Zyxel WiFi VDSL VMG1312-b30b dsl port off

[perseus142]

Dear all,

I am experiencing troubles with my wifi zyxel router VMG1312-b30b

DSL port is off, DSL cable isnt detected.
WiFi, Ethernet ports are working well, GUI accessible.

After inspection of the box is obvious, that resistors R8, R16 are damaged/burned. Unfortunatelly, I am not able to find electronic schematic so I dont know the resistance.

Could anyone help me with identification of SMD R8, R16 please ? These are next to DSL (RJ-11)and Ethernet(RJ-45) ports, close to H2001dg.

Also, could you help me with identification of GA1 which is parallel to DSL port ?

Pictures are attached.

Thank you in advance.

[diif]

Re: Zyxel WiFi VDSL VMG1312-b30b dsl port off

I would make an educated guess that R14 is the same as R8 and possibly R16.
GA1 looks like a diode to me. Does it measure like one ?

[stj]

Re: Zyxel WiFi VDSL VMG1312-b30b dsl port off

ga1 is a spark gap and should meter open-circuit.

[perseus142]

Re: Zyxel WiFi VDSL VMG1312-b30b dsl port off

ga1 is a spark gap and should meter open-circuit.

Thank you.

Right, I did measure open circuit in both directions, so it might be ok ? Or is there anything else what I could test/measure here ?

For education purposes, is there a way how to decode the color code/strip on it and find out the exact model ?

[stj]

Re: Zyxel WiFi VDSL VMG1312-b30b dsl port off

400v

[perseus142]

Re: Zyxel WiFi VDSL VMG1312-b30b dsl port off

400v

Thank you very much.

[perseus142]

Re: Zyxel WiFi VDSL VMG1312-b30b dsl port off

Another broken part - could you help me with identifiacion please ?

SMD diode HD1, HD2: O8W 4X - unable to find on google

Have you seen it before ?

[stj]

Re: Zyxel WiFi VDSL VMG1312-b30b dsl port off

MM5Z10V if it's a letter "O"
MM5Z4V3 if it's numeric "0"

[perseus142]

Re: Zyxel WiFi VDSL VMG1312-b30b dsl port off

MM5Z10V if it's a letter "O"
MM5Z4V3 if it's numeric "0"

Amazing
How did you decode the diode ?

[stj]

Re: Zyxel WiFi VDSL VMG1312-b30b dsl port off

https://www.badcaps.net/forum/showthread.php?p=507366

[perseus142]

Re: Zyxel WiFi VDSL VMG1312-b30b dsl port off

MM5Z10V if it's a letter "O"
MM5Z4V3 if it's numeric "0"

An idea how to determine whether is this 10V or 4,3V ?
0 and O looks similar

[stj]

Re: Zyxel WiFi VDSL VMG1312-b30b dsl port off

desolder a working one and stuff it on a zener tester.

[perseus142]

Re: Zyxel WiFi VDSL VMG1312-b30b dsl port off

Right. After desoldering the working one I measured Uz=9.36 V
My new 10V zener diode has got Uz=9.6V.
Is that suitable replacement part ?

[stj]

Re: Zyxel WiFi VDSL VMG1312-b30b dsl port off

close enough.
zeners are only acurate to the last 5% usually anyway.