Technical support ESAB Smashweld

[Mclinden]

Here is a picture I borrowed from this thread and made som arrowsk, showing which transistors I need to change.
I need to change all the foil capacitors too, as they have cracked (yellow capacitors) 0,1uF and 0,01uF.
My board is also 341399-001B.
Thank you in advance for help to find the type and numbers for these transistors.

[christianmoller]

Hello,

Mine is still around and working and of what is seeing you have the same board as mine.
i'll take a look tomorrow.
And sorry Torbjörn......i have not change the resistors yet.............

/Christian

[torbjorn_forsman]

Do NOT replace any transistors unless you have measured them and found that they beyond any doubt are faulty!
Such transistors are very reliable and will almost never fail by themselves, if they fail it is due to some other fault in the circuitry which then should be repaired first.

Start with replacement of any suspect RIFA capacitors, and check out all electrolytic capacitors and replace those that have lost capacitance or got high losses (dried out). Also, clean the PCB so there is no risk for creepage currents through dirt. Check the relays so they work properly and dont have welded or burnt contacts.

[Mclinden]

Hi Torbjorn an thank you very much for your answer.

The reason for changing the transistors is extensive corrosion on the legs of those 3 transistors ( for a reason I don't know) and a broken leg. The rest of the board look good, after cleaning it up.
Of cource the metal film capacitors 0,1uF don't look good and needs changing.

I got this machine from someone I know, because it didn't work, and I can see that someone has been tampering without any knowledge of electronics.
One of the transistors was bent over and the leg was broken. The other two of these 3 also seems to also have been fiddeled with.
This is the reason for changing them.
Since this card has been in such corrosive environment, I cannot reed the imprints on the transistors. It is compleetely gone.
The one I found to be a BC141-16 was from a picture I found from a Polish website, where I could see the imprint on this transistor.
The other 2 transistors I could not read clearly. However, it looked like they could be the same BC141-16 with TO39 metal casing.
As I cannot read all numbers clearly, it could easily be a small differens causing them to be PNP in stead of NPN.

[christianmoller]

Here is a pic of the transistors Both labeled "BC 141-16 8523"

[Mclinden]

Thank you very much Torbjorn
I really appreciate your help. You are a life saver

This is exactly what I neded.
Now I can place an order for my parts and get the card working again.
I can't wait to get my parts and replace them wit the old parts.

Have a wonderful sunday

[torbjorn_forsman]

A more modern equivalent to BC141 is BC639. However, observe that it has a plastic case and other pinning, collector is in the middle on BC639 while base is in the middle of BC141. The -16 digits of BC141 tells the current amplification ratio, and it is usually not critical in this type of circuitry, only when the transistors are used in for example a balanced audio amplifier where pairs of transistors must have the same rating.
Another transistor that often can replace the BC141 is the american type 2N2219.

[Mclinden]

Hi Again Torbjorn.
Thank you for the extended information about the transistors. I have got the BC 141-16 transistors and change them all, as the others didn't look very healthy either.
However, after taking them out, i tested them, and they were working fine, but now I have new shiny transistors where I can read the text.

If you are reading this? I encountered another problem, and that is the transformer for feeding the card and the relay/contactor.
The primary windings were burned and ther was no power anymore on the secondary side, of course.
First I contacted ESAB in hope to get at least their scematics with information about voltages on the card, to determind what voltage I need from the transformers secondary side.
The answer was that they no longer had any documnentation for the Smash Weld 180, as it was too old. They only had the user manual, and sait that parts were no longer available for this machine

Next, I tried to unwind the primary, and counting the windings, but I came to a stage where they were impossible to unwind anymore, as the Cu wire broke.

I now have the CU wire (0,22mm with coating. 0,2mm without coating) and my intention is to rewind it again, back to the original.
I have also a formula to calculate an average transformer core, but here are variations on thid from one manufacturer to the other, resulting in different output voltages, as the secondary windings are beeing used as they are.
To get the transformer correct, I need to know the voltages on the secondary side (to the card and the contactor). This way I can wind it according to my formula and then measure the voltage.
From this I can calculate if I need to remove or add windings, to get the right voltage.

It would be extreemely helpful, if you could have measured the voltage output on the primary side on your transformer.
Could you please help me with this?
I understand that in this thread, you are the one with most knowledge about electronics and the welding machine.

In return, I can send you all the documentation I have gatherede and made myself for this project.
If you give me the voltage output, i will return with all information needed to rewind the transformer from scratch, if something happens with your transformer.
The troubble is that this information is lost, and you have a burned transformer, there is no way to repair this again.

I really appreciate your help