Sziasztok! Végigolvastam az oldalon a HS 280 hangváltó bekötés problémát,ugyanebben a cipőben járok én is.Kaptam egy HS200-as 4 Ohm/25W orion hangfalat,gondoltam jó lessz centersugárzónak.A hangszórók kifogástalan állapotban vannak.A gondom az amit olvastam a fent emlitett topikban is.Miért van forditva bekötve a magassugárzó kondija(a pozitiv sarka megy a dómsugárzóra).És nem nagyon értem,hogy miért 10Mf,szerintem 4.7Mf kéne lennie.A középsugárzónál is 10Mf van ezt még értem.A mélynyomón 47Mf van paralel.Én kicserélném mind a hármat bipolárisra.És természetesen átkábelezem elfogadható kereszmetszetü vezetékkel.(ami benne van na az öv alatti)Azt kérdezném Tőletek hogy a magasra jó ha 4.7Mf kondit teszek? Szeretném ezt a hangfalat rendbe hozni. Üdv Mindenkinek! György
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
Üdv!
Valahogyan ellőtték a fenti erősítőben az egyik oldal egyik végtranyóját, HQ-ban nem találtam, helyettesítőnek BD317-et ír. Jó az helyette?