For a while now I have been dealing with an issue with my Panasonic RX-5050. Seems as though the speed on the cassette would drop over time. I would adjust it up and it would be good that day. Come back a week later and the speed had slowed again. Spent so much time adjusting the speed on the motor trim pot that I broke it. I took the motor apart and repaired the broken trim pot to where it functioned again and dialed it in again. Sounded good for a day or two, then it started running slow again. I tried everything. Oiling the motor shaft and capstan bearings....everything. Same thing.
So, I set out to find a replacement motor. I found a 12V CCW motor (which are a dime a dozen) and got it in a while back. I installed it and adjusted motor speed. It ran good for about a tape and a half then started becoming irregular in speed. I opened up the box and measured the running voltage. Not surprisingly, the voltage at the motor is the same as the voltage being supplied to the entire radio from the power supply. It's unregulated but usually sits around the 13.2V mark. It fluctuates with volume and can drop down to 12.5V at times. Since the voltage was the same as the input voltage going to the motor, I concluded that the voltage going to the motor is where it should be. The motors speed control circuit has an internal voltage regulator to prevent speed fluctuations from the unregulated power source. I ended up taking the NEW motor apart and measuring the current coming off the regulator to the motor. Sure enough, Chinese crap strikes again. I suspect the regulator in the original motor was going out also hence the change in speed.
So, I set out to grab another motor. I eventually found an original used OE Matsushita 15V motor but the guy was asking 25 buck with 12 dollars shipping. I managed to get him down to 12 dollars with shipping. So now I'm about 35 bucks into this ordeal. I get the motor and install it. Dial in the speed perfectly. Plays good while it's apart. Put the radio back together and go to hit play. The mechanism binds up and gets stuck. Capstan and flywheel not moving.
It's at this point where I was asked by my wife to take a break from it because I was about the smash it into tiny little pieces, cut my losses and chuck it into the trash. I did as she asked and came back to it today with a fresh mindset.
So now this new issue was the belt. It decided it no longer wanted to stay centered on the motor pulley. The motor pulley has a raised center to help guide the belt to the center. Well this thing was flopping up and down but refused to ride in the middle. When a load was applied, it would shift and then pop off the capstan flywheel.
Went to my tech today to see if he had a belt. The stock flat belt was incredibly skinny at only 2mm wide. We guest at the % the old belt had stretched and came up with a PRB belt (FRW 7.0). I installed the belt and it stayed centered and tracked well. Hallelujah! I adjusted the motor speed again and I'm finally able to enjoy it again.
A lot of this was a mixture of me not replacing everything that should've been replaced but I was trying to keep costs low. I guess that's what I get. The RX-5050 isn't a valuable radio so I hate that I am $40 dollars into the repair, but this is my Beach radio and the cassette has to work perfectly. Heck broken ones on ePay are 70 dollars, so I guess I can't be too bummed out about it. Last year I took it to the beach the pinch roller started letting go. I replaced it when I got back. So that's new also.
My goal is for this thing to make it though a beach trip with no issues with the cassette deck.
So far, it's been rock steady and sounds good. Also, as a future belt size, for anyone with a Panasonic RX-5050, the main flat belt works great with a FRW 7.0
Cheap Chinese motor that failed after a tape
Dialing in motor speed
Test and ensure all is well before going back together
So, I set out to find a replacement motor. I found a 12V CCW motor (which are a dime a dozen) and got it in a while back. I installed it and adjusted motor speed. It ran good for about a tape and a half then started becoming irregular in speed. I opened up the box and measured the running voltage. Not surprisingly, the voltage at the motor is the same as the voltage being supplied to the entire radio from the power supply. It's unregulated but usually sits around the 13.2V mark. It fluctuates with volume and can drop down to 12.5V at times. Since the voltage was the same as the input voltage going to the motor, I concluded that the voltage going to the motor is where it should be. The motors speed control circuit has an internal voltage regulator to prevent speed fluctuations from the unregulated power source. I ended up taking the NEW motor apart and measuring the current coming off the regulator to the motor. Sure enough, Chinese crap strikes again. I suspect the regulator in the original motor was going out also hence the change in speed.
So, I set out to grab another motor. I eventually found an original used OE Matsushita 15V motor but the guy was asking 25 buck with 12 dollars shipping. I managed to get him down to 12 dollars with shipping. So now I'm about 35 bucks into this ordeal. I get the motor and install it. Dial in the speed perfectly. Plays good while it's apart. Put the radio back together and go to hit play. The mechanism binds up and gets stuck. Capstan and flywheel not moving.
It's at this point where I was asked by my wife to take a break from it because I was about the smash it into tiny little pieces, cut my losses and chuck it into the trash. I did as she asked and came back to it today with a fresh mindset.
So now this new issue was the belt. It decided it no longer wanted to stay centered on the motor pulley. The motor pulley has a raised center to help guide the belt to the center. Well this thing was flopping up and down but refused to ride in the middle. When a load was applied, it would shift and then pop off the capstan flywheel.
Went to my tech today to see if he had a belt. The stock flat belt was incredibly skinny at only 2mm wide. We guest at the % the old belt had stretched and came up with a PRB belt (FRW 7.0). I installed the belt and it stayed centered and tracked well. Hallelujah! I adjusted the motor speed again and I'm finally able to enjoy it again.
A lot of this was a mixture of me not replacing everything that should've been replaced but I was trying to keep costs low. I guess that's what I get. The RX-5050 isn't a valuable radio so I hate that I am $40 dollars into the repair, but this is my Beach radio and the cassette has to work perfectly. Heck broken ones on ePay are 70 dollars, so I guess I can't be too bummed out about it. Last year I took it to the beach the pinch roller started letting go. I replaced it when I got back. So that's new also.
My goal is for this thing to make it though a beach trip with no issues with the cassette deck.
So far, it's been rock steady and sounds good. Also, as a future belt size, for anyone with a Panasonic RX-5050, the main flat belt works great with a FRW 7.0
Cheap Chinese motor that failed after a tape
Dialing in motor speed
Test and ensure all is well before going back together
