Lorch HT 180 AC DC : Fault code E3

[Weldoradoo]

What is "Adc bus"? What is "FPGA" ?
Make pictures, or point it out on a schematic or exploded view of this machine pls.

 

[Jan-DIY]

Hm.
ADC - analoge to digital converter
FPGA- Field programmable gate array
Try to have a look on google…
Bus- connection between the both above.

Please do yourself a favor and do not touch any internal parts while the machine is charged.

Give lorch or some other specialist a go to have a look at it.

 

[Weldoradoo]

I would only touch a unplugged machine of course.

 

[Weldoradoo]

I did of course google it. But thats out of my league.

 

[Weldoradoo]

I would have to send it to a Lorch specialist since I dont have one in my city or in a 50 km radius.

 

[Jan-DIY]

I would only touch a unplugged machine of course.

Unplugged is not equal to uncharged.
Take care of the capacitors. Where you coming from?

 

[Weldoradoo]

I live in Nijmegen, the Netherlands

 

[eddie49]

Do all welders have a shunt current sensor like this? Whats its purpose? It already gives the fault code E3 without me welding or connecting a weld cable to the plus Dinse socket.

An arc or TIG welder needs to provide a Constant Current ( CC ) supply. A machine that does this by electronic control, such as a thyristor-controlled transformer TIG or an inverter, needs a feedback control loop to automatically regulate the phase control or pulse-width modulation circuits to achieve CC. The current sensor provides the feedback.
( For a Constant Voltage ( CV ) MIG welder, the output voltage will be sampled to do this.)
The thick metal strip has an area that is alloyed or sintered to create a defined resistance, and the voltage measured across that known resistor indicates the current ( V=IR ).
All electronically-controlled welders have these sensors, but newer machines use Hall-effect sensors around a cable:

or in-line:

The small varying voltage may be measured and digitised using an analogue-digital converter ( adc ).
When the welder is first switched on an automatic power-on self-test ( POST ) will run in firmware, and if this test thinks there is an error in the sensor, or in reading from it, it will display the E03 error code, before any welding current actually flows through the shunt.

 

[Weldoradoo]

So this "POST" is to blame? And why would this test go wrong? Software issue or Hardware (Circuit board "Eprom" where this red cable ends at "X7")? The shunt looks fine, so that cant be it right?

 

[Weldoradoo]

"All electronically-controlled welders have these sensors, but newer machines use Hall-effect sensors around a cable"
At first I was looking for a Hall sensor. As I expected that and not just a metal strip (shunt). Later I deduced that it had to be that simple strip.

 

[Weldoradoo]

Well some "developments"...I checked the X1 - X5 20 pin ribbon connector. Looks fine. That is one of the checks that Lorch advises regarding E3 fault code. The shunt to Eprom board (X7 connection) red cable is fine. The shunt itself is dustfree and not corroded. Leaves the Mapro itself. But that circuit board has 5 Control LED's. And they indicate normal function. The middle one blinks which is normal.

 

[Weldoradoo]

So I dont know what to do next actually. If the Mapro, shunt and cable is fine, what else could it be

 

[matt1978]

Meier-Schultz Lastechniek B.V.

They would be your closest service centre

 

[Weldoradoo]

Look i want to solve it myself. Only when nobody knows anything anymore that would be last resort. But that would cost about 800 Euro is what the service centers I called estimate.

 

[matt1978]

Look i want to solve it myself. Only when nobody knows anything anymore that would be last resort. But that would cost about 800 Euro is what the service centers I called estimate.

I am not sure if it is a miscommunication because English is your second language, but considering I am trying to help you for no gain to myself (with it being a 16 year old machine) I find your replies quite abrupt and rude.

This is a forum aimed at DIY/Semi-Professional welders. There are some people who are very knowledgeable in electronics, but no one on this forum is a factory training Lorch service technician, which I feel are the only people who can offer the correct advice.

I wish you all the best in finding a solution. I shall be unfollowing this thread.

 

[Jim Davey]

Look i want to solve it myself. Only when nobody knows anything anymore that would be last resort. But that would cost about 800 Euro is what the service centers I called estimate.

I think the reply you're looking for is "Thanks Matt, if all else fails I'll give them a go. In the meantime I'd like to try and fix this myself if I can".

 

[Weldoradoo]

I called several Lorch service centers. I dont have the money to just send it over to the factory and let them fiddle till they find it. They are all very helpful and understand that I want to solve this myself. They send me service manuals and schematics. They all seem to understand that I will not invest hundreds of Euros in this old machine. So I dont understand why you keep telling me I should send it to a service center. Thats simply not how I want to solve it. Why would I use a forum if the only solution would be to send it to a Lorch center and for me to accept whatever repair price Lorch would charge me. No one would need a forum then. Thanks Matt but I will try to repair it myself.

 

[eddie49]

Did you try the three tests that I suggested in post #16 ?
( Confirm less than 1 Ohm for the current shunt across the two thin red wires at plug X7, test power-up without X7 connected - i.e. open-circuit, and test power-up with a dead short across the X7 pins on the PCB.)

So this "POST" is to blame? And why would this test go wrong? Software issue or Hardware (Circuit board "Eprom" where this red cable ends at "X7")? The shunt looks fine, so that cant be it right?

If the shunt is actually OK ( as per the tests I suggested ), then the error code may be displayed because the self-test thinks the shunt is faulty, or cannot decide due to a failure in communication with that part of the circuitry.
On some machines, error indicators or codes are "borrowed" to indicate multiple faults. This probably does not happen on a well-designed machine like a Lorch, but for example the "OT - Overtemperature" LED on an imported MIG can mean anything.

The blinking LED that you can see may indicate that the processor is running correctly, but that still does not exclude that it found a fault during start-up, or thought it did. After basic connection, voltage, and realistic discrete component tests, then without a flowchart for the firmware and a block diagram of the logic, it is not possible to say any more than "PCB fault".

 

[Weldoradoo]

@eddie49: Errrm I didnt try disconnecting the shunt cable at the X7 connector at mapro board yet.
But now I did and the result is quite astonishing. The E3 fault code is gone now . Is that good? :-p

 

[Weldoradoo]

Or is it dangerous to use the machine now as it might not respond to overcurrents in time with the risk of electric shocks for the welder or the machine burning down the house :-(