Hello everyone,
I recently bought a broken Technics SL-V5 turntable hoping I would be able to repair it. It turned out to be more difficult that anticipated.
When you turn the device on the disk size and tonearm indicator lights turn on. The tonearm itself doesn't slide to the start position on the left. It also smelled like something was getting hot so I turned it off.
At first I thought the problem was a broken cabinet switch so I opened the turntable. There was a broken switch but activating the switch doesn’t do anything. It also didn’t explain the burning smell.
There was nothing else to do than to fully open the turntable. With the circuit board visible I noticed a capacitor with black stains on it, I replaced it. The burning smell is coming from a resistor (R3) it is getting to hot to touch after a little while.
I looked up the service manual and began following the testing steps in it. When the turntable is off the transformer gives an output of 24v AC. This is in line with the service manual.
Turning on the turntable and measuring at the input of the rectifier (D1) gives a current of 19v AC. The output is around 16,5v DC. After the rectifier is a regulator (IC1) this gives an output of 16,5v, 12v and 0v (ground). The output of the rectifier should be 24v, 12v and 0v according to the service manual.
There is a resistor (R3, 38Ω) that is getting hot is after the regulator (IC1). This resistor is on the collector side of a regulator (Q1). The current over the resistor is 8v. Following the wiring diagram this should be around 2,4v. The regulator (Q1) is getting 2,4v at the base, 3,7v at the collector and 1,6v at the emitter. These values should be 5,6 at base, 9,6 at collector and 5 at emitter.
Does anyone have an idea what is wrong or broken? The replacements parts are pretty hard to find so I don’t really want to order replacements for components that aren’t broken. I feel like the transformer should provide 24v AC to the rectifier but I don’t know for sure. Also the hot resitor is getting to much power
Mark
I recently bought a broken Technics SL-V5 turntable hoping I would be able to repair it. It turned out to be more difficult that anticipated.
When you turn the device on the disk size and tonearm indicator lights turn on. The tonearm itself doesn't slide to the start position on the left. It also smelled like something was getting hot so I turned it off.
At first I thought the problem was a broken cabinet switch so I opened the turntable. There was a broken switch but activating the switch doesn’t do anything. It also didn’t explain the burning smell.
There was nothing else to do than to fully open the turntable. With the circuit board visible I noticed a capacitor with black stains on it, I replaced it. The burning smell is coming from a resistor (R3) it is getting to hot to touch after a little while.
I looked up the service manual and began following the testing steps in it. When the turntable is off the transformer gives an output of 24v AC. This is in line with the service manual.
Turning on the turntable and measuring at the input of the rectifier (D1) gives a current of 19v AC. The output is around 16,5v DC. After the rectifier is a regulator (IC1) this gives an output of 16,5v, 12v and 0v (ground). The output of the rectifier should be 24v, 12v and 0v according to the service manual.
There is a resistor (R3, 38Ω) that is getting hot is after the regulator (IC1). This resistor is on the collector side of a regulator (Q1). The current over the resistor is 8v. Following the wiring diagram this should be around 2,4v. The regulator (Q1) is getting 2,4v at the base, 3,7v at the collector and 1,6v at the emitter. These values should be 5,6 at base, 9,6 at collector and 5 at emitter.
Does anyone have an idea what is wrong or broken? The replacements parts are pretty hard to find so I don’t really want to order replacements for components that aren’t broken. I feel like the transformer should provide 24v AC to the rectifier but I don’t know for sure. Also the hot resitor is getting to much power
Mark