Odd motherboard or not?

[Curlypaul]

So unless I'm missing some details, but I seem to have an early motherboard without the white resistors above the gatearray.

I don't seem to have a pic of the gatearray, it was 40007 with no revision numbers. Apart from the resistors, it seems an identical pop to the ones on the wiki already, but is it worth me adding it to the page for the sake of completeness?

[robcfg]

Well, that's certainly interesting! 

On boards with slots for both old and new gate arrays, the white resistors are present only when the old GAs are installed, not the new ones.

In theory, yours should have those white resistors too.

Could you lift the heatsink and take a peek at which GA is installed and if resistors are fitted but without the white cover? 

It would also be nice to have a picture of the solder side to check for mods or service.

Cheers,
Rob

[Curlypaul]

Well, that's certainly interesting! 

On boards with slots for both old and new gate arrays, the white resistors are present only when the old GAs are installed, not the new ones.

In theory, yours should have those white resistors too.

Could you lift the heatsink and take a peek at which GA is installed and if resistors are fitted but without the white cover?

It would also be nice to have a picture of the solder side to check for mods or service.

Cheers,
Rob

I thought I took one, but obviously didn't, but it's a plain 40007 with no revisions. I'll get a pick tomorrow, and of the underside.

As I saw it, it matched the first production board listed in the wiki, sans the white resistor tube things.

I've not owned this since new, but it was an attic find listed on ebay I nabbed. Judging by the screw heads and the filth in here when I got it, plus the seller being unaware of what an fd1/ddi sell for, lead me to believe it I'd factory.

More pics to follow then!

[Curlypaul]

Finally got around to taking those pictures.

To my eyes, it doesn't look like anyone has switched those resistors, I'm sure I was the first to open it when I got it a couple of years back

[Curlypaul]

The back of the resistors and some board markings

[Curlypaul]

The rest of the board markings and a better shot of the first version of the gatearray 

[Curlypaul]

Just  realised this is in introductions, sorry I didn't mean to post it in here

[robcfg]

Thanks for the pictures!

So, the resistors are there, but they don't have the white mesh around them.

I checked the resistor color codes, and they are indeed 12 ohm ones.

The service manual tells that they should be fit for 0.5W, which maybe they are because the look a bit bigger than the other ones.

So the only difference is the white mesh.

Maybe you've got one of the very first boards before they started covering the resistors...

Cheers,
Rob

[Curlypaul]

It looks that way doesn't it! Nice to find something a bit unusual to share with the group 

[gerald]

Definitively one of the early made boards:
- sockets for ROM and RAM, which were quickly removed for cost savings.
- serial number on the bottom case which point to june 1984

[Curlypaul]

Definitively one of the early made boards:
- sockets for ROM and RAM, which were quickly removed for cost savings.
- serial number on the bottom case which point to june 1984

Yeah the sockets goy dropped didn't they, quite handy to have as some of the ram chips failed on me

[Bread80]

That's the same as my original one (that I got for Christmas in 1984): GA resistors mounted close to the board and socketed RAM. Revision Z70100. S/N 34212.

I figure the white on the resistors is to stop them shorting anything. I'm not sure why they leave them so long though. Is it a heat thing, or an electrical thing?

[Devlin]

Mine is the same type as this one!

[Curlypaul]

Awesome! So seems there is a gap I the wiki here

[robcfg]

I wouldn't call it exactly a gap since the board is the same that we have.

It is interesting to know that early ones had more socketed chips and no white mesh.

Thanks for the pictures!