Dead Falcon - no boot / coloured screen only

Hardware, coding, music, graphic and various applications

Moderators: Mug UK, moondog/.tSCc., [ProToS], lp, Moderator Team

Chandler
Atari God
Atari God
Posts: 1222
Joined: Tue Feb 14, 2006 12:15 am

Dead Falcon - no boot / coloured screen only

Postby Chandler » Sun Jan 13, 2019 6:29 pm

Trying to diagnose a non working Falcon mobo

It's completely stock and never been modded, it's very clean

So far i have changed TOS rom, new NVRAM fitted and fitted a known working memory card but all i get is this coloured screen pic using an RGB monitor with a VGA to ST adaptor

If i use a high res monitor then the screen is just black

No floppy drive LED

Where to look next?
You do not have the required permissions to view the files attached to this post.

mpattonm
Hardware Guru
Hardware Guru
Posts: 362
Joined: Mon Oct 21, 2002 8:52 am
Location: Czech republic
Contact:

Re: Dead Falcon - no boot / coloured screen only

Postby mpattonm » Sun Jan 13, 2019 7:03 pm

Is it consistent, if you reset the machine few times? How is the PSU, does it provide at least 4.9V, stable? What equipment do you have?

Chandler
Atari God
Atari God
Posts: 1222
Joined: Tue Feb 14, 2006 12:15 am

Re: Dead Falcon - no boot / coloured screen only

Postby Chandler » Sun Jan 13, 2019 8:00 pm

Yes screen is same after a few resets

Yes PSU is fine (as used in a working Falcon)

I have no test equipement other than a logic probe (what do i need)

User avatar
christos
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2412
Joined: Tue Apr 13, 2004 8:24 pm
Location: Greece
Contact:

Re: Dead Falcon - no boot / coloured screen only

Postby christos » Sun Jan 13, 2019 9:32 pm

Ram? Or it could be something with the nvram
Felix qui potuit rerum cognoscere causas.
My Atari blog

STOT Email address: stot(NoSPAM)atari(DOT)org

Chandler
Atari God
Atari God
Posts: 1222
Joined: Tue Feb 14, 2006 12:15 am

Re: Dead Falcon - no boot / coloured screen only

Postby Chandler » Sun Jan 13, 2019 11:28 pm

I have changed the ram to a known working 4mb factor type

new NVRAM chip works in another Falcon (along with the memory card)

User avatar
Arne
Captain Atari
Captain Atari
Posts: 472
Joined: Thu Nov 01, 2007 10:01 am

Re: Dead Falcon - no boot / coloured screen only

Postby Arne » Mon Jan 14, 2019 8:17 am

As usual in case of a dead unit:
  • download the service manual
  • read chapter Troubleshooting a dead unit ch.3.3 in my copy
  • act accordingly
As RAM seems to be completely down a test cart is probably of no use here.
Image

mzry
Atari Super Hero
Atari Super Hero
Posts: 542
Joined: Tue Jan 26, 2016 12:39 pm

Re: Dead Falcon - no boot / coloured screen only

Postby mzry » Mon Jan 14, 2019 9:29 am

Your problem seems very similar to this guys Falcon too:
https://www.exxoshost.co.uk/forum/viewt ... =23&t=1446
Perhaps you could work together to fix them both.
Falcon ct60e 060 - 256mb ram - phantom bus and dsp accel // Atari TT - Thunder and Storm IDE 64mb ram - Lightning VME - USB LAN - Ati Mach64 2mb // Atari STM 4160 - 4MB ram - 16Mhz exxos 1.5 booster - Ultrasatan

User avatar
calimero
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2260
Joined: Thu Sep 15, 2005 10:01 am
Location: STara Pazova, Serbia
Contact:

Re: Dead Falcon - no boot / coloured screen only

Postby calimero » Mon Jan 14, 2019 5:08 pm

mzry wrote:Your problem seems very similar to this guys Falcon too:
https://www.exxoshost.co.uk/forum/viewt ... =23&t=1446
Perhaps you could work together to fix them both.

If you remove RAM board completly, do you get same patern on screen.
I ask this because guy on exxos forum wrote:

"I removed the 4Mo Memory = same"

how can you get anything on screen if there is no RAM?!
using Atari since 1986.http://wet.atari.orghttp://milan.kovac.cc/atari/software/ ・ Atari Falcon030/CT63/SV ・ Atari STe ・ Atari Mega4/MegaFile30/SM124 ・ Amiga 1200/PPC ・ Amiga 500 ・ C64 ・ ZX Spectrum ・ RPi ・ MagiC! ・ MiNT 1.18 ・ OS X

User avatar
Greenious
Hardware Guru
Hardware Guru
Posts: 1300
Joined: Sat Apr 24, 2004 5:39 pm
Location: Sweden

Re: Dead Falcon - no boot / coloured screen only

Postby Greenious » Mon Jan 14, 2019 8:13 pm

mzry wrote:Your problem seems very similar to this guys Falcon too:
https://www.exxoshost.co.uk/forum/viewt ... =23&t=1446
Perhaps you could work together to fix them both.


That guy gave up and sold it on ebay last month...

Chandler... did you buy this? :D

Anyway, the servicemanual suggest checking on the 32MHz oscillator that provides the system clock.

Oh, if you haven't already, make sure to reseat all those GALs on the mobo.
Updated my guides as of june 28th, 2016. Check'em out and feedback!
viewtopic.php?t=5040

User avatar
Greenious
Hardware Guru
Hardware Guru
Posts: 1300
Joined: Sat Apr 24, 2004 5:39 pm
Location: Sweden

Re: Dead Falcon - no boot / coloured screen only

Postby Greenious » Mon Jan 14, 2019 8:23 pm

calimero wrote:how can you get anything on screen if there is no RAM?!


Oh, technically speaking, you always get something on the screen if the video circuit is working. Even though it is completely black or white.

The image is however not consistent with a working ram controller/circuit. The databus got pull-up resistors, and should read all 1's (or $ffffffffff.....) if the ram is removed, and something more random with ram plugged in if ram was working.

anyway... this suggests, after screening through the f030 service manual, that either the master clock (32MHz oscillator) is broken, or the COMBO IC. :coffe:

Swapping the oscillator is definately the easiest and cheapest option at this point, since you have no oscilloscope or frequency meter available to actually check it.
Updated my guides as of june 28th, 2016. Check'em out and feedback!
viewtopic.php?t=5040

Chandler
Atari God
Atari God
Posts: 1222
Joined: Tue Feb 14, 2006 12:15 am

Re: Dead Falcon - no boot / coloured screen only

Postby Chandler » Tue Jan 15, 2019 11:57 am

Which Oscillator is the master clock? there are 2 oscillators on the board

1 in the middle next to the large capacitor and the other next to the DSP chip

User avatar
Greenious
Hardware Guru
Hardware Guru
Posts: 1300
Joined: Sat Apr 24, 2004 5:39 pm
Location: Sweden

Re: Dead Falcon - no boot / coloured screen only

Postby Greenious » Tue Jan 15, 2019 2:27 pm

It would be the 4 pin oscillator that has 32.000Mhz stamped on it, U37, right hand side, under the floppy, next to the DSP.
Updated my guides as of june 28th, 2016. Check'em out and feedback!
viewtopic.php?t=5040

mpattonm
Hardware Guru
Hardware Guru
Posts: 362
Joined: Mon Oct 21, 2002 8:52 am
Location: Czech republic
Contact:

Re: Dead Falcon - no boot / coloured screen only

Postby mpattonm » Tue Jan 15, 2019 9:17 pm

The one next to the DSP chip with 32.000MHz printed on it is - for DSP. Its not the main clock. System bus clock is all the way down, left to the cooler. Its either DIP14/DIP8 package crystal generator, or (in case of Falcon equipped with TV modulator) two pin quartz crystal in HC49U package. In any case, its rather printed with 32.08498MHz (for PAL machine).
The former one is often failing, but without oscilloscope you will hardly find its really failing part. In any case, for the sake of simplicity, it can be replaced with generic 32.000MHz part, your Falcon would boot with it and you would only loose RGB output and of ability to run most demos.

mpattonm
Hardware Guru
Hardware Guru
Posts: 362
Joined: Mon Oct 21, 2002 8:52 am
Location: Czech republic
Contact:

Re: Dead Falcon - no boot / coloured screen only

Postby mpattonm » Tue Jan 15, 2019 9:33 pm

Take a look here: http://www.atari-wiki.com/images/b/b3/F ... EC_skt.jpg
System bus clock is either on U65 position, left to the Dallas chip, like in this case - or it would be on Y3, right next to the cooler.

Chandler
Atari God
Atari God
Posts: 1222
Joined: Tue Feb 14, 2006 12:15 am

Re: Dead Falcon - no boot / coloured screen only

Postby Chandler » Thu Jan 17, 2019 9:39 pm

OK on my mobo it's a 2 pin package on Y3

Any idea where i can get some of these? i'd rather get the exact part: 32.08498MHz

mpattonm
Hardware Guru
Hardware Guru
Posts: 362
Joined: Mon Oct 21, 2002 8:52 am
Location: Czech republic
Contact:

Re: Dead Falcon - no boot / coloured screen only

Postby mpattonm » Fri Jan 18, 2019 7:30 am

Thats a tough one: the only place I know of is http://www.best-electronics-ca.com/custom-i.htm
In the end it might be considerably easier for you to gain an access to oscilloscope and check the current component first.
In my opinion, based on first picture, CPU is at least partially working and getting clock signal. But of course I might be wrong.
I would also suggest you to get/borrow a diagnostic cartridge, it could give you some more information on what exactly is wrong with unit.
Last edited by mpattonm on Fri Jan 18, 2019 12:56 pm, edited 1 time in total.

joska
Hardware Guru
Hardware Guru
Posts: 4219
Joined: Tue Oct 30, 2007 2:55 pm
Location: Florø, Norway
Contact:

Re: Dead Falcon - no boot / coloured screen only

Postby joska » Fri Jan 18, 2019 8:31 am

mpattonm wrote:In any case, for the sake of simplicity, it can be replaced with generic 32.000MHz part, your Falcon would boot with it and you would only loose RGB output and of ability to run most demos.


Or lift the right side (the one pointing towards the fan) of L102, and connect the DSP-clock to the lifted side of it.
Jo Even

VanillaMiNT - Firebee - Falcon060 - Milan060 - Falcon040 - MIST - Mega ST - STM - STE - Amiga 600 - Sharp MZ700 - MSX - Amstrad CPC - C64

fidzen
Captain Atari
Captain Atari
Posts: 174
Joined: Tue Mar 31, 2015 5:13 pm
Location: Sweden

Re: Dead Falcon - no boot / coloured screen only

Postby fidzen » Fri Jan 18, 2019 6:46 pm

I had similar problems with one of my Falcons. I had some coloured pixels on black screen when booting.
I turned out to be the Combo IC. I bought it from Best Electronics.
Atari Falcon, 14Mb RAM, CT60e, Supervidel, Svetlana, 512Mb RAM, 8Gb CF.
Atari Falcon, 14Mb RAM, CT63, 256Mb RAM,4Gb CF.
Firebee Series 2, 16Gb CF, 2Gb SD, MEGA ST Keyboard and Atari Mice.
Atari Stacy 2 with 4Mb RAM and 20Mb HD.
Atari Lynx II with new LCD and VGA output.
Atari 2600 4-switch Woody

Chandler
Atari God
Atari God
Posts: 1222
Joined: Tue Feb 14, 2006 12:15 am

Re: Dead Falcon - no boot / coloured screen only

Postby Chandler » Fri Jan 18, 2019 6:54 pm

Can anyone advise a basic scope for testing things like this? will a cheap LCD type do it?


Social Media

     

Return to “Professionals”

Who is online

Users browsing this forum: No registered users and 8 guests