There actually were different relays used by Nakamichi. One set has a very easily accessed set of contacts on top, and the other has side mounted ones, impossible to clean in place. So if you are going to go through the trouble to remove it to clean them, a sealed replacement makes more sense (if you have one handy of course)

 

[Jiggz]

Thank you. This info will come in handy. As you mentioned, the relay I have is the easily accessible clear dome type which makes it easy to clean the contacts. Thanks again.