Fronius transpocket 1500 repair attempt

[Mikeva]

Hello guys,
Thanks for having me.
So,
I found an old fronius transpocket 1500 which had some issues and all the parts were all over the place in a box.
I managed to assembly the unit and I found a broken tvs diode 1.5ke which I replaced with new.
I replaced both of them with a non polarity tvs diodes.1.5ke200
The unit now starts and all seems correct.
-15volts + 15volts +5 volts are present...
I have 240v on the main and 320 vdc on the caps
I have 70 volts on the welding terminals.
The problem is that I have very weak ark and cannot weld anything...
The amperage potentiometer has no response.
I checked for lose connections and I resoldered most of the PCB but nothing changed.
The only thing I noticed is a very low ticking sound somewhere on the PCB but I cannot trace it.

Can somebody have any idea what to look for?

Thanks in advance.

 

[chrismac]

My eutectic power max did the same thing ( which I think is more or less the same machine), do yo get a blast of power when you switch from TIG to MMA while striking an arc, IGBT's were what the internet told me the issue was, I couldn't find the in the machine (possibly now I would have had a better chance with slightly more knowledge/information to hand) there used to be very through service manuals on the internet for them with various testing procedures too.

 

[Mikeva]

My eutectic power max did the same thing ( which I think is more or less the same machine), do yo get a blast of power when you switch from TIG to MMA while striking an arc, IGBT's were what the internet told me the issue was, I couldn't find the in the machine (possibly now I would have had a better chance with slightly more knowledge/information to hand) there used to be very through service manuals on the internet for them with various testing procedures too.

IGBT is the first thing I thought also, but it measures correct, at least with the measurements I did....

 

[dernt]

Following checks you should do:

- check secondary rectifier
- TVS diodes on the small PCB above the secondary recifier.
- Check transistors and zener diodes near the Igbt gates.

 

[premmington]

Ticking is normal on the Fronius and Lorch machines, it's part of the design which provides large power reserves for welding with cellulose electrodes

@bR39Da - I looking to buy another little light MMA invertor.

Not sure which way to go...? Fronius Ignis - Lorch - EWM...?


I got a Kemppi Miniarc EVO180 (and been pleased with it)

But I want another little 150amp DC welder MMA only welder.

 

[Porkypine]

i've got one of the Fronius transpocket things and tbh it's been brilliant, does what it says on the tin and ive used it on sites all over the place, and despite being 20 years old it hasn't died yet

 

[chrismac]

My eutectic power max did the same thing ( which I think is more or less the same machine), do yo get a blast of power when you switch from TIG to MMA while striking an arc, IGBT's were what the internet told me the issue was, I couldn't find the in the machine (possibly now I would have had a better chance with slightly more knowledge/information to hand) there used to be very through service manuals on the internet for them with various testing procedures too.

It was actually MOSFETs in the Power Max 2, my mistake.

I have found the Fronius service manual on my laptop but its too big to upload here, any pointers on how to get it uploaded its 5.7 Mb?