Troubleshooting a homemade Van de Graaff generator I am building a homemade VDG generator and it does not seem to provide any electrical charges. My construction is as follows:

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*The top roller is PVC, it is "pierced" (I don't know the phrasing, sorry) by an aluminum shaft over two standing acrylic boards. They are connected with some stainless steel bolts and nuts.

*The bottom roller is stainless steel. The shaft in the middle is the same aluminum shaft as the top roller. It is connected to a motor.

*The belt is a nylon cordura fabric, stitched and sewed together to make a belt.

*I am using a saw blade as the comb, I am not sure about the material.

The combs are connected to separate cables, about 5 meters, each to a stainless steel dome. The domes are all far from the VDG. In most design of VDG, I saw that one dome is placed encapsulating the top roller. But in my design, both domes are far apart connected with some cabling.
I do not feel any charge from the domes. I know there are some things that need to be rechecked and repaired, but I don't know where to start. As far as I understand:

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*The comb next to the upper roller should pick up charges, and should hold electric potential, this causes current to flow through the cable and to the dome. However, the cable is 5 meters

*I placed multimeter electrodes on both combs and do not see any potential

What should I check to troubleshoot and repair this generator? And how, using a multimeter, do you test the generator components to see if they work? Thank you in advance
Edit: here is the picture of the generator that I made. I haven't figured out how to create a top dome that encased the whole top roller though, like in the comments/answers.

 A: 
[My] domes are all far from the VDG. In most design of VDG, I saw that one dome is placed encapsulating the top roller. But in my design, both domes are far apart connected with some cabling.

That won't work. The fact that the upper dome encloses the apparatus that takes the charge off of the belt is the most important part of the design. It's literally what makes the machine work.
Read Wikipedia's Van de Graaff Article, and note the following passage:

By the principle illustrated in the Faraday ice pail experiment, i.e. by Gauss's law, the excess positive charge is accumulated on the outer surface of the outer shell (1), leaving no field inside the shell. Electrostatic induction by this method continues, building up very large amounts of charge on the shell.

With the dome enclosing the comb and roller, there is no electric field inside the dome, and therefore, nothing to inhibit charges from flowing off the belt, to the comb, and to the shell.  But if the dome does not enclose the comb and roller assembly, then that assembly will quickly reach the same (relatively low) voltage as the charges on the belt, and no more current will flow.
A: This answer is incomplete, as I'm no expert, but it may be of some help.
The idea of having the top roller assembly surrounded by the dome is that the charges that build up on the outside of the dome will not give rise to an electric field inside the dome, so charges arriving on the belt are not inhibited from leaving via the top comb.
I'm not at all sure about your arrangement at the bottom, either. I've not come across a VdG with a metal roller. There are, I believe, at least two ways of getting charge on to the belt. Either use a plastic bottom roller (one that gets the opposite charge from the plastic of the top roller) and connect the bottom comb to ground, or connect the comb to a high voltage (say 1000 V) source (with several Mohm internal resistance for safety).
