Hi, I'm looking for someone to help me with this circuit board here, I want to know if the gates and decoder exist on the board or not. I'm not that experienced with circuit boards, but it looks to me that there is a middle layer on the board (besides the top and bottom) so I'm wondering if the 'chips' might be embedded in the board, or if they were just plain left off for cost savings since the RAM chip is not present also (the decoder was used to decode the RAM address and the gates were for the bus controls for the chip).

The decoder is U4, I think I cut it off in the picture, but it is above and to the let of U3. The RAM chip, definitely not present, is U3, and the gates are at U8.

Thanks,
Ben

 

Nothing is embedded in the board. Those pads are just unpopulated.

 

Often, they design the boards for multiple uses/models. And they just leave out some parts. Very common with consumer electronics (TVs, radios, etc). That way, they can design and manufacture one board only but use it in multiple products/models by leaving out some parts.

Hope this helps.
Lou

 

I know about the designing for multiple use thing, I just wanted to confirm that the hardware was really not there. I wanted to install an NVSRAM chip and use that address space, looks like its not gonna work out.

Hm, I don't know about soldering something that small but can you tell me what the package/size would be for that? The RAM chip (U3 there) is 24-pin DIP, just for reference to the size. Wondering if I could also find those chips with the correct pinout (I have the pinouts). Would this be SOP (small outline package)?

 

Looks like SOP of some sort to me, SSOP or TSSOP or whatever.

 

Ok, I'll look at dimensions on some data sheets and compare with the board, maybe I can figure it out, might still be worth pursuing.

Thanks

 

What is this circuit board used for?

 

It's the '727 ecm thats running my car (well, spare),