TBS-6983 pc card repair

[zorrin]

Hello,
I found this TBS-6983 board for next to nothing.
His only problem is that the owner who only used one tuner had the bad idea to put a cap on the other unused one.



The plug has heated up and melted the internal insulation...



I found the right model of F connector on Ali.




And despite my very limited level in soldering, I managed to replace the connector.



And good news, both tuner are working well.

 

[satesco]

I also have a problem repairing (if possible) a 6983 board. Someone told me you could fix an (apparently) burned on the 6983 cards.
What is your impression/think of the burnt portion you see in the picture?

 

[dreamsat]

You would have to know how many layers the board is. If it's only two layers it should work. You can send it to me and I'll take a look.

 

[zorrin]

I also have a problem repairing (if possible) a 6983 board. Someone told me you could fix an (apparently) burned on the 6983 cards.
What is your impression/think of the burnt portion you see in the picture?

Sorry @satesco for my late reply but I didn't see the notification of your message....
I don't think she survived.
I hope @dreamsat was able to help you.

 

[satesco]

No problem, @zorrin.Thank you for your concern. I'm glad you got your card fixed.
The manufacturer told me that such a fault in my card could not be repaired. For this reason, I resigned myself to the situation and did not call @dreamsat to try to fix it. Anyway, thank him for his good intention.
I was lucky that someone sold his card, so I can still work with 6983. Best dvbs2 card tbs ever produced. My opinion.
Have a good day.

 

[zorrin]

No problem, @zorrin.Thank you for your concern. I'm glad you got your card fixed.
The manufacturer told me that such a fault in my card could not be repaired. For this reason, I resigned myself to the situation and did not call @dreamsat to try to fix it. Anyway, thank him for his good intention.
I was lucky that someone sold his card, so I can still work with 6983. Best dvbs2 card tbs ever produced. My opinion.
Have a good day.

I only did a few tests with mine to see if it worked after the repair.
I will surely come back to you for advice on its use.

 

[tom55]

I also have a problem repairing (if possible) a 6983 board. Someone told me you could fix an (apparently) burned on the 6983 cards.
What is your impression/think of the burnt portion you see in the picture?

If the burnt portion is the only damaged thing, you could fix it yourself with a bit of skills and basic repair equipment

 

[Terryl]

Sorry for the late reply on the new connector you used, but I don't think it's rated for 2.5 to 3 GHz, but for 900 MHz and blow, you should have looked (and used) for one that had the metal shielding all the way around it like the one you removed.

 

[Terryl]

And can't really tell from your photos of the burnt section, (not very clear) can you give us a photo of the other side of the PCB?

That will tell us if it's a multi layer PCB or not.

If it's just a double sided PCB (top and bottom only) then the traces may be fixable, if more then two then it may be toast.

 

[zorrin]

Sorry for the late reply on the new connector you used, but I don't think it's rated for 2.5 to 3 GHz, but for 900 MHz and blow, you should have looked (and used) for one that had the metal shielding all the way around it like the one you removed.

I would test between the two tuner to see if I have too different results.
If it's enough to add one shield like the other, I should be able to do it quickly.
This is the only difference, the rest is strictly identical between the two in my opinion.

 

[satesco]

@tom55,
I'm glad for your optimism, but the response of a specialist was a bitter but accurate diagnosis: the internal circuits (inserted in the card) are compromised.
An integrated can be replaced, but the burn has penetrated "the tissue." Only the robot that inserted/made them could rebuild it, but that too with problems.
@Terryl,
I'm getting hope again, which tom55 instills in me if you think it's possible to repair the card.
Here's what the two sides of the card look like:

 

[Terryl]

There are several different types of "F" sockets, one type is used for TV, CATV and FM radio work, these are only rated up to around 900 MHz to 1 GHz, the other type are used for satellites work, these are rated up to 3 GHz, they may look the same but it's all in the center insulator and if they are totally shielded or not.

 

[Terryl]

Well what I see from the photos is a multi layer PCB, (more traces located inside between the two outside layers) then it's in my professional opinion that the card is toast. Sorry..

 

[zorrin]

There are several different types of "F" sockets, one type is used for TV, CATV and FM radio work, these are only rated up to around 900 MHz to 1 GHz, the other type are used for satellites work, these are rated up to 3 GHz, they may look the same but it's all in the center insulator and if they are totally shielded or not.

I also had to make sure to find a model compatible with the holes in the card...
We'll see if it's good.

 

[tom55]

@tom55,
I'm glad for your optimism, but the response of a specialist was a bitter but accurate diagnosis: the internal circuits (inserted in the card) are compromised.
An integrated can be replaced, but the burn has penetrated "the tissue." Only the robot that inserted/made them could rebuild it, but that too with problems.
@Terryl,
I'm getting hope again, which tom55 instills in me if you think it's possible to repair the card.
Here's what the two sides of the card look like:

You have burnt conductors, possibly two capacitors. Easy to clean that, break conductors with knife where needed and bridge with wires. There should be no conductors in the interlayer around that area.
If you can tell what happened when you got it burning it may help in determining whether other chips onboard are compromised

 

[Terryl]

What I think what happened is the user (not satesco) used a 75 ohm terminator cap on an unused but active LNB input, this input has a DC voltage on it to run an LNB, a 75 ohm terminator is not a true 75 ohm inductive load but just a 75 ohm resistor, and should never be used on an active circuit with DC power on it.

This caused a DC current overload and fried the power supply input pins going down to the PC's motherboard, I'm surprised that the motherboard didn't have some damage.

The 75 ohm 1/4 watt resistor used in the cap with a minimum DC voltage of 13 volts applied to it would have an overload of almost 2.2 watts, it would get very hot, and in the long run melt the center insulator on that "F" connector.

 

[satesco]

What I think what happened is the user (not satesco) used a 75 ohm terminator cap on an unused but active LNB input, this input has a DC voltage on it to run an LNB, a 75 ohm terminator is not a true 75 ohm inductive load but just a 75 ohm resistor, and should never be used on an active circuit with DC power on it.

This caused a DC current overload and fried the power supply input pins going down to the PC's motherboard, I'm surprised that the motherboard didn't have some damage.

The 75 ohm 1/4 watt resistor used in the cap with a minimum DC voltage of 13 volts applied to it would have an overload of almost 2.2 watts, it would get very hot, and in the long run melt the center insulator on that "F" connector.

I didn't think it was necessary to say how the card was burned, but it is good to confirm the danger you mentioned:"...should never be used on an active circuit with DC power on it.", when you don't take the necessary precautions for such activities..
I have to admit that I stupidly left the cards on the computer while I cleaned the dust inside the computer.
Probably a particle of material (I don't know what it could have been) from the inside got to the slot where the card was inserted, and the moment I turned on the computer, immediately a flame, smell, and burning smoke came out of that slot with the 6983 cards on. It was clear that both the card and the motherboard slot were compromised because of this contact with foreign particles, which activated the circuitry the moment I turned on the computer. So the motherboard slot was also burnt, so I had to change it, and the DVB card looks like in the picture posted.
Thank God the other cards remained untouched and are in working order.
A lesson to learn.