Any tips for diagnosing a black screen on an Atari 130xe?

[bernie]

I recently purchased an Atari 130XE but unfortunately, it only displays a black screen when you turn it on (using RF)- so you go from static to a black screen. With the monitor cable, it displays only a black screen (briefly flickers white).

 

One time since purchasing it powered on (after trying like 20 times to turn off/on) but it has not done that again.

 

Any suggestions?

[Rybags]

Brown/red screen usually means that the OS isn't able to complete the earliest stages of powerup (after a soft delay of about 1/2 a second the IO registers are cleared which forces a black background, by default GTIA will often startup with a brown background and sometimes PM stripes overlayed).

 

That's a good sign which means the CPU, OS and MMU are probably OK. But it might mean that the Ram or Antic isn't OK. My guess would be that you have one or more bad Ram chips.

The quick/easiest way to diagnose is leave it on for several minutes, then put a finger on each chip in turn. Any that are hotter than the others are probably bad.

 

Quick/easy first thing to try is gently pry each one up then reseat but seeing it's an XE it's likely all the Ram is soldered in and most/all of the other chips the same.

 

Check the branding on the Ram chips. MT are notorious for going bad, if you have those then the best procedure is to replace all of them even if only a few are known to be bad.

How easy that job is can be dependant on which revision board you have. Early ones used 16 1-bit Ram chips so potentially a lot of work. Later ones use just 4 4-bit Ram chips which means a lot less work, and also the chips used are more easily obtained.

Edited April 5, 2017 by Rybags

[TangentAudio]

Also check the voltage on your power supply with a voltmeter to make sure it's outputting close to 5 volts. Some Atari supplies are known for failing in a way that will damage components on the motherboard by over-volting them - RAM in particular.

[bernie]

Brown/red screen usually means that the OS isn't able to complete the earliest stages of powerup (after a soft delay of about 1/2 a second the IO registers are cleared which forces a black background, by default GTIA will often startup with a brown background and sometimes PM stripes overlayed).

 

That's a good sign which means the CPU, OS and MMU are probably OK. But it might mean that the Ram or Antic isn't OK. My guess would be that you have one or more bad Ram chips.

The quick/easiest way to diagnose is leave it on for several minutes, then put a finger on each chip in turn. Any that are hotter than the others are probably bad.

 

Quick/easy first thing to try is gently pry each one up then reseat but seeing it's an XE it's likely all the Ram is soldered in and most/all of the other chips the same.

 

Check the branding on the Ram chips. MT are notorious for going bad, if you have those then the best procedure is to replace all of them even if only a few are known to be bad.

How easy that job is can be dependant on which revision board you have. Early ones used 16 1-bit Ram chips so potentially a lot of work. Later ones use just 4 4-bit Ram chips which means a lot less work, and also the chips used are more easily obtained.

 

 

 

So I ordered a tested PSU and plugged it in and no change- still get the black screen.

 

So I tried the heat test- the only chips that were warm to the touch (ok maybe even hot) were the CPU, ANTIC, and GTIA after a few minutes. Is this normal? Is the memory supposed to be hot?

 

I have an extra personality board from an atari 800 that I could remove the chips from and "piggy back" them on to see if it's any of those if that's worth trying? Would they be compatible?

[bernie]

Also check the voltage on your power supply with a voltmeter to make sure it's outputting close to 5 volts. Some Atari supplies are known for failing in a way that will damage components on the motherboard by over-volting them - RAM in particular.

Thanks, I assume the old PSU damaged the unit at this point. Any ideas of how to test them?

 

Is there a cheap place to get a whole motherboard?

[TangentAudio]

Thanks, I assume the old PSU damaged the unit at this point. Any ideas of how to test them?

 

Is there a cheap place to get a whole motherboard?

 

You can buy XE motherboards from MyAtari on Ebay, but you may be able to find another entire computer for a similar price from somewhere else.

[bernie]

 

You can buy XE motherboards from MyAtari on Ebay, but you may be able to find another entire computer for a similar price from somewhere else.

 

 

Thanks. Any way to test ram other than unsoldering and trying a new replacement?

[+DrVenkman]

 

 

Thanks. Any way to test ram other than unsoldering and trying a new replacement?

 

In the absence of a logic probe or oscilloscope, if you do a search of the forum, there are a number of memory test utilities available.

[Guest]

here's my own checklist

 

1] easiest thing to try first - leave machine on for ten minutes....are any ram chips "overheating"? - swap these

2] if the board is socketed, rather than soldered you may have some "unseated" ICs.
check to see if ram, OS Rom, Antic, MMU, PIA, CPU are fully in their sockets.
they can look "seated" but may not be. and oxidation/dirt/dust can cause faulty contacts. if your comfortable with doing so, you can remove them and reinsert - it won't do any harm (once removed) to blow compressed air through the sockets.

3] if still a black screen try this (turn TV volume up):
power up using OPTION key, wait five seconds, press SELECT key once, press START
do you hear the musical notes? if so your computer is working
now press HELP, then SELECT, the START
press different keys randomly....do you hear the keyboard BEEPS?
these are good signs that atari is fundamentally ok.

3] power supply may be a problem - it may not be supplying 5v. try another PSU.

4] RF or monitor output? if RF, does machine have a channel switch next to the RF output socket? try repeatedly moving it back and forth - it can get dirt inside and cause bad contact.
try a monitor cable - these are fairly standard these days and usually come in the form of monitor to scart, monitor to S-video and monitor to RCA varieties.

5] try booting with a cartridge in the slot -
Star Raiders cart runs a diag on Antic, CPU and GTIA - so if Star Raiders works then ALL three should be good
which narrows your fault down to PIA, OS Rom, MMU or Ram

[Rybags]

There's no point using Personality board chips, the OS is incompatible in both size of chips used as well as the actual OS code.

 

Plus, like I said earlier my opinion is that your OS Rom is probably fine.

If you have the means you could flash a diagnostic mode cart and see if it works. I'd recommend Star Raiders, Asteroids or the Salt cart.

Though you'd need to create the cart without the menu, the image has to be the default one when it powers up.

 

Is the motherboard the 4 or 16 Ram chip type?

Realistically it would probably be cheaper though more work to identify what components have failed and replace them rather than buying a new motherboard.

[KLund1]

This thread is very helpful. I have a130XE in a similar state.

I have one RAM chip that gets hot, and need to replace. I have a lot of 4164-15, will these work? With one bad ram it should still boot to self test, right? I tried the piggy-back method test, but no change.

Also, will it boot without a keyboard attached?

I have swapped out the the socketed C014806(6502), GTIA, & PIA, and get no change. Just black screen on RF and monitor jack. All the other IC's are soldered into the MB.

I tried the power up -Option - select - start and got no sound.

On the bottom of the board I did notice a lot of little scratches around the 8 pin IC near the RF modulator box labeled M8440 LN 358N. It looks like it may have been replaced in the past. The solder joints look ok under a 10x magnifying glass. Perhaps a re-flow might be in order,as long as I am swapping a ram with a socket & ram

Thoughts, suggestions?

[Vyper68]

I recently purchased an Atari 130XE but unfortunately, it only displays a black screen when you turn it on (using RF)- so you go from static to a black screen. With the monitor cable, it displays only a black screen (briefly flickers white).

 

One time since purchasing it powered on (after trying like 20 times to turn off/on) but it has not done that again.

 

Any suggestions?

It might be a bit simple and you may have said this earlier ( sorry if you have ) but have you checked you are getting power to the board from the switch. If you flicked it on/off twenty times and it worked once maybe the switch is badly oxidised i had this on a 65XE and CPC464 and CPC6128. Just a thought.

[shoestring]

This thread is very helpful. I have a130XE in a similar state.

I have one RAM chip that gets hot, and need to replace. I have a lot of 4164-15, will these work? With one bad ram it should still boot to self test, right? I tried the piggy-back method test, but no change.

Also, will it boot without a keyboard attached?

 

 

Doesn't always work, especially if they are shorted internally and I would refrain from piggybacking over something that gets hot. RAM chips can fail in so many ways.

[KLund1]

Thanks,

The PSU is know to be good. The board seems to be getting power. The red keyboard LED is lit when connected. So 5v is flowing somewhere.

[Tezz]

Syscheck can be helpful in identifying a fault with the RAM and/or the OS-ROM. Without an oscilloscope or a logic probe for diagnostics if you have at least a multimeter you should make some initial voltage and continuity checks and of course a good visual check of the board for anything obvious. Literally any one or more of the ICs or logic chips can be at fault. I have a 65XE that I'm looking at at the moment with a black screen output, as with most XEs nothing was socketed. So far I've replaced the RAM with 8x 41256, FREDDIE, MMU, OS ROM and the CPU (all previously tested and known working) to no avail. I'll try replacing PIA next then the logic chips rather than the remaining main ICs. You never know the extent of the damage when buying these faulty systems until you look into them. This one in my case may be another Commodore PSU casualty.

[KLund1]

What is syscheck? How can it work if there is no display?

Can an XE boot without a keyboard attached? At least for just checking screen output.

 

Also what is the best way to remove a large IC from this board without damaging it. I know these board were made cheaply and I want to do my best not to lift a pad, or kill a still good PIA, 6502, Freddy, etc.

Edited June 25, 2018 by KLund1

[+Stephen]

What is syscheck? How can it work if there is no display?

Can an XE boot without a keyboard attached? At least for just checking screen output.

 

Also what is the best way to remove a large IC from this board without damaging it. I know these board were made cheaply and I want to do my best not to lift a pad, or kill a still good PIA, 6502, Freddy, etc.

Syscheck is a hardware board that plugs into PBI or Cart+ECI port. It can make machines with bad RAM, bad OS ROM, and other issues boot.

 

Yes - the XE will boot fine without a keyboard present.

 

Practice and experience are required to remove the ICs from these XE machines. Here's a recent vid I posted.

[Tezz]

What is syscheck? How can it work if there is no display?

Can an XE boot without a keyboard attached? At least for just checking screen output.

http://atariage.com/forums/topic/278661-announcement-sys-check-got-some-siblings/

 

 

 

Also what is the best way to remove a large IC from this board without damaging it. I know these board were made cheaply and I want to do my best not to lift a pad, or kill a still good PIA, 6502, Freddy, etc.

It's possible to remove the ICs with a soldering iron (preferably temperature controlled) and a solder sucker although it's far easier with a dedicated desoldering gun, there's also no more stray solder bits coming out of the manual sucker to hunt and clean up afterwards. My usual method now is to remove the solder with the desoldering gun and check with a small screwdriver that each pin is freely moving, remember to add some flux to the pins at the start. If some solder remains on one of the pins (usually on the other side of the through hole), add some new solder and then remove again with the gun. If any pins remain stubborn I'll make the final removal with hot air. More often than not these days I'll just remove the solder with the gun and then go straight to the hot air to finish it off for a clean removal.

[KLund1]

Getting a bit off topic: I should probably get a desoldering gun. But they look expensive. the same for the hot air guns. Any suggestions for budget minded hobbiest?

[+DrVenkman]

Getting a bit off topic: I should probably get a desoldering gun. But they look expensive. the same for the hot air guns. Any suggestions for budget minded hobbiest?

 

This Hakko FR-301 is on my birthday wishlist (coming up in three weeks if anyone is feeling generous ). A friend has one and loves it for work on his old computers and arcade machine boards.

[+Stephen]

 

This Hakko FR-301 is on my birthday wishlist (coming up in three weeks if anyone is feeling generous ). A friend has one and loves it for work on his old computers and arcade machine boards.

Yeah - looks like they no longer sell the Hakko 808 I have. This seems to be the replacement.

[_The Doctor__]

ah but the 808 is so nice...

[shoestring]

What is syscheck? How can it work if there is no display?

 

 

I'm currently in the early stages of working on a diagnostic rom that installs in place of the OS ROM. It's similar to Syscheck except this will also verify the Basic ROM.

 

Each beep represents an algorithm that passes a specific test, exhaustive takes the longest ( this will beep every 100 bytes of a pass ). The beeps are also an indication that memory testing is taking place even if the display is messed up, provided you use the audio out and not the modulator.

 

It tests the address lines and the data lines. Following algorithms include.

 

Data Line Integrity Test: Walking 1s, Walking zeros, Ones, Zeros, Checkerboard, Inverse Checkerboard, Exhaustive tests.

Address Line Integrity Tests: Walking 1s, Walking Zeros.

Basic ROM: checksum is a simple sum of bytes, so the value calculated is compared with a table containing a list of precalculated known checksums.

 

Data Line Integrity Tests should detect 99% of ram faults, the others are overkill but I've included those as well.

 

The stuff on the screen are PML graphics, these are bit patterns based on the algorithm that is used to write to the memory.

 

It burns to a standard 27C128. Preview / video below, still have more work to do.

atari.mp4

Edited June 30, 2018 by shoestring

[+DrVenkman]

So reviewing this thread, I'm surprised no one has mentioned this yet: download the SAM'S COMPUTERFACTS for the 130XE. It's got a wealth of nuts-and-bolts-and-resistors details on the internals of the machines, logic charts for all the IC's, troubleshooting steps for pretty much any conceivable problem, and well-annotated photos all the internal components. Between the equivalent volume for the 800XL(*), a SALT Cart rom in my UNO Cart, and a cheap $18 logic probe, I was able to rescue a left-for-dead 1200XL last year.

 

(*) There is no SAM'S equivalent for the 1200XL, the Atari 1200XL Field Service Manual copies available online are terrible scans with mostly-illegible schematics, but the 800XL is broadly similar and you can use schematics from it to inform what you see inside as 1200XL).

[KLund1]

De-soldering gun on the way. Might as get one.

Sam's great idea! will attempt to use. Also need to watch a couple vids on how to use a logic probe.

Is syscheck bin or rom available.

Showstring, that looks very cool. that will be a very helpful tool for us restoreres

I think i have some blank 128 eproms around.