Troubleshooting of modified Palit 1070 GTX Dual problems

[rob-bits]

I am a Mechactronical engineer and I would like to restore a modified card into original state. I would like to ask for some help in troubleshooting.

Recently I bought a modified Palit GTX 1070 Dual videocard on eBay. Based on the item descriptions, two inductors were removed. One from the VRAM path and one from the PLL/PEX path. For VRAM voltage an AMPLE 20A Power Card is attached. The PLL has another power board for PEX voltage. I do not have much information about any further modifications. I found out a Mostfet is broken on the original 1.35V line so currently I cannot remove the AMPLE board until the replqcement has arrived. I set its output voltage to 1.35V. However I have removed the second external board from the PEX voltage and soldered back the missing inductor because that part of circuit seems ok.

When I plug the card into PC and start the system it starts. The windows recognised the card, the driver starts without any issue but there are some instabilities. Sometimes there are some screen glitches and sometimes it is frozing out. If I start a rendering test, the rendering stops after 5-6 sec. By the way the GPU temperature is ~50°C. When I try to use the card I got the following issues:

cuda error in CudaProgram.cu:465 an illegal memory access was encountered (700)
GPU1 search error: an illegal memory access

unable to get fan speed - unknown error (999)

The issues appears very randomly. Some come up after 30-40 sec. Some after 5 sec from start. Sometimes the windows crashes sometimes not.

What shall I check? What can be the problem?
Is the PEX voltage not sufficient?

For next step I would like to check the signals with scope on the PLL voltage controller and controller of voltage regulator for VRAM to check their functionality.

I am using Windows 10 with most recent Nvidia driver. The card has the EVGA GTX 1070 86.04.3B.00.3F bios (not original Palit bios)

Any help would be welcomed. Thank you.