onkyo T401 fm tuner

[[email protected]]

I've bought an old onkyo fm stereo tuner T401 on e-bay. It works
beautifully except that it does not rremember the push-button tuner
settings when it is switched off and later on again.

The owner's manual says the memory shouldnormall last for several
weeks butless under humid conditions. This suggests that the
standbypower comes from a capacitor.

I can't find the capacitor, and I haven't been able to get any
technical information such as circuit diagram or parts placement --
not from Sams nor from e-bay.

I'd be grateful for any help someone can give me on locating the
standby power source. Maybe I can replace it or simply add a samll
battery if I could know where to connect it.

Mel Levine

 

[Arfa Daily]

I've bought an old onkyo fm stereo tuner T401 on e-bay. It works
beautifully except that it does not rremember the push-button tuner
settings when it is switched off and later on again.

The owner's manual says the memory shouldnormall last for several
weeks butless under humid conditions. This suggests that the
standbypower comes from a capacitor.

I can't find the capacitor, and I haven't been able to get any
technical information such as circuit diagram or parts placement --
not from Sams nor from e-bay.

I'd be grateful for any help someone can give me on locating the
standby power source. Maybe I can replace it or simply add a samll
battery if I could know where to connect it.

Mel Levine

If it is capacitor backed, it will be one of the Supacap or Goldcap types.
They are usually green and about the size of two calculator batteries
stacked on top of each other. The value is usually around 0.5F at 5.5v
working. You would normally expect it to be located on the front pcb, near
to the system control processor.

Arfa

 

[Bob La Rocca]

Recently went through this with my T4500. The memory capacitor was bad.
Mine was on the front panel board. It may have been under the display. Got
a replacement from Mouser for very few $

Regards,

 

[Mark D. Zacharias]

I've bought an old onkyo fm stereo tuner T401 on e-bay. It works
beautifully except that it does not rremember the push-button tuner
settings when it is switched off and later on again.

The owner's manual says the memory shouldnormall last for several
weeks butless under humid conditions. This suggests that the
standbypower comes from a capacitor.

I can't find the capacitor, and I haven't been able to get any
technical information such as circuit diagram or parts placement --
not from Sams nor from e-bay.

I'd be grateful for any help someone can give me on locating the
standby power source. Maybe I can replace it or simply add a samll
battery if I could know where to connect it.

Mel Levine

It is C754, a 0.1F (Farad) 5.5 volt capacitor located on the front panel
circuit board, underneath the display tube, next to the microprocessor.

Mark Z.

 

[[email protected]]

Many thanks fo rthe prompt help you all gave me on my memory capacitor
problem. Your advice was right on the money. I could never have
found the guilty capacitor on my own!

I replaced the capacitor with some aaa dry cells and included a diode
to keep the receiver from trying to charge them. Working fine now.

Gratefully,
Mel