Event ASP8 repair

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Event ASP8 repair

Postby Lucas » Wed Jan 14, 2015 5:22 pm

Would it be appropriate to ask for some guidance in the repair (or at least diagnosis) of some Event ASP8 monitors here?

One has a HF driver that does not operate & the other has an intermittent "flutter" in the LF driver.

I don't have a lot of cash at the moment so I thought it a good oppurtunity to have a crack and learn something.

Cheers.
Lucas Martin
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Re: Event ASP8 repair

Postby rowmat » Fri Jan 16, 2015 12:25 am

Hi Lucas,

I have some experience with these speakers.
I purchased a pair from Ebay around 12 months ago.

They had/have the following issues.

One speaker had a noticable hum.
This turned out to be caused by a diode in the power supply having one unsoldered lead.

This was definitely an original manufacturing fault as the offending lead was bent at 90 degrees away from the PCB and had never been soldered to the PCB. Once the lead was soldered back into place the hum vanished.

Other issues are as follows...

When first turned on one speaker appeared to lack bass but this was in fact due to the tweeter being very much louder than it should have been as it sounded very tinny and harsh.

I've no doubt this was probably stressing the tweeter as it seemed the crossover was not filtering correctly during this condition and I could imagine the tweeter eventually failing if this fault was to continue.
(I would check your tweeter with a multimeter before replacing it)

However after a few minutes the speaker returned to normal but the bass driver occassionally suffered from random subsonic excursions which is likely the 'flutter' you are experiencing with yours.

These bass speaker anomolies generally occured also at initial turn on but often lasted longer than the loud tinny tweeter problem.

THE CAUSE? - Most of the problems associated with these series of Event monitors appear to be caused by excessive heat.

Each amplifier module is based around four LM3886 power amp chips. Three of these power the bass driver and the fourth powers the tweeter.

These are attached to an alumimium 'L' bracket which is then screwed to the inside of the rear plate which acts as a heasink and also contains the level and EQ controls and connections.

As it turns out this plate does not provide adequate heat dissipation.

Due to heat the main PCB flexes as it heats up and cools down.
This flexing can cause the solder joints of several surface mount components immediately adjacent to the power amp chips to fracture. In my case this caused the intermittent faults as described above which appear to be worse when the speakers are first turned on. As the amplifier warms up the loud harsh tweeter and bass driver flutter issues disappear.

I discovered this after removing the amplifier module when I noticed a fracture in a solder joint of a surface mount capacitor.

I ended up reflowing many surface mount solder joints in and around the main power amp chips where the heat is at its highest.

However this doesn't fix the heat issue and I also ended fitting the largest finned heatsink I could bolt to the outside of the amplifier plate which dramatically improved the heat dissipation.

One speaker is fully repaired and fitted with the additional heasink and the other is still awaiting repair and modification when I get some time.

If you search online you will see many posts re these speakers.

They are pretty decent when working properly but need a reasonable amount of space to perform at their best.

If you can solder reasonably well and use a multimeter then you are half way there.

Here's the service manual including schematics...

http://www.ladislavbrezovnik.com/diy/Event/ASP8/Event%20ASP8%20Service%20Manual.pdf

I'll attempt to post some pics in the next couple of days showing the surface mount components that are likely the culprits along with the heatsink modification.

Of course caveats apply when working with mains powered equipment so take all necessary safety precautions and if unsure leave any repairs to an expert.

Good Luck
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Re: Event ASP8 repair

Postby Lucas » Sat Jan 17, 2015 10:27 am

Awesome. I'll be away for a week & will get stuck into it when I get back.

I've got basic soldering skills. Only ever made leads though. Never been near a PCB.

Only ever used a multimeter for continuity checks.

Cheers!
Lucas Martin
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Re: Event ASP8 repair

Postby Lucas » Fri May 13, 2016 2:54 pm

Hi! I'm back to have a crack at this repair. Are you still around? Cheers.
Lucas Martin
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Re: Event ASP8 repair

Postby mylesgm » Fri May 27, 2016 7:58 pm

My first port of call would be to Rode as they distribute (own?) Event and their repairs and service policy are second to none. I've had mics and speakers replaced or serviced free of charge outside warranty periods a number of times and they have always been prompt in reply and delivery.

They don't advertise it but their service is the best I have ever experienced and I don't say that lightly.
Myles Mumford
Producer/Composer/Engineer/Sound Artist
Making records in sunny Melbourne

www.mylesmumford.com
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