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Hello. here is a message to share my experience in solving a problem that appeared on the home-cinema amplifier ONKYO tx-DS494. In order to sell this amplifier I had to check if all the outputs and all the functions works properly. On the back of this amplifier you have to frontal output : A and B. I connect a pair of speaker on A output : no problem. I can adjust volume. when i connect the pair to the b output and turn the volume knob no sound came out of the speakers until I reach a level defined by I don't know what. :hmmm: My volume level goes from 0 to 80db ( if I remember well ). from 0 to 23 db no sound and when I reach 24 dn sound increase and stabilize. With hearphone connected, i don' have this problem so I conculde that amplifing transistor could not be incriminated. I checked on the service manual and saw that there are two or three component that could be the source of the problem : the main processor, some capacitors on the output PCB and relays. I began testing capacitors: no pb. then I thought that if cannot be the main proc because it ( I think ) works in a binary mode: it works or it doesn't. so I decided to switch between themselves the two relay and :super: : it works. The relays was in fault and did not switches properly. here is my experience in repairing an amplifier

Sziasztok!
Abban kérném a segítségeteket, hogy egy Onkyo A830-as erősítőnek kellene a rajza. Pontosabban elég volna csak a végfokról. Föltettem az SM-keresőbe, de pont olyan nincs. A hasonlóak mind IC-s kivitelűek, ez pedig tranzisztoros, mégpedig jó sok tranz-al van felépítve Jó volna, ha valakinek volna a végforól rajza, mert a többi ákör, és a másik végfok működik.
Köszönettel:
Attila

Sziasztok! Remélem nem nagyon egyértelmű a kérdés amit felteszek :) Onkyo TX-840-hez kéne nekem egy motoros hangerőpoti. Alps gyártmány, de a HQnál ötletük sincs hol kéne keresnem. Az egyik oldala száz százalékos halott. Hasonló motor nélküli is megtenné, mert úgysincs meg a távja :) Ötleteket örömmel várok laci fotót holnap prezentálok. jelenleg egy "márkakereskedés-féle" is megtenné. ahol jártam: HQ, Lomex, Sini

Hi everyone

Could somebody tell me if I can replace a switching diode to another one, the one installed in the onkyo is a 1SS252 and is 10 times more expensive that a 1SS355.

Usually I order the same but they are pricey (around 10.00 usd for a 100) and not commonly used, not many sellers.
For the 1ss355 every seller on line has it in stock and it's around 1 to 2 usd for a 100.
Ans they are available locally, not in china waiting 5 weeks for the part.
Thank you.


1SS352
Characteristic Symbol Rating Unit
Maximum (peak) reverse voltage VRM 85 V
Reverse voltage VR 80 V
Maximum (peak) forward current IFM 200 mA
Average forward current IO 100 mA
Surge current (10ms) IFSM 1 A
Power dissipation P 200 (*) mW
Junction temperature Tj 125 °C
Storage temperature Tstg −55~125 °C

1SS355

Characteristic Symbol Rating Unit
Maximum (peak) reverse voltage VRM 90 V
Reverse voltage VR 80 V
Maximum (peak) forward current IFM 225 mA
Average forward current IO 100 mA
Surge current (1s) IFSM 500 mA
Junction temperature Tj 150 °C
Storage temperature Tstg −55~150 °C