Atari 1200XL w/possible problems

[JokerCPoC]

I have an Atari 1200XL w/possible problems, Lets see I have two power supplies one for My Indus GT(5200 game console compatible, C018187) and one 1200XL compatible Atari 50w psu brick(C017945), The C018187 powers up the 1200XL, Just not the C017945, But I get no sound or very little(scratchy? cause of the s-video cable? I have an RF cable But No RF to 75ohm converter for the moment, I'll have to find the one I have or buy another one), Also the Joysticks when the MsPacman cartridge is running don't seem to do anything, One is a CX40 and the other is a Wico Joystick that has been rebuilt, I do get color output off the 5 pin din to y/c or s-video cable on the black rca connector part of the cable, The red rca seems to give out noise only of course and the other two don't see anything, I'd tested the cable with a multimeter and all 5 seem to match the pinout. I also need to find that 13 pin SIO cable I'd kept, Oh and at least the Indus GT drive works perfectly too.

Edited January 15, 2008 by JokerCPoC

[Urchlay]

No sound, joysticks don't work... could be a bad POKEY. If you have another working XL machine, you could swap them (some desoldering may be required). The POKEY IC should be labelled "CO12294".

 

Another symptom of a bad POKEY would be that the keyboard doesn't work... have you tested this?

[JokerCPoC]

No sound, joysticks don't work... could be a bad POKEY. If you have another working XL machine, you could swap them (some desoldering may be required). The POKEY IC should be labelled "CO12294".

 

Another symptom of a bad POKEY would be that the keyboard doesn't work... have you tested this?

So far I only have Cartridge software(3), No Dos on any disk, I don't even have any 5.25" SSDD disks yet, So typing is out, Is the Reset Key part of the Keyboard? If Yes then the Keyboard works I think as the Reset button does work.(I've only seen a 1200XL keyboard once before when I had that 1450XL motherboard that I used to have, I should never have sold that, That computer was part 800XL and 1200XL at the same time).

 

As to desoldering I'd have to open her up and see sometime on Tuesday or Wednesday If Pokey is soldered down or not(Some Pokeys were and some weren't I think), Still got the dregs of that cold virus thats been going around(It makes things hard to do. In any case I have only the 1200XL and no other Atari 8 bit computers of any type, Oh and the 1200XL doesn't work when I use the 1200XL 50w 9vac psu brick(C017945), The 1200XL only seems to work with a 11.5vdc psu brick that is normally only for the 5200 or for the Indus GT(C018187), Good news is I found the NOS 13 pin SIO cable I was saving that I bought for some other reason and the Indus GT looks like It's not dead as It responds to power like I remember. Best Electronics seems to think the motherboard may be easier to replace, Of course I'd try the Pokey chip and on Tuesday I've got to test that 1200XL 9v AC psu brick with a multimeter to make sure It's not dead. I think the reason why Best Recommended the motherboard is cause the 1200XL motherboard (Uses a Bridge Rectifier to make) the 9vac into 5vdc and the fact that the 11.5vdc psu is powering the motherboard seems to indicate to Best that the Rectifier might be shot somehow, So I've got a parts board already I think, So $40 plus shipping may be easier maybe, Unless one knows the size and type of Bridge Rectifier and Who sells It still(Good Luck, We're talkin antique hardware here alrighty). Later.

[mimo]

I am surprised that the 1200 works at all with a DC power supply.

The 1200 XL needs an AC supply, that may be your problem

All of the 1200XLs ICs are socketed

Bridge rectifiers are a common part they look like this (but with 3 legs) bolted onto the heat sink

[yorgle]

You don't need a disk to test the keyboard. Power up without a cartridge inserted and once the Atari logo appears, press the help key. Then you can select the keyboard test to try out the keyboard. Almost certain you'll need to pull the keyboard apart to clean the contacts- they're nearly always corroded to the point where most or all of the keys won't work.\

[Urchlay]

So far I only have Cartridge software(3), No Dos on any disk, I don't even have any 5.25" SSDD disks yet, So typing is out, Is the Reset Key part of the Keyboard?

 

Reset is part of the keyboard, yes. Even without any software, you can boot a 1200XL with no cartridge or floppy, and you'll see a "rainbow" Atari logo... press the Help key to get into the built-in self-test, use Option/Select to choose the keyboard test, and press Start. Then you'll get a picture of the keyboard on the screen, and whatever keys you press will light up.

 

If you have large groups of keys that don't work, it doesn't necessarily mean the POKEY is bad. The keyboard PCB is made of carbon traces that degrade with age. My 1200XL keyboard died just from sitting in (un-airconditioned) storage for 7 years, but its POKEY and other chips were fine.

 

About the voltage regulator, AC vs. DC thing... if I were you, I'd fix that first, before considering chip swapping. It's possible that the POKEY is fine, but is getting the wrong voltage... or that it was damaged by getting the wrong voltage, in which case you don't want to put a good chip in there only to have it get fried, too.

[JokerCPoC]

I am surprised that the 1200 works at all with a DC power supply.

The 1200 XL needs an AC supply, that may be your problem

All of the 1200XLs ICs are socketed

Bridge rectifiers are a common part they look like this (but with 3 legs) bolted onto the heat sink

Oh well You're all going to love this, The 1200XL has 3 rectifiers It looks like, 2 3 leg types and 1 huge 4 leg type as seen below. Oh and Pokey is the big IC on the bottom left and It is socketed. Just getting all 10 screws and all 11 of the parts that hold both sets of the rf shields was a bit tedious, The screws were of course easy, The 11 parts(pop rivets?) needed to be squeezed a bit w/needle nose pliers and then use a knife blade on the back to remove each one, 1st pliers and then knife multiplied 11 times, They really wanted the shielding to stay. The 10 screws are all the same size and considering the case is plastic, well metal screws can strip or break plastic If one uses the wrong type or size. There are a few more screws, But they are around the keyboard and I don't need go into that area. The two rectifiers that I know about are Texas Instruments A8214 7805C, DigiKey and Mouser don't carry It at all, I wonder, Forget It there's a plastic rivet holding the heatsink on to the motherboard I'd have to drill out and the last two small screws that need to be removed, 1 I removed and the other is behind that HUGE capacitor and is not removable as a result of the cap being in the way. I did get the long screw and nut out for the large rectifier out, Lot of good that did. So a complete 1200XL motherboard seems to be needed.

 

Edited January 15, 2008 by JokerCPoC

[mimo]

Probably the easiest option, that and getting a correct PSU should see you good for the next 25 years or so(if the Keyboard isn't dead!)

Now you have got all that nasty rf shielding off, think of all the mods you can do

[+bob1200xl]

The three-legged things are regulators, not rectifiers. The rectifier is the big, square four-legged thing. The power supply rectfies the AC into 12 volts DC and then regulates it down to 5 volts for the computer. This is why you can use a 12 volt DC supply - it is just passed into the regulators unchanged. (DO NOT try an AC supply on a DC load, guys!)

 

The AC supply is probably dead. They have fuses in them that you can change - except you have to cut/crack the case open.

 

Bob

 

 

 

I am surprised that the 1200 works at all with a DC power supply.

The 1200 XL needs an AC supply, that may be your problem

All of the 1200XLs ICs are socketed

Bridge rectifiers are a common part they look like this (but with 3 legs) bolted onto the heat sink

Oh well You're all going to love this, The 1200XL has 3 rectifiers It looks like, 2 3 leg types and 1 huge 4 leg type as seen below. Oh and Pokey is the big IC on the bottom left and It is socketed. Just getting all 10 screws and all 11 of the parts that hold both sets of the rf shields was a bit tedious, The screws were of course easy, The 11 parts(pop rivets?) needed to be squeezed a bit w/needle nose pliers and then use a knife blade on the back to remove each one, 1st pliers and then knife multiplied 11 times, They really wanted the shielding to stay. The 10 screws are all the same size and considering the case is plastic, well metal screws can strip or break plastic If one uses the wrong type or size. There are a few more screws, But they are around the keyboard and I don't need go into that area. The two rectifiers that I know about are Texas Instruments A8214 7805C, DigiKey and Mouser don't carry It at all, I wonder, Forget It there's a plastic rivet holding the heatsink on to the motherboard I'd have to drill out and the last two small screws that need to be removed, 1 I removed and the other is behind that HUGE capacitor and is not removable as a result of the cap being in the way. I did get the long screw and nut out for the large rectifier out, Lot of good that did. So a complete 1200XL motherboard seems to be needed.

 

[JokerCPoC]

Probably the easiest option, that and getting a correct PSU should see you good for the next 25 years or so(if the Keyboard isn't dead!)

Now you have got all that nasty rf shielding off, think of all the mods you can do

My next step should be a new digital multimeter and for as little as possible and test that CO17945 psu that I have, If It's bad then get a new fuse or psu If I can't figure out how to open this one up.

[Defender II]

Did you get a working PSU? Is the 1200XL working yet?

[JokerCPoC]

Did you get a working PSU? Is the 1200XL working yet?

So far no, I've been a bit side tracked, I'm looking at July for some work on It, As I need someone that can do the work I need on It, It would only be the the mods in My sig right then, As My extra cash per month is limited.

[BillC]

I am surprised that the 1200 works at all with a DC power supply.

The 1200 XL needs an AC supply, that may be your problem

All of the 1200XLs ICs are socketed

Bridge rectifiers are a common part they look like this (but with 3 legs) bolted onto the heat sink

This is similar to the bridge rectifier used in the 1200XL, it sits under the heatsink at the back.

I see I was a little late, I hadn't read to the end of the thread when I replied.

Edited March 27, 2011 by BillC

[BillC]

I am surprised that the 1200 works at all with a DC power supply.

The 1200 XL needs an AC supply, that may be your problem

All of the 1200XLs ICs are socketed

Bridge rectifiers are a common part they look like this (but with 3 legs) bolted onto the heat sink

Oh well You're all going to love this, The 1200XL has 3 rectifiers It looks like, 2 3 leg types and 1 huge 4 leg type as seen below. Oh and Pokey is the big IC on the bottom left and It is socketed. Just getting all 10 screws and all 11 of the parts that hold both sets of the rf shields was a bit tedious, The screws were of course easy, The 11 parts(pop rivets?) needed to be squeezed a bit w/needle nose pliers and then use a knife blade on the back to remove each one, 1st pliers and then knife multiplied 11 times, They really wanted the shielding to stay. The 10 screws are all the same size and considering the case is plastic, well metal screws can strip or break plastic If one uses the wrong type or size. There are a few more screws, But they are around the keyboard and I don't need go into that area. The two rectifiers that I know about are Texas Instruments A8214 7805C, DigiKey and Mouser don't carry It at all, I wonder, Forget It there's a plastic rivet holding the heatsink on to the motherboard I'd have to drill out and the last two small screws that need to be removed, 1 I removed and the other is behind that HUGE capacitor and is not removable as a result of the cap being in the way. I did get the long screw and nut out for the large rectifier out, Lot of good that did. So a complete 1200XL motherboard seems to be needed.

 

I know there have been other replies to this, I just thought I would explain the markings on the 7805 voltage regulators, which you believed were rectifiers, this may help with understanding the markings of other chips.

 

7805C is the part #, this is a common 7805 +5V/1A voltage regulator. I'm sure Digikey and Mouser have it but you were searching with the wrong #.

A8214 contains the date code, this part was manufactured during the 14th week of 1982, I don't know what the A stands for.

A lot of chips are marked with a date code in this manner.

[JokerCPoC]

Did you get a working PSU? Is the 1200XL working yet?

So far no, I've been a bit side tracked, I'm looking at July for some work on It, As I need someone that can do the work I need on It, It would only be the the mods in My sig right then, As My extra cash per month is limited.

I should clarify the last post I made, a working psu: Yes, 1200XL working yet: No

As I think It does work, but since It's taken a part and in separate boxes, It will have to wait some more.

 

I know Best Electronics sells parts as does B&C, But does either one do actual 1200xl mods? As I'm not too handy with a soldering iron for the 2 mods in My sig, Besides seeing some things is hard to do, As My eyes aren't all that sharp.

[BillC]

Did you get a working PSU? Is the 1200XL working yet?

So far no, I've been a bit side tracked, I'm looking at July for some work on It, As I need someone that can do the work I need on It, It would only be the the mods in My sig right then, As My extra cash per month is limited.

I should clarify the last post I made, a working psu: Yes, 1200XL working yet: No

As I think It does work, but since It's taken a part and in separate boxes, It will have to wait some more.

 

I know Best Electronics sells parts as does B&C, But does either one do actual 1200xl mods? As I'm not too handy with a soldering iron for the 2 mods in My sig, Besides seeing some things is hard to do, As My eyes aren't all that sharp.

I don't believe either of them do any mods, Bob1200XL does but he is fairly busy these days with fixing/upgrading the excess inventory he is giving away.

 

You might try Ken Jones/MetalGuy66/(Houston, Texas), who does ATARI XL/XE hardware repair and who reverse engineered the ICD MIO, then produced updated versions for sale.

 

An alternative would be kjmann(southern Oregon), he sells power supplies/video upgrades for Ataris, and he recently picked up some 1200XLs he has been fixing/upgrading and selling.

Edited March 28, 2011 by BillC

[sloopy]

Metalguy is in Texas not San Francisco...

 

also you may want to also check into sloopy, he does repairs, and mod's. and also accepts A8 hardware trades as payment...

 

;')

sloopy.

[BillC]

Metalguy is in Texas not San Francisco...

 

also you may want to also check into sloopy, he does repairs, and mod's. and also accepts A8 hardware trades as payment...

 

;')

sloopy.

Location fixed, my mistake, I got mixed up. I checked his website but he doesn`t give any information there, I should have noticed on his profile here though since I linked to it.