TT030 CA400310

TT motherboards.
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winner61
Posts: 14
Joined: Thu May 24, 2018 12:34 pm

TT030 CA400310

Post by winner61 » Thu Jun 07, 2018 10:55 am

With and without the goodies. VME CrazyDots and ST RAM board. Also with Daughter board. Whats the difference by the way, with and without. Anyone?
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Atarian Computing
Posts: 154
Joined: Tue Aug 22, 2017 4:27 am

Re: TT030 CA400310

Post by Atarian Computing » Thu Jun 07, 2018 1:53 pm

You mean difference with and without daughterboard?

There are several revisions of the TT board but you can break them into three distinct groups.

1. Daughterboard model. This is the earliest revision and the one you have here
2. PGA model. This is pretty much the same layout as the daughterboard model but without the daughterboard. CPU and FPU are PGA.
3. "SMD" model. TOS located next to Fast-RAM connector and CPU and FPU are SMT

Those are not official names. I'm at work so can't really go into more details. I'll update later.

Atarian Computing
Posts: 154
Joined: Tue Aug 22, 2017 4:27 am

Re: TT030 CA400310

Post by Atarian Computing » Mon Jun 11, 2018 8:19 pm

I can't edit my previous post so here's a little addendum.

The very first model is the one in your pictures but without the daughterboard. Same motherboard but at 16Mhz. That and yours is CA400310, also known as REV.A

There don't seem to ever have been REV.B units in the wild. It's straight to REV.C which is the PGA model. The FPU was never PGA as I mistakenly wrote on the previous post. Atari's schematics and rework procedures do speak of B.1 but it is identical in every respect to what we know as CA400770 or REV.C

From REV.D onwards the design didn't change much. REV.D didn't have any of the rework done so it's relatively easy to spot. You can tell a very late TT revision by looking at the RTC circuit at the back near the battery. If there is no U402 and no holes on the PCB for it (just a blank spot) that is a later revision "SMT" model with the RTC patch already applied. This model went from revision D to K. Revision H doesn't seem to have the VME bus fix rework but J and K apparently do. Which also makes sense for them to have the latest patches already applied on the PCB and issue rework procedures for earlier ones. These later models are usually CA401146.

As for what's the best model? There is no downside for having an early model. Many actually prefer them because they can be easier to work with. My favorite is the REV.C by far.

winner61
Posts: 14
Joined: Thu May 24, 2018 12:34 pm

Re: TT030 CA400310

Post by winner61 » Mon Jun 11, 2018 10:21 pm

Thanks. Always nice to have some background info on this :D

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