Samsung M1630 stepdown transformer details
That model doesn't show up at my normal Samsung US parts supplier.
Can you post all the numbers found printed on the transformer?
One of them should be the Samsung part number.
Normally you can look at the voltage rating of the large filter capacitor on the control board and assume that the AC secondary voltage will be about 2V less (in ACrms) than that DC voltage.
Now what I'm saying may seem a bit twisted - and it is - but what I mean is this:
If the cap is rated at 15VDC, then I'm saying that a secondary voltage of about 13VAC rms should be a good safe level for testing.
To confirm this, multiply 13VAC by .635 (assuming it uses a full-wave rectifier) and you get about 8.26VDC.
Then allow for about 50% derating by mulitplying the 8.26VDC by 2.
This gives you 16.5VDC, which with my generous derating, is pretty close to the caps 15VDC.
Then you can remove the transformer and use an isolated Variac(tm) to apply that calculated AC voltage to the secondary connections at the circuit board to see if it powers up.
You can measure the DC voltage across the cap as you adjust the Variac(tm), making sure you don't get too close to or exceed the DC rating of the cap.
Once you get it working with a main DC voltage of about 50-75% of what's printed on the main electrolytic capacitor, you can start shopping for a sub transformer.
It's much easier if it's not a VFD display which would require a separate filament winding, but there's nothing wrong with using a small second transformer for that.
You can even mount them both on the chassis and run long leads to the board. As long as the leads are of sufficient gauge, routed and secured well, and protected from nicks, there's nothing worng with that technique.
You should make them long enough that if the front panel is later removed for service, the next technician will be able to see the wires before he pulls them out or otherwise damages them.
I would also add a varistor on the primary if there's not already one! *grin*
Sep 14, 2006 |
Samsung MC1360WA Convection/Microwave Oven