Welcome to Amiga Love! Tell us a little bit about yourself.
User avatar
ClockworkCoder

by ClockworkCoder posted Mon Sep 10, 2018 10:12 am

Stumbled on this site when looking at trouble-shooting the start-up sequence of an A1200. I've just recapped my beloved (trial by fire, as it was also my first foray into desoldering old parts, and soldering SMD components), and... unfortunately the video output isn't working (something monochrome and fuzzy appears for a time before the signal drops) - although component out is working fine, and it does boot nicely at least :)

Hopefully this can be resolved, and looking forward to continue modding it - already have a clear case, 3.1 roms, CF boot-up, Gotek drive, and also waiting for some replacement keys. Also have my name down for a BiFrost, and also looking at options for replacing the ageing power supply.

Anyway, thought I might as well say "hi" before lurking :) I do like the style of the site, and of course the cursor is awesome!
User avatar
Zippy Zapp
CA, USA

by Zippy Zapp posted Mon Sep 10, 2018 1:03 pm

Welcome. I hope you get your A1200 fully sorted. Recapping those systems can be scary for hobbyists like us. I have just finished removing the caps on my main A1200 and the hybrid/polymer replacements that I ordered should be waiting for me after work. Scary indeed.
User avatar
ClockworkCoder

by ClockworkCoder posted Mon Sep 10, 2018 2:30 pm

Thanks for the welcome. Actually I had a few problems removing some of the caps - surprisingly I found the through-hole ones tricky, as I ended up with solder stuck in the holes. Ended up holding the board upright, and holding a solder sucker one side, and the soldering iron the other to get it out.

The capacitor behind the keyboard was also tricky - I gave up attempting to remove the keyboard connector and used a suggested brutal-looking method of cutting the capacitor off. However, I burnt the plastic around it a bit mounting the new one, and that's one capacitor I'm not confident about. I also had one of the pads lifting (slightly), as the first of the capacitors I was attempting to remove by "walking" them off. Problems with melting the solder, even with plenty of flux, and added leaded solder, added to it.

However, even if it hasn't gone perfectly, and with the problem I still need to solve, I'm still really glad I did it. The display was originally showing vertical lines, so although the caps looked okay, I'm sure it was only a matter of time before they stopped working anyway.
User avatar
ClockworkCoder

by ClockworkCoder posted Tue Sep 11, 2018 10:06 am

Zippy Zapp wrote:Welcome. I hope you get your A1200 fully sorted. Recapping those systems can be scary for hobbyists like us. I have just finished removing the caps on my main A1200 and the hybrid/polymer replacements that I ordered should be waiting for me after work. Scary indeed.


It was remiss of me not to say good luck - I hope your recapping goes well. Hybrid caps? I presume they are better - not sure what they are I'm afraid to say.

Not sure why, but I tried again this evening, and it worked! I did clean the board again, and there were a couple of micro-sized blobs of solder, that likely popped out of the solder sucker, but they weren't in a position or size that would have likely caused a short... but I'll not ask too many question as now it seems to be working fine!

Additionally, the vertical lines that were present in the display before I started are now gone - so I think I can count the project as a success :)

Hope your resoldering also goes smoothly.
User avatar
dalek

by dalek posted Tue Sep 11, 2018 6:52 pm

Always practice on something unimportant first. Old PCs, printers, scanners, PCI cards are great sources of PCBs with SMD/T parts that are expendable, unlike our precious amigas :)
User avatar
ClockworkCoder

by ClockworkCoder posted Tue Sep 11, 2018 11:36 pm

:lol: "Always practice on something unimportant" - that's the advice I've always given. Unfortunately I don't always practice what I preach!

Having said that, I've learned a lot, really quickly. Making plenty of mistakes is good for that :)

In a way I was looking forward to diagnosing what the problem might have been as I would have learned more about the circuit layout, and how to test it... but, as it's working, I'm not going to touch it!
User avatar
Zippy Zapp
CA, USA

by Zippy Zapp posted Wed Sep 12, 2018 8:48 am

ClockworkCoder wrote:Thanks for the welcome. Actually I had a few problems removing some of the caps - surprisingly I found the through-hole ones tricky, as I ended up with solder stuck in the holes. Ended up holding the board upright, and holding a solder sucker one side, and the soldering iron the other to get it out.

Sounds familiar. I had the exact same problem on mine. Those caps are attached to a ground plane that was really stubborn to work with. I have a vacuum desoldering station and it had a hard time with this one too. I ended up doing the same, heating it and removing it from the other side. I then added solder to the hole and cranked up the heat on the desolder tool and it managed to clear it. It was the hardest part, next to the the capacitor behind the keyboard connector. I removed it no problem but getting my iron in there I melted a bit of the connector, but it doesn't affect it at all from working. In the future if I recap another 1200 (this was my 2nd) I would use solder paste and hot air to install the one behind the keyboard connector.

In hindsight I probably should have left the through-hole caps in as they were Rubycon and still in spec according to my meter after removal. Actually there was zero evidence of any leakage on any of the caps I replaced. They probably would have been fine for another couple of years. But since they are prone to leak I convinced myself to do it.

I installed all the new caps and at first I thought I hosed it because I was staring at a black screen for what seemed like an eternity. After about 15 seconds the floppy animation popped up. After I installed the HD, floppy and put everything back together it is now back to booting up from the HD in about 4 seconds and to the workbench in about 12. Without the HD installed though, it takes about 20 seconds to get to the floppy animation. Weird but I think this is how it was before but I don't remember for sure because it has always had the HD installed.

I still need to test the sound and all the ports before I look at it as a success, though.
User avatar
Zippy Zapp
CA, USA

by Zippy Zapp posted Wed Sep 12, 2018 9:47 am

ClockworkCoder wrote:It was remiss of me not to say good luck - I hope your recapping goes well. Hybrid caps? I presume they are better - not sure what they are I'm afraid to say.
Thank You! The hybrid caps are Hybrid Polymer caps sort of a cross between electrolytic and polymer caps, if I understand correctly (and I often don't). Here is the spec sheet.

In short, they are a replacement for the standard electrolytic caps and feature extended life (10000 hours @105 degrees vs usually 2000 hours on standard caps. So they should last longer and are supposed to not be prone to leaking. Apparently they are low ESR but I can't explain what that means. Someone that knows a lot more then I do recommended them so I went with it. However, they are triple the price of a good standard 7000 hour capacitor. Given how long even the standard ones will last I am not sure it is entirely worth the extra money as the rest of the components will probably fail before a new set of caps do.
User avatar
ClockworkCoder

by ClockworkCoder posted Wed Sep 12, 2018 10:50 am

Zippy Zapp wrote:However, they are triple the price of a good standard 7000 hour capacitor. Given how long even the standard ones will last I am not sure it is entirely worth the extra money as the rest of the components will probably fail before a new set of caps do.


I just went with a kit someone sold on Ebay - I did check and they are genuine Panasonic capacitors, and as far as I can tell seem well rated.

I was curious about ceramic capacitors - heard a few people have used those, which aren't polarised, and I think there are advantages to them. However, I also heard that they are much more easily damaged by heat when soldering them, if not careful.

It's something we're only planning on doing once, so my thinking is to go for the best option available. Good point about the other components - actually I noticed a couple of tiny... I'm guessing capacitors' solder joints were almost green and not smooth looking. I just tried cleaning them as best I could.

I slightly melted one of the audio connectors (again, it won't affect anything) when I was attempting to solder that cap, and I'm not entirely happy with it. I also still need to test the audio, but haven't had chance to yet.

Also now attempting to load something on my Gotek drive; it works, but I never got it fully sorted. I also think there's better firmware / software related to it now, which I'm just now looking in to.
User avatar
A1-X1000
Toronto, Canada

by A1-X1000 posted Thu Sep 20, 2018 3:14 pm

@ ClockworkCoder

welcome aboard where the Amiga projects never 'truly' stop & WorkBenches are never truly 100% optimized <3
c64-dual sids, A1000, A1200-060@50, A4000-CSMKIII
Indivision AGA & Catweasel MK4+= Amazing
! My Master Miggies-Amiga 1000 & AmigaOne X1000 !
--- www.mancave-ramblings.blogspot.ca ---
-***AmigaONE X1000- I BELIEVE ***

Who is online

Users browsing this forum: No registered users and 3 guests