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General Category => Amstrad CPC hardware => Topic started by: protek on 21:12, 27 February 20

Title: Issue with CPC6128 and the motor control of Philips NMS-1515
Post by: protek on 21:12, 27 February 20
I’ve been trying to figure out what’s wrong with the motor control of my Philips NMS-1515 datasette when it’s plugged into my 6128. The motor won’t start spinning after I’ve typed Itape and run”, and pressed play and any key. Also rewind and fast forward do not work while the remote is plugged in. Also the power led on my datasette PSU doesn’t lit while remote is plugged in, as if there was a short. If I short remote and ground on the DIN plug while the datasette is powered on the PSU led goes off. I can hear the relay click inside the 6128 when I press any key when prompted. The datasette used to work earlier until it stopped.


I opened the datasette up and studied the remote plug. When the plug is in, it separates two contacts and apparently opens a circuit. The datasette does operate normally if the plug is out and the contacts connected, as well as when the plug is in and the contacts separated. If remote is plugged in while connected to the CPC6128 the datasette will not operate.   


How should the motor control work under normal circumstances? I assume that play will not work until the relay turns it on but how about winding, does the motor control affect that too? What does the relay actually do when the CPU instructs it to latch? Does it close or open a circuit? Can the relay be bust even though it appears to click or is the problem in the datasette circuitry?
Title: Re: Issue with CPC6128 and the motor control of Philips NMS-1515
Post by: gerald on 22:03, 27 February 20
How should the motor control work under normal circumstances? I assume that play will not work until the relay turns it on but how about winding, does the motor control affect that too? What does the relay actually do when the CPU instructs it to latch? Does it close or open a circuit? Can the relay be bust even though it appears to click or is the problem in the datasette circuitry?
The relay close the circuit when you press a key.
If you can hear the relay in the CPC, there is a good chance that the relay contact are dirty / worn out.
So either you replace the relay or try a contact clean up (involving opening the relay that was not designed to be opened)

Title: Re: Issue with CPC6128 and the motor control of Philips NMS-1515
Post by: protek on 22:39, 27 February 20
I saw from reference pictures that the relay is an Omron make. Is there a place to source one or some alternative?
Title: Re: Issue with CPC6128 and the motor control of Philips NMS-1515
Post by: Bryce on 09:38, 28 February 20
It sounds like the cassette player has an issue. If the power LED is going out just by inserting the cable then something definitely isn't right. The CPC is acting as it should.

Bryce.
Title: Re: Issue with CPC6128 and the motor control of Philips NMS-1515
Post by: protek on 12:37, 28 February 20
It is specifically the PSU’s, which is a Vanson switching wall-wart, led that is going out. I don’t have the Philips’ own PSU. I could try getting half a dozen C batteries and try that too.
Title: Re: Issue with CPC6128 and the motor control of Philips NMS-1515
Post by: Bryce on 13:19, 28 February 20
Something is causing the PSU to go down. Either a short circuit or just too much current being pulled.

Bryce.
Title: Re: Issue with CPC6128 and the motor control of Philips NMS-1515
Post by: protek on 13:26, 28 February 20
I’d incline to the short as it has been working with the same PSU and still works if the remote isn’t connected.
Title: Re: Issue with CPC6128 and the motor control of Philips NMS-1515
Post by: Bryce on 13:40, 28 February 20
Likely, but it doesn't have to be a complete short. It could be a failing capacitor.

Bryce.