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Training interval timer

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Searcher

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Hi guys/girls?

Well I need some help as I can't find anyone over here that has the knowledge unfortunately?
I recently purchased at a not small expense from the U.S. two LED boxing / sport interval timers with a sound feature. Presuming (one should never presume) that being an internationally accessed website. that these timers would be fine for our 230/240 volt output? (why advertise or sell them without a warning) I stupidly after much deliberation a talking to our resident electricians plugged one in. Yes it worked for about 15 seconds then died a horrific death well the LEDS leaked and smoked a little. :-/

Now there were no labels on or in the case nor are there any switches to change voltage. there is really very little inside it other than a small PCB a speaker and a small copper wire wrapped transformer? :confused:I have pics of the internals for anyone that maybe interested enough to take up my cause?
I contacted the company and they were almost monosyllable in their reply and that reply was "220 volts"!

I want to know if I can convert the existing timer that still works to suit 240 volts and not have a total loss of over $300.00 AUD.
I am also quite willing to build one myself with my limited electronics knowledge if someone has a schematic I can follow.

Oh, they are capable of up to 10 rounds with breaks of 30 seconds or a minute round times are from 1 min to 3 mins. FYI

I am hoping this is a relevant question for this forum And I will leave it at that for now and wait to see if anyone wishes to help out?

Thanks in advance.
 

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You could always by a 220VAC to 110VAC converter for about $15.00
 
Thank you for the reply.

I am in Australia we use 240 Volts.

Also I have been offered a transformer ($100) from local electronic stores but they can apparently only be used for a short period consistently. Other than that none of the staff in these stores are permitted to give conversion or down to the board modification advice, nor do I get the impression many of them have the knowledge?
I was just hoping I might find some electronics guru out there.

:)

Thanks again anyways.
 
Hi searcher,

it would be good if you could identify the two vertically mounted ICs (pic.3)which should be voltage regulators.

They should be labelled XX7805 and/or XX7812. The XX is any combination of letters, probably LM or µC.

The mains transformer is the "thing" next to the loudspeaker. According to the size you could find an equivalent at your local electronics shop.

If you have a chance to measure the AC output of the transformer you could get an exact equivalent rated for 240VAC primary voltage.

If there is no chance to measure you could go by the highest voltage of the regulators and add 3V which will give you the secondary (output) voltage of the transformer.

Use this table to determine the power rating of the transformer:

core length (mm): core width (mm): Power rating (VA)
30 12.5 1.5
30 15.5 2.0
30 18.0 2.3
30 23.0 2.8

Regards

Boncuk
 
As Boncuk says, if you can establish the secondary voltage of the transformer then getting a replacement should be very straight forward. If you're near Brisbane then I have a step down transformer that could be used to measure it.

Mike.
 
This will work providing the power doesn't exceed 45W and it doesn't require an earth, it's probably much cheaper than replacing the transformer and is certainly easier and less risky.

**broken link removed**

You haven't filled your location in so we don't know what you need but this sort of thing can be bought in other countries too, if not order it from the UK and get a travel adaptor so it'll fit the sockets where you live.
 
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