DanP27 Posted February 26, 2019 Posted February 26, 2019 Hi all, I am hoping someone can help me. I bought an A&K M249 second hand from someone a little while ago (tested it on collection and all worked ok). I then took the gun out to my local field for a game day and half way into the second game the auto winding box mag stopped winding. I assumed at the time it was nothing serious and would investigate when i got home. I have now finally made time to investigate why but I've never done this kind of thing before. I have changed the batteries (AA's) and checked none of the wiring is loose, however it is still not working so i am stuck. Can anyone offer up any solutions/advice? Thanks Dan
DanP27 Posted February 26, 2019 Author Posted February 26, 2019 in case it helps, I've attached another photo after taking the mag apart a bit more in the hope to find a jam which has not worked out for me.
Iceni Posted February 26, 2019 Posted February 26, 2019 What is your level of electronics knowledge? Do you own a multimeter? It's hard to diagnose electronics if you don't have a multimeter. Because in a case like this the first thing you do is check each wire for continuity. Look for cold solder, and make sure the whole unit is intact. By intact I mean visually look at everything. There should be a spring for both batteries, and a contact bar acting as a bridge. You should check the battery circuit is making 3v, then make sure you are getting 3v at the +v input. The next thing to do is check the switch for much the same, Continuity to the ground, Continuity in switched positions, Continuity in switched positions to PCB. After that it's a series of investigations: Bridge the Mic. Put 3v on motor Check rest of cables Check PCB resistors. Check PCB diodes. At that point, if it's still not showing a fault it's scrap. If you can't follow that or don't have access to a soldering iron and multimeter then it's not worth even looking into the investigation stage. Checking the battery bridge and changing the batteries is about all you can do.
Podge1945 Posted March 5, 2019 Posted March 5, 2019 I had the same fault with my first box. Turned out it was a fault on the board, I was lucky that I had it replaced but I would look up a&k 1500 box mag on Amazon I found them for £50 with shipping which is still £50+ cheaper than getting them in the UK. They are a great addition so much smaller and easier to use and a rechargeable battery. Love mine works a gem.
DanP27 Posted March 8, 2019 Author Posted March 8, 2019 On 26/02/2019 at 23:05, Iceni said: What is your level of electronics knowledge? Do you own a multimeter? It's hard to diagnose electronics if you don't have a multimeter. Because in a case like this the first thing you do is check each wire for continuity. Look for cold solder, and make sure the whole unit is intact. By intact I mean visually look at everything. There should be a spring for both batteries, and a contact bar acting as a bridge. You should check the battery circuit is making 3v, then make sure you are getting 3v at the +v input. The next thing to do is check the switch for much the same, Continuity to the ground, Continuity in switched positions, Continuity in switched positions to PCB. After that it's a series of investigations: Bridge the Mic. Put 3v on motor Check rest of cables Check PCB resistors. Check PCB diodes. At that point, if it's still not showing a fault it's scrap. If you can't follow that or don't have access to a soldering iron and multimeter then it's not worth even looking into the investigation stage. Checking the battery bridge and changing the batteries is about all you can do. On 05/03/2019 at 23:24, Podge1945 said: I had the same fault with my first box. Turned out it was a fault on the board, I was lucky that I had it replaced but I would look up a&k 1500 box mag on Amazon I found them for £50 with shipping which is still £50+ cheaper than getting them in the UK. They are a great addition so much smaller and easier to use and a rechargeable battery. Love mine works a gem. Thank you both for your advice. Electrics are not something I know much about and so I am going to either leave this to a side to look at another time or maybe take it into a shop that hopefully wont charge much to do an initial assessment. I think I'm going to buy the 1500 box mag though thanks
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