Help with tamron 20-300mm f3.5-6.3vc pzd for nikon

[Stecco]

Hello everyone,

Recently, I acquired a batch of lenses to repair at auction, including a tamron 28-300mm f3.5-6.3 vc pzd. Unfortunately, the particular lens I obtained has an issue: it doesn't connect to the camera and displays the F-- error. I attempted to identify the cause by disassembling it, but I couldn't pinpoint the main problem. The only anomaly I found is the damaged connector, visible in the photo, which the previous owner tried to repair by gluing it. :O

Despite the attempted repair, I checked with a multimeter, and the connections seem to be working. However, the error persists. I have also tried cleaning any contacts. I would like to ask for your help in understanding if the issue could be related to the damaged connector or if there are other factors to consider.

Thank you in advance for your support and insights.

 

[koraks]

Welcome to Photrio, @Stecco!

Despite the attempted repair, I checked with a multimeter, and the connections seem to be working.

That surprises me greatly. Given the state that connector is in, I don't see how it would work reliably, if at all. Such FPC connectors rely on the pressure of the top part to press the FPC into the contacts below. Given that that part is gone, and glue is likely to have crept in between some of the contacts, I don't believe that this connection is very reliable. I wouldn't be surprised if it seems to work OK as long as you apply pressure to it (e.g. with your multimeter probe), but the contact breaks as soon as you release pressure. Also, under the mechanical stresses of normal use, this connection will likely not hold up.

The best solution would be to replace the connector with a new one; it's often possible to find a suitable part for replacement. Measure the pitch between the contacts and their number and find a new one.

I would like to ask for your help in understanding if the issue could be related to the damaged connector or if there are other factors to consider.

Yes, and yes. It's quite possible that this dodgy connector plays a role in the problem, and at the same time, the question arises how this connector became damaged in the first place. This sort of damage makes me think it's due to someone trying to release the cable without knowing how to, and forcing the connector in the process. This in turn begs the question why they were working on the lens, and the reason could very well be the problem you spotted initially (no camera-lens communication).

I'm not too optimistic of actually finding the problem due to the lack of good documentation of the electronics and the difficulty of making a useful test setup.

 

[Stecco]

T

Welcome to Photrio, @Stecco!



That surprises me greatly. Given the state that connector is in, I don't see how it would work reliably, if at all. Such FPC connectors rely on the pressure of the top part to press the FPC into the contacts below. Given that that part is gone, and glue is likely to have crept in between some of the contacts, I don't believe that this connection is very reliable. I wouldn't be surprised if it seems to work OK as long as you apply pressure to it (e.g. with your multimeter probe), but the contact breaks as soon as you release pressure. Also, under the mechanical stresses of normal use, this connection will likely not hold up.

The best solution would be to replace the connector with a new one; it's often possible to find a suitable part for replacement. Measure the pitch between the contacts and their number and find a new one.



Yes, and yes. It's quite possible that this dodgy connector plays a role in the problem, and at the same time, the question arises how this connector became damaged in the first place. This sort of damage makes me think it's due to someone trying to release the cable without knowing how to, and forcing the connector in the process. This in turn begs the question why they were working on the lens, and the reason could very well be the problem you spotted initially (no camera-lens communication).

I'm not too optimistic of actually finding the problem due to the lack of good documentation of the electronics and the difficulty of making a useful test setup.

thanks, do you think I can replace it with this one that is not in use? This way I avoid having to search for the new component. The pin number and pitch is the same.

 

[koraks]

That's worth a try. A hot air rework/solder station will be required to lift the connectors. You'll have to be careful not to melt the housing and also prevent damage to surrounding parts. It's best to remove the PCB so you can work on just that.