Fix a skipping Akai AP-A301 linear tracking turntable

A little personal introduction how I got this linear turntable

I bought my first and only record player somewhere in the second half of the eighties. I already had a CD-player and in 1988, more CDs than LPs were sold world-wide. Still, CDs were a lot more expensive and I already had a number of vinyl albums. The Philips record player of my parents had it’s flaws, so I saved until I could buy a brand new Akai AP-A301.

Well, new… it was an ‘open box’ sale, which meant that the shop had used it as a demonstration model and in fact it didn’t come with a box at all. I was a teenager and had to travel for hours to the city, by bus and other means of public transport to get to the store. I paid ƒ 150 (about € 68 without compensating for inflation), but hey, you had to pay serious money to get an Akai AP-A301 Linear Tracking Tone Arm!

The problem: A skipping Akai AP-A301 linear tracking turntable

About 25 years later, I still have this ‘FULL AUTOMATIC’ Akai linear record player. There is a problem with it though: As soon as the needle drops, the tone arm is advanced towards the center of the record much too fast. Soon, the needle is dragged across the record.

Tracking turntable tone arm maintenance

I’m not an expert on turntables, so I read up about their maintenance. Somelike to call them TT’s, for Tracking Turntables. I didn’t find a good maintenance manual so decided to write one myself. Some advice on how to open up the Akai AP-A301 turntable:

  • First remove the rubber mat, revealing the holes in the platter
  • Through the hole on the left, carefully take the fragile belt off the motor axis.
  • Lift off the platter and put it aside.
  • A strip in the case is now visible, held by a screw. Remove the screw and the strip.
  • Advance the tone arm to the left until it is over the hole where the strip was.
  • Unplug the A301 turntable.
  • Close the lid so you can put it upside-down on a cloth without scratching or damaging it.
  • Remove all screws. The black ones are slightly thicker than the bronze ones so try to remember where the were or make a picture if you want to place them back correctly.
  • Wipe off the old grease and dust on mechanics of the arm, where it drags along the metal sheet and on the worm gear sprocket. Particularly on the sprockets, there may be some hair or dirt that is tough to remove. A toothbrush or tweezers may come in handy. Take your time. Don’t use aggressive solutions but you may use alcohol.
  • Use some (just a very little bit) of silicon spray to refresh it instead. Wipe off any excess silicon spray.

Investigating the linear tracking tone arm over-advancement

However, the needle of the Akai still skipped the record, the arm still advanced too fast. I was not going to give up that easily though. After some studying of the inside of the turntable, I found out that the advancing of the arm is regulated by a controller that is sensible to light. The light of a red LED shines on a photo-electric transistor. As the record pull the needle to the left, the angle of the arm changes, partly blocking the light to the phototransistor. As a reaction, the motor of the arm is put to motion, advancing the arm until it is at a straight angle again.

I found out that, using a small LED flashlight on the sensor, I could slow down the advancement. There was no dust on either one of these parts. Possibly the amount of light that the LED produced had become less over the years, or the phototransistor had become less sensitive. Maybe there was even another problem, for example, too little power to the LED because of a problem with the power supply.

Fix a skipping Akai AP-A301 linear tracking turntable

Some googling brought up the Akai AP-A301 schematics. It even shows the PCBs. After studying the inside of the turntable and the schematics, it occurred to me that there is an adjustable resistor on the main board. This allows for the sensitivity of the position sensor to be adjusted. It makes sense to have such an adjustable resistor, since there will always be some deviation in the parts of the individual record players, so you’ll want to adjust them right after manufacturing them.

Toning down the advancement: The shortcut

You can even do this tone arm adjustment without opening the Akai AP-A301. Just turn it upside-down with the cap on, remove the mat, drive belt and platter and find the hole in the bottom above the adjustable resistor. It’s larger than the other holes. Start the turntable. After the tone arm is ‘dropped’ and advancing, use a 1 mm Philips screwdriver and slowly and carefully turn it a few degrees clockwise, until you see the arm is no longer being advanced.

When you are sure the arm is behaving correctly you can of course put everything together again in reverse order.

I hope sharing this little trick will save a some of these clunky eighties-style tracking turntables from the dumpster. Enjoy that old records!

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