On 11/10/2011 8:43 AM, Clueless wrote:
Hi all

I have a Hoseki Digital LED Alarm Clock Model H-5008 / 230VAC

The primary of the tiny transformer inside has gone open.

I have some similar transformers with me but I do not know what is the
output of the original transformer. There is no marking on the pcb
about the input voltage.

Is there any way to find out? Start at a low voltage with a variac
until the unit starts working?

Any help will be appreciated.


Look at any filter caps near some diodes that the output of the
transformer connects to. For example, 6.3 VDC marking on the caps
means the supply probably is designed for 5 vdc.

Also look around and see if there is a small 3 pin regulator with
markings like 7805 (5 volt) or 7812 (12 volt)

Jeff


--
"Everything from Crackers to Coffins"