Have I fried my Roberts radio

Have I fried my Roberts radio

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princeperch

Original Poster:

7,943 posts

248 months

Monday 23rd January 2017
quotequote all
I got myself an old Roberts revival 550'off eBay. To be fair to the bloke selling it to me he wrote on a post it note, make sure you use the right adapter withy it and that it has a negative polarity.

I didn't see this until too late, and tried a 9v adapter I that powers a more modern Roberts radio I also have.

Turns out that that adapter isn't the right polarity. The radio didn't turn on but when you turned the volume button you could hear a sort of pulsing from the speaker .

Have I fried my new radio after five minutes of owner ship? I'm going to pop out at lunch and get a big pp9 battery to see if that works as well. But I'm a bit worried I've buggered it now. Is it likely I could get away with it?

MitchT

15,947 posts

210 months

Monday 23rd January 2017
quotequote all
Possibly a similar thing here ...

We bought a new Roberts Solar DAB radio and, a few years later and long out of warranty, it started behaving weirdly. When it was switched on there'd simply be a repeated 'snap' sound coming from the speaker and the display would flash in time with it. We forgot about it but I had another look a few days ago and now the display simply lights up when the power is attached, but there's no noise and no information on the display. It's always been used with the adapter provided when it needed external power and it's only ever had the original batteries in.

motco

15,994 posts

247 months

Monday 23rd January 2017
quotequote all
If you're lucky the makers will have put a reverse polarity diode in the circuit. Trouble is series diodes drop the input voltage so if it's already marginal, they may leave it out. If you have cooked it, the damage might be limited to the first few components in the supply line, but you need a good analogue electronic bod to sort it.

ATG

20,697 posts

273 months

Monday 23rd January 2017
quotequote all
The pulsing sound suggests there wasn't reverse polarity protection, unfortunately. If you didn't hear anything go pop or smell burning, you may have got away with it. Fingers crossed.

Simpo Two

85,770 posts

266 months

Monday 23rd January 2017
quotequote all
Just get a PP9 battery surely?

princeperch

Original Poster:

7,943 posts

248 months

Monday 23rd January 2017
quotequote all
just purchased a pp9 battery from screwfix for 5 quid and the radio fired up. I was a bit worried I had knackered it earlier but I think ill stay with the batteries now.

they are nice old things Roberts radios aren't they. this one is a bit battle scarred but im sure it has a few more years of radio four left in it yet..

thanks all.

Dogwatch

6,242 posts

223 months

Monday 23rd January 2017
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Good job it was a Roberts and not some lesser breed!

motco

15,994 posts

247 months

Monday 23rd January 2017
quotequote all
Excellent! smile

LimaDelta

6,548 posts

219 months

Monday 23rd January 2017
quotequote all
My OH did this. Cat chewed through the power cable so she found one that looked 'just the same'. Cue pop and smoke. We sent it back to them and it was fully refurbished for around £50 IIRC.

Simpo Two

85,770 posts

266 months

Monday 23rd January 2017
quotequote all
princeperch said:
they are nice old things Roberts radios aren't they. this one is a bit battle scarred but im sure it has a few more years of radio four left in it yet..
My family had 4-5 of them, proper radios that weigh a ton, sound good and last forever. And now you see so-called 'Roberts' horrible plastic tiny DAB things, such a pity.