A1200 repair - no audio & much more
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- Опубліковано 30 тра 2013
- This Amiga 1200 motherboard first came in with an audio problem. It was easy to see during initial inspection that this motherboard had been "recapped" earlier. I was not very impressed by how the solder joints on the electrolytic capacitors looked like...
In fact, the extremely poor solder job done on this motherboard by the previous recapper was the reason the motherboard had to come in to me for repair in the first place.
In this documented repair, I go through the process of locating and repairing the audio problem. I also put some focus on the solder job, as well as a few other bits and pieces that I wanted to fix up before sending the motherboard back to its owner.
I also present to you a rather stupid mistake I made during the repair of this motherboard in order to make it possible for you guys to learn from my mistakes as well.
I then perform a lot of testing before finally packing the motherboard and sending it off.
The message from this video stands clear - If you do not have the right tools and skills to solder, you might be much better off just leaving your motherboard alone. Because soldering without any knowledge of how to do it right means that there is a big risk of damaging the motherboard, which can actually make it work worse than it did before. This whole repair is a very good example of such a result, since the motherboard would never have come in to me for repair if it hadn't been for the horrible work performed by the previous recapper.
It is of course not possible to learn how to solder without a bit of practice first. However, there are lots of electronic equipment out there to practice on, like scrap PC motherboards for example. In my opinion, Amiga motherboards should not be seen as solder practicing PCBs.
We, the people of the Amiga community, need to take good care of the hardware in order to preserve it. Anyone who cares about the maintained existence of Amiga hardware should realize that soldering onto the motherboard without any knowledge of how to do it correctly will most probably destroy the Amiga more than it will preserve it.
So if you have an Amiga or other piece of retro hardware that you want to have repaired, and if that repair requires soldering, I would recommend you to ask someone for help if you don't feel absolutely comfortable doing it yourself. This goes especially for hardware that you care about and want to preserve.
If you choose to not follow this advice, it's possible that your motherboard will end up lying on my workbench one day... :)
The transparent tape used in the video to attach the wire to the motherboard:
Google for "Double Sided Tape with Red Release Paper and Transparent Foam".
If you live in Sweden, you can buy it here:
www.clasohlson.com/se/Monterin...
The yellowish tape used in the video is called "kapton tape" or "polyimide tape".
Ebay, amazon, your local electronics store... It can be found just about anywhere.
Feel free to leave questions and comments in the comment section for the video. - Наука та технологія
Old Video, but still actual! ;-) It brings me to the solution with my board... Resistor in the +12V line was broken... Now he can make NOISE like a new one! Thank you for inspiring!
Although you made the comment in the video that this isn't an electronic tutorial, your videos should be required viewing for anyone that is currently or planning on doing electronics work. Having some electronics experience myself I have to say that I am extremely impressed with your technique and work ethic. Not only do you fix the problem, you go the extra mile and fix it RIGHT! In this day and age that's a rarity unfortunately. Cheers to you sir!
@RetroGameModz I want to thank you for these videos. I will be honest, I dont understand 60% of what you say... but I love your videos, and I simply watch them every night before going to bed. Problem is I am running out of your videos. I used to have Amiga 500(512K) when I was young (I am 38 now), but I did not have that TV modulator for color picture.
You have a way of making these kind of videos... please keep it going!!!!!!!!!!!!!!!!!!
It's really great to know that there are people out there enjoying watching my videos. It makes me feel that I'm not making them in vain. Since I don't earn a single cent from making these videos, the appreciation from my viewers and interaction with them is the thing which keeps me going.
Thanks for commenting.
This is the longest repair video Iv watched. Enjoyed every minute of it. Subscribed
Great stuff! I'm a computer tech and sometimes I have to do some soldering inside laptops. After all these years, I'm still learning useful tips and techniques from experts like you. Thank you for taking the time to do this. Really appreciated!
You are great surgeon. Lots of information I've learned by this video alone and in the entertaining way as well. Keep it up. I've subscribed.
Hi, I wanted to mention how much I appreciate the expertise, artistry, and care evident in your work. I picked up a damaged A1200 off eBay that looks like it was in the trash and had a hammer taken to it, in addition to some leaky caps and the evidence of a random person fumbling around with soldering on the motherboard. It does work though! After watching a few of your videos I feel like I know a ton more about electronics and the A1200 in particular, enough that I could start getting the right tools and knowledge to recognize and fix particular problems.
Very valid point about performing trial and error on less valuable equipment. I certainly would be interested in seeing a video from you on how to solder and use equipment like a professional.
You are for sure some kind of a crazy guy, but really really nice precise job - I love perfectionists... Happy new 2018.
Being entertained while learning its every students dream :)
Your retro vids will be around long after we are gone,they will float around in `cyber space` for all eternity !
Great job as always! Love the Test Drive 2 tune.
Thank you for your kind comment. I try to live with the motto that if you're going to do something, you might just as well take the time to do it properly. Doing a quick and sloppy job just to cut down on the time spent might be how some people choose to do it, but it's certainly not how I prefer to work. I always put quality in much higher priority than time. In fact, I don't care much about time at all. I just keep going until I feel that I'm satisfied with the work I've done. :)
Great vid ! Thanks for showing proper repair methods :)
Just finished replacing the caps on my 1200.. and now I have to find my disk with lost patrol on it because you played the damn tune :D
Wow. This is "Amiga 1200, The Repair" feature film. lol. Great stuff!
Interesting video. I'll have to go and look at the Amiga 2000 I repaired around 20 years ago. I bought a used A2000 in 1990 and later learned that the power traces going to the 23pin D-SUB video connector were completely burned up. I soldered some some budge wire around the traces and got my DCTV working.
That was around 20 years ago, so it may not be pretty. Thankfully, the A2000 was a fairly simple 2 layer board.
Thanks for this video, i learned so much!
Excellent video. Thank you!
Thanks for the info. I have never really investigated exactly what kind of substances either epoxy or instant superglue contains. Reading the warning texts on the packages has been enough for me to understand that we're dealing with some dangerous stuff here. I don't know much about the different epoxy formulas being used, but my common sense tells me that neither epoxy nor superglue is something you want to work with without taking proper precausions.
Great work!
It's also the difference between someone who takes pride in their work vs. someone who just does a quick and dirty fix. (and if you watch the video all the way through he even does say that he could have fixed it with just a jumper wire).
Granted we are talking about an A1200 motherboard that does have a green jumper wire smack dab in the middle of it from the factory, but that doesn't mean you need to repeat Commodore's blunders when you repair a board of theirs. :D
Yeah......you v done great job Sir... I like your approach...thanks v much.Sir
Great video again and looking forward to seeing the CD32 mod.
As for HDD loading times, the owner is using a FastATA expansion. It's not included in the video, but I cleaned all the pins on all the connectors and chips with alcohol. Dirty connections will result in higher contact resistance, which will in turn result in higher impedance on the data transmission lines. I don't know exactly how the error correction algorithm of the FastATA works, but more re-reads being performed on the HDD can, and most probably will, result in longer loading times.
Hi, and thanks for your comment. :) Nope, unfortunately I haven't had any time for my A3000 so far. I've had a lot of other repair jobs lately, so there hasn't been much time left for my A3000. I will most probably make a video out of it later when I have time to repair it.
Great video.
Exactly! I get the impression that there are many people out there who totally doesn't care about doing a proper repair, and instead only does a quick and ugly one and then just leaves it like that. I have never understood that way of thinking, and neither could I ever work like that. I prefer to try my best to do it right... either that, or not doing it at all. A quick and sloppy fix is usually not an option for me.
Those are your pictures? That's really cool! Hi-res pics of Amiga motherboards can be very helpful sometimes when you don't have a second motherboard at home with the exact same revision to compare with. Thanks for supporting the Amiga community. *thumbs up*
Great video
I will try to get hold of a 315 C heat resistant epoxy for next time.
But still, I would like to investigate a bit more on what kind of methods are used in the industry to stick the pad to the PCB substrate during manufacture. Because a pad usually doesn't release any vapors when heated up to even more than 315 C, so I'm thinking that the best kind of adhesive to use for repair would be the same one being used during manufacture of the board.
The problem you mentioned with the brown color can most probably be fixed by first converting the TTL RGB signals to standard analog RGB. This can be done with a pretty simple circuit that doesn't require many components at all. You should then be able to see all the colors on screen correctly if you couple the outputs of your little circuit to the inputs of the converter board.
Thanks. It might happen sometimes that I include footage of me doing silly things, but I thought that me making a fool out of myself might add a little to the entertainment value. Or at least for some people I hope it will. :)
Funny thing is, the A1200 video problem repair where I incoperated the smiley faces quite much is one of the videos that has gotten the most likes. I don't know if that is related to the appearance of my "helper" or not, but people seem to like the presentation anyway. :)
I haven't thought about it much until someone mentioned it in another post here down below. Is there any particular converter that you can recommend? Any specific model that you know works fine with Amiga?
You have me cracking up nice video.
Another awesome vid =)
Thanks for the advice. I have already managed to get myself an LCD TV that seems to work fine with Amiga through scart (check out my LCD TV repair video), but I'm thinking about maybe getting myself an even smaller one if I get the chance. The Samsung I'm currently using is a 20" one, and I only need something to display an image for testing purposes. The smaller the better. How many inch is your Sanyo TV and is the screen in 4:3 or 16:9 format?
That is most likely true so would indeed explain a faster cold-boot time. Also the chip and pin cleaning should help things along. Thank you for explaining.
I recapped my A1200. Looking at the schematics (Rev. 1 board) I saw that C324 and C334 are named "22uF - NP" there. I'm wondering if this should really be non polarized caps. The original ones looked exactly the same as the other 22uF caps (which are not marked "NP" in the schematics).
Just out of interest, what was the upgrade shown at about 52 minutes where you were demonstrating the double sided tape?
Hi where you get schematic and that double sided tape.
Some links for parts does not work.
Please make a video about different techniques for soldering and desoldering.
Thanks for your videos.
Great video. Finally we have someone that knows how to make a tech video that is very informative and entertaining at the same time. In regards to you wanting a small LCD TV with RGB support in the scart connector, i assume the LCD you want needs to have scart, correct?? I dont know of any LCD tv's that will support Amiga screen modes but i can tell you of a nice little 15 inch LCD monitor that supports native Amiga screen modes. Look out for an NEC AccuSync LCD 51V. Works on my A1200 fine.
The epoxy I used was just a generic one. But I do not really recommend using such an epoxy because of the hazards involved mentioned in the video. If possible, you should try to find a heat resistant epoxy for pad repair applications. It would be good if it could resist heat up to 310°C or so, because you could easily get away with using only 300°C on your iron when soldering a component into place as long as you're using leaded solder. Check the rated temp on the package when buying an epoxy.
Great Videos, you were asking about a cheap monitor,I currently use a Sanyo LCE22FS40-B TV/Monitor, it has HDMI/VGA/UHF and Scart sockets , perfect for my A1200, does display SuperHiResInterlace PAL very well, theres also no fishbone effect on lines either :)
Keep up the videos, great enthusiasm (its working!, its not!) lol. cant wait to see the A3000 up and running :)
IPC standards are quite strict. Measurements for accepted heel fillet, toe fillet and side fillet, land area coverage... the list goes on. I don't know if my joints really do fulfil IPC standards, but I try to do my best to come as close as possible. I don't think it hurts putting some effort into at least trying to do things right, even if it's only about performing a DIY repair. :)
Awesome pro job again buddy! and entertaining us with the osc as an Organ !!
Also bit dissapointed that your little yellow Bulb side-kick only made a brief appearence in the vid at 46.36:(
I am about to recap my CD32 wish me luck ,and no I will not show the results :) you might find a dry joint or even worse a wet one :)
About removing the capacitors close to the keyboard connector, check out my Amiga 600 boot problem repair video at 28:32. I don't go too much into details there, but I think you can get some idea of how I do it. I basically just use small tips when removing the caps, and try to stay steady on my hand in order to not accidently touch the plastic with my iron. Sometimes I try to protect the plastic in various ways as well.
What do you refer to with "color 6"?
But yes, you need to either brighten or dampen the intensity of the three RGB colors to be able to display all colors. That is what the intensity signal is there for. And that is why you need to build your own little converter for this purpose.
Yes, monitors like C1084 has circuitry inside the monitor that does this. These monitors also have a dedicated TTL RGB input for that purpose. Newer monitor don't have it since the technology is not used anymore.
Hi from Australia!
Thanks for posting such detailed videos, I really enjoy watching them. Did you get your A3000 up and running?
You are right, I looked it up, if I use one of those converters alone, I will only get 8 colours, and I do indeed need a RGBI to RGB converter circuit in between to get all 16 colours. The problem with the brown is that it has to be done in the screen, else it will also affect the bright yellow, I believe.
It's not convenient to have a slow and buggy tracker of course, but what's so bad about it using a screen mode with double the horizontal resolution? The layout of 3.x is not a problem for me, I think it looks ok. But I will try 2.3D and see what I think about it. Thanks for the advice. Btw, I've heard there is a version of ProTracker that supports midi. Do you know what version that would be?
For replacement of TV, have you considered a RGB to VGA converter?
Would you mind providing a source for the parts used. I am especially interested in the dual-side tape used and the epoxy. Also, what kind of tape was the yellow transparent tape used?
Very professional job, very well done!
Do you accept faulty A1200 motherboards for repairing?
Can you provide us with some information on what equipment you are using?
Soldering-iron, tip sizes, flux-type and so on....
What I'm very curious about is how you manage to desolder the caps near the keyboard connector on the A600/A1200 without damaging the connector? Very, very small tip?
What software you using test that repaired board ?
By the way, I don't really understand what you mean with "the brown has to be done in screen". Could you elaborate on that?
The orange/yellow tape used is called "kapton tape" or "polyimide tape". Search it on google or ebay and you will find it instantly. The tape is heat resistant up to 260°C/500°F, which makes it very suitable for electronic rework.
As for the red transparent tape, google "Double Sided Tape with Red Release Paper and Transparent Foam". I will put a link in the video description to where I buy it in Sweden, but I guess you should be able to find it on ebay or in your local hardware store.
Couldn't you have left the clock Header PINS in there and just solder the row in anyways?
Awesome idea! Damn, why didn't I think about that during the repair? :) :)
Very informative video. I wonder how much this repair cost.
Thanks! :) Wiggle tests in every video? Sorry to disappoint you, but I only perform that kind of test when it's called for. :P But keep watching and I'm sure you will see more of them every now and then. :)
Where do you find your schematic? I'm searching for a 661-6589 logic board.
I don't know exactly what kind of board the 661-6589 logic board is, but the schematics I have are very easy to find just by searching on google for "Amiga schematics" or something like that. You could also head over to the different Amiga forums and have a look. They often have links to Amiga schematics in some threads there.
I'm personally only interested in midi in. So if you or anyone else know of any specific version of ProTracker that has that, I would be happy to hear about it.
Heh..when you searched for "A1200" in BigBookofAmigaHardware i noticed that the first picture of the A1200 is actually MINE ;) Me and my friend made those pictures of about every model back in 2001 with a videocamera and a digitizer ;) Anyway, your videos are great! I will subscribe!
Then I guess the converter board must be able to accept TTL RGB as well. This is rather unusual for any kind of converter board like that, I believe. Or, it might be that the converter reads the signals as analog RGB and displays them as good as it can. It's easy to check this; If the converter has an input signal called "intensity", then it's designed to also handle TTL RGB. If there is no intensity input pin, you can not even connect the C128 properly because it has that signal on the output.
Which USB microscope do you use?
It's me you also replied to @ EAB.
I have just ordered an external drive for testing on the A1200.
We'll see how it goes from there. :)
So cleaning the motherboard was the only thing I did in this video? :P
There is nothing strange about the owner's statement. Let's take your car for example. If the screws that are holding the engine into place are completely loose which makes the engine vibrate violently when it's running, and if the engine and other parts need some other attention like oiling etc, do you think it's strange that your car runs better after it has gone through a full service and all these issues have been fixed?
DO YOU ALSO REPAIR RECEIVER HDMI BOARD'S I HAVE A BAD HDMI BOARD FOR A HARMAN KARDON 3600
Thanks for the advice, appreciate it. However, 22" is almost a bit too large for me. Since I'm only going to use it for testing purposes and I prefer to have as much space left as possible on my bench, I would prefer the TV to be as small as possible. Maybe 19" or even less, if it's possible to find one that small. I guess it might be possible to find a smaller version of the Samsung you have if I'm lucky enough. I will look into it.
Ah, I understand what you mean now. But still, it should be possible to just incorporate a green/2 circuit when building the RGBI to RGBs converter. It shouldn't be too hard. There is even a table on the site of how to do it which makes it even easier. According to the table, brown is just red + half green. You can include a function of #AAAA00 always becoming #AA5500. Should be easy to build with discrete components and maybe one or two ICs.
I guess you could easily fix that by reworking the pins of Alice that seem to have been soldered on earlier. Remove old solder from the pins with wick, apply flux and use new solder to rejoin the pins with the pads. Clean up with alcohol and Q-tips and you're done. I recommend you to use a fine tip on your iron for this. It makes it easier to do it without bridging the pins.
Not in while I'm afraid, since I don't have any more motherboards here with RF modulators that need to be removed. But I will definitely keep it in mind for the future.
what epoxy do you use to glue the pad?
should've watched it longer before asking. but what kind of proxy would be best?
Thanks
There are a few things I'm curious about here. Super glue only releases hazardous fumes when still being in liquid form. I've never had any problems with it once it has cured. Did it really take over one hour for it to cure? It usually cures much faster than that.
Also, how come you drove a car or even wore the glasses before the glue had cured? Didn't you have any spare glasses or contact lenses you could use instead? If not, why not just wait wearing them until the glue had cured?
Any chance of you making a short-ish tutorial vid for removing RF modulator on A600/A1200 safely? :)
The poor person whose soldering you let rip on :P But anyway, great video - and good lesson on how not to solder, for people like me who would probably send you mad with solder blobs :)
Some screen modes may not be 100% centered but if you muck around with the screen prefs or try modified prefs, that will help a lot. You will also need a video adapter to connect the Amiga to this NEC AccuSync LCD 51V, as it is a PC monitor after all.
I took a look at the pics. Like you say, that is really nothing compared to how the board in this video looked like. My guess is that someone has done a mod which required direct access to the chips. There is some solder on the last two pins of the keyboard MPU and a few pins of Alice, but they are not even near being shorted out through a solder bridge, so you don't have to worry. You can clean it up with some solder wick if you wish, but it's not necessary for the operation of the board.
superglue is very easy to remove- it's basically acrylic. so use acetone to dissolve it.
the main point is that superglue isn't heat resistant. and like you discovered, can release noxious fumes from soldering iron.
That's not a bad idea at all. I searched eBay for the model you mentioned but couldn't find it. However, I found a model called GBS-8220. I think that must be the one you meant. It is surprisingly not that expensive. I have seen many upscalers/scan doublers that cost a lot, much more so than a small LCD TV. That's why I haven't considered it earlier, but I can see now on eBay that this converter is selling for a quite reasonable price. Have you ever tested it with Amiga?
You are completely right about the car and I am sure you are helping the electrons flow a little better in your amazing service, but would it really make the Amiga boot faster? I meant you no disrespect so I apologize if I insulted you in my last comment.
Not only will you only get only 8 colors, you also risk damaging the converter if you use it alone like that, if the converter is not designed to handle TTL RGB voltages coming out from an RGBI source. So yes, you definitely need a RGBI to RGBs converter to first convert the RGB output of the C128 to analog RGB compatible voltages, as well as creating a composite sync signal out of the H/V sync signals. However, if the VGA converter has H/V-sync inputs, you can use those directly instead.
I'm not using anything fancy at all. If you can afford it, I would suggest that you buy a proper soldering station like a Hakko or a Weller for example. I will try to get one of those myself one day. But you can still do a pretty good job without spending lots on money on professional equipment. What I do recommend is to at least get a temperature controlled soldering station with temp feedback so you can see the set temp and current temp on a display. I might make a video on this topic someday.
I have a rev 1.D4 A1200 which recently died on me.
When I power it up I'm just greeted by a black screen and the floppy led lights up as a christmas tree.
I was told elsewhere that it's probably a dead CIA, is that repairable somehow ?
I forgot to mention, this board doesn't boot unless there's a bit of pressure applied to the Alice chip. There seems to be a gap between one of the Alice pins and the board which I just noticed in the photo. I'm going to try cleaning it up a bit to get a better look.
Yes, the floppy drive spins, it goes berzerk for a sec and then nothing but silence and a black screen.
The 3.1 roms and floppy drive works fine in my other A1200, so I know these are fine.
It happened during dumping an original disk using the CAPS dump disk, system halted at a gray screen and after waiting 10 minutes for something to happen I powered it off.
After that I've not been able to boot the system with or without my hdd connected.
Does the internal floppy drive spin at the same time as you turn on the power and the floppy LED is being lit? Try to put a disk inside the floppy before turning on the power to see if it spins the disk. You can hear whether it's spinning or not by listening to it closely.
Be sure that the ribbon cable to the floppy is the right way around. If it is, there could be a problem with Gayle or the Even CIA. If that's the case, and if you find a donator board or new chips, then yes, it's repairable.
Huh? Your comment is marked as spam..? That's strange. Wasn't me, at least.
Anyway, I don't feel particularily insulted, so don't worry. :)
The owner did not expain if he was referring to system boot up time or HDD loading time. I've read on Amiga forums that Amigas usually waits until the voltages have stabilized before it boot up after a power up. If there is any truth to this, the fact that I fixed up the caps can certainly make a difference.
I just got it out and took a look, and I take it back. It's nowhere near as bad as the one in this video. It's limited to the Alice chip, and there's some solder on the IC beside the keyboard socket. All the caps and resistors look untouched. I'd remembered it being worse than this - I guess your video has give me some perspective :)
Some pics: imgur.com/a/XSSxz
How can I contact you? I have an Amiga 1200 motherboard not working due to bad soldering... You surely would be the right person to repair it!
But I have seen articles of people using converter boards for Arcade machines like CGA to VGA with the C128. :| Only problem was that none of the converters reproduced the color brown, instead it became dark yellow.
There was a version of Noisetracker I used back in the day that had midi, although it 'only' had midi in, Hence why I reluctantly moved over to Octamed 4 to run my synths. :) AFAIK there are no Amiga Pro/Noise/Sound Trackers that have midi out. If I'm wrong, please could someone put a link up so I can check it out with a very big smile.
If I remember, it was on noisetracker 2.0 which was based on protracker 2.3. :)
No, I'm afraid I cannot recommend any particular converter, I do not have one myself. I have been thinking about getting one myself for my C128 computers, so that I can use VGA screens with the 80COL mode.
I mean that in order to get brown instead of dark yellow you have to somehow half the green on color 6. Most, if not all Commodore C128 compatible monitors and CGA monitors did this inside the monitors. But no VGA monitor does it. But I guess it could be done before the monitor too...
That will probably not work very well. The RGB output from a C128 in 80col mode are not standard analog RGB outputs, but digital TTL compatible signals. You probably cannot just hook that into a converter and expect it to work, since the converter is made to accept analog signals on the inputs. If you want to connect it like that, you will have to build yourself a TTL to analog converter circuit for the RGB and sync signals first and feed that into the converter.
i’d wish you’d come back
Just noticed the question in your video about what LCD TV works well with Amiga well I use a Samsung 22" model LE22D450G1W, it has every connector you will ever need :) and its cheap :)
haha ...You Funny :)) Good Video !!! Good Job !!!