Saltar al contenido principal
Ayuda

Versión actual por: jayeff ,

Texto:

Hi @whitelight ,
Prove that there is conductivity in one direction only '''through''' the diodes i.e. top to bottom in each diode. If none reverse the meter leads and test again as diodes only conduct in one direction.
Compare good ones as you did before to make sure it is the same.
I'd carefully remove the diodes as the tracks seem to go under them both and check for solder bridges or some other connection between the 2 diodes at the bottom end.
+
Check if there is still a connection between 3 and 4 with the diodes removed.
+
+=== Update (03/07/2018) ===
+
+Hi @whitelight ,
+What is it that is highlighted in the green circle?
+Is it a solder splash across two tracks?[image|1362478] (click on image to enlarge for better viewing)

Estatus:

open

Editado por: jayeff ,

Texto:

Hi @whitelight ,
Prove that there is conductivity in one direction only '''through''' the diodes i.e. top to bottom in each diode. If none reverse the meter leads and test again as diodes only conduct in one direction.
Compare good ones as you did before to make sure it is the same.
I'd carefully remove the diodes as the tracks seem to go under them both and check for solder bridges or some other connection between the 2 diodes at the bottom end.
+Check if there is still a connection between 3 and 4 with the diodes removed.

Estatus:

open

Editado por: jayeff ,

Texto:

Hi @whitelight ,
Prove that there is conductivity in one direction only '''through''' the diodes i.e. top to bottom in each diode. If none reverse the meter leads and test again as diodes only conduct in one direction.
Compare good ones as you did before to make sure it is the same.
-I'd carefully remove the diodes as the tracks seem to go under them both and check for solder bridges or some other connection between the 2 diodes.
+
+I'd carefully remove the diodes as the tracks seem to go under them both and check for solder bridges or some other connection between the 2 diodes at the bottom end.

Estatus:

open

Editado por: jayeff ,

Texto:

Hi @whitelight ,
Prove that there is conductivity in one direction only '''through''' the diodes i.e. top to bottom in each diode. If none reverse the meter leads and test again as diodes only conduct in one direction.
Compare good ones as you did before to make sure it is the same.
+I'd carefully remove the diodes as the tracks seem to go under them both and check for solder bridges or some other connection between the 2 diodes.

Estatus:

open

Editado por: jayeff ,

Texto:

Hi @whitelight ,
Prove that there is conductivity in one direction only '''through''' the diodes i.e. top to bottom in each diode. If none reverse the meter leads and test again as diodes only conduct in one direction.
Compare good ones as you did before to make sure it is the same.
-
-If they test the same as the good ones then because I cannot see the tracks that well in the picture I suggest that you verify what I've shown in the image below
-
-[image|1361417]
-
-.
-
-Test that there is a connection between the points 3 -d20 and 4-d21 so according to you there is a connection between 3-4 which means that somewhere between 3 >d20 > d21 > 4 there is a s/c ''when there shouldn't be''.
-
-To verify my thoughts test the same between F2 -d3 and F3 -d4 and verify that there is NO connection between F2 and F3.
-
-If this is correct then what I'm thinking is that there may be a connection between the two tracks round the area of d20 -d21 as that is the closest point between the two.
-
-Remove either d20 or d21 (or both) and take a close look with a magnifying glass to check if you can see anything obvious. Also check with the Ohmmeter if the connection between 3 and 4 is still there with the diode(s) removed.
-
-Hopefully this makes a bit of sense.

Estatus:

open

Editado por: jayeff ,

Texto:

Hi @whitelight ,
-Prove that there is conductivity in one direction only through the diodes i.e. top to bottom in each diode. If none reverse the meter leads and test again as diodes only conduct in one direction.
+Prove that there is conductivity in one direction only '''through''' the diodes i.e. top to bottom in each diode. If none reverse the meter leads and test again as diodes only conduct in one direction.
Compare good ones as you did before to make sure it is the same.
If they test the same as the good ones then because I cannot see the tracks that well in the picture I suggest that you verify what I've shown in the image below
[image|1361417]
.
Test that there is a connection between the points 3 -d20 and 4-d21 so according to you there is a connection between 3-4 which means that somewhere between 3 >d20 > d21 > 4 there is a s/c ''when there shouldn't be''.
To verify my thoughts test the same between F2 -d3 and F3 -d4 and verify that there is NO connection between F2 and F3.
If this is correct then what I'm thinking is that there may be a connection between the two tracks round the area of d20 -d21 as that is the closest point between the two.
Remove either d20 or d21 (or both) and take a close look with a magnifying glass to check if you can see anything obvious. Also check with the Ohmmeter if the connection between 3 and 4 is still there with the diode(s) removed.
Hopefully this makes a bit of sense.

Estatus:

open

Aporte original por: jayeff ,

Texto:

Hi @whitelight ,

Prove that there is conductivity in one direction only through the diodes i.e. top to bottom in each diode. If none reverse the meter leads and test again as diodes only conduct in one direction.

Compare good ones as you did before to make sure it is the same.

If they test the same as the good ones then because I cannot see the tracks that well in the picture I suggest that you verify what I've shown in the image below

[image|1361417]

.

Test that there is a connection between the points 3 -d20 and 4-d21 so according to you there is a connection between 3-4 which means that somewhere between 3 >d20 > d21 > 4 there is a s/c ''when there shouldn't be''.

To verify my thoughts test the same between F2 -d3 and F3 -d4 and verify that there is NO connection between F2 and F3.

If this is correct then what I'm thinking is that there may be a connection between the two tracks round the area of d20 -d21 as that is the closest point between the two.

Remove either d20 or d21 (or both) and take a close look with a magnifying glass to check if you can see anything obvious. Also check with the Ohmmeter if the connection between 3 and 4 is still there with the diode(s) removed.

Hopefully this makes a bit of sense.

Estatus:

open