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
Attached is the DSP2 Firmware for the Onkyo NR646.
Sziasztok,
egy Onkyo minihifi (CR-185) áramtalanítás után mindig lenullázza az óráját, gondoltam kicserélem benne a szuperkondit.
Azonban semmi nem változott, ugyanúgy 0:00 fogad ha kihúzom és visszadugom.
Merre érdemes elindulnom a hibakereséssel?
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