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Old 29 September 2014, 16:19   #1
Franchute13
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A3000. Diagram PCB and components.

++++++++++EDIT+++++++++++++++

Hello.
I'll rewrite everything to help someone else in the future.

Manuals.
http://www.1000bit.it/support/schema...00_schemas.pdf

http://www.amigawiki.de/dnl/schematics/a3000.pdf

http://www.ianstedman.co.uk/Amiga/am..._supplies.html

Note that according to the revision of the motherboard change some components.
It is recommended to take a picture of the motherboard. Each component removed noted on the picture to take a history.

My motherboard Rev 9.


Cleaned with alcohol to remove dirt from the area.

Remove the chip that are in sockets.
Use lemon juice to neutralize the acid from battery. Leave on for a while.
If the chip as Paula and Denis, etc, have stained legs, leaving them in lemon.
Clear the lemon juice with hot (NOT boiling) water and dry quickly.

On the motherboard, remove socket and chip that were hit by the acid. This should be done to see the tracks that pass under and to make a proper cleaning of the area.
The ceramic capacitors and resistors may not be damaged. Electrolytic capacitors, crystal and variable capacitors (yellow and blue) probably damaged and should be changed.

Use fine sandpaper (320-200) and remove all traces of rust or light green color.



Take another picture to see the tracks when we put the new components. It can also be used to document that tracks are cut.



Remember, the A3000 motherboard is multilayered. Check holes (through-hole).





You can check Paula and Denis chip on A500 to see if they work properly.

Check the power supply but do not connect to the system. DO NOT forget to connect something in the power supply to not work in a vacuum.

To test the A3000 requires the SCSI cable with terminator and daughter board are plugged.

To test the flicker is recommended to put the machine in NTSC and using a CRT monitor.
If you change the VC470 need adjusting. Please leave 5 minutes lit the A3000 to take temperature and then be adjusted slowly.




That's all.

I want to thank those users.
amiman99
pandy71
hese
Jope


++++++++++END++++++++++++++++




Hello.

I have a A3000 Rev9. It has corrosion on the tracks and components.
I need a diagram of connection between components. I also need what kind of components.
Any suggestions on how to fix it is also welcome.

Thank you

http://oi62.tinypic.com/2ev9pi9.jpg

Greetings.
Sorry for my English.

Last edited by Franchute13; 26 September 2015 at 02:42. Reason: update
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Old 29 September 2014, 16:55   #2
amiman99
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Good luck in your repairs!
Here is what you need: http://www.1000bit.it/support/schema...00_schemas.pdf
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Old 29 September 2014, 17:08   #3
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Good luck in your repairs!
Here is what you need: http://www.1000bit.it/support/schema...00_schemas.pdf
Thx!!!
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Old 30 September 2014, 14:51   #4
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Hello.
I have a question.
On page 10 are the capacitors, which is the voltage of the capacitor?
Thank you
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Old 01 October 2014, 14:59   #5
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Hello.
I have a question.
On page 10 are the capacitors, which is the voltage of the capacitor?
Thank you
As a principle something like 16 - 25V should be sufficient enough for any capacitor - older caps are usually bigger then with new caps you can go to somewhere 50V - this is for electrolytic caps, for regular one probably smallest one will be something around 63V - should be ok unless separately specified (check list of components provided in schematics).
Consider to replace electrolytic caps with non electrolityc. Some of caps in PLL can be with special (narrow) tolerance and particular dielectric type (thermal stability) - those need to be replaced 1:1 (ones marked as NPO - type of stable dielectric with low thermal and time drift).
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Old 02 October 2014, 15:08   #6
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Thanks for your feedback!
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Old 04 October 2014, 02:52   #7
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Hello.
I need information about these capacitors. What is the replacement?
390 a2j
102 a5j
112 rfa

http://i60.tinypic.com/b4erti.jpg
http://i62.tinypic.com/678743.jpg
thank you
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Old 06 October 2014, 11:55   #8
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Quote:
Originally Posted by Franchute13 View Post
Hello.
I need information about these capacitors. What is the replacement?
390 a2j
102 a5j
112 rfa

http://i60.tinypic.com/b4erti.jpg
http://i62.tinypic.com/678743.jpg
thank you
I found the solution.
These capacitors are printed on 2 sides. On the other side are the values.
A good guide to learn about capacitors.

http://www.tayloredge.com/reference/...apTraining.pdf
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Old 07 October 2014, 13:49   #9
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I found the solution.
These capacitors are printed on 2 sides. On the other side are the values.
A good guide to learn about capacitors.

http://www.tayloredge.com/reference/...apTraining.pdf

Once again check list of components provided in A3000 schematics at the beginning - check component number on PCB (for example C491) and read component value from page 8 (pdf 10) - compare with real one - that's all.
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Old 07 October 2014, 14:33   #10
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Hi Pandy.
The problem is that the diagram is not valid for the version of my motherboard. In the diagram there are different capacitors, my motherboard has more capacitors.
I'm using this manual
http://www.amigawiki.de/dnl/schematics/A3000T.pdf
Greetings and thanks.
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Old 14 October 2014, 15:17   #11
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Hi!
I need to replace the 74ALS74 but no stock. I get the 74LS74. I can use the 74LS74?
Not find differences in datasheet.
74ALS74
http://pdf1.alldatasheet.com/datashe...I/74ALS74.html
74LS74
http://pdf1.alldatasheet.es/datashee...LD/74LS74.html
thank you
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Old 14 October 2014, 23:15   #12
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Hi!
I need to replace the 74ALS74 but no stock. I get the 74LS74. I can use the 74LS74?
Not find differences in datasheet.
74ALS74
http://pdf1.alldatasheet.com/datashe...I/74ALS74.html
74LS74
http://pdf1.alldatasheet.es/datashee...LD/74LS74.html
thank you
Nope, difference is in speed and maximal work frequency - you can substitute ALS by ACT or by F parts so 74ACT74 or 74F74, AC may work but not recommended.
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Old 15 October 2014, 16:19   #13
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Nope, difference is in speed and maximal work frequency - you can substitute ALS by ACT or by F parts so 74ACT74 or 74F74, AC may work but not recommended.
Pandy!, Thank you again!
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Old 15 October 2014, 20:59   #14
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Pandy!, Thank you again!
No problemo, happy to help.

I forgot about FCT series (kind of rare but 74FCT74 was available).
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Old 22 October 2014, 15:31   #15
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Hi!
There are 2 variable capacitors, the VC 190 (yellow) and the VC 470 (Blue).
What function do these v. capacitors?
How do I find the correct value ?. The originals do not work and can not measure them.
greetings
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Old 22 October 2014, 16:17   #16
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VC190 value range is 22-47pF and VC470 is 3-11pF.
VC190 is used for adjusting the 32.768kHz crystal of RTC and VC470 is for adjusting the video output of Amber chip.
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Old 22 October 2014, 16:36   #17
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Thank you Hese!
Excuse my English.
The question is.
How to find the correct value for the VC190 between 22-47pF?
The same for the VC470, how to find the correct value for the system to function properly.
Thank you
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Old 23 October 2014, 07:25   #18
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Well, I'm not planning on desoldering the VCs from my motherboard to check the current values but you can boot the computer regardless what values your VCs have.

For example you can adjust the VC470 while the computer is running and check the results from the monitor that is connected to the VGA port. Adjusting VC470 should be done in very small steps, the range where you get picture is very narrow.
Before tuning the VC470, it's better to check that the computer is otherwise working, i.e. you get a picture from the RGB port.
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Old 10 November 2014, 13:48   #19
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Hello.
I need to try the Chip Paula and Denis from A3000. I can try on a A500 Rev 6?
Thank you
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Old 10 November 2014, 20:05   #20
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Yep, they are fully compatible.
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