Nad 3240 Pe

[TheInfamousJerry]

Well I acquired an old NAD 3240PE and it seems that one of the capacitors is blown and has leaked onto the board. It has 4 large capacitors, 2 - 80v 6800uF and 2 50v 6800uF(one of the 50v 6800 caps blew). 4 fuses were blown and I'm hesitant to replace them if they're just going to blow again. Stopped by RadiosHack and they didn't have a capacitor large enough for it. So my questions are:

Does anyone know what each of the 4 capacitors might be for? Since one 50v is still intact do you think it'd be possible to use just one channel, or might the capacitors not be seperated by channel.

Is there a retailer that will let me buy a few capacitors instead of in bulk?

Is there anything I should know before trying to replace it if I find a replacement? (I've replaced caps on mobos before so I'm someone familiar with it)

Any input would be appreciated and I'll answer any questions you have. Thanks guys.

[willawake]

Re: Nad 3240 Pe

pic please.....damn just as i was choosing a nad

you can get caps from http://www.digikey.com/ but the amp may have other probs. wait for one of the guys here to advise.

[TheInfamousJerry]

Re: Nad 3240 Pe

Unfortunately only camera I have is a webcam and it'd be a little difficult to take a snapshot, I can try though. I checked digikey and it looked like I had to order in bulk, I could be wrong though. Also, if I came across an axial capacitor with the same rating as the radial, could I substitute that do you know?

[TheInfamousJerry]

Re: Nad 3240 Pe













Sorry for the horrible quality of the pictures.

[willawake]

Re: Nad 3240 Pe

yes you can order from digikey not in bulk. i just dont know what to order, those specs are quite difficult. wait for kc8 to pass by and advise.

axial is ok, it is just a different way to place the leads.

are you trying to show those big can caps?

[TheInfamousJerry]

Re: Nad 3240 Pe

That's what I thought

[TheInfamousJerry]

Re: Nad 3240 Pe

are you trying to show those big can caps?

Yep, one of them is blown (pic above)

[willawake]

Re: Nad 3240 Pe

ugh that is ugly. gotta be something wrong with that amp. one of the guys will assist better if you wait a bit.

[TheInfamousJerry]

Re: Nad 3240 Pe

All I got is time

[willawake]

Re: Nad 3240 Pe

bump...cmon guys

[TheInfamousJerry]

Re: Nad 3240 Pe

Update:

Just ordered 2 capacitors from Digikey, should get here shortly. Out of curiousity, I threw some new fuses in there and turned it on. They blew immediately which isn't surprising. I'm also shocked that after researching local stores in my area for capacitors, I couldn't find a single retail store that sold them! What a world we live in.

[Rainbow]

Re: Nad 3240 Pe

There must be something shorted - check the transistors.

[TheInfamousJerry]

Re: Nad 3240 Pe

Not sure how to check em really.

[TheInfamousJerry]

Re: Nad 3240 Pe

Update:

I received and installed the new capacitor, plugged it in, new fuses, fuses blew again. Before it blew the speakers hummed for about a second. I did clean the board with alcohol and I'll try to research how to check/replace bad transistors as rainbow suggested.

[Rainbow]

Re: Nad 3240 Pe

Use diode test/beep function of a multimeter. Test NPN and PNP transistors as if they were two diodes - e.g. NPN means that base is P and both collector and emitter are N, so diode test from base to either collector or emitter should show voltage drop about 0.7V. Something is probably shorted so it will probably show very small number and beep somewhere. If there are transistors connected in parallel and they appear shorted, remove them from circuit and test one by one. It's likely that only one is bad.

[TheInfamousJerry]

Re: Nad 3240 Pe

Do you mean the small black transistors? I'm sorry I haven't worked on audio equipment boards much. I read somewhere about possibly the output transistor but damned if I know where that is, haha. Also, I assume you mean test while unit is on and in circuit right? How would I know if it was bad when I take them out? (Sorry for all the questions, tried google and it wasn't specific enough for me)

[Rainbow]

Re: Nad 3240 Pe

With power off and disconnected.
Power transistors should be attached to heatsink(s).

[willawake]

Re: Nad 3240 Pe

nobody should mess around inside ac powered equipment when it is ON or plugged in if they do not know exactly what they are doing.

[TheInfamousJerry]

Re: Nad 3240 Pe

Ok thanks, will check it when I get some more time and post back.

[kc8adu]

Re: Nad 3240 Pe

http://www.anatekcorp.com/qdmmvom.htm