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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: gary2000 on June 14, 2019, 02:48:11 PM

Title: A4000 motherboard-getting there
Post by: gary2000 on June 14, 2019, 02:48:11 PM
It's coming along...
Title: Re: A4000 motherboard-getting there
Post by: Acill on June 14, 2019, 09:53:37 PM
If you have any issues let me know! Also here is some good resource to help you. Its a part placement guide that John Hertell had another user help us put together. It makes builds a lot easier.

http://www.hertell.nu/locator/locator.php?project=A4000
Title: Re: A4000 motherboard-getting there
Post by: gary2000 on June 16, 2019, 09:09:19 PM
Thank you. I'm sure I will have questions.

Yes, that placement tool works well!
Title: Re: A4000 motherboard-getting there
Post by: gary2000 on June 29, 2019, 07:55:29 PM
Would anybody know what the part number is for the 6 pin power connector? I bought amp 350711-1, which looks to be correct, but has male contacts instead of female.
Title: Re: A4000 motherboard-getting there
Post by: Acill on June 30, 2019, 08:34:16 PM
I'll see if I can find it for you here in a bit. I am in Australia currently and need to search Mouser carts for my past orders.
Title: Re: A4000 motherboard-getting there
Post by: Acill on June 30, 2019, 08:55:40 PM
Here it is: https://www.mouser.com/ProductDetail/TE-Connectivity-AMP/350827-1?qs=%2Fha2pyFaduhO9K6hFWyj%252B9di953Oe11BRMqF7eT3GVg8f210t5DoTg%3D%3D

Mouser Part: 571-350827-1
Title: Re: A4000 motherboard-getting there
Post by: gary2000 on June 30, 2019, 10:31:50 PM
Thanks !
Title: Re: A4000 motherboard-getting there
Post by: gary2000 on September 07, 2019, 06:43:53 PM
First test result is a black screen , with video sync and no serial output to diagrom . Clocks look okay and voltages are fine , except -12 measures -11.13

Should sclk on Lisa be 3.571 MHz?

Should ECLK on U300 CIA be 714 KHz?

kbrst is always held low .  Should this go high on reboot?

 Seems to be no activity on Paula, Gary , Alice address lines

 This seems to be a global issue keeping the system down .

 Any other basic items I should check ? I'm trying to be methodical, but find myself stabbing in the dark .




Title: Re: A4000 motherboard-getting there
Post by: gary2000 on September 15, 2019, 04:50:28 PM
It's working!

 Fail pin was pulled low by power supply PG brown/ gray cable, so Gary would not reset . In Skynet power supply , IC7 I suspect is bad . I got impatient, and just cut the wire and ran to five volts.

 Diagrom checksum test okay, CPU and chip ram is seen .

 Hangs on fast ram check . But, that's progress .
Title: Re: A4000 motherboard-getting there
Post by: matt3k on September 17, 2019, 02:51:58 AM
Thanks Acill!  You and Chucky have saved the Amiga hardware community.
Title: Re: A4000 motherboard-getting there
Post by: gary2000 on September 17, 2019, 01:40:18 PM
Thanks Acill!  You and Chucky have saved the Amiga hardware community.

 Absolutely !
Title: Re: A4000 motherboard-getting there
Post by: gary2000 on October 07, 2019, 01:35:01 AM
Well, moving along smoothly until I inserted the Zorro daughterboard. The computer will boot one out of 10 times with errors if the daughterboard is in place . It works flawlessly without it , so far with diagrom. Will not boot with original ROMs , though.

 Anybody have a similar issue ? So far, checking u701/U714 pals , buster  and the CPU are involved as well.

 Will not be very expandable at this point , weird .