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Old 06 May 2020, 20:26   #61
torsti76
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Originally Posted by Ceason87 View Post
rvctech

what do you mean by "many of the EMI parts do change between the revisions. But apart from signal integrity issues, the values of these parts are not super important."

As I have a Rev 1.5 board and it seems identical to the files Mick has uploaded that are Rev 2B.

Am I correct in assuming you mean that they changed some of the parts for ones which are better quality and that's basically it?

Best Regards
Chris
Generally speaking, in the shape Commodore was in when the A600 was available, most changes were done to save production costs, not to use higher quality parts.

Also, the EMI prevention measures weren't quite as sophisticated in the early 90s as they are today. Hence the sheet metal around the Amiga mainboards and the experimental approach to some (very few) parts, especially caps.
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Old 06 May 2020, 20:37   #62
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So I could use the same parts from a Rev 1.5 Mainboard on a Rev 2B Mainboard then and it shouldn't cause any issues in theory?
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Old 06 May 2020, 20:57   #63
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So I could use the same parts from a Rev 1.5 Mainboard on a Rev 2B Mainboard then and it shouldn't cause any issues in theory?
I think so. At least for the bare machine. Problems usually arise when you try to accelerate a quirked machine as some of the parts influence the signal clarity and/or waveforms which doesn't matter much as long as there's enough margin for error.
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Old 06 May 2020, 21:24   #64
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I think so. At least for the bare machine. Problems usually arise when you try to accelerate a quirked machine as some of the parts influence the signal clarity and/or waveforms which doesn't matter much as long as there's enough margin for error.
That's fine as I am looking to create a Mainboard from scratch using Mick's KiCad Design and was just wanting to know so I can order the same parts that are on the Rev 1.5 board as the one I have is damaged beyond repair but I can use it to identify the components that I need to order but I wasn't sure if it would work with it being a different board revision.

Thanks for the input and when I get round to doing it I'll post a message on here letting you all know if it works
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Old 12 May 2020, 04:05   #65
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rvctech

what do you mean by "many of the EMI parts do change between the revisions. But apart from signal integrity issues, the values of these parts are not super important."

As I have a Rev 1.5 board and it seems identical to the files Mick has uploaded that are Rev 2B.

Am I correct in assuming you mean that they changed some of the parts for ones which are better quality and that's basically it?
What I meant is that I have looked at Rev 1.5, Rev 2B and Rev 2D mainboards and I can see that the values of certain EMI components do differ. Quality plays no part in this, but cost reductions probably do .

However as stated, for a basic A600 this is not super important, although it could affect signal integrity and EMI. This could then be a problem if your A600 is an edge case and you install an accelerator and other hardware.

If you just want to re-build a basic A600 it should be fine. Be advised that Mick's KiCad board is based on the Rev 2A Gerbers not Rev 2B (although I believe he updated it as much as he could).

But it's not a true Rev 2B mainboard as far as Commodore boards go.

What's the damage on your A600 like?
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Old 12 May 2020, 04:12   #66
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the mainboard is snapped in about 5 pieces where i was working on it and put it down for a few minutes and someond decided it would be a good idea to sit on it.
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Old 12 May 2020, 05:30   #67
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the mainboard is snapped in about 5 pieces where i was working on it and put it down for a few minutes and someond decided it would be a good idea to sit on it.

.. OK that definitely sounds like it is damaged beyond repair!

I strongly recommend that you install PLCC sockets on your replacement board for all PLCC ICs. These parts need to be spared of further re-work cycles in case anything goes wrong and they are the most valuable thing on your A600 motherboard.
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Old 14 May 2020, 00:42   #68
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All that was really recoverable from importing to KiCad was the routing and silkscreen (routing is a difficult part so not complaining) that's why the board looks so original, everything else had to be re-done from the ground up but fortunately I'd already done most of it from my previous attempt. It's good that someone is going to give it a try at least fingers crossed.

I used images of a rev. 2B board on bigbookamiga to find the differences between 2A and 2B, if anyone wants a challenge compare the images there to the KiCad files I uploaded and see if you can spot anything wrong.

Last edited by Mick; 14 May 2020 at 00:50.
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Old 15 May 2020, 12:58   #69
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In Sprint-Layout you can import an image as a background and scale it, this could help spot the differences :-)
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Old 20 May 2020, 16:35   #70
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Originally Posted by rvctech View Post
.. OK that definitely sounds like it is damaged beyond repair!

I strongly recommend that you install PLCC sockets on your replacement board for all PLCC ICs. These parts need to be spared of further re-work cycles in case anything goes wrong and they are the most valuable thing on your A600 motherboard.
Thanks I intend on using sockets for as many chips as possible to make possible fault finding in future easier should I need to.


I'll let everyone know how it goes as I am going to order the board next time I get paid and try to source all new parts (at least what can be bought new) so it's the newest A600 there is then it should be good for many years to come.

so It will be a slow process as it will probably take some time to track down certain parts like the 23 pin connectors but i will get there in the end.

While im on about it does anyone know if the Floppy drives were interchangeable between amigas as mine didn't work and it was a panasonic JU-253-043P and I can't find a replacement with the same model number but I can find a panasonic JU-253-033P from an a500/a500+ but wasn't 100% i think it should be ok but advice from someone who knows more would be appreciated
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Old 20 May 2020, 16:44   #71
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All that was really recoverable from importing to KiCad was the routing and silkscreen (routing is a difficult part so not complaining) that's why the board looks so original, everything else had to be re-done from the ground up but fortunately I'd already done most of it from my previous attempt. It's good that someone is going to give it a try at least fingers crossed.

I used images of a rev. 2B board on bigbookamiga to find the differences between 2A and 2B, if anyone wants a challenge compare the images there to the KiCad files I uploaded and see if you can spot anything wrong.

To be honest Mick it looks the same as the Rev. 1.5 board I had before it was broke. Also don't know if you had a look but I uploaded a copy of the service manual pages that tell you what every motherboard component is to The Zone as you were asking for hi-res images to work out what resistor values etc were so hope it helps.
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Old 21 May 2020, 05:22   #72
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To be honest Mick it looks the same as the Rev. 1.5 board I had before it was broke. Also don't know if you had a look but I uploaded a copy of the service manual pages that tell you what every motherboard component is to The Zone as you were asking for hi-res images to work out what resistor values etc were so hope it helps.

Hi Ceason,

There are a few subtle differences between revision 1.5 and 2A/B. In particular the Rev 2 doesn't support the old Rev 1 Gayle (it has no place for the work-around PAL/GAL).

This is important if you are purchasing a Gayle chip for your replacement motherboard.
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Old 25 May 2020, 23:32   #73
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Hi Ceason87, yeah I received it thanks but things have stalled. I was always reliant on others for the building side of things and I think people have been put off by the first board not working in a way that nobody knows why. I see no reason why the new one won't work though it's routed 99% identically to an original Commodore board, my only concern is the Gerbers having internal power planes but I've been assured numerous times Commodore boards were only 2 layer PCB's so I left them out.
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Old 26 May 2020, 01:32   #74
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Thanks I intend on using sockets for as many chips as possible to make possible fault finding in future easier should I need to.


While im on about it does anyone know if the Floppy drives were interchangeable between amigas as mine didn't work and it was a panasonic JU-253-043P and I can't find a replacement with the same model number but I can find a panasonic JU-253-033P from an a500/a500+ but wasn't 100% i think it should be ok but advice from someone who knows more would be appreciated
Electrically you can use almost any Amiga drive with it (except for the ones used in the ESCOM Amigas which are modified PC drives) but mechanically it's a bad fit because the A600 has it's own unique eject button AFAIK.

It is worth trying to repair the floppy drive that you already have if possible, I have done this a few times now with success.
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Old 26 May 2020, 15:54   #75
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Electrically you can use almost any Amiga drive with it (except for the ones used in the ESCOM Amigas which are modified PC drives) but mechanically it's a bad fit because the A600 has it's own unique eject button AFAIK.

It is worth trying to repair the floppy drive that you already have if possible, I have done this a few times now with success.
I thought of that and stripped the drive down and cleaned everything while I have access to another amiga but it just wont read anything from any floppy so I think the heads may have died somehow
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Old 26 May 2020, 15:58   #76
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Hi Ceason87, yeah I received it thanks but things have stalled. I was always reliant on others for the building side of things and I think people have been put off by the first board not working in a way that nobody knows why. I see no reason why the new one won't work though it's routed 99% identically to an original Commodore board, my only concern is the Gerbers having internal power planes but I've been assured numerous times Commodore boards were only 2 layer PCB's so I left them out.
Hi Mick,

From sending the gerber files of your board to a company and them saying they seem fine I don't see a reason why it shouldn't work and even if it doesn't it's not a fortune for a prototype these days it's only around £20 for something the size of an a600 motherboard so i'm going to have one manufactured next time i get paid and see if I can build a new board from scratch with as many new parts as possible so i'll let you know how it turns out as the board I have is beyond repair so I have nothing to loose in trying to make a new board except a few quid if it doesn't work.
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Old 27 May 2020, 01:34   #77
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I thought of that and stripped the drive down and cleaned everything while I have access to another amiga but it just wont read anything from any floppy so I think the heads may have died somehow
It's rare for the heads to die unless you see signs of physical damage. What happens if you try to format a disk and read it back in the same drive? Does the drive shaft motor spin smoothly and freely? I repaired a drive that couldn't read/write anything, during testing I noticed that the BLDC (shaft) motor rotation wasn't smooth. I don't believe in mass recapping for no reason, but on this drive there was an SMT cap on the motor control board. It looked fine but when I removed and measured it, it was out of specification (had lost around 40% of its capacitance). After replacing it with a new one, the drive motor rotation was smooth and the drive started to work again.

Last edited by rvctech; 27 May 2020 at 01:40.
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Old 27 May 2020, 14:31   #78
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It's rare for the heads to die unless you see signs of physical damage. What happens if you try to format a disk and read it back in the same drive? Does the drive shaft motor spin smoothly and freely? I repaired a drive that couldn't read/write anything, during testing I noticed that the BLDC (shaft) motor rotation wasn't smooth. I don't believe in mass recapping for no reason, but on this drive there was an SMT cap on the motor control board. It looked fine but when I removed and measured it, it was out of specification (had lost around 40% of its capacitance). After replacing it with a new one, the drive motor rotation was smooth and the drive started to work again.

I'll maybe try a new cap on it then as it seems as though it's spinning the disk a little slow all seems smooth though and I have noticed an electrolytic cap on the control board so maybe that's the culprit for the sake of a few pence I may aswell try changing it and see if it gives it new life.

Even though it's spinning slow it seems as though the heads are still trying to read the disk.

Unable to try formatting and reading from the drive as the amiga I have access to has no hard drive so no way of loading workbench and with the drive not reading I can't load x-copy so i'll try the cap idea and see what happens.

Thanks for the advice I hadn't even thought of looking for a cap on a floppy drive to be honest I didn't think it would of had one but live and learn.
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Old 27 May 2020, 15:06   #79
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I'll maybe try a new cap on it then as it seems as though it's spinning the disk a little slow all seems smooth though and I have noticed an electrolytic cap on the control board so maybe that's the culprit for the sake of a few pence I may aswell try changing it and see if it gives it new life.

Yes worth trying with not much else to lose. I would suggest to also check that the motor rotates smoothly and freely when you spin it with your hand (and no disk is inserted). The drive will normally always try to seek the heads (under control of the Amiga), even if the motor control board is completely dead or disconnected.

Head alignment could be an issue too. It's often obvious if the drive can read a disk that it wrote (formatted) itself, but not a disk from another drive. Unfortunately difficult to test in your situation though, without a separate drive to boot the machine.
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Old 27 May 2020, 15:17   #80
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Yes worth trying with not much else to lose. I would suggest to also check that the motor rotates smoothly and freely when you spin it with your hand (and no disk is inserted). The drive will normally always try to seek the heads (under control of the Amiga), even if the motor control board is completely dead or disconnected.

Head alignment could be an issue too. It's often obvious if the drive can read a disk that it wrote (formatted) itself, but not a disk from another drive. Unfortunately difficult to test in your situation though, without a separate drive to boot the machine.
Ok cheers i'll check that aswell.

I did try making a bootable hard drive in winUAE for the system but ran into issues as i just get a loadmodule error (devices still initialising) when trying it in the actual machine but it works fine in winUAE if I leave it a do a soft reset it just never reaches workbench so i gave up on that idea
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