Funai is one of the cheapest (both price and quality) DVD recorder makers still around, and combo decks are the flakiest of all DVD recorders. You're in double trouble. The drive has probably aged outside of being useful.
Then again, most manufacturers make stupid disc recommendations. Be very sure to only use the best media.
See the guide here: Blank DVD Media Quality Review
These are all-around horrible units for transferring VHS tapes to DVDs, as the DVD tends to look worse than the tape did. That's pathetic. DVDs can and should look better than the tape sources. The key to this is finding a quality DVD recorder known for making image quality better. This includes specific models from JVC and Toshiba, and are thoroughly discussed in past posts on the forum, and in guides on the site. Search for those.
Offhand, I recommend these...
- JVC: DR-M10, DR-M100, DR-MV1, DR-MV5, DR-MH30, DR-MH300
- Toshiba: RD-X34, RD-X35, KX-50
For the JVC combo decks, don't use the VCR. use a better external VCR for optimal archival quality.
See the guide here: VCR Buying Guide (S-VHS, D-VHS, Professional) for best video capturing
If you just have a few tapes (less than 40), consider paying a high-quality service to transfer them. It'll long-term be cheaper, and it will look/sound better.