Onkyo HT-R591 keeps clicking

[tibimakai]

Re: Onkyo HT-R591 keeps clicking

First I want to properly measure the transformer. I have started removing it, but there are a couple of connectors with wires that are going all over the receiver, so I have to take apart, most of the boards to reach to those connectors.
Did not have enough time to do all of that.
It seems that all the pins/wires are coated and it's very hard to get a good reading. I will remove the transformer tomorrow, clean up a couple of conections and I will measure them and I will let you know.
I have disconnected the transformer from the rest of the receiver, except those ribbon cables that are coming out from underneath the output PCB and it was still clicking.

[rievax_60]

Re: Onkyo HT-R591 keeps clicking

Using budm's illustration, you can test at the pins. There is no need to remove the transformer.

[tibimakai]

Re: Onkyo HT-R591 keeps clicking

What kind of resistance should be at the primary?
I have used the transformer's 110V connector and the ohm meter did not show anything(OL), but when I have measured the two pins of the primary, it had the 110V. Doesn't make sense.

[rievax_60]

Re: Onkyo HT-R591 keeps clicking

A few ohms for the primary winding. Near zero for the thermal fuse if its ok.

[tom66]

Re: Onkyo HT-R591 keeps clicking

What kind of resistance should be at the primary?
I have used the transformer's 110V connector and the ohm meter did not show anything(OL), but when I have measured the two pins of the primary, it had the 110V. Doesn't make sense.

No this makes perfect sense V = I * R with very low I and very high R you can have V volts just fine.

[tibimakai]

Re: Onkyo HT-R591 keeps clicking

So the resistance is so high, that my meter can't measure it?

[budm]

Re: Onkyo HT-R591 keeps clicking

You will still get 110 at the terminal of the White (neutral) and Yellow wires but the winding will not be getting it if the themal fuse is open. That is why you need to check the thermal fuse and the the resistance of the primary wind at the connection AFTER the thermal fuse.

[cheapie]

Re: Onkyo HT-R591 keeps clicking

So the resistance is so high, that my meter can't measure it?

Yes. Actually, it's most likely infinite.

[tibimakai]

Re: Onkyo HT-R591 keeps clicking

There is an easier way to remove the thermal fuse. Break away as many as it takes of the bobbin tabs to allow the fuse to be pulled upwards. In this case, breaking one should be enough, the 2nd from the right, the one with no pin.
The shinny wires belong to the fuse. Don't cut any enameled wires, they belong to the primary.
Is the thermal fuse open circuited?

That is how I did it. Only the second had to be broken to be able to remove it. Thank for the good idea.
I may need to brake the third one too, to be able to reinsert it though. I will see.
I have connected temporarily the primary, to see if it would work, and it did.
It seems like there is some kind of short/bad connection somewhere, because the sound comes and goes and when it's there I can't adjust it. If I bend the rear metal cover, the receiver turns off. It's not put together yet, so it may be something with that, I will check it out tomorrow.

[rievax_60]

Re: Onkyo HT-R591 keeps clicking

When you fit the replacement thermal fuse, be certain that it is insulated the same as the original or you might end up with a live amplifier. Also you need to be careful to not trip it while soldering it.
Most amplifiers malfunction while the back plate is loose because this where the input ground gets referenced to chassis.
I have never found a permanent underlying reason for open circuited thermal fuses in amplifier transformers.

[tibimakai]

Re: Onkyo HT-R591 keeps clicking

Thanks for the tips.
There is a special way of soldering them?
It can be a power surge?

[tom66]

Re: Onkyo HT-R591 keeps clicking

Soldering thermal fuses is difficult. I recommend wire-wrapping it if you can. If you do solder it, check the continuity after soldering to check it's still OK.

[Ashroyer05]

Re: Onkyo HT-R591 keeps clicking

.

[tibimakai]

Re: Onkyo HT-R591 keeps clicking

It seems like this component it's available only from Chinese suppliers.
V7F, 145*C, 3A/250V

[budm]

Re: Onkyo HT-R591 keeps clicking

Can I see the picture of this part? You can use higher current rating but keep about the same temp rating.
http://www.digikey.com/product-detai...134-ND/1014763
but you will have to wrap the body with KAPTON tape since it does not have the isolated ceramic body.
Is this the one?
http://fuse-china.en.alibaba.com/pro...l_cut_off.html

[tibimakai]

Re: Onkyo HT-R591 keeps clicking

I should get some 5A ones?

[tom66]

Re: Onkyo HT-R591 keeps clicking

There is a main fuse, as well, right? Thermal fuse is rarely intended to be a current limiter, that is the job of the mains input fuse.

[tibimakai]

Re: Onkyo HT-R591 keeps clicking

Yes there is one, F901.

[tom66]

Re: Onkyo HT-R591 keeps clicking

In which case current rating of the thermal fuse is an "equal to or higher" rating.

[tibimakai]

Re: Onkyo HT-R591 keeps clicking

Thanks, so a 5A should be fine then.
I'm looking at Digikey and there are to temperatures, one is the Holding Temperature and one Rated Functioning Temperature. Which one should be 145*C? How much can I be out of spec? There are none stocked around 145*C.