Hi, I had a problem with a link, which stopped working. Having no spare and time to resolve it, I have decided to try a repair. I found two SMD components that would be damaged. In the body of the same have the brand Z419 and Z415, I wanted to know if anyone knows the values of these diodes or their equivalences.



We think that these are D4004 and D4050 on the schematic. The Z419 and Z415 text appears to be the diode manufacturer's date code. These are the main surge protection diodes.


Hello Mark. Thanks for the answer, exactly are the diodes D4004 and D4050, is it possible to know the values of them?

D4004: LittelFuse - SMAJ58A, 58V, 400W, SMT, DO-214AC (SMA)

D4050: STMicroelectronics - SM6T100CA,100.0V,SMB,-65c to 175c

Datasheets attached for the two diodes.


Hello Ram, thanks for the response and the information. Excellent!.
If I can repair then I comment here


Hi Ram Nayak;

I am really impressed with the response and level of support given to the questions on the forum.  Just amazed.  That a user was able to post a possible PCB board issue (with a photo) and in turn Cambium assisted without hesitation.  Excellent.  Please continue to have such an open, honest, factual, respectful and cordial forum for all of us.



Hi Mark,
Do you have the schematics available even if their is a cost associated I would like to obtain them if possible I have had two of these fail and I tracked the program down to a failed seal on the back of the assembly allowing water to seep into the system board please look at the pictures so as an end user we can’t just open the unit without voiding the warranty so I’ve been putting silicone into that unused hole this should be something that never happens I thought it was lightning damaged but it’s just simply water entering the case because the sticker/seal didn’t get placed properly during production these are exspensive units to a small company and for a failure like this over a cheap seal is git me scratching my head makes me nervious

Hi Chris,

I'm sorry you've had problems with these units. I'll get my colleagues in the hardware team to take a look at the photos you supplied. Are these units under warranty?


Hi Mark,

At which specific location/point is the hole you are mentioning...

Getting conscious as well as we a a lot of PTP650's for installation.... might look as well now and have it documented the earliest time possible.

Thank you for the input...

Hi Chris,

The hole you identified is covered by a semi-permeable (Gore-Tex) patch that allows pressure inside the unit to equalize with the ambient pressure outside.  It may be that this patch has failed in your unit. We would need to have your unit back to be able to diagnose this reliably.

We can't recommend that you block the hole with silicone sealant; that will prevent breathing of the air in the unit, and is likely to lead to bigger problems in the longer term.


Dear Ram,

I have the same problem with a PTP670. (view image, blue dot). The same of the PTP670 can work?

Best Regards,


D4004 and D4050 are transient voltage suppression diodes used to protect the ODU against lightning-induced surges on the Ethernet interface. If these have failed, then the ODU has been exposed to a large surge, and it's likely that other damage will have occurred. We don't recommend trying to repair the PCB yourself. Our Support team will be able to arrange a repair for you.