Altec Lansing ADA885 No Power

[Logistics]

tl dr Does anyone have experience with this system not powering up?


So I saw these at the local surplus place I visit on the way home from work from time to time, they wanted $20, but then couldn't get them to power on, plus the DIN cable for the right speaker (the one with all the controls) had a broken pin so he offered it to me for $10. I had gone in the back and looked through the other miscellaneous speakers a few minutes before and there was still a set of used fronts for this system for sale, by themselves, which have been there for months, for $10, with good pins in both DIN cables. So I told the guy I'd by the system for $10, then I put it in my car, went back in and bought the other set of fronts for $10 so $20 is not bad for this system IF it worked.

Unfortunately, it will not power on. There is a hot spot on the bottom cover, which is right where one of several regulators are inside. I don't see any components inside which look obviously toasted and the fuse appears to be good.

I've been researching this system and no power seems to be a pretty common issue, but no solution is ever mentioned. I really want to make this system work, again so any ideas are greatly appreciated.

Pictures to come...

[Logistics]

Re: Altec Lansing ADA885 No Power

After inspecting, and taking pics, I found that on the subwoofer amplifier there is a thermal fuse connected to a huge resistor. It's obvious both of these got very hot as the traces to both, while still intact, are seperating from the PCB as I can wiggle them away slightly. Also, the two solder joints which stabilize the ground rail which both of the major IC's are bolted to has broken free at both joints and need to be tweet. This thing just screams heat problems.

Hopefully, that thermal fuse is my problem. If so then I will replace and upgrade the caps, and I suppose see if I can increase cooling in the unit. Polyfill? It is a ported sub so.

[Logistics]

Re: Altec Lansing ADA885 No Power

So at both ends of the aluminum rail connected to the main IC's are solder points to keep it stabilized; I re-wet those. Then that large resistor, at it's base and where it re-enters the PCB, as well as the hardline that runs NW off of it's leg (which ends up being a zener and not a thermal fuse? It reads 1N 47 35A 008) all have their solder joints intact, but the trace they are tied to is beginning to seperate from the PCB near the thru-holes. I re-wet all those joints just because. I'm going to try and bread-board it, right now...

Still nothing so I guess I'm just going to have to get this thing all taken apart on a bench and bust out my Fluke 77 to see if I can find out what's bad.

[momaka]

Re: Altec Lansing ADA885 No Power

I'm guessing this thing uses a regular transformer and not a SMPS. I would start there and make sure there is power coming from the power supply.

Polyfill? It is a ported sub so.

If it's a ported sub, you don't want to polyfill it. It will loose loudness and sound a lot more like an acoustic suspension speaker system.

[Logistics]

Re: Altec Lansing ADA885 No Power

I keep neglecting to upload pictures of the rest of the boards and such, but it uses a large toroidal transformer. With my newborn around, now I just haven't had the chance to grab my multimeter and probe around in there.

[musicman1101]

Re: Altec Lansing ADA885 No Power

Did you ever get it to power up?