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Hello Mindenkinek! Erősítő trafó melegedésről lenne szó. Igazság szerint önmaga melegszik fel(szinte forró) hálózatra kötve. Tekercsek mérve jók.  Próbáltam több működő erősítőből kitermeltet is azok is ugyanúgy kis idő elteltével melegednek.  Gerjedés lenne nem tudom de ha valaki találkozott ilyen hibával ossza meg velem mit javított vagy tett ez ügyben. 

This one had been sitting in a barn for years. Powered it up and the large power transistors on the heat sink would get hot
after a time....and the heat sink would also get quite hot. Speakers sounded like they had some DC on them....with a loud thump

Found the manual on Hi-Fi engine,
[ http://www.mediafire.com/file/b8mlsu7q3pz0bvf/hfe_nad_3140_service.pdf/file ]
and saw a video on youtube saying lots of capacitors dry out
due to their locations near resistors that get very hot, I guess sorta a poor
design. Went in and recapped almost the entire
product save for the (4) large 50V PS caps which appear to check ok.None of
the high power or driver transistors
mounted to the main heat sink were shorted..

Powered on but no audio, and noticed the fuses to Bridge D805 were melted open.
I believe they were ok before.
Replaced them and they started to light up like fiilaments, so shut down,
removed the bridge D805, then checked it, its ok.

There is about a 16 ohm short on the + / - lands where the bridge was. It
seems like something I did maybe is causing this,
like a capacitor in backwards, which I am doing alot of lately for some
reason.

Turns out, yep I put C805 (470/ 63) In backwards ! Capacitor still checks
ok, so will re-use it.

Short is still there though Im guessing R803 is adding in 5.6 ohms or so,
that means theres a 10 ohm short someplace. Q801, 802 arent reading short,
and looks like this becomes a +43V ps feed.

Any ideas out there on what to check next? I am guessing this cap in
backwards caused the voltage applied to a component to be
reverse and its shorted. Or would this be normal with a reversed cap installed,
and putting it in right would be how to fix it?

Steve Hearns
Technotronic Dimensions [USA]
WWW.TECHNOTRONIC-DIMENSIONS.COM
 

Se trata  de fallo localizado en placa E1205777-005 los elementos c1041 c1042 c1043 c1044 de valor 47 mF 25V los cuatro en mal estado y IC 612 e IC611 corroidos por acido de los condensadores electroliticos, me es imposible leer los valores de los mismos ; Y en el diagrama  no figura la placa del receptor RX- 1010  JVC. Codigo placa según diagrama 
E 12057-005
Alguien podria por favor ayudar a localizar los valores de estos transistores.
 

Üdv! Az U.S. területén levő gyártó honlapjáról nem sikerül letölteni az aktuális pdf fájlt, amin láthatnám az illető lemezek kontúrméreteit, praktikusan metrikus méretekkel. (ha nem azzal, üsse kő :) ) Bizonyára vannak köztünk, akik ebben segíteni tudnak, ismerik ezeket a lemeztípusokat. Köszönettel: Én