ATARI 65XE - No image or maybe dead?

[Jangle]

Hi! I own a Atari 65XE that doesn't show any image at all. It's from Argentina and it runs with PAL instead of NTSC.

It's my new project to revive this beauty and I don't know where to begin testing and what may be the problem so.. could anyone help me with this?

It seems that this console has been repaired long time along (I added pictures of that places) so if anyone notes anything rare , please let me know.

P.S : I don't know anything of this machines , so If anyone has some video or schematics explaining chips, etc I would be thankful

 

Here are some pics:

 

 

 

[Wilheim]

Hi!

 

You should start by installing sockets on the main ICs (the 40 pin ones) and also the drams. Those are the 8 ics on the left.

 

After that, I suggest to start by replacing the drams with new ones. The old ones are known for being buggy and they tend to malfunction.

 

By the way, IIRC, Argentina uses the PAL format, with NTSC color palette, that’s why it only has one clock.

[xrbrevin]

how are you connecting it to a screen?

it might be worth checking if any chips get hot when powered on. it could indicate what is at fault

[flashjazzcat]

Schematics here:

 

http://www.jsobola.atari8.info/dereatari/schematy.htm

 

[Jangle]

16 hours ago, xrbrevin said:

how are you connecting it to a screen?

it might be worth checking if any chips get hot when powered on. it could indicate what is at fault

I build a custom monitor cable using this schema (viewed from back of console)

 

I'll try the hot-chip test that you suggest..thx!

[Jangle]

20 hours ago, Wilheim said:

Hi!

 

You should start by installing sockets on the main ICs (the 40 pin ones) and also the drams. Those are the 8 ics on the left.

 

After that, I suggest to start by replacing the drams with new ones. The old ones are known for being buggy and they tend to malfunction.

 

By the way, IIRC, Argentina uses the PAL format, with NTSC color palette, that’s why it only has one clock.

Thanks for your reply!

This could sound dumb but there is a way to test those chips without replacing it? I mean with a oscilloscope or multi-meter or something?

Where I live is not easy to find these things.. Is there a trusted page where can I order those chips?

Yes, in Argentina we use PAL.. When you say clock , do you mean that crystal at the bottom?

 

I'm learning about this console and I managed to identify some chips (I don't know where is the EMMU)

This is a spec about what I found:

 

board CO70025 REV C
cpu CO14806-I2
antic CO21698-01
gtia CO14889-01
pia CO14795-I2
pokey CO12294B-01
freddie CO61921-31 (found in 130XE models)
os CO61598B
basic CO24947A-01
mmu CO61618-20

 

[Wilheim]

55 minutes ago, Jangle said:

Thanks for your reply!

This could sound dumb but there is a way to test those chips without replacing it? I mean with a oscilloscope or multi-meter or something?

Where I live is not easy to find these things.. Is there a trusted page where can I order those chips?

Yes, in Argentina we use PAL.. When you say clock , do you mean that crystal at the bottom?

 

I'm learning about this console and I managed to identify some chips (I don't know where is the EMMU)

This is a spec about what I found:

 

board CO70025 REV C
cpu CO14806-I2
antic CO21698-01
gtia CO14889-01
pia CO14795-I2
pokey CO12294B-01
freddie CO61921-31 (found in 130XE models)
os CO61598B
basic CO24947A-01
mmu CO61618-20

 

There’s no Emmu because it’s only used on the 130xe.

You can test the dram chips by using Syschek from tf_hh. Unfortunately, you will need an expansion port that lacks in your machine. The other alternative is by using a working Atari computer and replacing the drams one by one. On the other hand, I suppose there are other dram testers, but I don’t where they are. You can also buy drams from eBay or aliexpress. They are very cheap.

 

Yes, that crystal is the clock I’m mentioning. In PAL european models there are two crystal clocks to select the proper color pallete.

 

cheers!

 

[Jangle]

8 hours ago, Wilheim said:

There’s no Emmu because it’s only used on the 130xe.

You can test the dram chips by using Syschek from tf_hh. Unfortunately, you will need an expansion port that lacks in your machine. The other alternative is by using a working Atari computer and replacing the drams one by one. On the other hand, I suppose there are other dram testers, but I don’t where they are. You can also buy drams from eBay or aliexpress. They are very cheap.

 

Yes, that crystal is the clock I’m mentioning. In PAL european models there are two crystal clocks to select the proper color pallete.

 

cheers!

 

@tf_hh

On 2/16/2020 at 4:02 PM, xrbrevin said:

how are you connecting it to a screen?

it might be worth checking if any chips get hot when powered on. it could indicate what is at fault

 

I did the CI's HOT-TEST and the only one getting warm (not to hot) is the CPU but I think that is normal? the other chips seems fine (drams , GTIA , etc)

If the CPU is bad.. is there some thing that can I test before replacing it? In case something it's faulting and burn the chip again.

@tf_hh Can you help with any suggestion?

 

 

 

[manterola]

I agree, you should start with the RAM. It is pretty cheap, easy to get, and usually the most likely cause of problems. 

Try eBay or aliexpress and I would recommend to get 10 pack to have some spares just in case. Ah, and also get sockets. 

[shoestring]

 

On 2/17/2020 at 11:26 PM, Jangle said:

Thanks for your reply!

This could sound dumb but there is a way to test those chips without replacing it? I mean with a oscilloscope or multi-meter or something?

 

Custom chips aren't simple to test because they're quite complex. But you can check out the Atari 130 Service Manual which includes things like troubleshooting the Microprocessor ( operation ), clock/dividers and what signals to verify. It should all be relevant to the 65XE. You'll need a scope or at least a logic probe.

 

 

 

Edited February 19, 2020 by shoestring

[+tf_hh]

On 2/17/2020 at 11:21 PM, Jangle said:

@tf_hh

I did the CI's HOT-TEST and the only one getting warm (not to hot) is the CPU but I think that is normal? the other chips seems fine (drams , GTIA , etc)

If the CPU is bad.. is there some thing that can I test before replacing it? In case something it's faulting and burn the chip again.

@tf_hh Can you help with any suggestion?

 

Sorry, not beeing often online here this time. So much trouble in reallife these days.

 

Diagnostics over long distances are hard. The DRAMs used at this board are not known for often failures, but never mind, RAM failures are the most probable issue followed by bad CPUs... normally. My personal experience the last 2 or 3 years shows me, that more and more other chips went bad, too. Not only RAMs or CPUs, I got more and more defects with ANTIC, GTIA and the MMU, which is a standard PAL16L8 labeled with Atari markings. Also bad O.S. ROMs follows. It´s a mixture of culprits these days, and remembering the fact that nearly all chips were producted 35 years and more ago, it´s no wonder that the amount of failures over all chips raises.

 

If you have an oscilloscope, check out the usual points. Pin 7 of the CPU - is there execution of opcodes or not? What about CAS (pin 15 of all DRAMs), is the RAM accessed or not? Check CAS_Inhibit (Pin 16 of MMU), or also check Pin 6 of the MMU - there must be a toggle from high-low-high during power-on, this is when the selftest is mirrored for a short time. If this won´t happen, the memory size test fail and the O.S. hangs up. Much more possible, but without a scope there´s no real chance to check the major points.

 

[Jangle]

On 2/18/2020 at 9:35 PM, shoestring said:

 

 

Custom chips aren't simple to test because they're quite complex. But you can check out the Atari 130 Service Manual which includes things like troubleshooting the Microprocessor ( operation ), clock/dividers and what signals to verify. It should all be relevant to the 65XE. You'll need a scope or at least a logic probe.

 

 

 

 

On 2/28/2020 at 7:32 AM, tf_hh said:

 

Sorry, not beeing often online here this time. So much trouble in reallife these days.

 

Diagnostics over long distances are hard. The DRAMs used at this board are not known for often failures, but never mind, RAM failures are the most probable issue followed by bad CPUs... normally. My personal experience the last 2 or 3 years shows me, that more and more other chips went bad, too. Not only RAMs or CPUs, I got more and more defects with ANTIC, GTIA and the MMU, which is a standard PAL16L8 labeled with Atari markings. Also bad O.S. ROMs follows. It´s a mixture of culprits these days, and remembering the fact that nearly all chips were producted 35 years and more ago, it´s no wonder that the amount of failures over all chips raises.

 

If you have an oscilloscope, check out the usual points. Pin 7 of the CPU - is there execution of opcodes or not? What about CAS (pin 15 of all DRAMs), is the RAM accessed or not? Check CAS_Inhibit (Pin 16 of MMU), or also check Pin 6 of the MMU - there must be a toggle from high-low-high during power-on, this is when the selftest is mirrored for a short time. If this won´t happen, the memory size test fail and the O.S. hangs up. Much more possible, but without a scope there´s no real chance to check the major points.

 

 

Thanks for your replies!

I will read that manual and test when I get an Oscilloscope.

 

Any specific settings for the Osci?

@tf_hh Can I use Syschek on this? I need some kind of Extension Port or specific wiring connection ?

 

[+Nezgar]

16 hours ago, Jangle said:

Can I use Syschek on this? I need some kind of Extension Port or specific wiring connection ?

You can't use a Sys-check on that model of 65XE. (No ECI)

 

In lieu of that, you could try shoestring's memory tester - programmed to an EPROM to temporarily replace your OS ROM. You'd have to desolder and socket your existing OS ROM. PM me if you don't have the means to program one - I could mail you a socket and a programmed chip.

 

https://atariage.com/forums/topic/282022-shoestrings-atari-8bit-ram-tester/

https://www.jammarcade.net/shoestrings-atari-8bit-ram-tester/

[shoestring]

@Jangle

You say there's no image. Do you get a black screen or a blank screen ?

 

What power supply are you using ?

[Jangle]

7 minutes ago, shoestring said:

@Jangle

You say there's no image. Do you get a black screen or a blank screen ?

 

What power supply are you using ?

HI! No image at all , not blank not white , nothing , no signal .. Is like there is nothing connected to the TV.

I'm using a 220v to 5v 1.5A . It's an original PSU.

 

Edited March 22, 2020 by Jangle
grammar

[shoestring]

Pictures of the power supply ?

[Jangle]

7 minutes ago, shoestring said:

Pictures of the power supply ?

The PSU works fine I tested with a Multimeter.. Why do you ask?

Edited March 22, 2020 by Jangle

[Jangle]

The only thing that is weird are the Amps... Gives me 2.4 but after that everything is good

I used this image to test it

[shoestring]

Depending on the version, you may need to bin it. What does +5v measure under "load" from inside the machine at one of the rails or chips ?

 

If the power supply is good and you're not even getting a valid video signal to the monitor then most likely the cpu is not even running and all you have is power to it. Possibilities are bad clock circuit , dead short somewhere or bad psu (underpowered ). The problem is, completely dead machines can hide many faults, so it's not always going to be down to 1 specific problem and could be a combination of things especially if the machine has been previously worked on.

 

 

 

 

 

 

 

 

 

 

 

 

Edited March 23, 2020 by shoestring

[Jangle]

8 hours ago, shoestring said:

Depending on the version, you may need to bin it. What does +5v measure under "load" from inside the machine at one of the rails or chips ?

 

If the power supply is good and you're not even getting a valid video signal to the monitor then most likely the cpu is not even running and all you have is power to it. Possibilities are bad clock circuit , dead short somewhere or bad psu (underpowered ). The problem is, completely dead machines can hide many faults, so it's not always going to be down to 1 specific problem and could be a combination of things especially if the machine has been previously worked on.

 

 

 

 

 

 

 

 

 

 

 

 

What do you mean with "load" ? Test the chips voltage with the console on?

I managed to test the CPU a couple of days ago (pin 5 or 6 I don't remember well) and I get ~4.5V same with the ANTIC.

Maybe tomorrow I will post voltage on all the chips.. but I'm little suspicious about the Crystal and the Capacitor (?) attached next to it..

Any info about that? How can I test it? Only with an Oscillloscope ?

 

Another thing I noticed is that one user post the same Atari

 

And his board has and extra piece of hardware on the OSC that I don't have.
But mine has the Y1 that he doesn't have.. so I Don't know , maybe the Y1 Crystal is a replacement of that hardware he has.

 

Edited March 23, 2020 by Jangle

[shoestring]

You can probe VCC which is pin 8 of the CPU. Ideally, it and other chips should measure as close to 5 volts as possible with the machine powered on.
 

It’s perfectly normal to have a small voltage drop when the power supply is under some load. But too much of a drop say below 4.65v and your machine will start to act up and do unpredictable things or do nothing at all.

 

Im not sure what that is, it doesn’t look factory to me. Maybe someone else can confirm.

[_The Doctor__]

Yup 4.5 is way too low, sounds like power supply possibly in combination with short or near short on the pcb. Once a good supply is connected you may find a dead cap, memory or support chips. The brown out condition may damage the LSI chips. You may end up replacing cpu if that has been the case for too long.

[Jangle]

7 hours ago, shoestring said:

You can probe VCC which is pin 8 of the CPU. Ideally, it and other chips should measure as close to 5 volts as possible with the machine powered on.
 

It’s perfectly normal to have a small voltage drop when the power supply is under some load. But too much of a drop say below 4.65v and your machine will start to act up and do unpredictable things or do nothing at all.

 

Im not sure what that is, it doesn’t look factory to me. Maybe someone else can confirm.

 

2 hours ago, _The Doctor__ said:

Yup 4.5 is way too low, sounds like power supply possibly in combination with short or near short on the pcb. Once a good supply is connected you may find a dead cap, memory or support chips. The brown out condition may damage the LSI chips. You may end up replacing cpu if that has been the case for too long.

I check again because ~4.5 was barely accurate.

This was the result:

 

CPU

PIN 8 4.82
PIN 2 4.82
PIN 7 3.38
PIN 5 0
PIN 6 4,77

ANTIC
PIN 4 4,86
PIN 21 4,82

 

GTIA
PIN 27 4,79

 

POKEY
PIN 18 4,77
PIN 2 OSCILLATES AT 0.5 - 4.8

 

PIA
PIN 20 => 4.84

 

FREDDIE
PIN 40 => 4.88

 

CHIPS THAT I DON'T KNOW WHERE IS THE VCC (but managed to get volts) :

 

BASIC
PIN 13 => 4.81
PINS 14 15 16 17 18 => 4.82v

 

OS
PIN 1 => 4.81
PIN 12 => 4.88

 

MMU

PIN 12 => 4.88

 

Anything more to check?

About the Crystal Clock..do you have any info for test? What about the capacitor ? Shouldn't give any sign of continuity or something? Because I get nothing with the multimeter

 

Thanks!!

 

[+Nezgar]

2 hours ago, Jangle said:

BASIC
PIN 13 => 4.81
PINS 14 15 16 17 18 => 4.82v

BASIC is a 2364 mask ROM, so Vcc should be pin 24.

OS ROM (23128) Vcc should be pin 28.

MMU Vcc should be pin 20.

[TGB1718]

According to the datasheets for a 7805 regulator the output should be 5V +/- 0.1V

so the voltages you have measured all seem a little on the low side, also depends on how accurate your meter is too.

 

Maybe if you have a PSU somewhere you can measure to see how accurate your meter it.