Can the Amiga Diagnostic ROM help me figure out what was wrong with this Amiga 500?
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- เผยแพร่เมื่อ 20 ก.ย. 2024
- This Amiga 500 is giving me the green screen of death. Let's try to figure out exactly what's wrong with it, and then fix it. I end up trying to use the Amiga DiagROM to help me, but it was unfortunately of limited help.
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Programmer of DiagROM here.. the reason for "not good enough" ramtest at start is: there are NO memory so all tets is done using registers only. This includes serialhandling... There are simply enough no ram available for doing more advanced tests. D0-D7 and A0-A7 only. (Leaving a total of 64 bytes of ram to work with) However daily beta 1.3 handles adressissues aswell.
Also. As there are so many different combinations of rams on amiga it is impossible to do a pinpoint. So you simply need to look what bits are bad and check schematics. It is however more common that it is motherboardissues than it is chip issues. Agnus socket being the most responsible error.
@Mr Guru cant remember how it looks but i have a weak memory of it defaulting to yiu having an 500. Also dialogoca does not do this test at boottime as diagrom does. It does that when it got memory to work with, while the test he used is at startup before any memory whatsoever is detected
On amiga there are different chipsetups for a1000, 3 (i think) for 500, 2 for 2000, 2 different for a1200, a600, cd32, a3000 and a4000. So "impossible" to pinpoint the chip. As you cannot detected the different machines realibly enough
@Mr Guru as i told. I cant remember. And i by choise did not want a user to select what machine they have. And i must say after some years that was a good thing as many have not a clue what machine they are working with. Like what rev of motherboard etc... That is why i have a about screen in 1.3 tellibg that diagrom is not for those who want a program that say "chip x is dead" and diagrom also scans memory to use. And if no chipmem is found it tries fastmem to use as memory instead. Dialogoca will not do that and would not even run on his machine as it woudnt find any ram and not be able to tell why. Ao it is ironical as he only used the scanroutine. Not even the memtestroutine.
And also how do you detect a bad chip vs the way more common motherboard/socketissue? If it told chip xx is dead someone swaps it and it is still bad. People would complain. So it is a tool for people to find issues using their knowledge. Not for people without common knowledge of the system
Just nice to see an Amiga come back to life.
I thought it was the blue screen of Death I didn't know there was a green screen of death🤣
Having certain chips socketed and some not, enabled vendors of the day (including Commodore) to produce boards quickly, populated with off the shelf components and then hold them in stock. Production was not halted using this method, and gave the added benefit of having an inventory of "less expensive" boards that could be called off, populated, as and when required, according to demand. Easier to solder a socket, than waiting for a custom 8372A.
I love Commodore repair videos, can we have an Amiga repair-a-thon please!?!?!😅👍🏻
I totally agree ! Thx Bas !!!
Yes Adrian... I was one of those screaming at the screen lol, There is a useful feature of the diag rom you missed, right at the start the green and red bars that show after the flashing screen indicate individual data lines of each ram chip, you can easily isolate the bad chips by either disrupting the good ram data line or inject data onto the data lines and watch the screen in real time for changes... I saw instantly you had more than one bad just from those lines they should all be green and divided into four quarters you can see that your ram was bad on more than one.. I have found injecting CS (or maybe RAS or CAS its been a while) onto the bad chips data lines changes the red stripes to green thus highlighting the exact ram chip thats bad... I must admit though I did find this by accident as the diag rom manual was not super informative... Good stuff though I love repair videos so keep it up. (perhaps a recap video showing the feature and how to diagnose using it?)
this sounds like a great tip. thanks for contributing.
Green screen does not necessarily mean bad ram. It means there was a problem communicating over the chip data bus. Quite often in a machine that has had battery leakage near it (usually more the case with the 500+) the problem is in the "DATA PATH" section rather than the RAM itself
Yeah, every time I got a green screen it was because Fat Agnus was loose, and reseating it fixed the problem.
@Peter Mulholland I wondered if you'd watch this 🙂. @Adrian Diagrom's serial output comes in very handy sometimes👍. Especially if there is no video output, it gives you a good idea what is, and is not, working 🙂.
@Mr Guru DiagROM will run even when the machine cant boot. In this case the RAM was so badly gone the machine couldn't work at all. DiagROM is also capable of showing you exact memory fault locations.
@Mr Guru no logica requires chipmem to run. His machine did not have chipmem
Yup. I had a machine with a bad 8520 throw a green screen once. If something is on the bus that is inhibiting access to 00000-1FFFF for whatever reason, you'll get a green screen.
It's really weird: Those Siemens DRAM chips all seem to be failing these days!
I've repaired about 5 Amiga 500s this year in which about 12 of these Siemens chips were bad. It's like they all reached their expiry date or something. Usually Siemens is a pretty reliable brand in my experience (their CPUs for instance are excellent!), but not with these machines. It might be caused by bad PSUs of their previous owners though as DRAM is very sensitive to overvolting power supplies.. Anyway I always replace those crappy Siemens units with OKI chips. Japanese quality for the win. My all time favourite DRAM brand as not a single one has failed on me yet 👍
Amiga Diagrom is a cool product and I use it all the time (infinite kudos to Chucky), especially because of its very useful serial output feature but its RAM test routines are pretty flaky to say the least. They're very rudimentary indeed (no checkerboard test etc.). You should try Logica Dialoga. It's a way, way better diagnostics suite from back in 1991 which you can also run from a 27C400 EPROM on these machines👍 I can send you a de-XOR-ed copy if you want as its copyrights should've expired by now.. You can also find this ROM image if you have a copy of Amiga Forever but you'll need to grab the decrypted ROM while the (virtual) machine is running, using WINUAE for instance.. It's the most useful tool out there for catching bad RAM chips and catching things like CIA or interrupt errors.
Especially on a rev 4.3 Amiga 2000 for instance, which has 32 DRAM chips Logica Dialoga is a must have unless you really like desoldering ;-)
Oh and the TL866 can burn 27C400 EPROMs (up to 27C322 32mbit/4 meg units). You'll just need an adapter. Digicoolthings.com is one of the guys that sells these (not a sponsor, just bought mine there ;-) )👍
Thank you for the awesome info here. I hadn't seen these Siemen's ICs much before -- so fascinating they are all dying left and right. I will add them to the list to watch out for. Is it just the 44256 type or are others bad too?
And then Logic Diologa--- too cool. I hadn't heard of that one, so a better and higher quality ROM based RAM test is highly desirable. If you could email me, you can get my email at my channel about page -> business inquiries.
Thanks!
@@adriansdigitalbasement
Yeah, it's the 44256 units on these A500s you definitely should watch out for. I think it must be because of overvolting PSUs of their previous owners (if I had to guess as it's a pretty common phenomenon on A500s). I think these Siemens units are particularly sensitive to that. Amiga 2000 rev.6 machines use these exact same chips but I've never encountered a faulty one on those yet so it must be flaky external PSUs of the A500s that are causing this high failure rate..
Yeah, it's GadgetUK164 (another Amiga nut like me) who gave me the idea to use Logica Dialoga and it proved very useful to me. I use it a lot while piggybacking DRAM on Amiga 2000 boards as I repair a lot of broken rev. 4.3 units for my customers as they abundantly available here in the Netherlands being German machines and all.. This suite makes it pretty easy to spot flaky DRAM chips without having a fully booting machine..
All right, I will e-mail you the image Adrian. Keep up the good work producing awesome content 👍
@Mr Guru Ah so you are Gadget's friend he mentioned in his video. That's awesome, thank you for the (indirect) recommendation! I'm sure you helped out a lot of people in the retro community through his channel (y)
it must be something internal degrading or that moister is getting inside corroding the internal which is possible.
Maybe so, or it ould be caps failing and taking out other components with them as they go full short.
Nice to see an Amiga repair. If you plan on keeping the 500 I would suggest replacing the 2 large caps near the video port. I'm not a fan if just replacing caps but these two like to fail to a short and can take out your video.
having done plenty of amiga repairs i have never seen those capacitors go short. However, they can lead to noisy video.
All the time I was expecting you to get the RetroChipTester and test the memory chips individually (after desoldering) :-D Glad you got it working again!!
Glad to see you recovered, did you test those bad RAM chips on the Ultimate Retro Chip tester?
After all these years and your awesome repairing skills, it's still emotional to see a screen going from grey to the hand holding a workbench disc 👍😃
Adrian, why didn‘t you test the ram chips using your retrochip tester?
My guess: it's some place that would hurt to get to with his shoulder screwed up.
I asked the same thing. I'm guessing he gets so many donations, he forgets everything he has. Or he realized it wouldn't make for an exciting video. Just pop the chips in the tester and once they read bad swap the chips out. Wallah, an 8-minute video.
good question, but do any of those chip testers really stress test ram chips? they might only fail at full speed and i think those chip testers are pretty slow.
Thanks Adrian. Always glad to see your videos.
Really wanted to see the video end with a classic demo or the intro to Another World running. I feel like you should end all successful fixed Amigas with that Adrian. :)
I love a good Amiga video, especially where someone takes one that doesn't work, and makes it work! Thanks Adrian!
There are some revisions of the A500/A500+ board, and the Agnus chip that allow to address up to 2MB of chip RAM by using 4x1Mbit chips instead of the 4x256kbit ones, and some extra passive components (AFAIK a diode, and a few resistors). I can't recall the original source where I have my guide from (which is in storage together with my A500), I think it was one of the larger Amiga forums.
I couldn't find any 4x1M chips in a DIP socket, so I made some SOJ28 to DIP adapters (ordered them at PCBWay or JLCPCB, I can't recall) and used memory chips from 1MB 30 pin SIMMs :) It's not yet finished, since I had to move from my flat, and put lots of my stuff into storage, including the Amiga as well. Someday I might be able to finish it, hopefully... (or just get one of those Agnus riser boards with a singe 2MB chip on them)
3:00 in SouthAmerica the first C64s were of course imported directly from USA so they were 110V@60Hz, but many countries just used a stepdown transformer from 220V to 110V and disregarded the fact that their mains runs at 50Hz (which of course affected sound and video signals); several years later C64s were locally produced with a power supply input of 220V and internally modified according to the 50Hz frequency.
I remember back in the day, I had a C64 for a couple of years. Then we got some new neighbors, and they had an A500. I was absolutely floored by the graphics since the best I'd seen at that point on the 64 was a whole 16 colors. I wasw so envious of them for having that system. I practically begged my parents for one, but it just wasn't something they would do. It wasn't until 1995 that I got a computer (Pentium 166) capable of displaying more than 16 colors.
I was supposed to get the A500 from my uncle at around 1993/94. I was playing with that machine every time I visited him. But one evening he got drunk and sold that machine.. "my" A500.. to the brother of his wife. Little me was heartbroken. A year later in 1995 I've got his used Cyrix 5x86 100mhz PC instead, initially without a soundcard. It was not the same since I couldn't play my favourite Amiga games. It wasn't until 5 or 6 years ago, that I've got the fs-uae emulator working on my Linux PC, that I could *FINALLY* play "Lotus Turbo Challenge II" again! I was dancing in my appartment like a total fool for half an hour to the intro music of that game... lol! 😅😎
@@andreasklindt7144 LT II was fucking awesome
Great timing for an A500 video.
Just got a great condition Amiga 500 recently ntsc US machine with rev 6A mainboard with 8372A agnus just like the one in the video. Mine has TI ram chips though(checked after this video lol). Recapped the whole machine, and soldered in a new agnus socket because the stock one was cracked. The machine worked perfectly fine with the cracked socket but I wanted to replace it anyway because it bugged me, and should be more reliable now. Anyway great to have an Amiga again after alot of years, and I'm enjoying going through old games, love the tunes on this machine!
I'm always confident that whatever you work on, you're going to get it running, I only wish I had that much confidence in myself!
On a side note, today was a truly great day for me! I picked up a TRS 80 1 (first computer I ever touched), a TRS 80 4, and a Ti 4a in the box, all kinds of peripherals and software. They're all close to mint from the original school teacher owner! WooHoo!
You inspired me to touch base with the past, and boy, I did it today! Thanks Adrian...
Nice compositing of the video feeds.. Scope, CRT and your actions. Very COoL.
Socketing the RAM chips on an A500 is usually not recommended because the sockets raise the chips high enough to foul on the keyboard unless you use low profile sockets.
There are 2x74LS244 and 2x74LS373 that sit on the data line between the RAM and the ECS chips. A break in the traces on these lines or a bad logic IC will also cause a green screen. 90% of the faults on an A500+ are caused by battery leakage destroying the traces on these lines, usually under the chips themselves.
Also, DiagROM only performs a cursory RAM test at startup, mostly to check if RAM is present and usable because it takes several minutes to do a complete check of all the memory. In the menu there is an option to perform a complete memory test which is more like the test used in the Amiga Test Kit.
I've repaired a number of 500's and never seen a memory error like that one myself so I would have been scratching my head as well.
I wonder if battery leakage was the real problem, and these replacement chips just somehow bypass it. Damaged trace making the signal weak, but the new chips can still understand it while the old ones can't?
Hello, Adam.
I am from Monterrey, Mexico, and I can confirm that Commodore Amiga 500s were sold out of a major chain retail store called Soriana which is similar to Wal-Mart, in the late 80's or early 90's. Two friends bought Amiga 500s when they noticed the local Soriana branch where we lived had the machines on display but marked with a lower price than what they were actually worth. They quickly snatched the machines before the store managers noticed anything was wrong. That was the first time I had seen an Amiga computer. Before that, I was acquainted with the PC, the Tandy Color Computer and the VIC-20.
I don't think these Amiga computers were specially modified for the Mexican market because the TV format in Mexico is indeed NTSC but since my friends also bought Commodore monitors for their computers, then I could not really tell you if they had anything special other than the fact the store sold them at below cost by mistake.
When you have an upgraded agnus (8372A), DiagROM can use the add in memory (another 512K in the internal plug in port), to boot around the bad onboard RAM and let you test the bad ram.
Good to know!
Very
Thank you, that makes so much sense! Please have a great day
@@adriansdigitalbasement there is it seems a specific diag rom for the 500, 600, and 2000, or at least when I got mine there was the 2 options the other being for the 1200, 3000 & 4000, maybe you have the latter?
@@cleetusmacfarland9453 The only difference between the versions is that 500/600/2000 machines use a single 16 bit ROM, and 1200/3000/4000 require two ROMs due to the 32 bit data bus. The contents is otherwise the same.
Love your vids. Especially when you are learning an unfamiliar system. We learn with you!
The metal clip thing on the bottom of the sidecar slot looks like the one from a Commodore A590 hard disk/fast RAM/SCSI expansion.
I actually got one with my A570 CD-drive as well. (Long gone and was lost almost immediately.)
I see those motherboard standoffs on your bench and remember...
Hey, I was putting a computer together!
Thanks Adrian!
@Adrian There were several authorized resellers of Amiga computers in Mexico. Sigma-Commodore was long gone, having lost their contract with local retailer “Aurrerá” (a Walmart-like chain later bought by Walmart itself). The last distributor “Comtemex” was directly tied to Commodore International circa 1992. They were in Mexico until Commodore went bankrupt in 1994. This distributor sold Amigas 4000, 1200 and 500 with Spanish layout keyboards, I specifically remember the Amiga 500 with that long badge just like yours and, of course, they were NTSC. All manuals and documentation were in Spanish as well. Commodore and Amiga were very successful in Mexico by both shuttle trade and local resellers.
About Ç and Ñ; Ç is not used in Spanish, it is used in Portuguese and French which are not widely spoken in Mexico, most people speak Spanish and other native languages. International keyboards started to be a lot more popular in the 90’s with actual support in operating systems. That keyboard is useful in many countries and Commodore was big on cost-cutting, I can imagine that being an affordable way to support all of Latin America including French Guyana, Mexico and Brasil plus France and Spain. Spanish keyboards were common in Mexico even in the PC world, it was only a few years later that a Latin American keyboard was introduced for the PC market. Greetings Señor Adrian!
Mexicans would say Don Adrian, rather than "Señor Adrian". "Don" is a more widely used prefix across Mexico, rather than "señor" (unless you are from certain north Mexico places), and they will only use that if they want to be more polite for certain specific reason. As for example, in this case referring to a known repairman who is respected by everyone in the neighborhood because he does good jobs, plus he's friendly.
Also, they don't use, and don't like the usage of those prefixes lightly in conversations anymore. They would take it as an insult, specially coming from a foreigner. Actually they use that as sort of test to spot foreigners trying to pass as mexicans in conversations on internet.
@@Ed64 Ç is used in Spain too... But not when writing Spanish, but Catalan (maybe too in Galician, which is close cousin of Portuguese, although I'm not sure what are the differences and wether they are big or not). In Spain there are multiple co-oficial languages, including Catalan (I'm native bilingual Catalan and Spanish), Galician, Euskera... so to cover the whole range of languages Ç is needed.
@@tekniktdr The Ç is used in Occitan as well if I remeber correctly. Commodore probably didn't made an Latin american layout so they used the Spanish instead.
At first I thought it might be an brazilian machine but in Portuguese there is no Ñ and brazilian PAL-M would be black and white on an NTSC TV. Heared Commodore was big in Argentina in the early 90ies as well but this would be an PAL machine in that case. So it could be from every country south of the US except Brazil, Argentina, Uruguay, Paraguay which used PAL and of course French Guiana which used SECAM.
Thank you so much Adrian for all your videos. You bring me joy even in my darkest hours.
The 68000 actually has a 24-bit address space which allows it to address up to 16MB, but it is possible that the way it is implemented in the Amiga doesn't allow the whole address space to be used at one time.
sure, but this dude is so self-proclaimed "pro" he has no idea what the heck he's doing 😅
@@nneeerrrd he never proclaimed his self pro and he did mention in the video that he doesn't have much experience with these 16bit systems.
It can address 16MB total but that includes a lot of stuff like IO space so only a little over half can be occupied by RAM.
About Desoldering stuff:
I found it to be very helpful to have a Hot Air gun at low temperature (200°C or so) warm up the board a bt and then use the desoldering gun while also heating up the Board with the Hot Air.
Had the same metal shield on my A500. It was delivered with an external HDD, helped that the 2 pieces hold together.
I had an Amiga 500 from 1988 to 1992 and for the last year of having it, i used to get a green screen about a third of the time when turning on. Out of frustration, I stared tapping the side of the machine when it happened and unbelievably it used to fix the problem. When I sold the Amiga to a friend, he said the problem and solution lasted another 2 years, until he eventually sold it. I don’t think todays electronics would stand up to that type of punishment these days. Great video👍
aaaa, the old slap the machine until it works again method. very popular also on tv's.
Agnus chip not making good contact in the socket can also throw these colors. Re-seating it usually fixes the trouble.
...or a trace is broken/damaged and only makes contact sometimes...
Great video as always Adrian! I really missed out on the whole Amiga/Atari ST generation of computers, I was using an AT&T PC 6300 at the time. Looking forward to you fixing a Coleco Adam in the future!
One of the issues of the early '80's I assume was simply that Commodore was maxed out in production, trying to keep up with the 64. They cut corners, obviously
They had a dodgy method to re expose a section of the die to repair wafers that should have been binned. It was discussed on an episode of the Amphour podcast. I suspect the "repaired" dies were not so reliable in the long run.
Cool fix :)
My PAL Amiga 500 with Scandinavian keyboard layout has the same English warning sticker and mine has the same Rev 6A motherboard, manufactured in late 1990. My Kickstart version is 34.5 and Workbench 1.3.3. (34.34, Sweden/Finland version).
I know you want to avoid desoldering the memory chips, but would it have been an option after you had them out to run them through your Retro Chip Tester? I don't know more about that device than I have seen on your channel, so I don't know if that particular DRAM chip type is supported by it. But if that's an option, it would sure be interesting to see the exact failure mode of the RAM chips.
Thanks for the upload Adrian. I really like when you are using the oscilloskope. I learn alot from these videos. Thanks.
I enjoy videos that revive an Amiga. Please make more of this, I prefer this over primetime TV
DiagROM boot ram test doesnt to a complete test. Just enough to know if its completely dead or not. Since DiagROM doesnt run from RAM its not the cause of your issue. You're supposed to use the main ram tool once it boots.
Yes, I was also going to say there's a full battery of RAM tests available once you get to the DiagROM main menu.
The shield on the side expansion slot is part of the A590 HDD upgrade package. I believe it help to ties the shield ground inside the A590 to the ground on the A500 shield.
Great video Adrian!! Although I couldn't play my usual drinking game: Taking a shot every time you say Deoxit!
My liver thanks you though, Adrians Deoxit Basement 🤣🤣
Love your vids Adrian
I believe John is the only person that is behind DiagRom. And he does it in his free time. I'm sure if you wanted to help enhance it, he'd be up for any assistance you might offer for coding.
I love how TH-camrs imitate each other.
"We're in like Flynn!"
Or
"Let's get this out on to a tray. Nice."
"We're in like Flynn" predates TH-cam (and therefore TH-camrs) by many years. It's pretty common saying for us Gen-Xers.
It was popularized by EEVblog though, where it’s such a regular that it has become a bit of a meme.
I don’t recognize the tray quote.
@@nickwallette6201 Steve1989mreinfo
Hi Adrian, just a little note why piggy bagging didn't work. Piggy bagging can fix situations where bad chips failed to signal for whatever reason but as you saw in diagnostics the bad ram chips were pulling the bits high and thus the address line remained faulty. Great video, I love the A500!
Great to see an amiga 500 troubleshoot :)
Loads of A500s here in the UK back in the day.
A500s are fun! There's a boundless possibility of combinations of motherboard revisions, installed amounts of RAM, Fat Agnus versions, and possible memory upgrades. Never been lucky engough to get an ECS Denise... 😄
Also, when you said about the keyboard layout i was staring at my spanish keyboard thinking "Oh, i don't see anything wrong, it has all the keys" lol
Hey Adrian, The 16-Bit Dance Party Song is "Spice It Up" By Jester/Sanity that on the Amiga Test Kit! Please play it next time! :-)
We need more Amiga videos! That was such an amazing machine for it's time. In fact, if you see this, i think i have a half dozen Amiga 1200's. If you'd like one, i can certainly ship you one. No clue if they work or not, i impulse bought a lot back in the early 2000's. But i can say they all look good from the outside! ^-^
The A500 Plus motherboard with its built-in clock and battery often leaves a trail of destruction around the battery. The standard A500 motherboard is therefore much more robust and reliable. Nice job, Adrian.
FYI, if you want that motherboard model to be switchable between PAL and NTSC, you can add a switch across JP4 next to the Agnus chip. You have to reboot after switching it, but it does give you an easy option if you have software designed for both formats.
Adrian, it's been a year for this video. In case you have not yet found out (I am sure you did) that metal strip on the expansion bus comes with the GVP hard drive and helps to secure it to the Amiga :)
I still have my original Amiga 500 computer + games 😺👍.
I might as well switch it back on
and play the old games, again 😺👍🕹️.
Greetings from Vantaa, Finland 🇫🇮.
Glad you found the problem, defective DRAMs on Amigas become more and more common after 30 and more years.
Can also be a problem with a worn-out Agnus-socket. This things are nowadays only hold together by the patina that built up between the chip and the socket. If you remove the Agnus (for cleaning the socket) and reinsert it the 30 year long marriage between chip and socket may be divorced permanently and the computer no longer works. That may also happen if the computer get shaken by incompetent delivery associates while in transport.
You can hook up an Amiga with installed Diagrom via serial connection and read out informations on any computer with a terminal program like Putty, even if the display is only showing color codes and no text.
Yep, piggybacking RAM chips is definitely a crap shoot… where you don’t even know the house odds! You could have a functioning (but weak) output driver on the chip on the board, and a nice, strong driver on the piggyback chip. Then, when you power it up, the bits could be in any state and the chips would compete to drive one of the data pins high and low at the same time. Then, what was a functional - but weak - chip, is now a bad, open-circuit chip! 😬
😂😂 I always found the piggyback look astonishing as a child, I was like, that works? 🤔🤔
Yep I agree. If Piggyback works, the chip is definitely bad, if it doesn't then the chip could still be bad. I think as long as the person testing that knows that, then it's ok, but if they piggyback each chip and it all still fails, then they assume that all the the chips are good, then it's a bad assumption.
The "earth plate" in the bottom of the expansion slot might have been left there from a hard drive controller module. I got one with mine but I'm not using it, works A-OK.
The expansion port for the A500 is a somehow inverted Zorro II, plus it is a male edge connector and not a female socket. I have understood that the more or less legendary Amiga1500 desktop case has a riser for that, so you could add cards intended for A2000.
It is a newer 1.3 machine with (what we called) a "fat Agnus" (compared to older 1.2 ROM machines). I had a trapdoor RAM module on A500 and it had 512Kb fast RAM, but some newer gamers required 1Mb Chip RAM . With that jumper connected it "converted" that 512 Fast RAM (and 512kb onboard) to total of 1Mb Chip RAM.
Btw, my Agnus had a bad socket and it worked only when pressed firmly into it... in the lack of better solution (i.e. socket), it got a U-shaped thin steel sheet under the shield to press upon it as a persuasive measure to stay in socket, and the sheet also worked as a cooler as my Amiga's stubborn Agnus was quite warm :)
Not quite. Every A500 ever produced has a "Fat Agnus" or "Fatter Agnus" (PLCC, the square package) Both OCS and ECS Agnus chips are "fat" - only the A1000 has a "regular" or "skinny" Agnus (DIP - In-line "straight" package).
The metal bracket on the side port is from a GVP external side-car hard drive. It was used to connect the sheidling between the two units.
Chuckled when you said "In like Flynn" :)
I have an old MEGAMAX programmer that I used way back in the day. I can't believe I still have it. It still worked the last time I had it plugged in. I am going to see if I can get any info from the original company to write my own drivers and get it back to modern day working order. If not then Its like a museum piece.
Very awesome but I did wish you had a socket soldering montage...I love your soldering montages!!
30:37 "Amiga Test Kit, Macintosh Version" LOL
Wikipedia Spain noted there was a different version for PAL region, principally different clock (wiki/Commodore_Amiga_500). They also noted the 500 was very popular in Europe, especially for videogaming.
I have zero interest in these old systems, however the way you present the information and my ability to follow along because I can read schematics makes the diagnostic process you use familiar and interesting., thanks for the ride along and the time it takes to produce, edit and UL these for me to enjoy.
I've literally developed 14 Amiga accelerators against DiagROM. Its absolutely amazing at what it does. What it doesnt do is send you an email with what is wrong with your machine. Its a set of tools that, once you master them, can enable you to find what is up. You need to master your tools though
Just yesterday I fixed an A500 with a green screen. One thing I found out is that if the system has ANY bad chip or slow memory, the machine won't boot. In my case, the chip RAM was fine, but it was a 2 MB slow RAM board that caused the problem. Turns out, all the RAM chips were fine, but there was some minor corrosion on the jumper configuration pins, so while the memory showed up in the memory map (and I could ramscan it), AmigaOS just couldn't initialize and use it properly. And, yes, you can put 2MB of memory in the trapdoor slot, but the system will only be able to use 1.8 MB of it, as the tail end will conflict with the realtime clock space at $DC0000.
For anyone who is interested, the A1000 boot ROM will only test the first 256K of chip RAM and the WCS, so if the machine boots to the Kickstart screen, but fails with a green screen instead of the Workbench prompt, the problem is likely with the front-mounted 256K expansion module.
Chip names Denise, Paula, Gary, Agnus looks like the designers branded their work
@@ricardofunes413 contraction maybe?
I used to own a PET, and I have VIC-20s, C64s, and a 128, but I have never owned an Amiga. Wanted one for years. A friend of the family had a CDTV, and I told them if they ever decided to get rid of it, I'd buy it, but some time later they just threw it away... I never did forget that. Still bums me out to this day. They had a full rubbermaid tote filled with software for it. Prices are getting to a point where I've just accepted I'll probably only ever be able to emulate one. Oh well.
Would have like to see the ram address and data lines on the scope once you knew they were working for comparison.
yes, maybe it looked the same, he just didn't say.
Yeah. I am wondering this as well. I will be putting out an HDMI for Amiga video soon. I suppose I can check when I pull my A500 out.
Cheers from Spain! Indeed, it seems like a spanish keyboard layout. My machine has a Warning sticker written in English, also.
There is another option for a rom based diagnostic, called 'logica'. You can find it in the Amiga Forever roms folder. It is quite good too. I regularly use both.
Hey Adrian. As always, great troubleshooting. BTW, where did you get that teeshirt?
Those coloured bars that show up are a graphical representation of the data lines that the DiagROM considers bad.
Looks like a Spanish ISO keyboard, I believe it is actually from Spain and not Latin American because it has a Ç key, which is not very used in Spanish(Castilian) but in other languages used in Spain (Catalan, Galician) is used more frequently. I don't think keyboard layouts for Latin American Spanish have this key.
First thing I noticed! I was like "Why the hell does it have a Spanish keyboard layout??!"
Commodore was cheap. "It's Spanish, so you get the Spain layout" is totally in the realm of things I would expect from them.
Except as he notes it has an NTSC crystal which means it wouldn't work on standard displays in Spain. Yes, it could be a bitsa but he notes the crystal have very similar rust to the other parts so it doesn't seem that likely.
And there's several countries in Latin America which has Spanish and use NTSC, it seems far more likely that the Ç key is just that they're using their already existing Spanish layout rather than bothering to spend money (the horror!) on making a new "correct" one. :-) Much simpler explaination.
@@Torbjorn.Lindgren Yeah, it definitely wouldn't work here, at least until the multi-region compatible TVs were available, but those didn't come up until the late 90's...
It's not uncommon to find Spain layout keyboards in Mexico, also, the localisation and distribution of Commodore computers wasn't done by Commodore itself, but a third party (Sigma), so I imagine they didn't bother to make a Latin American specific keyboard
You're right about the keyboard.
It's a keyboard with the key distribution for Spain(Latin American board don't have the letter 'ç' as it doesn't exist on Spanish language)
I still have the 512k upgrade card (and sme other chips) from my old Amiga that is long gone now.
The mem upgade board has a disable/enable jumper on it, so I would think you did not need to desolder anything on the motherboard.
great vid btw. Amiga 500 really felt like an "amiga" ... so much fun
A3000 has socketed RAM chips.
Diagnostic ROM is pretty cool, nice to see the serial port info option.
Did you ever figure out what the extra metal by the expansion port was for? Grounding of some sort?
@Adrian and @ChuckyGang please collaborate on bringing the March Test to Diagrom.
When fixing an A2000 I had similiar issues with a green screen, but it was caused by dirt and grime build up on the fat agnus chip, I popped the chip out and cleaned the pins with isopropyl alchohol and re-installed it and the A2000 then started as normal.
Great video as always! Bad RAM seems like a common culprit. With all of your skills and tools, is there any way to repair bad RAM? I have never seen anyone attempt it.
No Rammy coffin for the bad chips! We miss Rammy!
Great Video Adrian! -Mark
My dad bought me the Amiga 500 in a Mexican superstore called Hipermercado (Now Walmart) and the box, manuals and keyboards were in English. All of my friend's Amigas were also in boxes and had manuals/keyboard in English and they were imported from US. There was not a Mexican (latin american) version that I remember. I never saw an Amiga with an "Ñ" key until this video and by the look of the special chars arragement in the keyboard is definitely Spain layout.
"...except" hehehe. Great story, Adrian. Thanks.
@Adrian's Digital Basement , have you thought about trying the "hot plate" method of desoldering or removing non-socketed chips from their motherboard? I believe Bruce on the Branchus Creations channel has info on how to do that.
Another great video. The Amiga 3000 has socketed RAM , My 3000 came with 2 megabytes of RAM 1 megabyte of chip ram soldered on the motherboard net to that are 8 empty sockets it also came with 1 megabyte of fast ram in sockets. I moved the fast into the chip sockets and ended up getting 8 megs of fast ram in the zip sockets.
I saw an Amiga with the Spanish keyboard in Mexico back in 1990. I can't confirm if it was imported from Europe or not, but I do remember the keyboard looked like the one in the video
I had similar problem with amiga, it was agnus socket, little bit of contact spray helped!
Firstly the Amiga 500 NEVER came with Kickstart 2.0. The A500+ did and so did the A600, but not the A500. That was limited to Kickstart v1.2 with a read power light and Kickstart v1.3 with a green power light.
brill vid yet again thank you ( uk viewer )
always enjoy your channel. thanks.
Adrian, why didn't you use that retro chip tester to test those chips for errors?
I can feel your concern, but it is always a pain to diagnose bad chip (especially with edge case fails) when they're complementing each other to make a wide bus, so if one is bad you have basicly whole memory space out of commision. Good to have some spares, saves a lot hassle and hairs sometimes :)
My second computer (after my 64) was an A500, so this was a bit of a trip down memory lane. Two things. If three of the four original RAM chips were bad, I would definitely NOT trust the fourth one to continue working, I’d replace it. The other thing is that I believe any RAM added through the trapdoor slot would be categorized as Fast RAM, not Chip.
Absolutely agree on replacing the 4th chip.
Would also like to see if Retro chip tester sees a problem with those.
I have no idea if that is true, but Adrian meant that this specific board had a feature that allowed some RAM on a memory card module specifically compatible with this feature to be mapped into "chip RAM" area, possibly with discrete chips dedicated to that. No clue if such cards were ever produced either. Probably "normal" memory cards would still just show up as "fast/slow RAM".
So what you're saying is that two out of three ain't bad, but three out of four bad _is_ bad?
Seriously though, anything with a failure rate of 75% to date deserves to get the boot even if it's still working.
Not sure if anyone has said it yet but the clip on the side expansion came with the A590 (at least here in the states). I don't know, if it's just shielding or some kind of ground clip but i have seen a couple with it still in place on ebay.
Hi Adrian! Nice to see another Amiga 500 in life! Just have one question and i hope that you can help! When i turn my Amiga 500 it just show white screen!? No disk activity? No drive clicking? When i turn it on and put my finger on Gary chip, it is cold!? I think that my Gary chip is dead or kickstart chip! What you think? Did you have similar experience?
Loved the RAM upgrade
Great video as always, but I'm not really a fan of those new titles, the motion is distracting and the word note all over just makes them cover more of the screen.
Maybe so, but it's likely to stave off the armchair experts who comment on every little mistake before they've even watched the full video. There's a few of them in here already, regurgitating information he already covered in the video as if he hadn't already said it. I hope he keeps them.
Great video !!, re signals on memory chips , it would be ideal if you kept a library of images of the signals from a working Amiga etc so there's no question what the line should look like 🙂