A590 not detected

[finite9]

Hi,


I've got:


A500 Rev.6a
Kickstart 1.3 rev 34.5

512KB trapdoor memory expansion


A590 with Rev.7 board & Rev.4.6 ROMs
Fully populated 2MB chips and jumper set to 2MB

dead 20MB WD XT hard drive


The drive overheated and smelt burnt on first turn on since 1990. I assume it's dead. No matter, I'll get a ZuluSCSI for it. But first I need to verify that the board works, and that's where the problems start. Power light comes on, board does get warm; can't detect any overheating signs of any single chip to the touch, but the A590 Memory Test disk reports no memory.


How can I verify that the board is actually working?

[btp]

Overheating and burned smells usually points out to a short circuit!
How do you power your A590? Do you use it's original PSU or is it modded to draw power from the Amiga?

[btp]

BTW if you have a multimeter can you measure the resistance between 5V and ground on your A590 (of course disconnected from the Amiga and powered off).

I have the same controller and I'm measuring a value of just 28 ohms.

[finite9]

Was just about to edit post. U30, an IC labelled 390398-01 feels quite hot at one end.

I'm powering it with the original separate power supply. It's not modded. It was the drive itself that smelt bad, im assuming the motor in the drive or stuck heads. I smelt nothing on the board itself at the time it happened.

I run "A590_RAM_TEST" and it says "No fast memory available to test".

[btp]

Could it be bad contact issue then? Try reseating the A590 into the side port of your A500 and cleaning the pins with a pencil eraser.

Also you can try using Keir Fraser's excellent Amiga Test Kit to check your RAM: https://github.com/keirf/amiga-stuff

[finite9]

I've already tried Amiga test Kit and it only reports the A500 memory and the trapdoor expansion memory. I had tried cleaning the contacts with a fibre glass pen, but not the contacts on the A590 itself. I'll get the multimeter out then...

[DisasterIncarna]

weird, this topic shows up not long after i just watched this about an A590.
[ Show youtube player ]

[finite9]

Originally Posted by btp

BTW if you have a multimeter can you measure the resistance between 5V and ground on your A590 (of course disconnected from the Amiga and powered off).

I have the same controller and I'm measuring a value of just 28 ohms.

I have the same controller and I'm measuring a value of just 28 ohms.[/QUOTE]


Pin 1 (5 volts) on the power connector CN1 is giving 21 ohms to ground.


I tested the power and at the connector im getting 5.2v on pin 1 and 12.4v on pin 4.


The fan power connector is reading 12v on pin 1 & 3, however the internal power connector for the drive is showing nothing. I'm getting maybe 2v intermittently. I tested it again and this time it was showing 7-8v on pin 1 and 6-7v on pin 4. I guess something did go wrong with the board after all.

[finite9]

Originally Posted by DisasterIncarna

weird, this topic shows up not long after i just watched this about an A590.
[ Show youtube player ]

That is so freaky! Same here! I'm watching that video right now.

[finite9]

I did a new test after watching that video, and set the memory jumper to only 512K, and now Amiga Test Kit recognises that there is 0.5MB fast ram installed which I didn't see before.

Unfortunately, trying to do a memory test on this ram results in immediate errors.

If I set the jumper to 1MB in the A590, Kickstart won't even boot and generates guru med.

Setting it to 2MB none of the fast ram is detected at all.

Maybe some of the chips are bad, and I can start taking them out and putting in 4 at a time to try to get a working 512K. Is there an easier way to test ram chips or is it trial and error?

Can anyone confirm what voltages I should be getting on that internal drive power connector? It should be +5v and +12v according to the A590 Service Manual, but that only shows a molex connector and i've got a rev.7 board with the smaller connector with one of the middle ground pins missing. Should I be getting a straight 5v and 12v on those pins without a drive connected? Sometimes when I test, they slowly increase from 2v up to 7-8v over a period of 10 sec or so.

[levo-ace]

Sounds like you have a connection issue . If you are powering from an external supply then I would suggest resoldering the power connector for the A590 . I had to do this on mine , when I first got it . Clear one pin of solder and then re-solder it , do this with all the pins . It solved my issue and might solve yours as well .

And , as the drive was dead and smelly , check for any burnt traces on the board .

The only thing in the A590 that uses 12v is the fan and HDD .

[levo-ace]

If you want to know a bit more about the A590 have a look on my website . There are a couple of articles on it .

https://levosretrocomputerprojects.co.uk/a590-psu

https://levosretrocomputerprojects.co.uk/a590-20mhz-mod

[finite9]

Originally Posted by levo-ace

Sounds like you have a connection issue . If you are powering from an external supply then I would suggest resoldering the power connector for the A590 . I had to do this on mine , when I first got it . Clear one pin of solder and then re-solder it , do this with all the pins . It solved my issue and might solve yours as well .

And , as the drive was dead and smelly , check for any burnt traces on the board .

The only thing in the A590 that uses 12v is the fan and HDD .

I did a continuity test between the 12v of the power DIN and the internal drive power connector and it was ok; same with the 5v, so they are connected. Maybe needs recapping, but I don't have an ESR meter to test the caps.

[levo-ace]

Those types of caps are usually OK , you would measure a short on faulty ones , or if they have leaked the solder joints around them would be very dull , even ' crusty ' .