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:( lupo on fire...


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Got in the lupo after 1 year and three months of having the same amp powering my sub, not having one problem ever before, Turned on the ignition, the radio fired up (no pun intended) then i look in my mirror to reverse off the drive, and WTF! i couldn't see out of my window! Smoke everywhere! Quickly turned off the car and radio, And opened the boot to find my poor poor baby rockford monoblock smoking like a pensioner!

Never before has my heart sank the way it did when i saw that!

So, rushed to the front of the car and got the fuse out, Tried removing the amp but couldn't touch it as it was so hot!, Eventually managed to remove the amp and opened it up to find two of the mosfets had cooked themselves ffs1.jpg border="0" class="linked-image" /> border="0" alt="" />

ffs2.jpg border="0" class="linked-image" /> border="0" alt="" />

Now, this amp pushes 652w RMS @ 2 ohms, I'm looking at:

i) Having it professionally repaired by Raf (the engineer at the car audio shop i used to work for)

ii) Replacing it.

So... questions

i) How much am i looking at paying for the mosfets themselves, not the labour as i already know the cost of the labour, just like to know the price. Also are their different qualities available? and how do i make sure i get the right one (M1 Lupo i'm hoping you may beable to shed some light on this)

ii) If i was in the market for a new amp, Hoping for the 650w RMS @ 2 ohm figure, what amps would you recomend? I'm not well up on the products to be honest, just the theorys behind car audio. As those of you who will be answering these questions will know, I am into good sound quality, but also like a decent amount of power behind my sub.

Thanks for any help.

Messages of condonance also greatfully recieved ouch.gif style="vertical-align:middle" emoid=":ouch:" border="0" alt="ouch.gif" />

Edited by nfbr
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Sorry to see that dude, however there is a light at the end of the tunnel! I once cooked a 1200RMS MTX amp & As well as burning most of the mosfets (6 in total) I also took out the PSU, repair including parts only came to £85 (& most of that was labour). If it is purely just the mosfets you've burnt you could source the parts yourself through somewhere like Maplins & do it yourself, as you can see its only 3 solder points per mosfet so its hardly challenging! wink.gif style="vertical-align:middle" emoid=";)" border="0" alt="wink.gif" />

(Forgot to say, the spec of the mosfets are actually marked on them so its just a case of getting a matching part.)

Edited by Max69vk
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Al, the mosfets are usually anywhere from 60p each to £3 each. It would depends if it has burned the tracks off the back of the board as to if its repairable to be honest.

If you could take some good macro photo's of the mosfets in that row. So I can read the code and work out if there paired up or grouped that would be excellent. I might be able to work out what mosfets are in the locations that have been cooked. Quality wise there all around the same sort of quality as there all mass produced to a reasonable standard these days. But in the case of pairs for push and pull I normally buy twice the quantity and hand match them with a meter and scope.

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The board that the mosfets are on is bonded onto the amp itself with a white heat transfare type glue sad.gif style="vertical-align:middle" emoid=":(" border="0" alt="sad.gif" />

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Still not a problem, as its usually removable.

Second picture down. The two semiconductors on the top left with two legs, is the casing split on them?

Edited by M1 Lupo
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The amp still works mate if thats any help so i'm guessint the tracks on the board are ok.

I think i know why its happened but i'm not 100% sure yet...

Will PM you with the full size photo dan.

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Mosfets are marked up as follows

IRF3205

I¥R 303H

37 06

the ¥ symbol isnt identical to that but its not far off...

The all the three pin mosfets on the board are identical if that helps.

http://www.aprh28.dsl.pipex.com/826.jpg <--- heres a link to a full size pic taken in macro mode.

Aparently their transistors not mosfets. although thats probably the same thing?

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Well, there made by International Rectifier. I recognise the I R logo. Same brand of mosfets I use in headphone amps.

But back to business, you can buy them from Conrad Electronics. For £2.79 each.

The two semiconductors I pointed out look like high current T022 package Diode's. I would replace them too, as they look like there split. Do they say UO3305? or UQ3305??

The burn has wiped out the surface mount resistors next to the mosfets, so they would need to be measured to get replacements. I'd meter R99 and R86 to see what they are.

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With the multimeter set to "200" on ohms R86 reads 4.6 as does R100

R99 reads 10.3, R76 reads 10.2, R92 reads 10.2, and R93 reads 36.9

The two semiconductors are UO3305, they arent actually split, ive just run my finger accross them, and it looks like they had a bit of residue/dust on them from the smoke/exploding mosfet.

Looks like the one.

159247_SZ_00_FB.EPS.jpg border="0" class="linked-image" /> border="0" alt="" />

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Well turns out its done too much damage for it to be worth repairing.

Looks like i'm giving up on car audio now, as my left hand side has gone far quieter than it should be and i dont have a damn clue what that is caused by sad.gif style="vertical-align:middle" emoid=":(" border="0" alt="sad.gif" />

totally depressed now as my car sounds shít.

Edited by nfbr
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Sounds like the stereo system in my lupo now then mate wink.gif style="vertical-align:middle" emoid=";)" border="0" alt="wink.gif" />

haha and mine. i have the original system and to top it all off, the drivers side speakers crackle on and off when ever they want! its brillinat!!! angry.gif style="vertical-align:middle" emoid=":angry2:" border="0" alt="angry.gif" /> wink.gif style="vertical-align:middle" emoid=";)" border="0" alt="wink.gif" />

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haha and mine. i have the original system and to top it all off, the drivers side speakers crackle on and off when ever they want! its brillinat!!! angry.gif style="vertical-align:middle" emoid=":angry2:" border="0" alt="angry.gif" /> wink.gif style="vertical-align:middle" emoid=";)" border="0" alt="wink.gif" />

laugh.gif style="vertical-align:middle" emoid=":lol:" border="0" alt="laugh.gif" />

Mine isnt that bad tongue.gif style="vertical-align:middle" emoid=":P" border="0" alt="tongue.gif" />

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it shouldn't sound as crap as it does as their is £600 worth of head unit, amp and components in their still! but since the sub amp gave up their just seems to be no colour nor clarity to it sad.gif style="vertical-align:middle" emoid=":(" border="0" alt="sad.gif" />

Edited by nfbr
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it shouldn't sound as crap as it does as their is £600 worth of head unit, amp and components in their still! but since the sub amp gave up their just seems to be no colour nor clarity to it sad.gif style="vertical-align:middle" emoid=":(" border="0" alt="sad.gif" />

i know how you feel mate. my amps blown up again! angry.gif style="vertical-align:middle" emoid=":angry2:" border="0" alt="angry.gif" /> angry.gif style="vertical-align:middle" emoid=":angry2:" border="0" alt="angry.gif" /> angry.gif style="vertical-align:middle" emoid=":angry2:" border="0" alt="angry.gif" /> third one ive had! and my head unit keeps over heating powering just the speakers! ohmy.gif style="vertical-align:middle" emoid=":o" border="0" alt="ohmy.gif" /> . pile of ***** that it is. 300 kenwood ***** unit! getting a new 12" alpine type r sub, in phase ipa2400 amp to run it and and alpine hu shortly after. the head unit is rubbish and lets the speakers down big time.

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An alpine isnt gonna do a better job of powering the speakers, there is a reason headunits over heat, they cram about 20wrms x4 into an enclosed space with a load of other electronics. Even a 2x50wrms amp is bigger than the headunit itself and it doesnt have cd players, tuners etc in there aswell.

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just ordered a brand new Blaupunkt which will put out 650wRMS @ 2 ohms for £160

I can't afford to be with the big boys any more as i have things to save for, however i'm sure it'll still sound respectable to say the least...

tha1400.jpg border="0" class="linked-image" /> border="0" alt="" />

shouldnt be much different i hope, as with bass, 650wRMS is not gona sound any different from one amp to another really...

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I presume your going to VW Festival - If so i'll run you off the entire of my '80's collection buddy smile.gif style="vertical-align:middle" emoid=":)" border="0" alt="smile.gif" />

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aww gutted for you mate. nothing worse than one of your prize possesions breaks

repaired by raf at the pioneer shop in primrose bank? didnt know you used to work there.

but think of it this way, now may be the time to upgrade your amp for something newer. wink.gif style="vertical-align:middle" emoid=";)" border="0" alt="wink.gif" />

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well since today is a good week for bad news, turns out the damage has stretched further and has also screwed over my sub/rear pre outs on the becker, so i'm stuck using the front preout and a passive from my front amp to power my new sub amp... sounds more than respectable though.

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