Infinity TSS-450 sub assistance

[jibber]

Hello,

I have this TSS-450 sub that has been great for 7 years, It recently started making noise after about 3 min of running (works flawless at first). It starts with a hum and then all hell breaks loose when the squelching vibration starts in.

I pulled it apart to find some pretty warm areas under a few 3 leg transistors? And a couple of the small caps.

Any direction on where to go now would be great!

Thanks

Josh

[jibber]

Re: Infinity TSS-450 sub assistance

Is there a method of testing these transistors? I am assuming the mosfets are attached to the heatsink.

[budm]

Re: Infinity TSS-450 sub assistance

Post good well focused pictures will be a good start.

[jibber]

Re: Infinity TSS-450 sub assistance

Will do the next time I am at home. I have the board pulled out already. Thanks!

[jibber]

Re: Infinity TSS-450 sub assistance






Here you go, you can see the discoloration on the board where it got hot.

Thanks for any help you can provide.

Josh

[momaka]

Re: Infinity TSS-450 sub assistance

If it works fine but then starts having problems, you are looking at either bad solder joints, thermal runaway on a semiconductor, or perhaps those electrolytic caps in the hot areas are going bad.

My #1 advice would be to replace all caps in those areas where it gets hot as they have likely gone dry by now. Better yet, replace all caps, except possibly for the big two. Use good quality 105C rated Japanese parts (so Panasonic, Nichicon, Rubycon, or United Chemicon). Order from Digikey, Mouser, or badcaps.net/store (this place). Avoid local stores/Radio Shack for caps - they don't sell suitable caps. And more than anything, AVOID eBay for caps and replacement transistors/ICs (too many counterfeits).

Next, check all solder joints, and if in doubt, resolder any that look dry. You may also want to resolder the joints on that transistor that seems to have been running hot (Q117?), even if they do look good.

You also have some tan glue on the right side of the first two pictures you posted - now that stuff tends to go conductive, especially over time with exposure to moisture and heat. Clean it off - at least from the leads on components.

If you have some piece of scrap aluminum, consider making a heatsink for that hot transistor. Maybe the others behind it too if they are running hot and discoloring the board.

That's as far as my suggestions go for now. I'm no expert in the matter of amplifier problems, but in general when things are running hot or have ran hot, I always change the caps in those affected areas because they often go high-ESR.

[jibber]

Re: Infinity TSS-450 sub assistance

Thanks for the time looking at this. I will pull and log all the caps specs and their board locations. I have been successful purchasing from digikey before so I will try them first.

After I get all the caps replaced and the tan glue cleaned off I will let you know how it all worked out.

Thanks again for the space and the assistance!

Josh

[jibber]

Re: Infinity TSS-450 sub assistance

So I replaced 11 of the 12 small caps.... I missed one when ordering. I also re soldered a number of the transistors.

Result is the same. about 5 min then humming popping and general terror starts.

Any other thoughts?

[jibber]

Re: Infinity TSS-450 sub assistance

I did not clean the glue off, what works well to assist that?

[momaka]

Re: Infinity TSS-450 sub assistance

Any other thoughts?

No idea, but it sounds like bad solder joints. (I know you checked them, but perhaps resolder some more - even those that don't appear bad)

As far as cleaning the glue... just a small sharp screwdriver, tweezers, cutters... really anything that can pry that stuff. Really no other way I know of to take it off. It's a big annoyance, I know! Older Bestec PC PSUs have it spilled everywhere in them and many here who have ventured to fix one will tell you how much they hate this stuff (myself included).

[pnwatlast]

Re: Infinity TSS-450 sub assistance

Hi, did you ever fix your Tss-450? How about those big caps--replaced?