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1450 XLD motherboard build, assorted questions

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That would be:

U25 FREDDIE RAM CONTROL C061922/C061991

 

I got my (C061991) from Brad...

 

The latest BOM is in this post:

http://atariage.com/forums/topic/186380-1450-xld-motherboard-build-assorted-questions/page-15?do=findComment&comment=2397285

 

And swap out R141 with a 1K...

Edited by AtariGeezer

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That would be:

U25 FREDDIE RAM CONTROL C061922/C061991

 

I got my (C061991) from Brad...

 

The latest BOM is in this post:

http://atariage.com/forums/topic/186380-1450-xld-motherboard-build-assorted-questions/page-15?do=findComment&comment=2397285

 

And swap out R141 with a 1K...

 

I was wondering about the Freddie chip, if that replaced the original MMU, but Best shows the XL MMU as being for the XL/XE (CO61618(XL / XE Memory Management)). I have used the CO61618 MMU any times in the 1200XL while doing the XLOS and Basic mod.

 

I do have the latest BOM and even made the edit to use the 1K @ R141. Given enough devoted time, I will be #3!!! (unless someone else has finished theirs!!!)

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I was wondering about the Freddie chip, if that replaced the original MMU, but Best shows the XL MMU as being for the XL/XE (CO61618(XL / XE Memory Management)). I have used the CO61618 MMU any times in the 1200XL while doing the XLOS and Basic mod.

 

I do have the latest BOM and even made the edit to use the 1K @ R141. Given enough devoted time, I will be #3!!! (unless someone else has finished theirs!!!)

Okay my mistake, I see what you mean, the MMU in the 1400/1450 is

U12 PALA1201 (PAL16L8) C061919

Don't know what the differences are in the code between the CO61618 and C061919...

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It looks like the MMU differences between the 1200XL and the 800XL/600XL was addressing the OS roms. The 1200XL had two and the 800XL had one. So when doing the OS and Basic mod for the 1200XL, you have to switch the MMU so that it will access the OS ROM properly.

 

This is from Bob's original instructions:

Take a look inside your 1200XL. See the chip that has 20 pins (U14)? That is your MMU. It is the main difference between a 1200XL and an 800XL. Same number of little pins, same number of inputs and outputs ..... But the 800XL IC has the 16K select for the OS ROM. So, lets jump right in and swap the MMU with the 800XL part (CO61618). Fits just fine, doesn't it? Pull out all the jumpers except W11, W12 and W9 and you have a ROM select line that will select the address range from $C000 to $FFFF in a single ROM, like the 800XL.

 

 

Atari probably needed special code for the 1400/1450XL MMU so they went with something different.

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C93 200PF 25v SAME TINY INSTALLED DigiKey 490-3636-ND

C98 200PF 25v SAME TINY, ERRONEOUSLY MARKED AS 200UF ON POLISH INSTALLED DigiKey 490-3636-ND

 

Looks like I'm going to have to purchase a bag of 100 from eBay as DigiKey and Mouser do not stock these anymore!!! Crap

 

Would either of these work??

 

Silver Mica Cap 200pF 100V 5% CDE CD5FA201JO3 NEW Qty:10

 

100pcs Ceramic Capacitor C-Cap 50V 200pF 201pF FREESHIP

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DigiKey does not get a hit on that part number. This is odd because they usually list parts even if they do not stock them - check the part #?

 

You need to know the lead spacing and the type (ceramic, mica, electrolytic, etc.).

 

For practical purposes that 200pf value is a 5% tolerance. A 10% (180 or 220) will probably work just fine. Or, if the caps are in filter/tuning circuits, you could get 2% or 1% parts, instead.

 

Bob

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DigiKey does not get a hit on that part number. This is odd because they usually list parts even if they do not stock them - check the part #?

 

You need to know the lead spacing and the type (ceramic, mica, electrolytic, etc.).

 

For practical purposes that 200pf value is a 5% tolerance. A 10% (180 or 220) will probably work just fine. Or, if the caps are in filter/tuning circuits, you could get 2% or 1% parts, instead.

 

Bob

 

This looks like the closest I can find. It is 100V as opposed to 25V so it should work fine (I hope).

 

Mouser Part #: 80-C410C201J1G Multilayer Ceramic Capacitors MLCC - Leaded 100volts 200pF 5%

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That is an axial lead component. What is the lead spacing on the m/b? (just measure from the center of the mounting holes)

 

At $1.24, it should turn the Atari into a 1450XLD...

 

Bob

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Well, just sent my part orders to DigiKey and Mouser. Since I'm not using a donor, I ordered as many of the components as I could new. I have just a handful of parts that I will source from a 600XL. The rest I will get from Best.

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C93 200PF 25v SAME TINY INSTALLED DigiKey 490-3636-ND

C98 200PF 25v SAME TINY, ERRONEOUSLY MARKED AS 200UF ON POLISH INSTALLED DigiKey 490-3636-ND

 

Looks like I'm going to have to purchase a bag of 100 from eBay as DigiKey and Mouser do not stock these anymore!!! Crap

 

Would either of these work??

 

Silver Mica Cap 200pF 100V 5% CDE CD5FA201JO3 NEW Qty:10

 

100pcs Ceramic Capacitor C-Cap 50V 200pF 201pF FREESHIP

 

The cached page shows:

Manufacturer Part Number RPE5C2A201J2P1Z03B

DescriptionCAP CER 200PF 100V 5% RADIAL

 

Mouser has them:

http://www.mouser.com/ProductDetail/Murata/RPE5C2A201J2P1Z03B/?qs=%2Fha2pyFadugEVyMCQOk%2F0eqvUp7plFwam503V%2FqSEMNEgxsFJdjo%2FCzWo7STu9US

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I saw that one but they are out of stock. I when with this one, which is an axial and what is called out on the original Atari BOM.

 

http://www.mouser.com/Search/ProductDetail.aspx?R=C410C201J1G5TAvirtualkey64600000virtualkey80-C410C201J1G

 

Okay, you're going to have to stand them up and bend one end over as there isn't space to lay it down flat, but that should be ok...

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Thank you, I actually gave that same talk twice with slight differences. Both are on youtube, but the video on the first one is so quiet that it's hard to hear what's going on. I did incorporate your R141 fix and the resistor now runs cool.

 

Best,

v

 

I never thought my kitchen door carpet would become famous as the background on a 1450XL board in this video. :)

Contrary to the video, its not a flat bed scan of the board, although I do have one of those as well but I couldn't get the entire board to fit. So, I did a nice day shot using a Canon G7 on the kitchen door floor.

 

I'm glad to see the 1450XL put together and complete. Do we have an official BOM yet using all known materials and working boards?

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@kheller2, if I ever give the talk again, I'll be sure to give the proper credit to your Canon G7 :) The BOM that I posted originally is correct and complete (to Atari's version), and will yield a working board. Since then, I have incorporated AtariGeezer's resistor swap which makes it run cooler and I came up with a video tweak which corrects the typical Atari video errors and gives a nicer output. I thought that I had posted it previously, but in-case I didn't here it is.

 

 

Grrrrr...... something changed on AtariAge, getting an error that says "Error You aren't permitted to upload this kind of file" Uploading as PDF instead.

 

cheers,

c

Atari 1450 Mobo BOM.pdf

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I have attached the working BOM. It accounts for the change at R141 which used to be listed as 100ohm. It is now listed as 1K and the link for the part has been changed to point to the DigiKey part.

 

Atari 1450 Mobo BOM New.zip

 

 

 

Opps.........Vandel beat me to it. My attachment will not have any video tweaks!!!

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BTW, the newest version of this file includes all the information to build it several different ways. With/without the supervideo mod, with/without Atarigeezer's resistor mod, etc. Nothing has been removed relative to the older versions of the file, additional information has been added. IE: if you have the latest ver, you don't need the old one for any reason, everything from the older ver. is still in there and more.

 

Also, if anyone has a board that they don't think that they'll ever build, please contact me. While figuring out this project I bought all the parts necessary to make two (except for the mobo). If I get the chance to build another, I will do a detailed photo-essay on the actual build process.

 

cheers,

c

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Well, got all my parts so ready to dig in. Still have to pull a handful of things from a 600XL and 1200XL board, but 98% of the parts are new from DigiKey, Mouser and Best. I got the modem, speech, SY6551 and GAL16V8 chips from eBay. I wrote the JED file for U11 (Pal-C) to a GAL and got the other two PALs from Best. I had some 2732 EPROMs so I erased one and wrote that one also. Getting excited!!!

 

post-6701-138120330976_thumb.jpg

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Well, got all my parts so ready to dig in. Still have to pull a handful of things from a 600XL and 1200XL board, but 98% of the parts are new from DigiKey, Mouser and Best. I got the modem, speech, SY6551 and GAL16V8 chips from eBay. I wrote the JED file for U11 (Pal-C) to a GAL and got the other two PALs from Best. I had some 2732 EPROMs so I erased one and wrote that one also. Getting excited!!!

 

attachicon.gifImageUploadedByTapatalk1381203308.177710.jpg

I beieve Atari ROMS under 16K tend to be 25XX compatible not 27XX, while 16K and largers ROMS are 27XX compatible. The 1050 has 4 jumpers which allow selecting between 2532/2732.

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I beieve Atari ROMS under 16K tend to be 25XX compatible not 27XX, while 16K and largers ROMS are 27XX compatible. The 1050 has 4 jumpers which allow selecting between 2532/2732.

 

Eventhough U6 only uses 4k, a 2732 is called out in both schematics (Atari and Jerzy's). It's what I used and works ;)

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I beieve Atari ROMS under 16K tend to be 25XX compatible not 27XX, while 16K and largers ROMS are 27XX compatible. The 1050 has 4 jumpers which allow selecting between 2532/2732.

In the 1450XL, there was one 2732 that was programmed with handler code (U6)( 4K*8 ) and isn't a normal masked rom. The parts list calls out a 27128 and a 2764 chip but these are the OS and Basic roms, which I have the Atari parts for.

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Well, got all my parts so ready to dig in. Still have to pull a handful of things from a 600XL and 1200XL board, but 98% of the parts are new from DigiKey, Mouser and Best. I got the modem, speech, SY6551 and GAL16V8 chips from eBay. I wrote the JED file for U11 (Pal-C) to a GAL and got the other two PALs from Best. I had some 2732 EPROMs so I erased one and wrote that one also. Getting excited!!!

 

attachicon.gifImageUploadedByTapatalk1381203308.177710.jpg

 

To bring a new life into the world is always exciting :)

 

Don't forget those hi-rez pics ;)

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To bring a new life into the world is always exciting :)

 

Don't forget those hi-rez pics ;)

Will do. I will also be snapping pics throughout the build.

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Here are a couple of photos of the front and back of the 1450XL board. The attached ZIP file has the full res shots. When I uploaded to the gallery, it reduced the resolution, although you can still see the details if you view the large version. Hopefully this will help when trying to diagnose a board with the parts in place.

 

1450XL Board Front Detail

1450XL Board Back Detail

 

1450XL Board Hi Res.zip

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