ISP issue

Here is what is going on
I'll try to make the story as short as possible not to bore you.
My high speed internet (RCN, cable, Boston area, US) has been very
slow for a while.
It stopped working altogether ~1month ago (I get connection at ~5% of
attempts). I called ISP, after several attempts I was told my modem
was losing packets. Other modems on the same line were not.
I I though of buying another modem....
Being a cheapscate and not wanting to add stuff to landfills:
I opened my modem (~6 years old Toshiba 2200). Lost packets=> dried/
popped aluminum caps (the thing runs pretty warm), lousy rails, you
know.
Checked rails. Found some ~0.5V pk-pk ripple on 2V (strange value)
rail - cleaned it up. No joy
I took my whole system ("beige box" and cable modem) to my
girlfriend's (same ISP, same service) - works fine.
I brought it back - does not work.
I swapped modems with my girlfriend. Both have been working fine for a
week or so. I mean mine at my girlfriend's and hers at my house.
It's neither modem nor lousy signal from ISP. What is it ???????

Mystery?????

 

It's the signal level. You have too much signal loss in your cable at home.
Try using less splitters, or get a "digital" amp. Her modem is happier with
your borderline signal level.