The Return of 1950's Gramophone

by ryan141298 in Circuits > Audio

1397 Views, 3 Favorites, 0 Comments

The Return of 1950's Gramophone

1e.jpg
Record Player Done

Gramophone is one of the best invention human made till 20th Century. But after so much invention in audio industry, no other device could replicate the depth and quality of music played from Gramophones. I had a Gramophone of 1950s, purchased by my grandfather. It was very close to my heart, but it stopped working from 2006. We went to every other shop which repair Gramophones, but in vain, it couldn't get fixed as the parts of that Gramophone was stopped manufacturing. Then we kept it in the shelf. Fast forwarding to 2018 when i was studying engineering, i tried to repair it and accomplished it which professional repair person couldn't do by using jugaad (A flexible approach to problem-solving that uses limited resources in an innovative way.)

Finding What Is the Problem

2.jpg
Speaker.jpg
IMG_20180909_163335_HDR.jpg
IMG_20180909_161858_HDR.jpg

When i plugged it and played, the main light glowed but the disk didn't rotate. Concluding either motor is out of order or the circuit has a problem. I checked with multi-meter the continuity of the motor, and the multimeter didn't beeped, hence concluded there is a problem with the motor. I went to shop to purchase similar motor but couldn't get the same motor as it was not being manufactured. So i purchased a local motor. I also checked the continuity of the speaker, but here as well the multimeter didn't beeped. So the speaker was also not good.

Fixing the Motor

IMG_20180626_215101.jpg
IMG_20180626_221634.jpg
IMG_20180626_221626.jpg
IMG_20180626_221645.jpg

I placed the new motor in place of the original motor and fixed with the same wires. But as soon as i switched the Gramophone on, the disk was moving very slowly. As it was not the same motor it was not moving as same speed. and in gramophone constant and similar RPM is very important otherwise either the music would be played in slow motion ( as in my case) or fast motion.

Solve Speed Problem of Motor

Circuit Connection.jpg
WhatsApp Image 2018-06-27 at 8.50.50 AM (2).jpeg
WhatsApp Image 2018-06-27 at 8.50.50 AM (1).jpeg
Speed Problem of motor

Speed of a DC motor can be varied by varying flux, armature resistance or applied voltage. Different speed control methods for different DC shunt and series methods are there. The easiest among them is to change the applied voltage to the motor. The voltage is changed by using a boost converter with inbuilt potentiometer to change the voltage according to our wish. Connect the Components as given in the figure. Capacitor is used to make the voltage constant as much as possible so that the disk speed is constant. After making the circuit i placed all things in position.

Testing

Testing 1
Testing 2

I tested it by adding a jbl speaker from the original speakers input but the volume was very low and sound quality was also very bad

Fixing Speaker Problem

Needle.jpeg
Proper testing

I thought rather than adding another small speaker, why not give the output of gramophones amplifier to my home theater speakers to get better sound quality. I also purchased another Philips needle form the website ( https://ngh.co.in/philips-needle.html ) and Attached to the gramophone.

Fixing Sound Input

IMG_20180909_162012_HDR.jpg
IMG_20180909_162024_HDR.jpg
IMG_20180909_162007_HDR.jpg

I attached the input of home theater to the main output of amplifier.

Putting the Booster

IMG_20180626_215121.jpg
IMG_20180909_162049_HDR.jpg
IMG_20180909_162056_HDR.jpg
voltage.jpg
IMG_20180626_215112.jpg
IMG_20180909_162829_HDR.jpg

I drilled the the front part of gramophone and attached the booster by using screws. I placed booster outside so that we can calibrate the speed of disk by using a screw driver and rotating the knob from front.

Finished

IMG_20180909_161455.jpg
IMG_20180909_161506.jpg
IMG_20180909_161607_HDR.jpg
IMG_20180909_161602_HDR.jpg
IMG_20180909_161614_HDR.jpg
IMG_20180909_162032_HDR.jpg
Finishing Product

The gramophone has come to life and is working perfectly

Done

Record Player Done