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Thread: 'FleetWood' branded 6100-05 powered subwoofer repair - a horrowshow.

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    Default 'FleetWood' branded 6100-05 powered subwoofer repair - a horrowshow.



    You may come across these for sale in ebay, FB, gumtree and the like ; you will find reviews online, many in the form of youtube videos...you can weigh out the bad versus good review ratios for yourself.

    This unit was given to me by a friend cleaning out stuff they never use, and they can't remember who gave it to them, or why. In fact, first question I was asked was "what's this?". I took it off their hands, else it was headed to the local tip.

    Upon testing the unit, it 'sort of' worked for around 15minutes, before the heatsink became so warm, the amplifier thermal management was kicking in so hard, there was very little sound and enough heat to be a room heater. I noticed that both the volume & rollover frequency pots had really viscous, overly dampened movement, and the volume control was erratic at best, and both pots were noisy/scratchy. I wrote this as I thought it at the time, in retrospect at lot here is in error =)

    One thing you really get to know 'touch me feel me' well when you've spent decades in the electronics service/repair game, is how much stuff out there is junk, behind marketing hype & advertising BS...like reviews you'd find above I mention.




    You also learn the fine art of proper interpretation of certain warnings & words ...ie; "Caution ; Risk of electric shock ; do not open" ...I've found over the years, that actually means "Caution ; do not open or you will see the horror, and it will shock you"

    That image above is of the 240v only unit - I have the 110/240v model, which increases ugly factor. I suppose they marketed these as having a 10inch/250mm bass driver in them, but effective size is more like 8"/200mm in this universe where it's actually the moving bits that matter, not the flange plate.

    All good horror stories have multiple elements of fear & mystery, and the FleetWood 6100-05 doesn't disappoint! How long has it been since you've seen any of the "what could possibly go wrong" mains input wiring like this, of course replete with the flavorsome coloured earth/ground wire, appearing lower left corner of stage...




    Note the copious use of hot-melt glue, which afaict is there the seal off the speaker enclosure and stop it breathing out these fittings. but it could as well be to cover the fact the wires have aluminium wire strands, not copper, and they're trying to stop the wire bouncing/vibrating and work hardening/fracturing. The again, it might be abstract art versus a caulking gun, and 'oh mister hart, what a mess!' my apply here, and we're looking at a work of art here.

    Next, we have the much hated, steam-pipe extruded pig-iron toriodal mains step-down transformer, and here's the sticker telling who was prepared to own up for doing this, along with a datestamp..3 days before Xmas, 2003..




    Not joking in description ~ this is one of those slim, tall toriods (70mmx75mm w/h) that always made us wonder, 'why not just use a conventional transformer?'...seeing as you weren't taking advantage of the flat, lower profile form factor typical toroid mains transformers offered you. About 2 decades ago, we wondered too much about that, and cut one open, and found a piece of what could only be described as a section of thick walled steam-pipe, made of a soft ductile iron/steel material that just left us scratching our heads. None the less, if this was salvage then a 2 x 33v @ 100VA mains transformer is a good gain for the bits&pieces shelf...provided you can live with cheap chinese made transformers ; good battery charger source =) Also a handy voltage/winding pair for many an audio poweramp thang one supposes.


    The input/tone/volume control board, is glued&screwed to a plastic riser piece, which is glued&screwed to the amp panel...you need remove the 6 screws, then carefully going around the PCB periphery and pries it up to break the glue bonding..




    I've already desoldered/removed the pots here. The board itself has obviously been designed for some other model/purpose/whatever, and been abridged into duty here. Of course, the dual op-amp of choice used, is a pair of the ubiquitous chinese made 4558 ICs, known to disappoint time and again. The actual PCB layout is archaic at best...ie; the 4558 lower right is the active lowpass/hicut filter, but the center frequency control is the pot at the top of the board =) The pot adjacent this IC is the volume (attenuater) and it's traces go up and back down the length of the board, to the other op-amp...??...wtf? It's like that everywhere...





    There...see what I mean? That is some of the whackiest routing I've seen for a while, for an audio circuit that is. Oh yes, and lets use the exotic 6pin 25k log pot...and solder 4 pins together, so it's your usual 3 pin pot... well, not really - it changes the pinout from 1-2-3 to 2-1-3 ..the center wiper is connected to the 4pins soldered together bottom of image above -- keep that in mind when wiring in the replacement pot, and best bet there if a small pot nutted to the panel, and flying wires to the board because the pots are weird as, as you can see from the PCB earth/support holes...hmm...should've take pic of pots before I pulled them apart.

    The cause of the viscous/heavily damped rotary movement of the pots themselves, I think was bourbon&cola =) At least, that's what the sticky residue smells like that's gummed up the bushing/shaft, and is still in the back cavity of the knobs ...which had been removed before and replaced unaligned to panel markings btw ; someone did a quick clean up. Not good enough of course .. if this was CSI and they were trying to conceal the fact they'd used this subwoofer to bludgeon a can of JD&cola to death, the victim's blood was still hidden under the amp panel at the bottom ..you're nicked <grin>

    The 4558's are of course pin4pin and electrically interchangeable with other dual op-amps of better/different performance, but I doubt there's a lot to gain here...I have some TL072 in a drawer somewhere, they'd be ok for this. Note the 3 test pads and no-stuff next to the 4558 top right, there's a main ground test pad at the other end of the board out of shot. This has been noted before in a lot of chinese implementations of the 4558 op-amp ; they leave the FB res out. FTR, the test pads are untouched & unused. I've yet to read of any feasible explanation, aside from the observation it's typically 'knock-off' designs where you see this.


    The power/amplifier board, in all it's wire linked beauty. The 2 main storage caps (8200uF/50v) I've already pulled here - part of the problems. Both were bulged at the base, the positive supply rail cap lifting it's lid as well... and one of the most renowned wprst electrolytic caps in the world, are these things... 'Jakec' ...these can go to bulge just sitting on the shelf unused.




    The transistor (resistors, zener) about top center, is the pass regulator for the 15v rail to input/tone board, and also feeds the pre-amp stage of the main amp... which is class-B, bipolar push-pull. Oddly enough, the output pair appear to be genuine Toshiba parts, and the pre-driver stage is all real Hitachi...and all the TO92 signal transistors have JIS markings...if it wasn't for what I've seen so far, I'd be starting to believe this was made in Japan.

    They, however, wouldn't have mounted the PCB assembly to the heatsink like that, with it literally capable of bouncing/vibrating using the legs of the mounted transistors as a hinge...tsk tsk, that's so piss poor...

    In that regard, another odd bit of nostalgia comes with these PCB assemblies....in fact, it's probably the best thing about them, I wanna go turn on the soldering iron and have another sniff now ; that sweet smelling old-school burning rosin flux...mmm. It's been a long, long time since I'm smelt that, it has an unmistakable frangrance all of it's own. I should get on it with a scalpel and scrape all the excess off into a little specimen bottle, so I can burn a little when I want to reminisc.

    The cabinet itself seems to be made of repurposed paper&cardboard, bound by epoxy, and no as strong as it's weight would suggest...or wood suggest if you want a pun ... as per assembly damage ;




    The box itself would be about 35L cavity volume, and it is obviously a ported box -- the bass driver/speaker is absolutely no-name. and notice how the bass port design incorporates nothing but the best of domestic household plumbing items;




    Oh, speaker voice coil measures 3Ohm, which is an odd-bod number in my book, so perhaps the coil's burnt or it's just because cheap chinese copper and that's the way it is.

    Somewhat by accident, I put hand on the port assembly, and...



    ..it popped straight out, because it hadn't been glued in properly, coz they used all the glue up on the mains wiring...I guess.

    Notice the attention to detail, with someones having to spray paint the inside of the while elbow black, so no-one shining a touch in to port would see the obvious.




    Can anyone identify that? I'd like to know the name of their plumbing parts supplier 8)

    When I was checking the toshiba markings on the output drivers 2SA1943/2SC5200 (and they appear to be real), these are a complimentary pair made primarily for 100w audio power amp applications- google '2sa1943 amplifier circuit'

    Then I think, is it worth fixing? The caps I can get for $15/pair local, $15 for 5 from china. A lot of small amp modules these days are 2.1, so with one of them it'd still be a powered sub + powered satellites. (BT connectivity) Could also cut a panel, and turn it into an unpowered sub instead...but I guess I might just do that much anyhow, just to see what it sounds like, before I waste any more effort on it.


    Conclusion: good coffee table height stand to put family size pizzas on, for that big night in.

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    bob_m_54 (23-09-20),gulliver (25-09-20),Johnno (23-09-20),lsemmens (23-09-20)



Look Here ->
  • 23-09-20, 04:09 AM


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    Interesting story Wotnot. Just looking at the soldering on the board made me cringe. Your story made me desire to NEVER own one.
    I'm out of my mind, but feel free to leave a message...

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    wotnot (29-09-20)

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    That's what you get when you buy speakers at an incredible discount, from the guys who happen to have over ordered for a job, and decide to try and sell the excess off from the back of their White Van

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    wotnot (29-09-20)

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    Interesting plumbing supplier. salvage what you can and stock up the bits & pieces shelf...
    Add a couple of mid range speakers plus a blue tooth network adapter /dongle
    Wire up a few usb sockets and a 10" smart display (coupler wires here & there) and now you have a Bluetooth video beatbox... /well kind of

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    wotnot (29-09-20)

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    Quote Originally Posted by Johnno View Post
    Interesting plumbing supplier. salvage what you can and stock up the bits & pieces shelf...
    Add a couple of mid range speakers plus a blue tooth network adapter /dongle
    Wire up a few usb sockets and a 10" smart display (coupler wires here & there) and now you have a Bluetooth video beatbox... /well kind of
    Please, sir, can I have some of whatever it is you are on?

    Real life was just as funny, yeah...found the time to complete the rework, put it back together on the bench, pervert thy eyes whilst applying the ergs and nothing exploded or smoked into oblivion. Check out voltage/ripple, note I'm seeing 50hz noise, shrug and plop it on it's cabinet, connect the sub-woofer & L/R outputs from the bt amp thingme and speaker renders 50hz signal into thick mains hum and wtf is wrong now conclusion involving giving it the evil eye and reaching for something liquid to tip into while powered up. Sigh...do I really want to find the fault, no, I don't.... I've done too much already.

    I think I'll go this way ;



    Remove amp module, cut fresh backing plate to seal hole & add speaker terminals.

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    Your just having technical difficulties.. Please Stand By Peeps.. (Tip the liquid in while it's powered up).

    Don't forget to add a Raspberry Pi..


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    SS Dave (15-10-20)

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    Plan B...



    =)

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    Johnno (21-10-20)

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    Add terminal posts and I'm done with this thing -- does balance the panels' low-end well though (another thread I need to get back to =)


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    Johnno (21-10-20)

  • 14-11-20, 08:58 PM


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