Accusound N11640 Subwoofer- Clicking sound

[Soundproof 23]

When switching on it keeps making a clicking noise without any sound output. However, the clicking frequency slowed down and would stop and sound would come on.

This happened a few times and now the clicks would just keep going on. I've emailed accusound with pictures and they said it's the auto standby that had failed and it's an easy fix. But the shipping cost to Sydney itself is going to not make it worth it.

I clicks are coming from the relay on the amplifier I think.
Happy to open it up and attach pictures or videos if anyone can tell me what to fix please..

My wife's an electronics technician but I'll have to tell her exactly what to replace.

 

[dasdoing]

I had a clicking noise when a capacitor on my sub board started leaking.
if it is not coming from the driver it is a very bad sign and you should not turn it on again before someone takes a look at the board

 

[Soundproof 23]

I had a look at the board. The clicking is from the relay turning on and off. What I don't know is if it's the relay itself that should be replaced or something else entirely.

This is the exact relay that's on the board https://m.yoycart.com/Product/521400673453/

 

[Lazy_Crab]

Please did you manage to eventually diagnose the problem? I have same issue and if I can resurrect this sub-woofer it would be fantastic.

 

[SayLay]

Same issue with ACCUSOUND Reference XD

 

[AdamG]

Same issue with ACCUSOUND Reference XD

Welcome Aboard @SayLay.

 

[restorer-john]

The Accusound subwoofers fail due to poor quality small value capacitors in the auto signal sense part of the circuitry. The relay is for the power stage output rails, the rest of the sub is powered on all the time.

I repaired one for a friend a while back and told him the same problem would occur down the track again. It did right on schedule. Actually, it's at his place of work waiting for me to collect it and repair it.

I may pick it up today if I get the chance and show you guys.

 

[SayLay]

The Accusound subwoofers fail due to poor quality small value capacitors in the auto signal sense part of the circuitry. The relay is for the power stage output rails, the rest of the sub is powered on all the time.

I repaired one for a friend a while back and told him the same problem would occur down the track again. It did right on schedule. Actually, it's at his place of work waiting for me to collect it and repair it.

I may pick it up today if I get the chance and show you guys.

is it an easy fix? I can solder very well but am not too comfortable around amps and power supplies, would assume they're dangerous for a novice

 

[restorer-john]

is it an easy fix? I can solder very well but am not too comfortable around amps and power supplies, would assume they're dangerous for a novice

Let me get the sub from my friend first, then we can compare the internals and take it from there. IIRC, it was fiddly and a tight squeeze with the caps I put in last time with the boards all glued down. There wasn't space for caps of a higher voltage and the cheap Chinese ones they had were marginal at best with optimistic working voltages for their size- hence the premature failures.

 

[restorer-john]

Just an update @SayLay , I've picked up the sub from my friend and it is, as I suspected the same model as yours.

I'm heading to the beach today, but I can walk you through the repair tomorrow (Sunday) (with pics in this thread) if you want.

 

[SayLay]

Just an update @SayLay , I've picked up the sub from my friend and it is, as I suspected the same model as yours.

I'm heading to the beach today, but I can walk you through the repair tomorrow (Sunday) (with pics in this thread) if you want.

That'd be great mate

 

[restorer-john]

Here's the Accusound PS100 (N11640) subwoofer repair.

Rear plate, not too bad.

Decent enough woofer, magnetic grille attachment- nice.

150W claimed output, likely pretty accurate at 4R based on power supply.

Internal brace and reasonable magnet structure. Cabinet a bit resonant, but OK overall.

Main boards OK quality, lots of damping glue/adhesive makes for less fun when repairing. Transformer is a lovely toroid, nicely made and mounted on sub bracket. Capacitor quality- extremely poor.

Proper 240V toroid (Australia) and decent 10,000uF in filtering. Topcon brand however.

Nice to see component values screen printed on the PCB. Note the +/-15V rail connection to this PCB. Decoupled via a few 100R resistors and filtered with 100uF caps. These are your problem. The front end circuitry and the auto switch comparator are supplied from this. IIRC, the original caps were 100uF and maybe 50WV (you'd have to check yours), but very small for that WV and capacity. They were very high in ESR. These caps are replacements at 220uF. Check the voltage across the caps in operation and also check for excess upstream ripple from the main +/-15V regulators (zener/tr based) on the main board.

Replace the two caps and report back with you findings.

The entire subwoofer really could benefit from having all the lower tier capacitors replaced if you had nothing better to do, but from a time/cost perspective, it's probably not worth it.

 

[SayLay]

Thanks for the comprehensive guide @restorer-john

so you're thinking replace both the 100uf caps with 220's?

like these: https://www.jaycar.com.au/220uf-50v...os=1&queryId=7996912688b1c55aac8714883d2b0e47

 

[restorer-john]

so you're thinking replace both the 100uf caps with 220's?

I used the 220uF caps as my stock of 100uF were only marginal at 16WV. There's absolutely no harm in going up in that space, in fact it should help.

Thing is, you don't need 50V caps, the supply is 15V, so a 16V is borderline and a 25V is fine. The 50V ones will be too big to fit alongside the components unless you put them on the track side (there is space).

The important thing to check is the upstream ripple, in case the main supply is dirty. Put your DMM onto AC mV and check the ripple over the caps in question. Wait several seconds for it to stabilize and give a solid reading. It should be <1.5mV or so. More than that, and you will get 100Hz hum in the unit. (it already has a bit)

 

[SayLay]

I used the 220uF caps as my stock of 100uF were only marginal at 16WV. There's absolutely no harm in going up in that space, in fact it should help.

Thing is, you don't need 50V caps, the supply is 15V, so a 16V is borderline and a 25V is fine. The 50V ones will be too big to fit alongside the components unless you put them on the track side (there is space).

The important thing to check is the upstream ripple, in case the main supply is dirty. Put your DMM onto AC mV and check the ripple over the caps in question. Wait several seconds for it to stabilize and give a solid reading. It should be <1.5mV or so. More than that, and you will get 100Hz hum in the unit. (it already has a bit)

Hey john, I finally had time to do this and I replaced both 100uf 15v caps with 220uf 25v low esr's but the problem still persists, what would you advise?

 

[restorer-john]

Hey john, I finally had time to do this and I replaced both 100uf 15v caps with 220uf 25v low esr's but the problem still persists, what would you advise?

It's definitely some caps, in or near the auto switch circuitry. Basically, the entire subwoofer is full of caps which go high in ESR when they are cold and once they warm up a bit, the ESR drops (caps do this) and the circuit functions. If it's the relay clicking on/off quickly and then slowing and staying on, it's likely very close to the transistors driving the relay. As the most common issue was the +/-V decoupling caps, that is what I showed you when I repaired this one.

I've buttoned up this subwoofer, but I can pull it apart and point you to the likely area of the problem. It will be on the main board, which is a pain to remove. Basically, you need to desolder the BCE terminals of the two output transistors and pick the adhesive out of the PCB mount screw heads and remove the board.

 

[SayLay]

It's definitely some caps, in or near the auto switch circuitry. Basically, the entire subwoofer is full of caps which go high in ESR when they are cold and once they warm up a bit, the ESR drops (caps do this) and the circuit functions. If it's the relay clicking on/off quickly and then slowing and staying on, it's likely very close to the transistors driving the relay. As the most common issue was the +/-V decoupling caps, that is what I showed you when I repaired this one.

I've buttoned up this subwoofer, but I can pull it apart and point you to the likely area of the problem. It will be on the main board, which is a pain to remove. Basically, you need to desolder the BCE terminals of the two output transistors and pick the adhesive out of the PCB mount screw heads and remove the board.

the relay slows a little bit after 20 seconds or so but even after a minute doesn't stop clicking

repairing anything on the main board seems more trouble than its worth for a $250 7 year old sub

thanks for your help so far

 

[Wayno]

When switching on it keeps making a clicking noise without any sound output. However, the clicking frequency slowed down and would stop and sound would come on.

This happened a few times and now the clicks would just keep going on. I've emailed accusound with pictures and they said it's the auto standby that had failed and it's an easy fix. But the shipping cost to Sydney itself is going to not make it worth it.

I clicks are coming from the relay on the amplifier I think.
Happy to open it up and attach pictures or videos if anyone can tell me what to fix please..

My wife's an electronics technician but I'll have to tell her exactly what to replace.

I have the same problem. What e-mail address did you use to contact Accusound? I tried the "[email protected]" one and my mail bounced. Accusound used to have a factory in Kirrawee which isn't too far from where I live so would be happy to drop my unit off for repair and pick up after since I'm not that great with a soldering iron.

 

[MaxBuck]

 

[S0und_Junkie]

restorer-john, I'm glad i stumbled across this thread today.
I replaced the main power caps today in this exact sub (with some 1000uF 63V Mundorf) as I was having the same issue being described. I didn't test the board further as they both tested bad and hoped by replacing them I might jag it and resolve the issue, it didn't. Thinking I might as well (mainly for the fun of it) replace all the caps.

I saw you mention that when you first repaired your friend's sub that you told them it would likely happen again. Why was this and how can that be avoided? Can i choose a type/make/value of cap which will increase the longevity of the unit?