Atari 65XE -> 320kb Upgrade / Confused???

[macsonny]

Hi All,

 

So I have an Atari 65XE with the same motherboard as pictured. Apparently I can easily take the unit up to 320kb by adding in two 44256 chips. But the existing RAM is 18 pin and the 44256 is 20 pin. The instructions here (https://atari-owner.com/club/articles/atari-65xe-128k-upgrade.19/) suggest I just remove the existing sockets and add in 20 pin sockets, add in the RAM (assume top two slots) and I then have 320kb.

 

So a few questions:

 

1. How does a 20 pin socket go where the existing 18 pin sockets are? Just as a FYI - the capacitors hole at the end of the current memory IC's (18 pin) doesn't align in I was to remove the capacitors and put in a 20 pin IC socket.

 

2. Do I just put in two x 44256 chips assuming it's in the first two slots only per above photo?

 

FYI - I already have the upgraded CO25953 as the machine has been upgraded to 128kb previously by me..

 

Thanks in advance.

 

macsonny

Edited March 13, 2023 by macsonny
Fixed misinformation

[Peri Noid]

It's not enough only to replace RAM chips with bigger ones. You need an adapter board. You also need additional logic and wires.

[macsonny]

4 minutes ago, Peri Noid said:

It's not enough only to replace RAM chips with bigger ones. You need an adapter board. You also need additional logic and wires.

I guessed as much. And links to what I need to do?

[TGB1718]

59 minutes ago, macsonny said:

The instructions here (https://atari-owner.com/club/articles/atari-65xe-128k-upgrade.19/)

Those instructions are as clear as mud 🙃

and as @Peri Noid says, it's not as simple as those instruction appear to be, apart from the power pins, you need some bank switching too

 

Can imagine the pain if someone actually tried to do that upgrade.

[macsonny]

6 minutes ago, TGB1718 said:

Those instructions are as clear as mud 🙃

and as @Peri Noid says, it's not as simple as those instruction appear to be, apart from the power pins, you need some bank switching too

 

Can imagine the pain if someone actually tried to do that upgrade.

I remember seeing a site some time back where someone had worked it out by adding in a few chips and a few jumper wires. For the life of me I can't find the site now 😞

[Peri Noid]

4 minutes ago, macsonny said:

I guessed as much. And links to what I need to do?

I don't have them. There are schematics of an upgrade for a 16-chip motherboard (for instance the one below), which can be used to implement it (the lower "CAS part" is not needed). But pinctures and descriptions - you'd need to make them yourself.

[Rybags]

Such an upgrade needs an EMMU or equivalent.

In the modern day you'd probably be better off just getting something like an Ultimate 1 Meg or an expansion that plugs into the ECI port.

Legacy type upgrades with daughterboards and bunches of wires, or piggybacked chips and the like tend to be unreliable plug you're often heavily modifying your system.

Edited March 13, 2023 by Rybags

[macsonny]

38 minutes ago, Rybags said:

Such an upgrade needs an EMMU or equivalent.

In the modern day you'd probably be better off just getting something like an Ultimate 1 Meg or an expansion that plugs into the ECI port.

Legacy type upgrades with daughterboards and bunches of wires, or piggybacked chips and the like tend to be unreliable plug you're often heavily modifying your system.

Sigh - was really interested in this upgrade too 😞

[Peri Noid]

Based on schematics above, I made something like this. This small board that you can see, is this additional logic for bank switching. The same logic can be used to drive a similar expansion for a board with 4-bit RAM chips. The only difference is in the RAM chips - since 44256 cannot seamlessly replace 4464 chips, a bit of additional work around them would be necessary.

[macsonny]

4 minutes ago, Peri Noid said:

Based on schematics above, I made something like this. This small board that you can see, is this additional logic for bank switching. The same logic can be used to drive a similar expansion for a board with 4-bit RAM chips. The only difference is in the RAM chips - since 44256 cannot seamlessly replace 4464 chips, a bit of additional work around them would be necessary.

Nice. Can you show specifics of what you did?

[+kheller2]

This instructions at that link are pretty sparse.  Those instructions however are to go to 128K which you said you already did.  The 20 pin socket is not for the RAM and he is incorrect in stating you can just drop in 44256 chips and magically have a 320. 

[MVladimir]

For 320K expansion, but if you have MoBo with 16 memory chip placement,  you can use solution by TFHH from this post: https://exxosforum.co.uk/forum/viewtopic.php?p=707&sid=9aaa4cf3bb1d61054380eaba5cf8011f#p707

Read more detailed attachment of this post - article contain more detailed description of 320K update.

Edited March 13, 2023 by MVladimir

[Beeblebrox]

the 320k mod for XE boards with the 16 x pcb placements here is a nice and easy one, although I appreciate this doesn't apply to the OP's specific XE board. (I believe this is one of TF_hh's methods for upgrading to 320k):

 

 

Edited March 13, 2023 by Beeblebrox

[macsonny]

4 hours ago, Beeblebrox said:

the 320k mod for XE boards with the 16 x pcb placements here is a nice and easy one, although I appreciate this doesn't apply to the OP's specific XE board. (I believe this is one of TF_hh's methods for upgrading to 320k):

 

 

There seems to be lots of information on boards with 16 RAM slots but my version of the board has the 4 RAM slots per my original photo so not sure how the 16 slot upgrade translate to a 4 slot board?

[Beeblebrox]

Yeah, I know. was just posting it generally should others with the more common kind of XE board benefit.

 

I'd just go for the U1MB. Gives you way more that just the 1mb ram. You just need to socket the MMU and O/S chips and hook up the 4 x wired signals and you are sorted. 

 

Or get a syscheck II plug in unit which goes into the eci/cart slot. (it has a pass thru BTW). Aside giving you 512k of plug in ram, it also has all those lovely diagnostic modes and optional O/S. 

 

Either method is approx the same cost. 

[ClausB]

6 hours ago, Beeblebrox said:

U1MB. Gives you way more that just the 1mb ram.

Yes, one megabyte is way, way more than one millibit!

[macsonny]

On 3/15/2023 at 12:28 AM, ClausB said:

Yes, one megabyte is way, way more than one millibit!

Ended up buying the 512 kb external upgrade with the pass-through from TF_hh. Bought a heap of stuff from him recently. Wonder if I get loyalty points at some point?

[Beeblebrox]

@macsonny  so you went for the Syscheck II then?

 

The BBU version?

 

[macsonny]

1 hour ago, Beeblebrox said:

@macsonny  so you went for the Syscheck II then?

 

The BBU version?

 

Yes - but I didn't bother with the battery backup version.

[Beeblebrox]

2 minutes ago, macsonny said:

Yes - but I didn't bother with the battery backup version.

Nice. There is a simple free public domain 3D case for it btw, (Not Mr Robort's design)

 

https://www.thingiverse.com/thing:4818469

 

...as well as of course Mr Robort's purchasable one from ABBUC shop which is nicer to look at, (no offence to the creator of the above ):

 

[+slx]

17 hours ago, Beeblebrox said:

...as well as of course Mr Robort's purchasable one from ABBUC shop which is nicer to look at, (no offence to the creator of the above 😞

 

Didn‘t Mr. Robot put his designs into the public domain recently?

[Beeblebrox]

2 minutes ago, slx said:

Didn‘t Mr. Robot put his designs into the public domain recently?

yeah, that was the case with the exception of the Syscheck II case for which the rights/licence was sold to ABBUC and you have to pay for via their shop - AFAIK.

 

For the free Mr Robot deisngs for other A8 hardware, see here: https://www.printables.com/social/439944-mr-robot/models

 

There are quite a few excellent designs still available for free.

[+slx]

8 minutes ago, Beeblebrox said:

yeah, that was the case with the exception of the Syscheck II case for which the rights/licence was sold to ABBUC and you have to pay for via their shop - AFAIK.

Found it. It‘s 15€ from the members‘ store but probably too expensive to ship to the US. 

[Beeblebrox]

16 minutes ago, slx said:

Found it. It‘s 15€ from the members‘ store but probably too expensive to ship to the US. 

Yeah, there is that.

 

When Mr Robot was selling from his US based online shop I paid for one including shipping to the UK. Since (regreattably) sold the Syscheck II and the case.

 

[manterola]

I think syscheck was a great decision. You not only get extended ram, but also the external OS selection. Basically, you can choose to use one of the OS versions included. I really like the HS (high speed?) SIO Hias version, or QMeg when need to boot from D2: without dealing with the drive select switches.

And another feature that gets daily use is the right angle cartridge extension, so inserting cartridges is much easier in the 65XE (aka 800XE) and 130XE computers.

Edited March 17, 2023 by manterola