Hi all,
I'm trying to repair a board and have found a short in a diode. I'm having trouble identifying it since there are no markings... I'm not an electronics professional but have some basic knowledge. It not enough thought to know the specs that the diode should have in this application.
The diode is in parallel to the coil of a DSP1a AGP2003 12V relay.
I've found that the relay worked correctly with 12V applied once I removed the diode, so it seams to be the only damaged part.
The same board has another relay/diode mirror pair that is working correctly so I removed the diode to do some tests.
I put it in series with a 220ohm resistance and an unregulated (finished this at home...) 12V power supply. Plugging the '12V' power supply only to the resistance I measured 15,15V.
Plugging the power supply to the diode in series with the resistor I measured 18,05V across the diode and 0V across the resistor, and no current. Changing polarity had the same results.
I attach a photo of the diode.
Its approximately 2,5mm long by 1,75 diameter.
I can't make anything else of the circuit...The relay output goes to a connector and to another board. The controlling signal to the replay passes through a potentiometer and then to an enclosed small board with several ICs but all covered with no way to identify ICs or the tracks. The diode is probably to protect the controlling ICs on relay switching.

I'm trying to repair a board and have found a short in a diode. I'm having trouble identifying it since there are no markings... I'm not an electronics professional but have some basic knowledge. It not enough thought to know the specs that the diode should have in this application.
The diode is in parallel to the coil of a DSP1a AGP2003 12V relay.
I've found that the relay worked correctly with 12V applied once I removed the diode, so it seams to be the only damaged part.
The same board has another relay/diode mirror pair that is working correctly so I removed the diode to do some tests.
I put it in series with a 220ohm resistance and an unregulated (finished this at home...) 12V power supply. Plugging the '12V' power supply only to the resistance I measured 15,15V.
Plugging the power supply to the diode in series with the resistor I measured 18,05V across the diode and 0V across the resistor, and no current. Changing polarity had the same results.
I attach a photo of the diode.
Its approximately 2,5mm long by 1,75 diameter.
I can't make anything else of the circuit...The relay output goes to a connector and to another board. The controlling signal to the replay passes through a potentiometer and then to an enclosed small board with several ICs but all covered with no way to identify ICs or the tracks. The diode is probably to protect the controlling ICs on relay switching.

