Well I woke up this morning.....

Dec 28, 2023 Last reply: 2 years ago 32 Replies

(This is not a blues song!)



... to discover that my radio alarm clock was not working. It's fairly old, probably 15 years or so, DAB/FM.



Imvestigation has shown that the SMPS rated at 5 volts, 1 amp has failed, although when I disconnected it, it was very warm.



Any thoughts, please?


Measure the voltage at the 5v end. That's a flyer with such limited information.

Yes, the power supply has failed! :-) What sort of 'thoughts' are you hoping for? Wall-wart 5v power supplies are two-a-penny, what sort of connection does it require?

A device like that can be had for less than a fiver on ebay, if you are happy to bodge it in

You say 'disconnected'...is it some kind of wall wart? Does the thing produce volts when disconnected from the clock?

99% of electronic faults in modern kit seem to fall into two categories

- corrosion on the board, or shorted capacitors across the supply rails.

And with today's surface mount boards, repair needs an infra red camera, a hot air station, plenty of IPA and flux, and probably a microscope and a very steady hand. And usefully some paint on UV activated resist and and a UV lamp.

So if the clock *itself* is the issue rather than the power supply, expect to spend up to £120 to get it fixed...two hours of painstaking work with a well equipped service person.

The sort that repair smart phones and tablets....

If the PSU is externel and is the issue, buy a new one . 5V 1A is pretty much what any wall wart USB PSU will deliver to e.g. a raspberry Pi. Or smart phone.

You just have to find or bodge an adapter cable.

OTOH if the PSU is good and the clock is bad, chuck the radio and get a new one if the PCB is all surface mounted blocks.

Given we are rapidly ditching DAB for DAB+ I would ditch the radio.

Dave

I have a Sony Cube Clock Radio my wife bought in May 1989. It's AM/FM and despite its diminutive size it sounds quite good. It has been in use continuously since it was bought apart from a 3 week period in 2000 when we moved house.

The VFD (Vacuum Fluorescent) display is now very dim. I don't know if it's the display or PSU. Maybe spot-knocking (as done to old CRTs) may help or possibly the HT isn't so H any more. Apart from the dimness it works perfectly still after 34.5 years.

It's outlasted my need for an alarm clock as I only work part time now and no longer have 7am starts. For the last 15 years I've not needed a alarm clock, my body wakes me between 6.45 and 7.15 every day anyway!

How many stations moving from DAB to DAB+ are remaining on FM? If the OP listens to one of those, the radio should be okay for at least a while.

For me, it was the loss of Mellow Magic that sealed the fate of my little Roberts Radio. Over 20 national stations are now on DAB+

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Dave

The VFD I had on my hobbyist clock, was only 27V. It's not dangerously high.

You've probably seen the filaments in the thing. If those thin out, the filament current will drop. And the metal could be deposited on the glass.

The clock here has 27V tubes as well, which might be similar to mine. For mine, I had a turquoise plastic cover, that set off the tubes nicely (you just see the light from the tubes and not all the infrastructure).

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The problem with my clock, is the PCB was a poorly made one done in the kitchen sink. No passivation. Just bare copper, and the copper was completely rotted after about ten years. But that clock used to wake me up every morning, and the control to kill the alarm was on a long wire so I had to get out of bed to stop it.

Paul

And how many are offering internet radio access as well?

I could build an alarm clock radio that was preset tuned to a single radio station out of a raspberry Pi and an audio hat, or use a TV style hat to get DVB DAB or FM radio..

The main problem is the planned obsolescence and all the internet radio sites keep changing how they are accessed so you cant just grab them on an icecast stream. You have to pay someone to get the access to your internet radio hardware, and that keeps changing, making old hardware obsolete.

The lifespan of VFDs is very unpredictable. I've got a tuner used almost every day since I bought it in 1990 and the display is as bright as ever; and a LaserDisc player whose display started fading after just a few years, though I only used it occasionally. I had a Humax PVR where the first four characters faded (ones on most of the time), suggesting that it is loss of luminescence of the anodes that is the issue.

At the risk of upsetting you all, I actually use an Amazon Echo....

Dave

Thanks to all who responded. Sorry I wasn't clear.

It's a wallwart. Output when plugged in is zero volts. The lead (to connect to the radio) terminates in a plug with external diameter 5.5 mm. I don't know what this type of plug is called, but they appear to be quite common these days.

barrel plug, internal diameter varies as well as external.

Even when not plugged in to the clock?

the 5.5 mm is a barrel connector

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There are two common sizes of these, 2.1mm and 2.5mm internal diameter.

*Always* suspect the wall-wart first.

The jack plug on my Sony cube clock radio is colour coded.

Not sure about the OP's, but I got a USB to to jack plug lead so it runs off a portable USB power thing.

Be careful. Not all USB power supplies will deliver enough current

It is possible to get wallwarts with a lead having multiple outputs (different size connectors) and a polarity change connector.

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