Corrections: PC floppy drives DO have a disk change switch (or the drive wouldn't know when you've changed disks!) - my memory failing there lol. The point I was measuring that pull up (before I tried to fit a 3K3 resistor) - it showed 10K on the meter (9.98K) - no idea how I thought that said 1K... At 47:02 I decided to refer to D800 as D900 - no idea why lol. Thanks to Mr T Guru for recommending Logica to test RAM. The CPU is not always disabled by use of the CPU slot (some cards can disabled it, others need you to remove it) - something I was surprised to find. I think I am thinking of the 1200 where the onboard CPU can be disabled via the expansion slot. It seems on the 2000 you have to remove the 68K. Links to things mentioned in this video:- Part 1 - ua-cam.com/video/uDhxK5NUcFk/v-deo.html Amiga Forever - www.amigaforever.com/ 41256 DRAM Equivalents - www.minuszerodegrees.net/memory/41256.htm Ian Stedman Amiga Blog - www.ianstedman.co.uk/Amiga/amiga.html Another World Complete Play Through (Morgan Just Games) - ua-cam.com/video/ovMF4MFD-8U/v-deo.html
Totally amazing Videos on the Amiga 500/2000s! I've watched them all and will go back over them in the coming weeks...I've picked up an Amiga 2000 since the one I had in storage is in parts but I now think I will find the parts to that and re-cap it along with the PSU. 10 out of 10 on these Videos! -Mark.
Be careful with those schottky diodes! They have a much greater reverse leakage current than normal silicon diodes and might actually charge the battery when the system is turned on, causing it to leak at some point. Your 1N5711 has a maximum specified leakage current of 0.3µA at 50°C which is likely still okay (Energizer specifies their CR2032 at max. 1µA charge current), however other diodes might not work as well. An 1N5817, for example, has a specified maximum reverse leakage current of 1mA(!) - that'd be a guaranteed leaking battery. In any case, I'm loving your videos, keep up the great work!
Excellent as always :) About the Elec&Eltek powersupply: If you have a white little sticker which says "00" near the serial number batch it has already the 0.01uF mod. I've recapped 2 of them and both had the sticker. If you do a video it would be great if you're gong into detail with this mod. If you're going to replace the old and loud fan, for sure, you have to make sure that the fan takes a minimal ammount of around 0,6 amps because if it's less the powersupply's saftey function switches off a few seconds after you switch on. This would be really great to see this in detail because there are always the same problems which people have if they're replacng the fan. Also, look out for a fan with a maximum of 1500rpm at 12V to get it quiet. Also take care, on some eleks the 80x80x25 have a very very tight fit, but it fits. Sometimes these eleks have original 80x80x25 and sometimes 80x80x20. For the big capacitors i've choosen 250v nichicon 105°C as 105°C for all the oher capacitors as well.
Thanks! Yes, was aware of the "00" marking! Will be recapping it, but won't swap the fan at this stage as mine is nice and quiet. I've added some additional internal cooling in the main case.
I've been a fan of Commodore computers for years but, unfortunately, they were never released in my country and even now they are almost impossible to find but I still hope to be able to get an Amiga 2000 some day.
I have the DIAGROM chips for a couple Amiga's but never really put them to use yet. I did not know there was a Diagnostic ROM on Amiga Forever so I will have to look at the CD's. I am always amazed at what Amiga Forever has on it. I have my A2000HD fitted with PS/2 adapters and with an Indivision Board I have it connected to a KVM Switch. I have my A2000HD sitting in my server rack to save space because its a beast of a system but its out now for some modifications and hopefully soon I will get around to pulling the motherboard out to test the caps and I might recap it but I am more interested in working on the Zorro Bus because its been acting strange so I want to look at it under the microscope to examine the edge connectors, solder joins and look for micro-cracks.
The A500 keyboard does have a reset circuit on it that pulls the reset line low when you hold down CTRL and the two Amiga keys. The A2000 has such a circuit on the motherboard itself, which is why its connector doesn't have the reset signal.
Thanks! My understanding is that the Ctrl+Amiga+Amiga is done differently on the 2000 though - ie. some clever technique is used on either the clock or data line, rather than how it works on the 500 where the keyboard pulls the reset line low for the system.
@@GadgetUK164I have done extensive work on this. I have a A2000 keyboard with only 4 pins from the factory! The A1000 keyboard has only 4 pins as well, and believe it or not is theoretically compatible with the A500/A2000. So there is an actual keycode for reset that comes on the data pin (and I believe it is still sent on keyboards with the 5th reset wire). See my posts as "Dr Remulak" on: forum.arduino.cc/index.php?topic=139358.0
Edit: Sorry commenting as I watched, I see you picked up on the info below later in the video :) I should have known you'd catch up on that! Indeed on the earlier Amiga 2000s the Fast RAM is mapped to true (Zorro II) Fast RAM memory space, whereas on the Amiga 500 it's mapped to the so-called Ranger memory space at $C00000-$D7FFFF also called Slow RAM. It does make these earlier Amiga 2000s faster due to the CPU having some direct memory it can access without the Agnus bottleneck that gives the A501 and similar card's name of Slow RAM.
When I saw you preparing the cable and plug for A500 keyboard and said you didn't have a shell for it I was thinking of using a whole Amiga 500 case as shell for the keyboard. LOL. That would have been ridiculous. Maybe making some feets for the Amiga 500 keyboard would have been a solution for more permanent use with an Amiga 2000. Wouldn't look very good but would work I guess. Running Diagnostic in WinUAE! LOL! Good one!
Haha - yes, i thought about using full A500 case for the keyboard enclosure too! If you had a spare case you could cut it down at the back end I guess and somehow make it not as long as it is.
Actually, that's the easiest way to get the rom saved to a file - works also great with Logica Diagnostica... Just run WINUAE with the Logica-Rom and enter the debugger (I guess, F12?). There you can save the whole region of the rom to a file. Done. So, at least, there is a usage... 🤣
Great video, as usual. I'm late to the comment party, as usual, too. =/ It's interesting to see the differences between DiagROM and Logica in action. I see _chucky_ has just released a stable V1.2 of DiagROM with some improvements (as well as a framework for upcoming RAM test improvements). Also -- and I am no expert -- I was going to ask about using a Schottky diode for reverse voltage protection, but I see Jonathan Strobl already commented on this. I would love to learn more, though.
Excellent video again mate, and just to mention Ebay prices for amgia hardware absolutely crazy prices mate you can buy atop quality lap top for what they are asking for lol.
3.5 inch PC floppy drives have disk detection switch. You can find the disk change signal on pin 34 (also you can hear them spinning briefly to engage the hub when you insert a disk). The problem is there were no agreement between manufacturers so you'll find some drives spitting an active low signal while others spit an active high. That prevented Microsoft to implement autorun for floppy drives back in Windows 95. Maybe there were cheap units without that switch, but I've never seen one.
Thanks, yes - see my correction up top! I worked that out whilst it was uploading lol. My memory just failing! Without a detect switch any FDD would not know if the disk had been changed or not.
IMO replacing all the RAM chips would be prudent. In a few months another chip may fail, and a few months after another will fail, repeat... Doing them all at once would also avoid damaging the replacement sockets when removing adjacent chips, etc.
Yeah, that can be the case - hence why I mentioned it at the end of the video. But... On many occasion I've just swapped the faulty IC and the others have been fine for years, which is why I haven't replaced them all yet. I've been using that board a fair bit and OK so far! Only time will tell!
Top video Chris, That Amiga 2000 board is looking \ working Sweeeet now. £200 for a keyboard, ouch. I too can't wait for the TF536; it's going to rock in my Amiga 500.
I didn't know Amiga Forever had the Logica ROM on it, thanks for the information. However, after taking a look at the files on the disk, the Logica ROM doesn't appear to have the key applied to it and is the right length (524,288 bytes).
It might be a case that "early" purchases of Amiga Forever have an unencrypted version of the ROM? I just know that I checked the website and it seemed to suggest they were for use only with WinUAE, and I see lots of people moaning about it too.
Great video but why did you have to put that idea in my head at the end. Please excuse me while I go to ebay to find an A2000 board 😂 Am looking forward to your A500+ repair since I have one myself that needs a bit of love.
Thanks! LOL! Apparently the checkmate cases won't fit a 2000 board =/ There are spare 2000 cases on eBay from time to time though - 2 on there the other day.
Can you provide some more info on the Demagnetizer as I think I will have to get one for more than my 1541s. Also, which Molykot are you using? You mentioned it in a previous Video but I couldn't readily find it. Thanks. -Mark.
You want something like this:- www.ebay.co.uk/itm/Analogue-Studio-Tape-Head-Demagnetiser/392296317884?hash=item5b56aec3bc:g:yA8AAOSwo51dQHVA It is seldom used but can sometimes fix heads that seem to be magentized (or the surrounding chasis parts etc). It's also useful for degausing old CRT TV / monitors too.
Amigas are crazy prices these days across the board - I saw someone on ebay trying to sell an A600 with no video output for £80 and I wouldn't be surprised if someone buys it at that price. Only about 3/4 years ago I picked up a couple of A600s in good condition for about £30 each.
@@barnabas5688 Yep. I just bid on a busted A1200, non-working board only. It looked to be pretty badly damaged. I thought screw ot snd went to about £55. It went for £125. That is just the board 🤣
I got an "untested" (aka messed around, lost the screws, couldn't fix, put on ebay) A600 for 60 quid not long ago. It had all the usual a600 issues like leaked caps and broken composite output. There are some reasonably priced Amigas out there if you don't mind fixing them.
Mine was that price too (£200) - from Poland! No other bids though, I think I lucked out because due to the description it wasn't coming back when you searched for Amiga 2000.
Where did you get the text file ? Can you give the link/make it available ? - I found the Commodore TechTopics, but need to browse a bit :) I have a 4.1 rev A2000 (B2000) motherboard, bought in '87 with 8088 Bridgeboard, with the 470 Ohm resistor from Point f5, and the R5719 installed without the resistor suggested. I kept it uptodate with the Fat Agnus ECS, Denise ECS and Kickstart 3.1 (want to get 3.1.2, though), but something on the PSU or the MB blew smoke recently after switching on from long time no use. I now removed C910 and C911 and had/have to do a little battery leakage clean-up (need to clean up part of the 68000 socket for which I got some replacments) replacing the 3V, so your diode bit is exactly what I need. Do you have a part number/naming for that Schottky Diode ? - never mind, found my answer in the comments :)
I wondered about Fairchild too when editing, but if you look at the link to the different DRAM chips (up top in the pinned comment) you will see that these are Fujitsu!
Hi Chris can you please check your messages on EAB board. I left a message about a possible repair, and some donations, dont use twitter so cannot contact you. Excellent video as always. Thanks
Corrections: PC floppy drives DO have a disk change switch (or the drive wouldn't know when you've changed disks!) - my memory failing there lol. The point I was measuring that pull up (before I tried to fit a 3K3 resistor) - it showed 10K on the meter (9.98K) - no idea how I thought that said 1K...
At 47:02 I decided to refer to D800 as D900 - no idea why lol.
Thanks to Mr T Guru for recommending Logica to test RAM.
The CPU is not always disabled by use of the CPU slot (some cards can disabled it, others need you to remove it) - something I was surprised to find. I think I am thinking of the 1200 where the onboard CPU can be disabled via the expansion slot. It seems on the 2000 you have to remove the 68K.
Links to things mentioned in this video:-
Part 1 - ua-cam.com/video/uDhxK5NUcFk/v-deo.html
Amiga Forever - www.amigaforever.com/
41256 DRAM Equivalents - www.minuszerodegrees.net/memory/41256.htm
Ian Stedman Amiga Blog - www.ianstedman.co.uk/Amiga/amiga.html
Another World Complete Play Through (Morgan Just Games) - ua-cam.com/video/ovMF4MFD-8U/v-deo.html
Totally amazing Videos on the Amiga 500/2000s! I've watched them all and will go back over them in the coming weeks...I've picked up an Amiga 2000 since the one I had in storage is in parts but I now think I will find the parts to that and re-cap it along with the PSU. 10 out of 10 on these Videos! -Mark.
Thanks =D Much appreciated!
Been waiting for this part 2. Thanks for another great repair video. Cannot wait for more Amiga/C64 related repair videos. Keep em coming!
Thanks! A small break this weekend but back to the Amiga soon as I've got a lot more queued up Amiga vids yet.
Be careful with those schottky diodes! They have a much greater reverse leakage current than normal silicon diodes and might actually charge the battery when the system is turned on, causing it to leak at some point. Your 1N5711 has a maximum specified leakage current of 0.3µA at 50°C which is likely still okay (Energizer specifies their CR2032 at max. 1µA charge current), however other diodes might not work as well. An 1N5817, for example, has a specified maximum reverse leakage current of 1mA(!) - that'd be a guaranteed leaking battery.
In any case, I'm loving your videos, keep up the great work!
Thanks! I am aware of leakage current, but will be honest - didn't check that before I ordered them. I think I just lucked out with this one.
Excellent as always :)
About the Elec&Eltek powersupply: If you have a white little sticker which says "00" near the serial number batch it has already the 0.01uF mod. I've recapped 2 of them and both had the sticker. If you do a video it would be great if you're gong into detail with this mod.
If you're going to replace the old and loud fan, for sure, you have to make sure that the fan takes a minimal ammount of around 0,6 amps because if it's less the powersupply's saftey function switches off a few seconds after you switch on. This would be really great to see this in detail because there are always the same problems which people have if they're replacng the fan.
Also, look out for a fan with a maximum of 1500rpm at 12V to get it quiet. Also take care, on some eleks the 80x80x25 have a very very tight fit, but it fits. Sometimes these eleks have original 80x80x25 and sometimes 80x80x20. For the big capacitors i've choosen 250v nichicon 105°C as 105°C for all the oher capacitors as well.
Thanks! Yes, was aware of the "00" marking! Will be recapping it, but won't swap the fan at this stage as mine is nice and quiet. I've added some additional internal cooling in the main case.
I've been a fan of Commodore computers for years but, unfortunately, they were never released in my country and even now they are almost impossible to find but I still hope to be able to get an Amiga 2000 some day.
I have the DIAGROM chips for a couple Amiga's but never really put them to use yet. I did not know there was a Diagnostic ROM on Amiga Forever so I will have to look at the CD's. I am always amazed at what Amiga Forever has on it. I have my A2000HD fitted with PS/2 adapters and with an Indivision Board I have it connected to a KVM Switch. I have my A2000HD sitting in my server rack to save space because its a beast of a system but its out now for some modifications and hopefully soon I will get around to pulling the motherboard out to test the caps and I might recap it but I am more interested in working on the Zorro Bus because its been acting strange so I want to look at it under the microscope to examine the edge connectors, solder joins and look for micro-cracks.
The A500 keyboard does have a reset circuit on it that pulls the reset line low when you hold down CTRL and the two Amiga keys. The A2000 has such a circuit on the motherboard itself, which is why its connector doesn't have the reset signal.
Thanks! My understanding is that the Ctrl+Amiga+Amiga is done differently on the 2000 though - ie. some clever technique is used on either the clock or data line, rather than how it works on the 500 where the keyboard pulls the reset line low for the system.
@@GadgetUK164I have done extensive work on this. I have a A2000 keyboard with only 4 pins from the factory! The A1000 keyboard has only 4 pins as well, and believe it or not is theoretically compatible with the A500/A2000. So there is an actual keycode for reset that comes on the data pin (and I believe it is still sent on keyboards with the 5th reset wire). See my posts as "Dr Remulak" on: forum.arduino.cc/index.php?topic=139358.0
To expand on my comment there - The A500 keyboard pulls the KBRESET line low - not the main reset. It's done via Gary.
Edit: Sorry commenting as I watched, I see you picked up on the info below later in the video :) I should have known you'd catch up on that!
Indeed on the earlier Amiga 2000s the Fast RAM is mapped to true (Zorro II) Fast RAM memory space, whereas on the Amiga 500 it's mapped to the so-called Ranger memory space at $C00000-$D7FFFF also called Slow RAM. It does make these earlier Amiga 2000s faster due to the CPU having some direct memory it can access without the Agnus bottleneck that gives the A501 and similar card's name of Slow RAM.
When I saw you preparing the cable and plug for A500 keyboard and said you didn't have a shell for it I was thinking of using a whole Amiga 500 case as shell for the keyboard. LOL. That would have been ridiculous. Maybe making some feets for the Amiga 500 keyboard would have been a solution for more permanent use with an Amiga 2000. Wouldn't look very good but would work I guess. Running Diagnostic in WinUAE! LOL! Good one!
Haha - yes, i thought about using full A500 case for the keyboard enclosure too! If you had a spare case you could cut it down at the back end I guess and somehow make it not as long as it is.
Actually, that's the easiest way to get the rom saved to a file - works also great with Logica Diagnostica... Just run WINUAE with the Logica-Rom and enter the debugger (I guess, F12?). There you can save the whole region of the rom to a file. Done. So, at least, there is a usage... 🤣
Thanks for sharing your work bud this is great!
Great video, as usual. I'm late to the comment party, as usual, too. =/ It's interesting to see the differences between DiagROM and Logica in action. I see _chucky_ has just released a stable V1.2 of DiagROM with some improvements (as well as a framework for upcoming RAM test improvements). Also -- and I am no expert -- I was going to ask about using a Schottky diode for reverse voltage protection, but I see
Jonathan Strobl already commented on this. I would love to learn more, though.
Excellent video again mate, and just to mention Ebay prices for amgia hardware absolutely crazy prices mate you can buy atop quality lap top for what they are asking for lol.
Thanks =D Yes, prices are getting crazy =/
3.5 inch PC floppy drives have disk detection switch. You can find the disk change signal on pin 34 (also you can hear them spinning briefly to engage the hub when you insert a disk). The problem is there were no agreement between manufacturers so you'll find some drives spitting an active low signal while others spit an active high. That prevented Microsoft to implement autorun for floppy drives back in Windows 95.
Maybe there were cheap units without that switch, but I've never seen one.
Thanks, yes - see my correction up top! I worked that out whilst it was uploading lol. My memory just failing! Without a detect switch any FDD would not know if the disk had been changed or not.
IMO replacing all the RAM chips would be prudent. In a few months another chip may fail, and a few months after another will fail, repeat... Doing them all at once would also avoid damaging the replacement sockets when removing adjacent chips, etc.
Yeah, that can be the case - hence why I mentioned it at the end of the video. But... On many occasion I've just swapped the faulty IC and the others have been fine for years, which is why I haven't replaced them all yet. I've been using that board a fair bit and OK so far! Only time will tell!
Top video Chris, That Amiga 2000 board is looking \ working Sweeeet now. £200 for a keyboard, ouch. I too can't wait for the TF536; it's going to rock in my Amiga 500.
Thanks mate! Yeah, £200 = crazy!!! There are other solutions - I am using a wireless keyboard with it atm!
That was AWSOME!
Greate work.
Cheers =D
Never used an Amiga in my life, but really want to get my hands on one someday. Seem to be rarer than hens teeth here in Canada.
Excellent video.
Thanks =D
You do have the French version of Another World. I've only seen it in English, and over here it was called Out of this World.
Thanks for another quality video Chris love these videos
How much for a keyboard 😮
Thanks! Much appreciated! Next video is not Amiga related, but there are 5 or more that will follow soon after.
I didn't know Amiga Forever had the Logica ROM on it, thanks for the information. However, after taking a look at the files on the disk, the Logica ROM doesn't appear to have the key applied to it and is the right length (524,288 bytes).
It might be a case that "early" purchases of Amiga Forever have an unencrypted version of the ROM? I just know that I checked the website and it seemed to suggest they were for use only with WinUAE, and I see lots of people moaning about it too.
Great video but why did you have to put that idea in my head at the end. Please excuse me while I go to ebay to find an A2000 board 😂
Am looking forward to your A500+ repair since I have one myself that needs a bit of love.
Thanks! LOL! Apparently the checkmate cases won't fit a 2000 board =/ There are spare 2000 cases on eBay from time to time though - 2 on there the other day.
Thanks for posting enjoyed the video!
Cheers =D
Can you provide some more info on the Demagnetizer as I think I will have to get one for more than my 1541s. Also, which Molykot are you using? You mentioned it in a previous Video but I couldn't readily find it. Thanks. -Mark.
You want something like this:- www.ebay.co.uk/itm/Analogue-Studio-Tape-Head-Demagnetiser/392296317884?hash=item5b56aec3bc:g:yA8AAOSwo51dQHVA
It is seldom used but can sometimes fix heads that seem to be magentized (or the surrounding chasis parts etc). It's also useful for degausing old CRT TV / monitors too.
Outstanding video! £200 for a keyboard? I nearly spit my coffee lol.
LOL! I did too when I saw the price!
Maybe it was RGB? Everyone knows that RGB is essential for a proper keyboard. £200 is a bargain! :P
Amigas are crazy prices these days across the board - I saw someone on ebay trying to sell an A600 with no video output for £80 and I wouldn't be surprised if someone buys it at that price. Only about 3/4 years ago I picked up a couple of A600s in good condition for about £30 each.
@@barnabas5688 Yep. I just bid on a busted A1200, non-working board only. It looked to be pretty badly damaged. I thought screw ot snd went to about £55. It went for £125. That is just the board 🤣
I got an "untested" (aka messed around, lost the screws, couldn't fix, put on ebay) A600 for 60 quid not long ago. It had all the usual a600 issues like leaked caps and broken composite output. There are some reasonably priced Amigas out there if you don't mind fixing them.
I missec out on an AMIGA 2000 on ebay the other day, Rev 6.2, sold for £200!
Mine was that price too (£200) - from Poland! No other bids though, I think I lucked out because due to the description it wasn't coming back when you searched for Amiga 2000.
I take it your constant stating and on screen notes about how the board was not on the carpet was aimed at the trolls?
Yep lol, but also to make it clear to anyone that is watching that you should use an ESD mat.
Chris, do you have a link where I could find replacement or equivalents for DRAM 514256 256kx4? The one in description is not working.
Just search eBay for 41256 DRAM - there are a number for sale there!
I read that the A2000 can handle hd floppy drives, the same ones as used in the A4000? Presumably you would need to be running kickstart 3.1 though?
Not something I've looked at! I didn't even know the 4000 had HD drives!
GadgetUK164 - Retro Gaming Repairs & Mods I believe they also were supplied with a copy of WB on High Density disks.
Where did you get the text file ? Can you give the link/make it available ? - I found the Commodore TechTopics, but need to browse a bit :)
I have a 4.1 rev A2000 (B2000) motherboard, bought in '87 with 8088 Bridgeboard, with the 470 Ohm resistor from Point f5, and the R5719 installed without the resistor suggested.
I kept it uptodate with the Fat Agnus ECS, Denise ECS and Kickstart 3.1 (want to get 3.1.2, though),
but something on the PSU or the MB blew smoke recently after switching on from long time no use.
I now removed C910 and C911 and had/have to do a little battery leakage clean-up (need to clean up part of the 68000 socket for which I got some replacments) replacing the 3V,
so your diode bit is exactly what I need. Do you have a part number/naming for that Schottky Diode ? - never mind, found my answer in the comments :)
It's linked in the video description and the pinned comment up top!
16:00 the way a lot of retro hardware and software is licensed and sold is pretty messed up :(.
the F on the chips stands for Foocked.i repair arcade pcb's and i check power rails clock and look for the F chips.think its fairchild
I wondered about Fairchild too when editing, but if you look at the link to the different DRAM chips (up top in the pinned comment) you will see that these are Fujitsu!
24:06 Just say "shot key". :)
Thanks, will try and remember that =D
shot-key diode
Thanks! Will try and remember that =D
Argh. Seen it!
LOL =D
Hi Chris can you please check your messages on EAB board. I left a message about a possible repair, and some donations, dont use twitter so cannot contact you. Excellent video as always. Thanks
Will respond shortly - catching up!