Stereo recorder cassette player

Thread Starter

TieBravo

Joined Aug 21, 2021
50
Sorry for posting thse back to back, I'm just trying to revive a 60s stereo recorder cassette player tapedeck. My problem is, motor isn't responding on button press, but amplifier power led is on. I have checked the motor directing using 12v dc and its in working condition. My question is, can i use a step down to 12v transformer to spin the motor (using that switch of black and green wire)? Would it work (play cassettes)? Motor isn't spinning when i insert the jack on the amplifier.
 

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SamR

Joined Mar 19, 2019
3,538
I'd first do a web search for the manual and then see if there is a free PDF of the old Sam's PhotoFacts for it or even one to purchase. You didn't tell us if this is an automotive, home, or portable unit? Make and model!
 

AlbertHall

Joined Jun 4, 2014
11,539
The motor will need some form of speed control to keep the speed constant despite changes in supply voltage and variations in the motor loading. That control may be built in to the motor or it may be an external circuit. From your diagrams the motor power comes through the amplifier board and near that connection there is what looks like a power transistor. These things suggest to me that the speed control is on the main board.
 

Thread Starter

TieBravo

Joined Aug 21, 2021
50
The motor will need some form of speed control to keep the speed constant despite changes in supply voltage and variations in the motor loading. That control may be built in to the motor or it may be an external circuit. From your diagrams the motor power comes through the amplifier board and near that connection there is what looks like a power transistor. These things suggest to me that the speed control is on the main board.
I noticed one thing, when i press forward or rewind, the buttons lets the motor spin freely because pressing these two buttons with detach any other gears from the motor. And when i hit the play button, there are some gears attached with belts are slowing the motor down because to play a cassette the motor must not spin that fast. So maybe this is the mechanical speed control, i think amplifier board is providing it a constant speed.
 

Thread Starter

TieBravo

Joined Aug 21, 2021
50
TV
I'd first do a web search for the manual and then see if there is a free PDF of the old Sam's PhotoFacts for it or even one to purchase. You didn't tell us if this is an automotive, home, or portable unit? Make and model!
Its the SRC 1080 sonodyne. A stereo cassette recorder tapedeck output of 8ohms. It got two boxes, each got one tweetr and one woofer. And each boxes got impedance of 8 ohms. Its a home unit i think
 

MisterBill2

Joined Jan 23, 2018
9,551
First do a check of the mechanical portion. it may be that something is binding, that does happen. If you can take the drive belt off the motor and see that it runs in the play mode then the problem is mechanical. I have seen cassette decks with all kinds of mechanical problems.
And if the speed is regulated by an off-motor regulator then the external speed adjustment may be set too low. THAT was common back in the mid 1970's era.
 

Tonyr1084

Joined Sep 24, 2015
6,383
You didn't tell us if this is an automotive, home, or portable unit?
Looks too big to be an automotive player. Rather, looks a lot like the tape decks I've torn apart in the past.
I noticed one thing, when i press forward or rewind, the buttons lets the motor spin freely because pressing these two buttons with detach any other gears from the motor. And when i hit the play button, there are some gears attached with belts are slowing the motor down because to play a cassette the motor must not spin that fast. So maybe this is the mechanical speed control, i think amplifier board is providing it a constant speed.
Try this: remove the drive belt from the motor, insert a tape and press play. If the motor spins then there's a chance the problem is mechanical. Those old decks have grease on spindle and pulley shafts. Something could be bogged down because old grease may have hardened. OR something could be broken and the motor is spinning in the PLAY configuration but because of a broken cog, catch, clutch, whatever - it's not playing.

Bypassing the motor run switch isn't the solution I'd be looking for. Doing so means the motor will be any time the stereo is turned on. Possibly even running when not turned on. Powering it from an external 12 volts (DC) will likely make the motor run at the wrong speed. It may even hurt the motor. It's been a good few years since I've pulled one apart and couldn't tell you what the motor voltage should be; or how it's designed to run. So try a few tests and try to determine if there's something mechanical that is stuck or broken. DON'T FORCE anything. If stuck, you could break it.

Those switches that detect the presence of a tape are quite small and not able to handle much power. Likely they're just sensor switches that tell the main board when to run a tape and when to allow recording on a cassette. Those cassettes have a break-out tab so that once you've recorded a track you break out the tab so that you can't accidentally erase the tape. If ever in the future you want to re-record on the cassette you just put a small piece of tape over the broken-out notch and you can again record on that cassette.

@MisterBill2 - you beat me by three minutes. Mechanical issue is my first guess too.
 

AnalogKid

Joined Aug 1, 2013
9,414
Put a scope on the motor leads when it is running, to confirm that the motor is either AC or DC.

Also, what is the total number of motors in the device?

ak
 
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Ramussons

Joined May 3, 2013
1,096
Unless there is an option to use the amplifier of the system as a stand alone unit (whic is not likely), pushing any button will power ON the amplifier and the motor.
The only difference is that, in the FF / Rewind and Play is a Mechanical movement that moves the Pinch Roller to the Capstan and the pressure pads to the Erase and Record/Playback heads.
If the FF and RW is not working, check your main belt. Normally, that is the culprit.
If FF / RW is OK, but Play is no go, check your Pinch Roller / Capstan mating. Check the Capstan belt.
Other than that, nothing else can normally go faulty in such mechanisms.
The culprits usually are the Belts, Pinch Roller and Lubrication.
 

Thread Starter

TieBravo

Joined Aug 21, 2021
50
O
Looks too big to be an automotive player. Rather, looks a lot like the tape decks I've torn apart in the past.
Try this: remove the drive belt from the motor, insert a tape and press play. If the motor spins then there's a chance the problem is mechanical. Those old decks have grease on spindle and pulley shafts. Something could be bogged down because old grease may have hardened. OR something could be broken and the motor is spinning in the PLAY configuration but because of a broken cog, catch, clutch, whatever - it's not playing.

Bypassing the motor run switch isn't the solution I'd be looking for. Doing so means the motor will be any time the stereo is turned on. Possibly even running when not turned on. Powering it from an external 12 volts (DC) will likely make the motor run at the wrong speed. It may even hurt the motor. It's been a good few years since I've pulled one apart and couldn't tell you what the motor voltage should be; or how it's designed to run. So try a few tests and try to determine if there's something mechanical that is stuck or broken. DON'T FORCE anything. If stuck, you could break it.

Those switches that detect the presence of a tape are quite small and not able to handle much power. Likely they're just sensor switches that tell the main board when to run a tape and when to allow recording on a cassette. Those cassettes have a break-out tab so that once you've recorded a track you break out the tab so that you can't accidentally erase the tape. If ever in the future you want to re-record on the cassette you just put a small piece of tape over the broken-out notch and you can again record on that cassette.

@MisterBill2 - you beat me by three minutes. Mechanical issue is my first guess too.
Okay here is the thing i want you to know, without removing any belts from the motor, i tried connecting it to a additional 12v. The motor worked perfectly, and the belts are cooperating too no jamming at all. Play button also working. Now my question is that, giving the motor a additional power source will play a cassette (its all about that head right?)?
And motor will only run when i press any button. How? just look at the green and the black wire clip, i am soldering the positive end of the transformer on the black wire clip, and another separate wire on the green clip which goes straight to the positive end of the motor. And the negative end of the motor connected directly to the gnd of transformer.
And as for speed, i think its not really controlled my electric, the motor spins at a constant speed its just the gears that minimises the rpm and slows the cassette spinner. When i press the ff all the gears are detached from the motor so the cassette spinner spinning at the motors rpm.
 
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Thread Starter

TieBravo

Joined Aug 21, 2021
50
Unless there is an option to use the amplifier of the system as a stand alone unit (whic is not likely), pushing any button will power ON the amplifier and the motor.
The only difference is that, in the FF / Rewind and Play is a Mechanical movement that moves the Pinch Roller to the Capstan and the pressure pads to the Erase and Record/Playback heads.
If the FF and RW is not working, check your main belt. Normally, that is the culprit.
If FF / RW is OK, but Play is no go, check your Pinch Roller / Capstan mating. Check the Capstan belt.
Other than that, nothing else can normally go faulty in such mechanisms.
The culprits usually are the Belts, Pinch Roller and Lubrication.
I thought that too, but belts are not jamming the motor neither any mechanical error. How did i know that? I connected both ends of the motor to a 12v dc (step down transformer age of) and without removing any belt the spinning mechanism worked perfectly when i hit the play button (and there is a mechanical number reading when a cassette plays it changes every moment like "001","002"...., And thats also working).
 

MisterBill2

Joined Jan 23, 2018
9,551
Put a scope on the motor leads when it is running, to confirm that the motor is either AC or DC.

Also, what is the total number of motors in the device?

ak
Given what the motor looks like and given the lead wires connecting to it the motor is a DC motor. Quite likely with an external speed control, possibly even tachometer feedback. There were at least two of them in that era that did have actual speed servo control. Others used cheaper methods.
 

Tonyr1084

Joined Sep 24, 2015
6,383
Okay here is the thing i want you to know, without removing any belts from the motor, i tried connecting it to a additional 12v. The motor worked perfectly, and the belts are cooperating too no jamming at all. Play button also working. Now my question is that, giving the motor a additional power source will play a cassette (its all about that head right?)?
Confused here. Thought we were talking about the motor. Don't understand "it's all about that head, right?".
And motor will only run when i press any button. How? just look at the green and the black wire clip, i am soldering the positive end of the transformer on the black wire clip, and another separate wire on the green clip which goes straight to the positive end of the motor. And the negative end of the motor connected directly to the gnd of transformer.
Terminology is important. When you talk about a transformer you are talking about an AC device, not a DC device. If you're talking about a power supply (wall wart) then we will understand that a power supply connected to a DC motor is providing Direct Current, not Alternating Current.
And as for speed, i think its not really controlled my electric, the motor spins at a constant speed its just the gears that minimises the rpm and slows the cassette spinner. When i press the ff all the gears are detached from the motor so the cassette spinner spinning at the motors rpm.
A DC motor will spin at different speeds based on the voltage applied. We can not assume that the PS (power supply) you're using makes no difference to the motor. There MUST be some speed governing system in place.

Years ago I took apart an old 8-Track player. The motor had a set of weights and a switch that governed speed. If the motor spun too fast the switch would open up and remove power from the motor. When its speed slowed back down the switch would again make contact. To adjust the motor speed there was a mechanical screw inside the motor that you had to adjust. It adjusted the spring tension against the switch so that you could tweak the final speed of the motor. IF (that's a big "If") you gave the motor too low a voltage the motor would not spin at full speed. So there IS the possibility the motor on your tape deck is internally regulated. The regulation of the motor happens so fast that you can't see or hear any difference. But bottom line - somewhere, either electronic or mechanical, there's something controlling the speed of the motor.

Take great care when applying an external power source to the circuitry. Some things don't like over voltage conditions. With that OLD tape deck it may not be as sensitive, but there's a chance you could back-feed something and end up worse off.
 

Thread Starter

TieBravo

Joined Aug 21, 2021
50
Confused here. Thought we were talking about the motor. Don't understand "it's all about that head, right?".
Terminology is important. When you talk about a transformer you are talking about an AC device, not a DC device. If you're talking about a power supply (wall wart) then we will understand that a power supply connected to a DC motor is providing Direct Current, not Alternating Current.
A DC motor will spin at different speeds based on the voltage applied. We can not assume that the PS (power supply) you're using makes no difference to the motor. There MUST be some speed governing system in place.

Years ago I took apart an old 8-Track player. The motor had a set of weights and a switch that governed speed. If the motor spun too fast the switch would open up and remove power from the motor. When its speed slowed back down the switch would again make contact. To adjust the motor speed there was a mechanical screw inside the motor that you had to adjust. It adjusted the spring tension against the switch so that you could tweak the final speed of the motor. IF (that's a big "If") you gave the motor too low a voltage the motor would not spin at full speed. So there IS the possibility the motor on your tape deck is internally regulated. The regulation of the motor happens so fast that you can't see or hear any difference. But bottom line - somewhere, either electronic or mechanical, there's something controlling the speed of the motor.

Take great care when applying an external power source to the circuitry. Some things don't like over voltage conditions. With that OLD tape deck it may not be as sensitive, but there's a chance you could back-feed something and end up worse off.
Confused here. Thought we were talking about the motor. Don't understand "it's all about that head, right?".
Terminology is important. When you talk about a transformer you are talking about an AC device, not a DC device. If you're talking about a power supply (wall wart) then we will understand that a power supply connected to a DC motor is providing Direct Current, not Alternating Current.
A DC motor will spin at different speeds based on the voltage applied. We can not assume that the PS (power supply) you're using makes no difference to the motor. There MUST be some speed governing system in place.

Years ago I took apart an old 8-Track player. The motor had a set of weights and a switch that governed speed. If the motor spun too fast the switch would open up and remove power from the motor. When its speed slowed back down the switch would again make contact. To adjust the motor speed there was a mechanical screw inside the motor that you had to adjust. It adjusted the spring tension against the switch so that you could tweak the final speed of the motor. IF (that's a big "If") you gave the motor too low a voltage the motor would not spin at full speed. So there IS the possibility the motor on your tape deck is internally regulated. The regulation of the motor happens so fast that you can't see or hear any difference. But bottom line - somewhere, either electronic or mechanical, there's something controlling the speed of the motor.

Take great care when applying an external power source to the circuitry. Some things don't like over voltage conditions. With that OLD tape deck it may not be as sensitive, but there's a chance you could back-feed something and end up worse off.
You're right there is another yellow wire connected to the motor, I didnt see it at first.
Every time i try to fix this thing i end up realising this thing is beyond of my reach, this tapedeck got karaoke noise filters, mic ports, 5 bamd equaliser and lot more other features like Co2, metal etc i don't even know what they are.
But one thing for sure i won't give up on this one i will need a experienced technician for this.
And i tried to mean the cassette reading head that touches the tape of the cassette when we hit play.
 

Tonyr1084

Joined Sep 24, 2015
6,383
i tried to mean the cassette reading head that touches the tape of the cassette when we hit play.
The head is entirely separate from the motor. Regardless of what the motor is doing the head is listening for magnetic fluctuations on the surface of the cassette tape. That's where the music comes from. Or recorded voice - or whatever. In the past I've used (at a company I worked for) tapes to hold programming for continuity test equipment. You "Play" the tape into the unit and the data is captured and entered for the unit to perform multi-point continuity tests as well as testing for shorts. The tape medium is just information. If the tape plays too fast or too slow you will hear the difference. I used to attend lectures that were just a few minutes longer than 60 minutes. I skinned down the drive pulley to slow the tape down so I could get more than 60 minutes of lecture on a 60 minute tape. When played back in a regular (unmodified) tape deck the speaker was speaking slightly faster than normal, but you could still understand what was being said. So the job of the motor is to present a regulated speed that is set for an "Industry Standard Speed" so that no matter who's tape you put in it - it plays at the proper speed.

Without a schematic you will have a difficult time discerning what that yellow wire does. Probably is a feedback signal for the board to regulate the speed of the motor. But until we see a schematic - all is just guesswork.

Without looking back through the thread - someone suggested looking for the "Sam's" schematic. It's been a while since I've looked for that source, but I recall getting information that was otherwise difficult to attain. That's the place to start - getting the schematic. Then zero in on the motor and speed control circuitry to start figuring out what may be going on.

And stop forcing voltages into things. Especially when you don't understand what you're doing. You COULD release the magic smoke from one or more components.
 
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