Help! noob in over his head with new ("used") Tenlog TL-D3-pro setup :-(

[fred_dot_u]

I don't think your heart needs to sink, as you've provided a focus, narrowed things down nicely.

If the results of moving the "bad" sensor to the other side is that it suddenly becomes "good," you won't have too many variables to address. Making a guess on your connectors, I would suggest to examine that all leads of the specific connection to ensure the tiny metal prongs inside the plastic housing are pushed fully into the housing. The metal prongs are slightly spring loaded and the back side has a finger that sticks up in the opposite direction. When the prong is pushed into the housing, the finger pops up into a recess, preventing back travel. If the finger doesn't get fully into the recess, the prong can be pushed backwards when the connection is made.

If that doesn't solve the problem, you could have a cold solder joint. Those can be visibly obvious but can also be invisibly "un-obvious" and require a touch with a hot soldering iron to resolve.

It's best if you can identify the specific wire and the contact points at each end. It's apparent that the module assembly is in acceptable shape if you can move it completely from one side to the other. That leaves the connector into which it plugs (or is it a sub-board) on the way to the main board?

More details about the cable routing and connectors involved would be helpful. Photos might be helpful but not necessarily, as it could be challenging to get suitable detail amidst a bundle of wires. Photos of the connectors involved in the circuit would be good.

[minneapolis-matt]

I don't think your heart needs to sink, as you've provided a focus, narrowed things down nicely.

If the results of moving the "bad" sensor to the other side is that it suddenly becomes "good," you won't have too many variables to address. Making a guess on your connectors, I would suggest to examine that all leads of the specific connection to ensure the tiny metal prongs inside the plastic housing are pushed fully into the housing. The metal prongs are slightly spring loaded and the back side has a finger that sticks up in the opposite direction. When the prong is pushed into the housing, the finger pops up into a recess, preventing back travel. If the finger doesn't get fully into the recess, the prong can be pushed backwards when the connection is made.

If that doesn't solve the problem, you could have a cold solder joint. Those can be visibly obvious but can also be invisibly "un-obvious" and require a touch with a hot soldering iron to resolve.

It's best if you can identify the specific wire and the contact points at each end. It's apparent that the module assembly is in acceptable shape if you can move it completely from one side to the other. That leaves the connector into which it plugs (or is it a sub-board) on the way to the main board?

More details about the cable routing and connectors involved would be helpful. Photos might be helpful but not necessarily, as it could be challenging to get suitable detail amidst a bundle of wires. Photos of the connectors involved in the circuit would be good.

Fiddling seems to show the bad connection is just inside where the wrapped bundle of cables enters the case. Immobilizing all movement of the wires within the cable bundle at any point close to the base unit almost halts the blinking out of the LED even with lots of fiddling downstream of the immobilization point whereas any slight movement upstream of the immobilized wires (towards the base unit) causes tons of blinking and great difficulty getting it to light again. I would almost be tempted to just attempt to immobilize the wires near the base except that the large range of motion demanded by the attached bridge would probably defeat any immobilization scheme and I'm not sure if there would be enough slack left over for normal operation and finally any small vibration would probably still break the sensor connection (probably with infuriatingly stupid timing) and really make me regret relying on that solution. So, I'm thinking I need to open the case, inspect the cable connections for obvious opportunities to fix and if nothing can be done there, close up the patient note time of death and print up my RMA labels.

[minneapolis-matt]

Ok! Seven underside screws gets you into the case of the TL-D3 Pro. The cable connections are not soldered which is helpful but I do not have a replacement handy and do not see an obvious break. Wires can have internal breaks quite easily so ordinarily I'd assume replacement is my only prudent option unfortunately. Although, note in the closeup that X1 is the only sensor wire that will have to thread a path under the mainboard should I attempt to replace the whole wire, probably necessitating lifting the mainboard. Also, unlike the other neighboring 4 optical sensor cable connectors to the mainboard the x1 optical sensors connector to the mainboard is wiggly in the socket. Surely I can assume that is the cause of the loose connection in this case? Can a loose socket be repaired? I've tried just snapping it back in with no luck but I also don't see any sign of broken plastic in the socket.

[fred_dot_u]

I'm not sure which is which in the photos, but if the limit switches/sensors are in the upper right of the second photo, it gives me a clean view of the connections. You have a couple useful tasks ahead.

Identify the working sensor wiring and swap it for the non-working connection. For this, you're really only looking for the steady LED at this point, as you don't want movement or want to keep things to a minimum. Swapping at the board will give you a better reference. If suddenly the good one goes bad, it's on the board, which is the more likely circumstance. That will be confirmed if the bad one goes good, obviously.

Examine the connectors as you remove them, perhaps tugging on the individual wires that enter each connector. If any single wire moves freely and/or comes out of the connector, that's a good/bad sign. Good that you found it and will fix it.

With everything connected in the usual manner, push on the socket for the bad sensor connection. If there's a cold solder joint on the board inside the socket, this may create the intermittent connection. It's an easy fix if you have a cold solder joint, but the labor in disconnecting everything isn't all that much fun.

You suggest that wires can have internal breaks, but it's been years since I've come across such a failure. Your printer would have to have been misused and many years older for that to be high on the list. I won't reject it outright, but it's less likely than a cold solder joint or a loose prong inside the connector.

Do you have a digital multimeter and/or a soldering iron? Either are pretty inexpensive if you buy cheap, but if you plan to be a 3D printer mechanic (plan for it), you'll want a decent DMM and a soldering iron with a couple different size tips in the 25-40 Watt range.

[minneapolis-matt]

I'm not sure which is which in the photos, but if the limit switches/sensors are in the upper right of the second photo, it gives me a clean view of the connections. You have a couple useful tasks ahead.

Identify the working sensor wiring and swap it for the non-working connection. For this, you're really only looking for the steady LED at this point, as you don't want movement or want to keep things to a minimum. Swapping at the board will give you a better reference. If suddenly the good one goes bad, it's on the board, which is the more likely circumstance. That will be confirmed if the bad one goes good, obviously.

Examine the connectors as you remove them, perhaps tugging on the individual wires that enter each connector. If any single wire moves freely and/or comes out of the connector, that's a good/bad sign. Good that you found it and will fix it.

With everything connected in the usual manner, push on the socket for the bad sensor connection. If there's a cold solder joint on the board inside the socket, this may create the intermittent connection. It's an easy fix if you have a cold solder joint, but the labor in disconnecting everything isn't all that much fun.

You suggest that wires can have internal breaks, but it's been years since I've come across such a failure. Your printer would have to have been misused and many years older for that to be high on the list. I won't reject it outright, but it's less likely than a cold solder joint or a loose prong inside the connector.

Do you have a digital multimeter and/or a soldering iron? Either are pretty inexpensive if you buy cheap, but if you plan to be a 3D printer mechanic (plan for it), you'll want a decent DMM and a soldering iron with a couple different size tips in the 25-40 Watt range.

Thanks Fred!

I have both but hopefully in this case I won't need them.

The X1 sensor socket clearly is the culprit. It makes a loose and sloppy connection and one of the JST wire connections even came out with little provocation. I opted to try a very conservative fix of using 3 plastic shims to immobilize the JST connections within the plastic connector housings which has removed all of the apparent wiggliness from the socket. I'm looking for any opportunities to further insulate the internal connections from any external pulls on the cable bundles and then I'm going to close her up and see if i get all of the optical sensors to light up in the face of a bit of simulated jostling. If they pass that, I'll be overjoyed and proceed to trying to home the device, level the device, and await the arrival of the replacement extruder.