Gameboy Player assistance needed

[gramh]

Ok I've tore apart cleaned and fixed everything I can find between my Gamecube, my Gameboy Player and my carts. All of my GB carts work fine, all of my GBA carts work fine, but none of my GBC carts get past the Gameboy logo screen with either no Nintendo logo or a fuzzy Nintendo logo. I've gone so far as to refresh the connections of the chips on the carts, used every cart cleaning method on Youtube, nothing is working here. I honestly don't want to find another Gameboy Player but if that's my only option then it's my only option. There is almost nothing easily searchable for support for these things so I'm throwing myself out here for some hope.

[Papy.G]

What software do you use with your GBPlayer (original boot disc, its Dump, or GBI?)
Do you have many GBC games, are you sure they are originals, are the SRAM batteries OK, are they confirmed working on a GBA or GBC recently?

As GB and GBA games are running fine, I suspect it is a problem with the carts, not the GBPlayer.

[gramh]

I use the original boot disc, the carts are originals, as far as I'm aware they were confirmed working from the seller but I only have 2 to compare, no clue about the batteries I don't see any on the board itself.

[gramh]

Update: It was most definitely the carts that were the issue, I refreshed the solder on one of them for a second time and it now works perfectly. Unfortunately the seller, JJ Games, is out of business and I can't do anything about the bunk carts but at least they were cheap and I managed to save the one that had value. Thanks for the suggestions though!