Two 32-in-1 cartridges with same layout not working(ish) on various machine

[Tone-la]

Hi,

 

This is my first post, so hopefully I'll have the etiquette right! And have been lurking and enjoying all the content to date - so thanks!

 

I have two 32-in-1 cartridges, both are acting strangely but in the same way. I've noticed when you cycle the games, they both on cycle 3 or 4 display a blue and black chequers board for a couple of seconds then disappears. So that's the good news - the below is my analysis of these so far.

 

I've opened both up and with the help of other forums here (people discussing 16 x 4k games on eprom etc) and this link:

http://wiki.electronics-irc.net/Atari_2600_32-in-1_game_selection_fun

I think I have my head around how it's meant to work.

 

I've cleaned and followed various steps to ensure contact when plugged in.

I've tested on a 4 switch vader, 4 switch woody and 6 switch woody.

I'm mainly working on the 4 switch woody for the rest of the analysis

 

With the carts in - I've checked out the cycling mechanism (the 4024 chip) checking the high pins for the bits increment correctly when the power is switched - seems fine

I've also checked the hex inversion through the 74HC14 (ins and outs switched correctly)

I've checked power to the ROM and multimetered the caps and resistors, and they seem to be capaciting and resisting fine

 

On one of the carts I've even retinned

 

With the screen flickering to a game I get the feeling this is salvagable, but think this is taking electronics to a new level for me. I'm not frightened of having a go, so any suggestions welcomed

 

I've attached a couple of pictures - one thing I've noticed on one other 32-in-1 circuit ive seen imaged on the net is that all seven connections on the left of the ROM are pulled to ground through resistors - but owning two that aren't I thought this a stretch...

 

Thanks in advance

Tony

[Tone-la]

bump... maybe one for the weekend shift