Noob attempting to fix a blown NAD T-760 AV receiver

[Gatchaman]

Hi guys and maybe girls ( I hope so ).

I need to edit my introduction to add more info from where I'm coming from and what I hope to achieve but for now please bear with me.

Cut a long story short I took a chance on a NAD T-760 which according to the owner "it switched on but went into standby mode after a few seconds". I have no idea what made me go for it but something just said go for it! And I did. Anyway, bought it an brought it back to the cave at work ( still under construction ). Plugged it in and pop it went!! Quickly took the cover off to find out what went pop and it was a blue medium sized capacitor next to two huge capacitors. I was so happy when I saw that leaky domed cap!!!!

The marking on the blue capacitor are.... Lelon 470uF , 63v, 85oC(M), H007.
I have no idea what to buy to replace it as I've suddenly found out that there are so many types of capacitors !!! Copy and pasting the specs into google takes me to farnell Order Code: 9692550. Any recommendations for anything better?

Will try to post some pics of the T-760 and the blown cap. Pics are on my phone so will update this post asap.

While I'm trying to upload some pics could somebody with experience tell me if it would be advisable to replace surrounding non damaged capacitors, the blown caps twin, or just the blown one. Seeing as I've taken the NAD apart I might as well ask , purchase and upgrade the cap(s) all in one go.

[T30M31]

Re: Noob attempting to fix a blown NAD T-760 AV receiver

I would at the very least replace the twin.

Do you know the age of the receiver?

You stated that it is 470uF rated for 63 volts and 85 degrees C. Can you give the physical dimensions? The blue sleeve and physical dimensions may help narrow down the Lelon series. Would you say the sleeve is normal blue or dark blue?

[Gatchaman]

Re: Noob attempting to fix a blown NAD T-760 AV receiver

Thanks for replying. Just updated my post with pictures.

And to answer your question. I think this particular model came out in 2000.

The twin looks mint to tell you the truth. And everything else in the locality of the blown cap "looks" fine.

[T30M31]

Re: Noob attempting to fix a blown NAD T-760 AV receiver

I believe the capacitor you referenced in your first post has a different physical size based on the information I found in the service manual. You might look at Farnell order code 1167950 and 1351545.

http://uk.farnell.com/illinois-capac...-20/dp/1167950
http://uk.farnell.com/vishay-sprague...-20/dp/1351545

I am including the service manual I located. It states that capacitors C525 and C526 on the front amplifier board are 12.5 x 25 mm in size. Does that match what you are looking at?

[Gatchaman]

Re: Noob attempting to fix a blown NAD T-760 AV receiver

Okay, looking at C525 and C526 right now....... and I'd say 12.5mm x 20mm.

And thanks for posting the service manual.

The two caps you kindly suggested cost £16 to post!! :-( And I don't think there are any UK stock according to Farnell.

Did a search and collected these Farnell ECA1JAM471X , ECA1JM471 and MCGPR63V477M13X26. In your opinion would they be what I'm looking for or is your selection more to my needs?
The dimensions in the service manual don't fit what is on the board :-S

[Gatchaman]

Re: Noob attempting to fix a blown NAD T-760 AV receiver

Okay I think I'll have to go for the ECA1JM471 based on the spec and the fact that I can hopefully just order 5x as they are virtually the same price as 2 of the ECA1JAM471X and the other caps come in a minimum of 10 per order.

If anybody else has any other suggestions then please chip in!

And thank you T30M31. You have been a great help in starting me off. :-)

[tom66]

Re: Noob attempting to fix a blown NAD T-760 AV receiver

with free 3-5 day delivery:
http://cpc.farnell.com/panasonic/eeu...63v/dp/CA05191

[Gatchaman]

Re: Noob attempting to fix a blown NAD T-760 AV receiver

Was just about to search for CPC as they are a division of Farnell ! Thanks Tom66 :-).

Let's see if my account is still active.

Does size play a major role Tom66? T30 pointed me to the service man and what was in the service man didn't tally with what was on the circuit board. And I take it you are suggesting I go for the CPC : EEUFC1J471 as they all fall within the same spec.

[tom66]

Re: Noob attempting to fix a blown NAD T-760 AV receiver

Size is just a matter of "will it fit"... so check that it will.

Those originals are probably 10? 20? years old. Capacitor technology has improved considerably, so it can almost be guaranteed a Panasonic FC capacitor is superior to some capacitor that old. Also, in that position, it doesn't look particularly critical, you should be able to use almost any capacitor.

If those capacitors look like the originals, I would change like for like, if on the other hand there is evidence they have been soldered/replaced I would use the service manual values.

[Gatchaman]

Re: Noob attempting to fix a blown NAD T-760 AV receiver

They look like the original caps and from what I can see nothing has been altered on any of the circuit boards.

I think I'll order 4x. I'll replace those two and keep 2 as spares as they are also components c829 and c830 on another board in the amp.

Thanks once again for the help.

Okay then! They've been ordered. Will take out the old ones tomorrow, wait for the new caps to turn up then replace and hope for the best :-).
Will post back, with pics, when I've completed the job!

[Sparks88]

Re: Noob attempting to fix a blown NAD T-760 AV receiver

because of the age of the amp i would do a total recap of the whole board, you have a service manual so doing a list is going to be pretty easy, i did my harman kardon pm625 not so long ago and it really made a big difference, i used panasonic fm or fr series caps, all low esr 105 degree everywhere and a lot of the older caps taken out when tested were well out of spec, also a good resoldering of the board helped as well.

[Gatchaman]

Re: Noob attempting to fix a blown NAD T-760 AV receiver

Thanks for the suggestion Sparks. For now though I'd just like to get it up and running. Yeah it is a bit old but I took a chance on it so I'd like to enjoy my well spent £20 for a little bit. I'll build a list of caps as you suggested and see how much it cost to recap.

Just joined CPC so it shouldn't take me that long to get all the caps. I think it'll be a summer time project when things are super quiet at work.

Can anyone recommend a cheap tester that targets the specifics of capacitors? I've got two types of multi-meters but you lot are the experts!!

[Gatchaman]

Re: Noob attempting to fix a blown NAD T-760 AV receiver

So after doing a bit of home work I figure I'll need to purchase a ESR meter and a cap meter. Checked my multi-meters and they don't have anything on caps. Anyone have any suggestions before I go for it? Have you purchased good equipment from the bay, Maplins or CPC that you can recommend?

I've settled on a A6013L cap meter from the bay to start of with. It's simple and doesn't cost the Earth. And I'm looking at a ESR100 for later on. Will buying just cap meter suffice for just checking out the rest of the caps in the amp or is it best buy both? I'm not going to have a go recapping the amp till later on in the year anyway.

1 A6013L bought!

Let the testing begin!

[Gatchaman]

Re: Noob attempting to fix a blown NAD T-760 AV receiver

Got the caps from cpc today. That was quick! And while I was delving inside the amp I found this little beauty right at the bottom of the heat sink that runs down the centre of the amp! :-(. Not sure if that caused the cap to blow or maybe it was the other way round.

No problem! Now it just poses even more of a challenge! Looks like I'll be buying the ESR meter after all.

And I can't thank you enough for posting the service manual T30M31.

[T30M31]

Re: Noob attempting to fix a blown NAD T-760 AV receiver

It looks like you will have the opportunity to put that service manual to good use!

[Gatchaman]

Re: Noob attempting to fix a blown NAD T-760 AV receiver

Cheers, man! :-)

[Gatchaman]

Re: Noob attempting to fix a blown NAD T-760 AV receiver

Ordered caps and resistors from CPC but having trouble sourcing transistors like the 2sa1941 (blown) , 2sc1740s, 2sc5171, 2sa1930, 2sc1845 (all near by)...... Going to have to chance it on the bay it seems.

Anyone in the UK have a good source of transistors that they use. Haven't got my test gear yet so I might be jumping the gun a little.

Going with the bay for now. I hope these are the real deal.... Well I'll soon find out!

[Agent24]

Re: Noob attempting to fix a blown NAD T-760 AV receiver

Going with the bay for now. I hope these are the real deal.... Well I'll soon find out!

If you get Japanese power transistors from China they are 99.9% going to be fake.

[Gatchaman]

Re: Noob attempting to fix a blown NAD T-760 AV receiver

I ticked the from Ebay UK tick box so hopefully the parts are 60%- 40% kosher. But who's to say that the seller didn't get them from Chi.... sorry I meant Japan.

Sellers are : littlediode_components
mkpianosupplies and mayflo818.

I have no idea where they source there gear from but I tried CPC the most legit source for components I could think of and no joy. Google just can up with spec sheets really.

I guess things have moved on since the amp was made and components aren't getting made/stocked anymore or something.

[Agent24]

Re: Noob attempting to fix a blown NAD T-760 AV receiver

If the seller is actually located in UK then I guess you have a higher chance of being genuine.

Even if they are EOL, often times you can substitute some other newer (better) transistor anyway though.