eightbit Posted November 15, 2019 Share Posted November 15, 2019 (edited) So the other day I noticed the two large caps that are for the video matrix looks a bit crappy. One looks rusty (or leaking maybe) and the other one was super wobbly. I decided to do some preventative maintenance and replace them with new ones. I am not recapping the whole board right now (I do not have the time atm and the other caps look fine) but I wanted to get these replaced as I know from past experience that if they go they actually short and blow the video matrix. That is something I want to avoid. As a matter of fact, all A500 and A500+ owners should consider replacing these. They were actually pretty hard to remove due to the old solder that was probably contaminated with electrolytic , and the one on the left (which was obviously starting to leak from the stains on the board) left a piece of the canister cover on the board. That little blue piece. It feels like it is crazy glued on. I am afraid to pry it off as it is sitting right on that trace. What do you guys think? Do you think prying it off is a concern for that trace or just be safe and leave it there? It is not a metal piece or anything. It is like the rubberish wrap from the bottom of the cap. The piece just melted or molded itself right to the board! Edited November 15, 2019 by eightbit Quote Link to comment Share on other sites More sharing options...
Daedalus2097 Posted November 15, 2019 Share Posted November 15, 2019 Hmmm... I think it could be that your capacitors were in fact glued to the board. It's common to glue taller components down so that stresses from movement don't pull the legs out. I've seen many A500s with these capacitors glued down, and you'll find it's very common in PSUs where the capacitors are quite tall too. So the "leakage" you were seeing could simply have been old glue. There's always a risk removing something that's glued down so tightly, but you should be able to shave it down almost flat with a sharp blade or very careful use of abrasives. It won't do any harm to leave it there, other than perhaps interfering with the fit of the replacement part. As for those capacitors killing the video hybrid, I'm not so sure. All they do is filter the video power supply rail - if they fail short, they'll burn out the supply resistors which will have a similar result (no video output), but the hybrid itself should be unharmed. It's a different story if the 12V rail goes out of spec, but the capacitors here won't cause that. I have seen them bulge and fail before without affecting the hybrid, so it's probably still a sound idea to replace them. 2 Quote Link to comment Share on other sites More sharing options...
eightbit Posted November 15, 2019 Author Share Posted November 15, 2019 Thanks for the response. Shaving it down with a blade sounds like the best idea. I just do not want it to interfere with the replacement cap. I think you might be right with it being glued. Oddly, the other one was not. And even more odd is that the one that was "glued" is also the one that was super wobbly. I wonder if someone squirted some glue under it at one point. I am not the original owner and I can see little things touched up (like the power connector was reflowed at some point) Even though the caps were not bulging, they really didn't look so great. I have some nice Panasonic FM series replacements coming tomorrow. Quote Link to comment Share on other sites More sharing options...
cbmeeks Posted November 15, 2019 Share Posted November 15, 2019 Keep in mind too that those caps are tied to very large traces and ground pours. So, worse case, would be easy to repair. Unless you used jackhammer to pry the glue off. ? Quote Link to comment Share on other sites More sharing options...
+chue Posted November 15, 2019 Share Posted November 15, 2019 For removal of hot glue, I use a little isopropyl alcohol. It will pull right off if you can get a little alcohol between the glue and the pcb. Just give the alcohol a few minutes to work. 2 Quote Link to comment Share on other sites More sharing options...
cbmeeks Posted November 15, 2019 Share Posted November 15, 2019 Yep, I've done that too. In fact, the hot glue will pretty much pop right off. If it's another type of glue, like maybe rubber cement, you may try a little acetone. But be careful around any plastic and make sure you wash off quickly. Quote Link to comment Share on other sites More sharing options...
eightbit Posted November 16, 2019 Author Share Posted November 16, 2019 I just took an exacto and got it off for the most part. They must have used some super duper glue on that cap I never understood gluing them down like that. They were very well soldered...guess that wasn't enough. And it seems in the case of these machines they really didn't care about the possibility of future servicing. Quote Link to comment Share on other sites More sharing options...
eightbit Posted November 16, 2019 Author Share Posted November 16, 2019 (edited) Yep, shaving that bit down made the new cap nice and flush. Nice Panasonic FM replacements (same spec as the original but higher temp tolerance) and I am surprised exactly the same height I have to admit though I really miss Radio Shack. Waiting for this stuff really kills me. Edited November 16, 2019 by eightbit 1 Quote Link to comment Share on other sites More sharing options...
Daedalus2097 Posted November 18, 2019 Share Posted November 18, 2019 Good stuff You'll find a lot of devices with glued parts to increase their resilience to bumps and knocks. A high centre of gravity gives a tall part some good leverage for pulling its own legs off if you happened to drop the computer on its side for example (or if it happened in storage or distribution when new). It's more commonly seen in power supplies, which have large capacitors by their nature. 1 Quote Link to comment Share on other sites More sharing options...
+OLD CS1 Posted November 18, 2019 Share Posted November 18, 2019 On 11/16/2019 at 4:24 PM, eightbit said: I really miss Radio Shack. I just discovered this weekend that HobbyTown has partnered with Radio Shack to co-lo a Radio Shack Express section within their stores. I was able to pick up three caps I need to refresh my old Sears Tele-Games (Atari 2600 re-branded) console. You can browse it on-line, as well. Quote Link to comment Share on other sites More sharing options...
eightbit Posted November 18, 2019 Author Share Posted November 18, 2019 Cool! Looks like the closest one to me is 60 miles however Quote Link to comment Share on other sites More sharing options...
+OLD CS1 Posted November 18, 2019 Share Posted November 18, 2019 20 minutes ago, eightbit said: Cool! Looks like the closest one to me is 60 miles however ROAD TRIP! 1 Quote Link to comment Share on other sites More sharing options...
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