Teleton STP812 8 Track player

[RWM1513]

Hi guys

Hope your all well.

I have an 8 track....make and model as above.

Never had an issue with it until recently.

As you know, to activate the tape, it needs to be pushed in to play and pulled out to power it down.

It's decided to be constantly on.....no tape in it and the motor is going round and the program number is lit.

Even with it being on constantly, you can put a cartridge in and it will automatically start playing, remove it, the music stops, yet it continues to operate.

I disconnected the micro switch, which is a MATSUSHITA AM43009 but no difference, still the motor goes round.

Would anyone have an idea as to what the issue may be?

Thanks in advance

Robert.

[TonyDuell]

Is there a suppressor capacitor in parallel with the microswitch? It could be shorted.

[RWM1513]

Originally Posted by TonyDuell

Is there a suppressor capacitor in parallel with the microswitch? It could be shorted.

Please accept my apologies, but I've not got a clue.

[TonyDuell]

I assume the cartridge-inserted microswitch is the red-topped one shown in your photos. It seems to have 2 pink wires connected to it. Can you take a photo of where those wires go, please.

[RWM1513]

Originally Posted by TonyDuell

I assume the cartridge-inserted microswitch is the red-topped one shown in your photos. It seems to have 2 pink wires connected to it. Can you take a photo of where those wires go, please.

Yes it is.

[RWM1513]

A better picture

[TonyDuell]

I assume the brown and blue wires in that photo are the mains input cable from the plug. The 2 red wires go to the mains transfomer?

What is the black thing that appears to be on one of the pink wires?

How did you disconnect the microswitch? Is the black thing some insulating tape to cover where you cut and re-joined one of the wires? If so be careful, those wires carry mains!

Is there anything on the underside of the circuit board that the wires connect to?

[RWM1513]

Underneath, the pink wires go to the joints marked in yellow

[RWM1513]

It's insulating tape.
I powered up down for around 30 minutes before I clipped it, which made no difference to it.

[Restoration73]

In the two pictures above, the black component is a paper capacitor which has gone
short circuit - to prove it, cut one of its wires, and if things return to normal that's it.
Without it there may be an annoying audible click when the cartridge is inserted.
The capacitor should really be replaced with a snubber, thats a 100n capacitor in series
with a 100 ohm resistor, capacitor rated at 250 volts AC.

[TonyDuell]

Aha.. That black cylindrical component on the underside of the board seems to be connected to the same 2 points (electrically) as the pink wires from the switch. It looks suspiciously like a supressor capacitor too.

Assuming you have a soldering iron, I'd next desolder that component from the board and try the machine briefly again. If it now behaves you need to get a replacement capacitor and solder it to the board. We'll need to see the markings on the old one to know what to replace it by,

Incidentally there are no stored high voltages in this machine. If you unplug it from the mains it's safe to work on, you don't need to wait 30 minutes.

[RWM1513]

Originally Posted by TonyDuell

Aha.. That black cylindrical component on the underside of the board seems to be connected to the same 2 points (electrically) as the pink wires from the switch. It looks suspiciously like a supressor capacitor too.

Assuming you have a soldering iron, I'd next desolder that component from the board and try the machine briefly again. If it now behaves you need to get a replacement capacitor and solder it to the board. We'll need to see the markings on the old one to know what to replace it by,

Incidentally there are no stored high voltages in this machine. If you unplug it from the mains it's safe to work on, you don't need to wait 30 minutes.

I can't thank you enough for your help.
I'll remove it tomorrow afternoon when I'm home from work and then get some pictures of the markings.

Will these type of items still be available to buy?

[Restoration73]

I would recommend a snubber ;
https://uk.farnell.com/roxburgh/re12...-20/dp/2336109

Whilst i realise you want to get it going, the way this is wired would not be permitted
today. instead the switch would be in the low voltage dc circuit.

[DMcMahon]

If it turns out to be the black component which must be a suppressor capacitor (the fault cannot really be anything else from your results) and you decide to go for a snubber as opposed to just a replacement suppressor capacitor, note that the stated value above (at Post 10) of 100nF (100 nanofarad) is the same as 0.1uF (0.1 microfarad).

The snubber capacitor and suppresion capacitor (whichever is used as a replacement) should be X2 class rated.

David

[RWM1513]

Originally Posted by Restoration73

I would recommend a snubber ;
https://uk.farnell.com/roxburgh/re12...-20/dp/2336109

Whilst i realise you want to get it going, the way this is wired would not be permitted
today. instead the switch would be in the low voltage dc circuit.

I'm a novice so if you could explain a little more, it would be really appreciated.

BTW........that's one of my all time favourite songs

[RWM1513]

Originally Posted by DMcMahon

If it turns out to be the black component which must be a suppressor capacitor (the fault cannot really be anything else from your results) and you decide to go for a snubber as opposed to just a replacement suppressor capacitor, note that the stated value above (at Post 10) of 100nF (100 nanofarad) is the same as 0.1uF (0.1 microfarad).

The snubber capacitor and suppresion capacitor (whichever is used as a replacement) should be X2 class rated.

David

Hi David

That's went right over my head, sorry.
I feel embarrassed as I'm not clued up on these things like you guys.

[Restoration73]

Sorry if the guidance seems heavy, but we're dealing with the mains supply. If you
replace the original capacitor with a snubber, that is satisfactory.
Many manufacturers exporting to the US market (110 volts mains) simply changed
the transformer for 240V for europe. A single pole switch in live mains is not ideal but that's
how it is.

[DMcMahon]

No problem.

The snubber that Restoration73 recommended at his Post # 13 link is X2 rated (a safety spec rating) and the capacitor part of the snubber is 0.1uF (identical value to 100nF).

First prove it is the black component that is the culprit and if so, then post a photo of it showing its markings.

David

[RWM1513]

Originally Posted by Restoration73

Sorry if the guidance seems heavy, but we're dealing with the mains supply. If you
replace the original capacitor with a snubber, that is satisfactory.
Many manufacturers exporting to the US market (110 volts mains) simply changed
the transformer for 240V for europe. A single pole switch in live mains is not ideal but that's
how it is.

So if I bought the snubber, is it a straight fit....no additional stuff to add?

[RWM1513]

Originally Posted by DMcMahon

No problem.

The snubber that Restoration73 recommended at his Post # 13 link is X2 rated (a safety spec rating) and the capacitor part of the snubber is 0.1uF (identical value to 100nF).

First prove it is the black component that is the culprit and if so, then post a photo of it showing its markings.

David

I certainly will...thank you.