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krazycat
Joined: 18 Feb 2017
Posts: 32
Location: Europe
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 Posted: Tue Dec 12, 2017 1:16 pm Post subject: Cube 68030 Scrambled video on boot |
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Hi
I have a 68030 Cube with booting problems. After I replaced the caps, the cube starts to a scrambled screen and the red LED on the board is flashing 4 times fast. I also replaced the RAM and the CPU without luck. Does anyone have the electrical schematics of the 68030 board, or any idea how to solve it? The problem could be the nvram chip?
This board was previously stored in a box for 20 years, I don't know if it was working.
Here the screen at boot:
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barcher174
Joined: 07 Dec 2012
Posts: 594
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| Posted: Tue Dec 12, 2017 9:51 pm Post subject: |
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Here are the LED code descriptions:
LED Blink Codes (LED on the logic board if system can not boot to ROM)
1,2 ROM CRC check failures
3 Bad VRAM
4 Bad NVRAM (The NVRAM store in the clock chip)
5 No usable DRAM
Try removing the battery and reseating the ROM chip. Did you desolder the CPU? I've never seen a socketed 68030. There are no schematics for this board. |
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krazycat
Joined: 18 Feb 2017
Posts: 32
Location: Europe
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| Posted: Wed Dec 13, 2017 3:46 pm Post subject: |
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| barcher174 wrote: | Here are the LED code descriptions:
LED Blink Codes (LED on the logic board if system can not boot to ROM)
1,2 ROM CRC check failures
3 Bad VRAM
4 Bad NVRAM (The NVRAM store in the clock chip)
5 No usable DRAM
Try removing the battery and reseating the ROM chip. Did you desolder the CPU? I've never seen a socketed 68030. There are no schematics for this board. |
Thanks for codes Brian.
Sorry for the mistaken, I was wrong to write. I also replaced the RAM and the ROM (NOT the CPU) but I did not have luck...  |
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barcher174
Joined: 07 Dec 2012
Posts: 594
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| Posted: Wed Dec 13, 2017 11:07 pm Post subject: |
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My experience with these symptoms has unfortunately not been good. I've seen this with bad CPU's and with bad NeXT ASICs. Both require a significant amount of effort to rework. If you don't have an emotional attachment to the board it may be easier to buy a new one. You can see an example here:
http://www.nextcomputers.org/forums/viewtopic.php?t=3875&highlight=led+code |
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krazycat
Joined: 18 Feb 2017
Posts: 32
Location: Europe
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| Posted: Thu Dec 14, 2017 12:50 pm Post subject: |
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| barcher174 wrote: | | My experience with these symptoms has unfortunately not been good. I've seen this with bad CPU's and with bad NeXT ASICs. Both require a significant amount of effort to rework. If you don't have an emotional attachment to the board it may be easier to buy a new one. |
Thanks for your support, I'm not particularly attached to this board so if the replacement of the MC68HC68 Real-Time Clock (a SO16L chip) will have no effect, I'll look for another motherboard.
Does anyone have a working 68030 board to sell at a reasonable price?  |
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Rob Blessin Black Hole
Site Admin
Joined: 05 Sep 2006
Posts: 656
Location: Ft. Collins, Colorado
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| Posted: Sun Dec 17, 2017 4:12 pm Post subject: |
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Hello Krazycat: I've had that happen with non compatible ram, try putting the old ram back in.... I have a 68030 25Mhz for $99 or with new professionally replaced caps $164 , tested / compatible ram $1 a mb in sets of 4. Also which version of the rom did you use as 030's tend to be finicky? Best regards Rob Blessin
_________________
Rob Blessin President computerpowwow ebay sales@blackholeinc.com http://www.blackholeinc.com
303-741-9998 Serving the NeXT Community since 2/9/93 |
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krazycat
Joined: 18 Feb 2017
Posts: 32
Location: Europe
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| Posted: Mon Dec 18, 2017 1:30 am Post subject: |
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| Rob Blessin Black Hole wrote: | | Hello Krazycat: I've had that happen with non compatible ram, try putting the old ram back in.... I have a 68030 25Mhz for $99 or with new professionally replaced caps $164 , tested / compatible ram $1 a mb in sets of 4. Also which version of the rom did you use as 030's tend to be finicky? Best regards Rob Blessin |
Hi Rob, for testing I used RAM and ROM Release 1.1 from a working 030 cube from a friend of mine. Thanks for your offer, if after the last tests my board will not work, I will write to you to buy a $ 99 board. |
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krazycat
Joined: 18 Feb 2017
Posts: 32
Location: Europe
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| Posted: Fri Jan 19, 2018 8:27 am Post subject: |
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| krazycat wrote: |
Thanks for your support, I'm not particularly attached to this board so if the replacement of the MC68HC68 Real-Time Clock (a SO16L chip) will have no effect, I'll look for another motherboard.
Does anyone have a working 68030 board to sell at a reasonable price? |
This story has a happy ending: I had the MC68HC68 Real-Time Clock chip replaced, and now the cube works!
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barcher174
Joined: 07 Dec 2012
Posts: 594
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| Posted: Fri Jan 19, 2018 1:54 pm Post subject: |
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| Nice work! |
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bobo68
Joined: 03 Jun 2015
Posts: 212
Location: Germany
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| Posted: Sat Jan 20, 2018 7:05 am Post subject: |
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| Very good! And good to know another fix for our beloved NeXT's. |
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krazycat
Joined: 18 Feb 2017
Posts: 32
Location: Europe
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| Posted: Sat Jan 20, 2018 10:43 am Post subject: |
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And now to complete this cube, I have to find a power supply and a backplane (this revived motherboard has been tested on a friend's cube)  |
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Rob Blessin Black Hole
Site Admin
Joined: 05 Sep 2006
Posts: 656
Location: Ft. Collins, Colorado
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| Posted: Mon Jan 22, 2018 10:58 am Post subject: |
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Hello: I have a working NeXT Cube model 152 power supply for $99 and internal backplain for Used $20 or $30 New Old Stock, do you need the drive harness as well $25? Best Regards Rob Blessin
_________________
Rob Blessin President computerpowwow ebay sales@blackholeinc.com http://www.blackholeinc.com
303-741-9998 Serving the NeXT Community since 2/9/93 |
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