Amiga 1200 recapping of this classic computer

After repairing the floppy drive in this A1200 we discovered it needed a recap. I asked the question if that was something you wanted to see, the over whelming response was yes and so here it is.
Lets dive into this A1200 and get its capacitors changed.
Not just that simple though, one mistake along the way costs me some extra parts and there's a weird random fault to track down.
Warning: This video shows recording of a CRT with flicker.
Amiga capacitor list - www.ikod.se/repairs/capacitor...
Amiga PCB explorer - www.amigapcb.org/
I mentioned Chris from  @005 AGIMA  so only fair to link his channel - / 005agima and of course his podcast - / thisweekinretro
CRG twitter - / yt_crg
CRG patreon - www.patreon.com/user?u=139190...
End Theme - Modspire by NaokiS ( / naokisaito )
Chapters
00:00 Intro
00:46 Getting old caps off
05:34 Fitting the first two
07:17 Too close to plastic
10:53 What I should have done
13:13 Removing the through hole caps
15:34 Dealing with the crusty cap
17:07 Which cap went where?
18:04 Somethings wrong
19:48 Could it be roms
20:39 E113R and the timing fix
21:51 That seemed to work
23:53 Back together
25:14 One last thing
29:11 Conclusions and credits

[@toneycassel4448]

Ok, ya got me. I started watching this video last week and when I got to the part where you ripped the capacitor off the board, I said a few choice words, threw my hands up, and moved on. I must apologize for my rude words! I watched the rest of the video today, I was curious how it turned out, and you restored my faith in you. I've enjoyed your videos, thanks, great job!

[@CRG]

Sorry it was just for a joke but I knew it would catch a few people out 😂

[@brynjarborgersen8131]

I am 50, with severe COPD and on the lung transplant list..... you almost made me being taken off that list...... For real. It is good that you leave the mistakes you make in the videos, I learn a lot from watching them and what happens if I should get back in the soldering saddle. And now, even me wife who has no electronic interest whatsoever, says you make it look interesting and ahe doesn't mind me having it on..... she even put the book down and watched with me...... Keep up the good work, you have a very good thing going with these info-tutorial videos

[@CRG]

Thanks for the kind words, its great to hear that both you and your wife enjoyed the video.

[@eugenekiselev]

First of all: Thank you so much for this video. This is the best A1200 recap video I found! Very precise with lot of details. I learned a lot from it ! Yesterday I tried to hot-air SMD caps off my recently acquired insanely expensive first-in-my-life Amiga 1200. I started from 275 C then went up to 343 C and ... no luck (yeah I re-flew the solder on both sides of caps first which didn't help). I hope I didn't overheat the board and surrounding components (yet to find out soon when I assemble and solder back all sockets etc and switch my amiga back on). Then I managed to desolder one of those caps somehow using desoldering iron (almost lifted a pad, at list one side of it got detached from pcb) and then trained with it on a small empty pcb (from one of those cheap amazon electronic kits). I soldered and desoldered it several times. Well with all fresh solder the hot air works like a charm and still no luck with 30 years old solder with some fresh solder on top of it (and a lot of flux of course). I ended up using two irons (yeah did my best to control my hands tremor) and desoldered the rest of those SMDs. Pads look fine, the process went quite swiftly (I protected the surrounding elements with heat resistance tape anyway just in case). Three outcomes: 1. Doing SMD desoldering first time on an expensive A1200 board is really very stupid idea and it can give you a heart attack (I'm still yet to find out if my A1200 still works after all that "job" done); 2. Hot air doesn't work on old solder even if you reflew the solder it doesn't get under the legs anyway so it doesn't really refresh the old solder (or I did all wrong, then look at above #1: "stupid idea" ); 3. Desoldering with one iron trying to turn the cap to a side and then desoldering the other side can be almost same destructive or even more destructive than simply twisting caps off the board.

[@CRG]

Sorry to hear about your problems. I think your issue is the temperature. In the video I had my hot air at 360 and even at that it takes a fair bit of heating before the caps come off. If they have leaked it will be worse. The two irons method is favoured by GadgetUK, I just prefer the air. There is also the cutting method favoured by Chris Edwards but I'm not keen on this to be honest. Works great for him though. The best thing to do would be to practice on something scrap first although I accept that's easier said than done. It does sound like you've done ok though, the next one will be easier 😉

[@eugenekiselev]

@@CRG you're right! temperature was a bit low on my side, this explains it. Next time will try 360 C. This time the recap's completed and Amiga survived my double-irons method and seems to work just fine hooray :)

[@deborahberi3249]

I swear by Chris Edwards' method, I believe dubbed the 'Lorena Bobbit' method. Works like a charm and NO chance of lifted traces. I on the other hand deferred my Amiga 600 and 1200 to Frank @ RetroRewind who luckily lives really close to me! I should take a Photo to show off the exceptionally professional work but I would agree with you on changing them. My Amiga 1200 worked perfectly as far as I could tell but I changed them regardless and am happy I did it. Great Video btw! -Mark.

[@CRG]

I must take another look at Chris Edwards stuff, I have watch a few of his videos. I think he snips through the caps to remove them and while it does put less stress through onto the board it surely must still apply some pressure. The hot air method carries its own risks, as I clearly showed by melting things. I suppose at the end of the day each method carries its own risks and its up to the individual to make the decision of how to remove the old caps.

[@dozern]

Cue instant heart attack at 1:02. Seriously, I'm getting old, you can't scare me like that :D That being said, excellent video, good explanations and a very nice end result (Oh, and I remember those 2MB SRAM-cards. Such an eye-opening experience when we removed it from the machine and it was suddenly a lot faster... :)

[@CRG]

Yeah sorry for the heart attack moment, I knew it would catch a few people out 🤣 I remember seeing the SRAM expansions back in the 90s but never had one. Have to admit when running this 1200 at first I thought why is it so slow but put it down to maybe I'm just used to my 030. Could hardly believe just how slow it made it though, 0.68 the speed of a normal 1200 is some slowdown.

[@dozern]

I had one friend who had one and brought it for a local swapmeet/lan/copyparty-thing.. It took a while before we connected the "16-bit stuff on a 32-bit machine" and all that :)

[@CheshireNoir]

A trick I got from Bruce from Branchus Creations (who does more recapping that any other KZbinr I have seen) to shield things from heat, is he uses blades from box cutters. They can soak and wick a LOT of heat and they can sit right down low on the board. Those and the kapton tape you've been using is my "go to" solution for working with hot air.

[@CRG]

That is a fantastic idea I think I'll try that with the next one. Thanks for the tip.

[@005AGIMA]

Great work mate. Thanks for sharing the outcome on the FDD caps, and for the shout-out :)

[@JARVIS1187]

That ripping off the cap gave me a heart attack. Please... NEVER do that again! :O I thought that was the Amiga!

[@CRG]

I knew it would catch people out 🤣. Honestly that playstation board is dead, I had put it aside for parts and thought I'd use it to play a trick on everyone.

[@JARVIS1187]

@@CRG this surely was a great use of a dead board, yeah ^^ to be honest, I may have done the same.

[@DaveVelociraptor]

Well done Glen, you absolutely got me!

[@CRG]

I knew it would catch some people out 😂, apologies for any undue stress caused.

[@RudysRetroIntel]

Thanks for sharing! It's important to show the reapirs but also the issues that arise.

[@chriswareham]

I'm a fan of using Polymer caps to replace old electrolytic ones, as they never leak. Much more expensive, but worth it for the peace of mind.

[@CRG]

True but in this instance the guy who owned it was happy with new electrolytics. Should be good for another 30 years anyway :)

[@fra4455]

Great video👏👏

[@CRG]

Thanks 👍

[@miked4377]

very good crg....you did a comendable job!....

[@CRG]

Thank you

[@Stefan_Payne]

My preferred way to remove big SMD Caps is the Dual Iron Method. That works really well. ANd you don't blow off other components in the process :)

[@CRG]

I've used the dual iron method before, its just on the 1200 access to some of the solder points is a bit tight and with my shaky hands I just find it easier to use air, even if I do end up melting things...

[@TPau65]

On my Rev 1D.1 board E113R is equipped... and located at a totally different position somewhere in the middle of the board! Removing E123C and E125C is only neccessary afaik, if you use accelerator cards like e.g. TF1260. When I got my A1200 with TF1260 this year it was totally unstable and crashed on WB right after a few seconds, opening windows etc. Removing these caps and it's rock solid now! Interesting to see that the SMD components on the bottom side seemed not to be glued in place on your board. I just went nuts removing the two caps, because of that red glue! 🤪

[@YogSothoth1969]

Thanks for sharing, I always learn from mistakes, so it is worthy showing for avoiding, thanks for that!! Best wishes and o7 Cmdr 🙂

[@CRG]

Thanks for the kind words. o7 🙂

[@YogSothoth1969]

😀

[@thespectator2976]

Lovley stuff :) I am so lucky to have alot of commodore stuff. But my pride has to be that 1200 and after that comes my a4000 030 :) well done, and yes, i subbed :)

[@Stefan_Payne]

A Tip for the strong ground planes: Use hot air at low temperature (100-150°C is enough) to warm up the PCB a bit, then use the Desoldering Gun. Another possibility is the 2 Iron Method: You use your Iron to warm up the joint and then come in with the Desolder Gun and suck it up. THat works decently too, but you might need a bit more Solder...

[@CRG]

Thanks for the tip

[@MaksymilianParadys]

Nice video ;) The fact is that the better tools you have, the easier it is to replace parts ;) I can't imagine removing ports without desolder gun ;) About capacitors... if you don't have the hotair, you can try to hold them with pliers and gently and slightly twist them back and forth until they release but there's always a risk of damaging the pads. I prefer hotair method ;)

[@CRG]

Thank you for the comment. I have twisted caps off before but as you say there is potential for damage to pads. Hot air is my preferred method, even if it runs risk of melting things.

[@VenturiLife]

Best thing you can do for an older machine, can save other components from damage. More rarely, resistors and transistors, and fixing any known power-supply issues.

[@MechaFenris]

Howdy fellow lefty! :) We're the few in our right minds. :) Great video as usual.... :)

[@CRG]

Thanks!

[@Arti9m]

My 6 cents on this: 1. Use two layers of aluminium tape instead of yellow "capton" tape, will work much better. But it's painful to remove the glue after heating it up. 2. If you ever choose to melt the connectors again, you can plug something into them to partially take heat of metallic parts. In my experience, it is enough for connector to remain fully functional, even if the plastic is melted a little bit. 3. Best way to remove surface mount components is to use two irons with needle tips at high temps. Heat one leg with one hand, heat the 2nd leg with another hand and remove the component with your 3rd hand. As easy as that. 4. If you don't care about the originality of the machine, you can determine which capacitors are put between a voltage rail and GND and put superior solid state caps (or modern ceramics) instead of liquid electrolytics. 5. Hopefully, whoever opens up the machine won't think that you fully recapped a floppy drive 😛 6. Great video! =)

[@CRG]

Aluminium tape sounds like a good protective layer but I'm sure it is hard to remove after as you said. All 4 connectors still work fine its just with it not being my board I couldn't send it back like that. I've used the 2 iron method before with some success, its just on the 1200 access to some of the caps is very tight. Solid state caps is a good idea but in this instance the guy who owns the machine was happy with new electrolytics. That very thought crossed my mind, the next person to open is going to think "well, at least the floppy drive is done" Thanks, glad to hear you enjoyed the video 👍

[@CraZy88uk]

chris edwards has a good method for removing those pesky electrolytics

[@CRG]

Thanks I'll take a look

[@jasejj]

To be fair, while I certainly would be extra careful with such a valuable and relatively rare machine, the yanking caps off the board method is effective and fairly safe if you twist the cap with pliers (certainly never just pull!). The internals of the cap are much weaker than the solder joints and the cap effectively breaks apart when you twist it - very little force needed. I've done this quite a bit with low-value stuff and have never had a broken trace - the top of the cap comes away and you're left with a couple of leads, still soldered to the board with the plastic base still surrounding them - this can then just be removed with the soldering iron. This is also the method advocated by 12voltvids.

[@CRG]

I'll openly admit I've done it before too, twisting caps off, but I have seen plenty of pictures of horror story Amigas with pads lifted or missing because someone has applied to much force. Lots of folk on KZbin will twist or cuts the caps off and if they want to do it that way then fair enough, I have seen some big KZbinrs use this method and damage the PCB in the process. Despite the damage I cause by melting plastic (such a silly mistake on my part) I still believe hot air is the best method.

[@jasejj]

@@CRG Yeah I guess it's a question of how long it's going to take vs the value of the board. As I say I wouldn't do it on a 1200, my personal preferred approach is to hit them with two soldering irons if I need to be careful (I did this recapping a £700 CD player and came out alive) but heat gun works as well.

[@DaveDoc1984]

Definitely a wise move to remove those ports / connectors. I have also made the same mistake previously and regretted it.

[@CRG]

If only I had made that decision 5 minute earlier... Lesson learnt though.

[@MrLukealbanese]

Chris Edwards has a good system for getting the caps off Glen. 👍👍

[@CRG]

A fair few folk have mentioned that. I must take a closer look at Chris's channel 👍

[@MrLukealbanese]

@@CRG Jan Beta also does this and he recapped something recently on his channel.

[@MrLukealbanese]

@@CRG kzbin.info/www/bejne/fmPVepmnmcRgqMk Check this guy at 12:45 onwards he shows the technique well, and he's not Chris!!

[@hamishgrove7722]

I like Chris Edwards way of removing surface mount capacitors the best. I have just finished recapping an A4000 board with very leaky caps. Now just have to replace a cia chip that was removed before i got it.

[@CRG]

How does Chris remove the capacitors? Good luck getting your A4000 up and running, lovely machine.

[@MrLukealbanese]

​​@@CRG he cuts the body of the cap off above the plastic base, using side cutters, and then removes the plastic base, it just comes off. This leaves just two vertical legs which go to the pads. Just remove them with iron and tweezers 👍. Jan Beta uses this method as well. Their videos cover the method extensively.

[@hamishgrove7722]

Cut the top off just above the plastic base. Watch his youtube videos just search chris edwards and watch his latest videos on A4000 repairs.

[@donfurioso3566]

I think the airflow was way too high, thus spreading the heat in a larger area an melting the connectors. U might try 20% airflow next time to pinpoint the heat.

[@RetrogradeScene]

Nice job! I some bigger pliers will help you speed through the rest of that playstation. I was surprised it didn't damage it that much.

[@CRG]

It didn't do much damage but there is some. I might revisit this whole capacitor removal thing if I can think of a means of measuring the force applied.

[@RetrogradeScene]

@@CRG yeah it’s a crazy method. I’m with you not one I’d really want to ever use

[@42markk42]

If it was my own board I wouldn't have minded a little melted plastic, that had no effect on the operation, but as it was someone else's board I suppose you wanted it mint. Did you consider taking off the old (probably unused) RF modulator ? I removed mine to fit a HDMI port :)

[@CRG]

Yes if it had have been my machine I probably would have just put up with the partly melted bits. The RGB and parallel ports aren't that bad to be honest but it wasn't mine so needed put right. The guy who owns this uses RGB for video but he didn't ask for the RF modulator to be removed so I jut left it. The thought did cross my mind though while I was working at it.

[@volkerwinkler6121]

I would use simply two solder tips to remove a SMD cap. Hot air is good for devices with exposed ground paddles or for desoldering larger packages, where you can't connect the pins with solder.

[@CRG]

I've used the two irons method before with some success but on the 1200 with some of the caps being hard to get into hot air is my preferred method of working. And yes I made a mess with my hot air melting those ports but then again I should have removed the ports to begin with and probably would have had to do that even if using two irons just for access.

[@volkerwinkler6121]

@@CRG In order to protect plastic connector I sometimes use some bended aluminium metal sheets in order to get some cavity. This helps to heat up the desired areas faster.

[@danlogue1268]

Have you ever tried to replace the SMD caps as shown in this video "Replacing Surface Mount Capacitors - The Safe Way"?

[@CRG]

By cutting them off? No I've never done that. Each to their own and if someone wants to cut, or twist, I'm not going to say that's wrong but I will say it's not how I do it. Yes in this instance I caused a bit of silly damage with the hot air but while some plastic got melted there is no risk to the PCB. Ultimately though every method has its issues but you just need to do what you're comfortable doing.

[@EgonOlsen71]

While pulling them isn't a good idea, snipping them off and then removing the left over legs with the iron is fool proof. No need to remove any ports (except for maybe the keyboard connector) or tape off anything that way. At least I never had a problem using that method.

[@terosaarela4555]

I concur. Snipping the capacitor can carefully doesn’t cause any strain on the pads and it saves you from having to desolder any ports. Having said that, I did desolder the keyboard connector to give myself some room to work on.

[@CRG]

Each to their own and if you want to remove them by cutting or twisting well that's fine. I have used that method myself in the past successfully but I just prefer working with the hot air now. While I'm sure if done properly it places minimal strain on the legs it must transfer some about of force onto the PCB which is weaken, may very well fail. And look I openly hold my hands up in causing the damage to the plastic but as I tried to say in the video that was a silly mistake on my part. If something had to be damaged though I'm glad it was the plastic ports and not the PCB.

[@terosaarela4555]

@@CRG Yes, you can still get new connectors, so rather those than the PCB.

[@Mind-your-own-beeswax]

Glen you seem to have a fair bit of knowledge on amigas. Can I just pick your brains for a minute. I’ve a 600 with a green screen fault. Consensus seems to be it’s a ram fault. Would you say this is correct? I’ve never done any kind of chip removal at all so if that’s the case I’m dreading it.

[@CRG]

Yep, a green screen is a classic symptom of a ram fault, but it doesn't necessarily mean you have bad ram chips. It could be ram, the logic that drives it, Gary or Agnus. With it being a 600 though the first thing I'd ask is has it been recapped? That machine has serious problems with leaky caps which can cause damage and all sorts of issues, including a green screen.

[@Plan-C]

Nice job!

[@CRG]

Thanks!

[@kxb07]

Too scared to do this to mine...

[@CRG]

You don't have to do it yourself but its worth getting someone to do it for you if you can.

[@davethorne3925]

to do the timing fix on the rev 2b do you simply remove e123r and e125r from the underneath of the board ?. i have the same rev 2b board and mine are still on the board also the cap you put back on e113r is not on my board . i have an amitek 8mb trapdoor expansion and have been told it wont work whilst in 8mb mode with the pcmcia slot is that true ?. and to get it working nicely i have to remove e123r and e125r ?.

[@CRG]

If you look at this site - www.ianstedman.co.uk/amiga-a1200-motherboard-fixes/ there is a good breakdown of the timing fix. On this board all I did was to remove the recommended caps E123C and E125C. There are some other further recommended fixes but I've never had need to do them. As for you're 8mb ram card that is separate to the timing fix but you unfortunately can't have 8mb in the trap door and use PCMCIA slot at the same time. This is due to the memory map of the Amiga. The ram on 8mb trap door expansion is mapped into a 4mb lower space and 4mb upper space. The 4mb upper space though is shared with the PCMCIA port so you can't have both. I think most of those trap door expansions had jumpers to configure the amount of ram, if you limit it to 4mb the PCMCIA slot should work again. The additional resistor I fitted is not required so don't worry about that and just to be clear its 2 ceramic capacitors you are removing, not resistors. In that link above there's a picture of the parts to remove.

[@davethorne3925]

@@CRG thank you very much well explained .. yeah i know i can adjust the memory on the jumpers it also has sockets for a chip and crystal back in the early 90's these were very expensive so i got the bare bones version .. lucky for me now in the early 2020's there cheap . i wasnt sure if the ceramic caps to do the timing fix id heard about in the early 90's were the "C" or the "R" from your video so thanks for clearing that up .. as you have explained in great detail in your comment and the way i use my amiga im gunna leave them in place for now as i dont use the pcmcia slot ... in the future if and when i do start to use the pcmcia ill do what i used to do back in the day and just remove the card from the trapdoor to do the file transfer ... i should have learned to just swap the jumper but i think its kinda hidden so just as quick to remove the board .. funny how we get setin our ways and even after not seeing this amiga in 30 years you still get used to having it always open and working on it the fast was . will be nice to finally have the top screwed down with no more tinkering to do a thought 30 years ago id have gone to see the quack about lol . 😄

[@danielyttervoll1907]

how can a A1200 become so yellow:)

[@CRG]

It is very yellow isn't it. I've no idea why some go like this and other don't. My two are still as white as they day they were new (more or less). I suppose its down to different mixtures of the plastic used, or something like that.

[@danielyttervoll1907]

@@CRG Yes mine is white as snow also :) Nice videos!

[@2009numan]

usually the positive on a cap is the side with a dark band

[@CRG]

On any of these capacitors I've worked with the negative side has the dark band.