Lincoln V200 t resistor value needed

[Terry Coughlan]

Hi Guys,

I have a Lincoln V200 T which has a resistor blown on the control pcb. It is marked R28 and is beside one of the plugs. I have marked it in this picture. If anyone knows the value of the resistor or could take a sharp picture of it or let me know what the colours of the bands are I would be very grateful. Many thanks. Terry

 

[eddie49]

According to this post:
https://www.mig-welding.co.uk/forum/threads/lincoln-v200-t.92634/
forum member @Troy has one of these machines.

 

[Bobbes]

I think this is an encoder and not a potentometer.

 

[bwservices]

My v200t has a slightly different design but you can see the resistor in question

 

[bwservices]

Red brown brown gold
210ohm

 

[Epace]

Red purple brown gold ?
270 ohm

 

[bwservices]

think it is purple,thanks

 

[Epace]

It's nothing.
These two colors are similarly dark, so it's easily mistaken.
I accidentally saw that the second color was purple because I was looking in more detail at the control panel that was on my
V200 T.

Someone replaced the potentiometers marked in red, so I don't know what the original values are.
I don't even know what type of remote connector it is.
However, the worst thing I definitely have to deal with is that my Lincoln only works at maximum power all the time.
Does anyone know what could be the reason for my welder to do this?

Regards

 

[bwservices]

I can check the values of those pots for you

 

[Epace]

OK, Great...

 

[Epace]

Until we know the value of those pots, maybe someone knows which connector is in the bottom left corner ...

 

[Hopefuldave]

It's nothing.
These two colors are similarly dark, so it's easily mistaken.
I accidentally saw that the second color was purple because I was looking in more detail at the control panel that was on my
V200 T.
View attachment 203438
Someone replaced the potentiometers marked in red, so I don't know what the original values are.
I don't even know what type of remote connector it is.
However, the worst thing I definitely have to deal with is that my Lincoln only works at maximum power all the time.
Does anyone know what could be the reason for my welder to do this?

Regards

always full power could be a fault with the current sensor (transformer?) on the output (guessing), if the board doesn't get feedback it'll probably keep trying to increase the output amps until it does?

Dave H. (the other one)

 

[Hopefuldave]

Might be worth looking at:

https://www.mig-welding.co.uk/forum/attachments/service-engineering-manual-pdf.77699/

Dave H. (the other one)

 

[Epace]

Thanks for the service manual, I've already looked at it.

I’ve done the following:

I made a fake load out of salted water and a couple of electrodes which I’ve used to burden the welder and I’ve done the following measurements:
output voltage ie. Open circuit voltage is about 80VD,
output current is set to 5A, but the current clamp was reading about 12A no matter the sett current
and in the meantime I’ve also measured the voltage on the pin 13 on the control board which was about 7mV.

As I reduced the load by pulling out the electrodes out of the water, voltage on pin 13 dropped.

I forgot to say when i hook up the load the voltage drops from 80VDC to about 63VDC.

 

[Epace]

In a manual I found for the welders V200T, V260T and V400T I found a part of schematic for the welder V260T

V260T and V200T are very similar. Some parts of the schematic from the V260T are the same as for the V200T.

In the schematics I found a SHUNT resistor on which a voltage is measured and used to adjust the output current . This is the part with the marking “SH1”. On the schematic it says that the value of the SHUNT is 0.25 mOhm (mili Ohms).

I’ve decided to measure it. The SHUNT is under a PCB which you can see in the picture bellow. I’ve disconnected one of the leads connected to the SHUNT and I “loaded” it with a current of 1.00A exactly and I measured the voltage drop across it. The measured voltage was 0.5-0.6mV which gets us, through a simple equation, that the SHUNT value for the model V200T is 0.5 or 0.60 mOhm.

When we use this information in combination with the earlier measured current we get U=I * R,
U=12 A * 0.0005 Ohm which gets us exactly 6mV (or 7.2mV).

This matches my measurements ie. the 7mV measured on the pin 13.

If I did everything correctly, and I hope I did, this tells us that this part is also good and is sending good voltage to the control PCB.

 

[Epace]

In the French manual, I found a list of pots on the control panel.

There are 8 items:
32 W2010001 Potentiometer 1M ohm 2
34 W2002500 Potentiometer 2.5K ohm 4
35 W2010000 Potentiometer 100K ohm 1
36 W2047000 Potentiometer 470K ohm 1

Here is a picture with marked ICs and pots

 

[Epace]

I found out that the 5 PIN CABLE PLUG connector is a type marked CON05CCP.
Besides Lincoln, it is used by Cebora, Migatronic, Hobart ...

Maybe this helps someone.

 

[tungluong]

Might be worth looking at:

https://www.mig-welding.co.uk/forum/attachments/service-engineering-manual-pdf.77699/

Dave H. (the other one)

pls share it for me! i'm new guy so do not have permission to view this page or perform this action.
could you send to my email: mr.tung.ckd@gmail.com? pls!

 

[Seadog]

It's not a good idea to advertise your mail address on an open forum.

 

[badabec]

This is an old thread. That page probably doesn't exist anymore. I get the same message.