Motorola TM 316S Car 8 Track player - UK Vintage Radio Repair and Restoration Discussion Forum

AD360 Rob · 17th Mar 2024, 5:10 pm

Afternoon all,
Calling on the collective wisdom of you all now. I have a problem with an 8 track player in for repair. The motor doesn't turn with voltage applied, it's a matsushita 13.2vdc motor with an extra winding (for fast forwarding the tape) This motor tests open circuit. I've stripped it down and found that there is a small inductor in series with the +12v line which has burned up. My question is Would anyone have an idea as to the value of said inductor (I imagine it it there for some RFI suppression) I'm pretty sure the reason it has failed is due to the motor being stalled for a reasonable amount of time due to a sticky belt.

Many thanks in advance

Rob

Silicon · 23rd Mar 2024, 10:24 pm

Could you count the number of windings as you unravel it and rewind it with similar wire?

AD360 Rob · 28th Mar 2024, 10:55 pm

I did think of that however for now I have bypassed it and once I get the flipping thing to revolve the right way (It's running backwards for some reason), I'll asess the amount of RF noise present and take it from there. I did think of trying to measure the inductance of what's left of the winding but I don't have an LCR meter only a chinese transistor tester that does capacitance, ESR and resistance.

G6ONEDave · 29th Mar 2024, 3:03 pm

This might be a silly comment but I take it that you have checked the polarity of this Motorola unit. Being an 8-track it could be either positive earth or negative earth. if connected the wrong way round that would explain why the motor is going backwards.

Dave

17th Mar 2024, 5:10 pm	#1
AD360 Rob Hexode Join Date: Jun 2012 Location: Chester, Cheshire, UK. Posts: 421	Motorola TM 316S Car 8 Track player Afternoon all, Calling on the collective wisdom of you all now. I have a problem with an 8 track player in for repair. The motor doesn't turn with voltage applied, it's a matsushita 13.2vdc motor with an extra winding (for fast forwarding the tape) This motor tests open circuit. I've stripped it down and found that there is a small inductor in series with the +12v line which has burned up. My question is Would anyone have an idea as to the value of said inductor (I imagine it it there for some RFI suppression) I'm pretty sure the reason it has failed is due to the motor being stalled for a reasonable amount of time due to a sticky belt. Many thanks in advance Rob Attached Thumbnails

23rd Mar 2024, 10:24 pm	#2
Silicon Nonode Join Date: Jun 2007 Location: Coulsdon, London, UK. Posts: 2,171	Re: Motorola TM 316S Car 8 Track player Could you count the number of windings as you unravel it and rewind it with similar wire?

28th Mar 2024, 10:55 pm	#3
AD360 Rob Hexode Join Date: Jun 2012 Location: Chester, Cheshire, UK. Posts: 421	Re: Motorola TM 316S Car 8 Track player I did think of that however for now I have bypassed it and once I get the flipping thing to revolve the right way (It's running backwards for some reason), I'll asess the amount of RF noise present and take it from there. I did think of trying to measure the inductance of what's left of the winding but I don't have an LCR meter only a chinese transistor tester that does capacitance, ESR and resistance.

29th Mar 2024, 3:03 pm	#4
G6ONEDave Octode Join Date: Dec 2019 Location: Owston Ferry, North Lincolnshire, UK. Posts: 1,704	Re: Motorola TM 316S Car 8 Track player This might be a silly comment but I take it that you have checked the polarity of this Motorola unit. Being an 8-track it could be either positive earth or negative earth. if connected the wrong way round that would explain why the motor is going backwards. Dave __________________ Quote "All is hyperthetical, until it isn't!" (President Laura Roslin, Battlestar Galactica)