Jump to content
Have You Played Atari Today?
2600|5200|7800|Lynx|Jaguar|Forums|Store
  • entries
    23
  • comments
    26
  • views
    46,529

The Poor Man's 1400XL (or Adding a rear-mounted PBI to a 1200XL and making it run off a 5v PSU)

flashjazzcat

Entry posted by flashjazzcat

2,096 views

 Share

In light of all the excitement surrounding the recent 1400XL and 1450XLD developments and the speculative $1000 price tag for repro models, I decided my 1200XL offered me a better stab at a bit of Atari luxury. It had lain in the cupboard for most of the time since I received it (as a very generous donation from a Canadian forum member) a year or so back, and the crappy video output, the fact that my 1084S won't sync to the NTSC luma, and the lack of a PBI made the machine seem more of a decorative piece than day-to-day machine.

 

However, those pictures of the 1400XL with the rear-mounted PBI fired my imagination. A parallel interface opens up all kind of possibilities and makes the 1200XL a genuinely useful machine for my needs. In addition, Ultimate 1MB is on its way, and I have a VBXE board which still hasn't found a permanent home (well - it has, but it's gonna move house anyway). The last piece of the puzzle was realizing the huge heatsink at the back of the 1200XL's case was there to cool the bridge rectifier, and if I removed that and fitted a direct 5v supply, the heatsink could also go, opening up a perfect spot for the 50 way female centronics connector which would form the PBI.

 

So, everything having aligned perfectly, it was time to start the job. I used the hottest iron I could find to remove the rectifier, regulators, the huge capacitor (C39), and the old power connector (bascially everything between the power switch and the 5v outputs of the two regulators).

 

blogentry-21964-0-07631300-1315565023_thumb.jpg

 

Above, we see the cleared rectifier bridge area. The larger components were hard to remove, but patience is the name of the game.

 

blogentry-21964-0-21801900-1315565019_thumb.jpg

 

The RF modulator has also been removed to make way for a 13-pin DIN connector for the VBXE's RGB output, and the old power connector will be replaced by a "traditional" 7-pin DIN arrangement. I cleaned up the desoldering with acetone when I was done.

 

blogentry-21964-0-57891200-1315565015_thumb.jpg

 

Here's the board, looking rather sparse it must be said. I now have a non-working 1200XL, so this isn't the time to falter. In the next instalment, I'll be drilling holes for the new power connector, soldering it in, and wiring it up to the power switch.

 Share

4 Comments

Recommended Comments

Gunstar

Hello Flashjazzcat!

 

As you know from the main 8-bit forum, I'm repairing and upgrading a couple 1200's right now, so I've gotten excited about upgrades again since I have to take them apart for repairs anyway.

So, discussions with you have led me to your blog, just getting started here, but right off the bat I see something that piqued my curiosity. You say that you were having problems getting your 1084S to sync to the luma. I also use that same monitor, 1084S 50/60HZ (they all are aren't they), and I've never had any luma sync problems. (on a fully working 1200XL that is)

Can you explain further?

Link to comment
flashjazzcat

Hello Flashjazzcat! As you know from the main 8-bit forum, I'm repairing and upgrading a couple 1200's right now, so I've gotten excited about upgrades again since I have to take them apart for repairs anyway. So, discussions with you have led me to your blog, just getting started here, but right off the bat I see something that piqued my curiosity. You say that you were having problems getting your 1084S to sync to the luma. I also use that same monitor, 1084S 50/60HZ (they all are aren't they), and I've never had any luma sync problems. (on a fully working 1200XL that is) Can you explain further?

Sorry for delay - comment reports don't seem to come through via email any more. Anyway - I may have explained myself badly - it was the chroma that the 1084S wouldn't sync to, not the luma. I get great mono images with the US GTIA and Antic chips installed, but no colour. Meanwhile, both my LCDs picked up the chroma just fine from the same machine. Of course, with PAL GTIA and Antic installed, nothing picks up the legacy chroma since I still haven't built a PAL oscillator circuit (VBXE's fine, though, since it always puts out the same colour clock).

 

Anyway - is colour also working fine on your setup? Specifically which sub-variant of 1084S are you using? (I have a 1084S-P and 1084S-D1).

Link to comment
Gunstar

Yeah, I never had a problem with my 1084S and my Atari's, of course I'm using NTSC machines or one NTSC with PAL Antic, but all work fine for chroma and luma. my 1084's sub-variant is 1084S-P

 

Are you aware that the 1200XL doesn;t have it's chroma attached? Without a video mod, you have to use composite for the chroma out. There's a simple mod for connecting the chroma line with the rest of the video-circuit as-is, if you don't want to do a full video upgrade like the Clearpic or SuperVideo upgrades. This is something I assumed you knew since you seem to be quite adept at upgrading, but I'm just making sure, especially now that I know it's a chroma problem and not luma. I'm guessing that hooking up to LCD is not through RCA chroma/luma inputs? If so, the LCD's are getting the composite signal for the chroma would be my guess...are you hooking up to the LCD's via composite or a S-video cable of some type (which might be using the composite for the chroma)?

Link to comment
rockdoc2010

I have recently completed the clearpic 2002 upgrade. I am using a monitor to composite or monitor to svid cable as a video output. I am looking at removing the modulator for more space as well as the ac/dc components as well. I do have two 2400 mA battery pacs that I am looking to incorperate into my mods. The reason that I wish to lose the heavy space consuming components is because I intend on mounting a 1020 printer into the right side of the 1200, all big stuff removed and delicate carving of the upper case to accomodate the smoke glass cover and paper roll. The question is "how can I justify the two power

supplys to power both the computer and the printer on a current consumption basis?"

Link to comment
Guest
Add a comment...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×

  • Recently Browsing   0 members

    • No registered users viewing this page.
AtariAge
Forums
Store
General
Follow AtariAge

Copyright ©1998-2023 AtariAge

×
×
  • Create New...