Falcon with hard drive interface issue

[snuci]

Hi all,

 

I am working on an Atari Falcon that has a CF card hard drive interface.  When I start up the Falcon, the hard drive is not recognized. 

 

I've recently tried a different known working CF hard drive interface that has some status lights on it and the power and master/slave LEDs flash while the memory is being checked.  This interface also does not allow the hard drive to boot up.  Is there a IC that I can replace or something else I might be able to try to fix this?  Attached is a picture of the interface and the lights that flash.  Yes, i know, the CF card has an Amiga logo on it.  That's how I got it.

 

Any help is much appreciated.

Edited June 2, 2021 by snuci
Added picture.

[larrylaffer]

Let's start from simple: Have you preped the CF drive? Does it have valid partitions and a hard driver installed?

[snuci]

The temporary CF card and CF interface (pictured above) was used in another Falcon and works fine.  I also took the original CF card and interface (from the Falcon with the issue) and tried it in a working Falcon and there is no problem with it.  I am confident it is the Falcon with the issue.  Good question.  I should have been more clear.

Edited June 2, 2021 by snuci

[larrylaffer]

Ok, this is good info! And has this Falcon ever booted any hard drive/cf/sd card?

[snuci]

I got it that one recently and it hasn't worked in my possession.  Note: I did have to replace the HD connector on the motherboard so I thought that was the only issue.

Edited June 2, 2021 by snuci

[larrylaffer]

You might want to try with another device. A 2.5 inch real hard drive would be the best. Just to confirm your ide interface works (or not). Then you can plan your next step...

[snuci]

I appreciate the thoroughness but I've never had a real hard drive in a Falcon and this is my fourth.  I am confident it's the IDE interface.  Is there a chip that controls the IDE interface that I might try troubleshooting or even replacing?  

 

[snarkdluG]

Tried swapping PSU for a known good one?  Is the power on the faulty falcon good? 5V and 12V? recapped PSU?

[snarkdluG]

https://docs.dev-docs.org/htm/search.php?find=_5

[snuci]

9 minutes ago, snarkdluG said:

Tried swapping PSU for a known good one?  Is the power on the faulty falcon good? 5V and 12V? recapped PSU?

Power supplies swapped.  Same issue.  The power supply caps do look fine on both Falcons.

 

8 minutes ago, snarkdluG said:

https://docs.dev-docs.org/htm/search.php?find=_5

Thank you for the link.  I'll look around.

 

[snuci]

According to the documentation, the internal IDE interface is connected to the COMBEL chip.  Knowing that and having the schematics can give me something to check to make sure the 44 pin IDE connector pins are all connected properly.  It's hard not to solder that connector on properly but I'll double check.  Thanks @snarkdluG. That documentation helps a great deal.

[ParanoidLittleMan]

Yep, IDE interface is in Combel chip. What is worth is to check carefully with good light and maybe magnifier all soldering of 44 pin connector to motherboard - some may be broken, then need to resolder with fresh tin-lead wire.

And of course, there is a chance that error is in Combel chip self.

[snuci]

To follow up, I am confused but the hard drive is working now.  In the first picture, you can see the bottom side of the Falcon motherboard with a "black spot".  The second pictures shows the via where the black spot corresponds to with a black substance on it.  This via is on the VCC circuit for the IDE drive.  While 5v was measured with no issues, I found that this black stuff was as hard as an enamel.  The top side of the motherboard shows no black enamel on it but it almost looks like this substance dripped through the via.  I needed sharp tweezers to scrape off this enamel from the motherboard.  This black spot is still on the cardboard backing.  

 

I don't know if it's related but after I did this, the hard drive worked fine.  The substance was not conductive and even if it was, it would not contact any other circuitry.  I have taken this motherboard out several times when I replaced the IDE connector but, to be honest, I never really noticed the black spot but all of this said, the hard drive is now working like a charm. It doesn't make sense that his little drip of black substance makes a difference but I did probe around with a volt meter and ohm meter.  I don't have any other explanation.

 

I do want to thank those who replied and I am very glad to have the schematics.  That really helped.

 

 

[ParanoidLittleMan]

This is actually what I talked about - broken soldering, or dry joint, as some say. That black 'substance' is burnt pertinax (motherboard's material) - coalized. Sorry if my terminology is bad. Never talked about this in English.

Bad contact = heat generation because increased resistance. Everyone working with electronic (repair) will see such thing sooner or later.   And you need to clean up it (that soldering in red circle) and solder over - otherwise it will not work for long. There can not be hole like that.