K4000 output transformer

I am getting distortion on one channel of my K4000 amp when I turn up the volume. I have swapped or replaced everything (left and right power amp boards swapped, leads from pre-amp board swapped, diodes and caps on PSU board swapped, etc, etc.), except the output transformers and binding post. I am going to try swapping them next, or at least use flying leads to avoid moving the trannies.
If one of the OP trannies is faulty, can I get a replacement?

Yes, if the unit is still under warranty (2 year, proof of purchase) and if you return the assumed defective transformer for inspection to:

Velleman Projects Tech. Dept.
Legen Heirweg 33
9890 Gavere
Belgium

This is nearly 20 years old! Of course it won’t be under warranty, I will need to pay for a transformer.
Can I do that, and who do I contact?

Sorry, we have no means of knowing if you just bought the kit or not.
Warranty runs from the day you purchase the kit, not from the date it was manufacturer or stocked by your distributor. This also goes for obsolete kits.

Anyway, in this case, no need to return the transformer.
Sorry, no direct or online sales.
You can order the transformer from your Velleman distributor.
Please note that this is not a stock item, your distributor will have to special order it for you.
The Velleman order code is ZD043.

Ok, thanks.