Sony STR-7055

[HiFi in WYO]

Anyone familiar with the 7055 receiver? I have one and it works fine, at loud volume. The volume/balance pot seems to be scratchy and deoxit didn't work. It works fine when you crank it up, but loses it when you turn it down.

So, I would like to tackle this project, replace it and then find a replacement clear plastic balance knob and volume knob. Joeloldaudio on ebay has the two knobs but they're for a 6065 receiver.

Will those work? Haven't checked, but he's parting this thing out, so wondering if the pot will work as well.

Thanks in advance.

 

[Leestereo]

Anyone familiar with the 7055 receiver? I have one and it works fine, at loud volume. The volume/balance pot seems to be scratchy and deoxit didn't work. It works fine when you crank it up, but loses it when you turn it down.

Do you mean that the sound drops out and/or is "scratchy" at low volume settings? If that is the case, I would suspect speaker switch contacts; you can try cleaning this switch with deoxit.

 

[BBRN]

Sometimes it takes multiple passes with the deoxit, I just did a 7065 and had to pass 3x's on the controls before totally clean.

 

[HiFi in WYO]

Do you mean that the sound drops out and/or is "scratchy" at low volume settings? If that is the case, I would suspect speaker switch contacts; you can try cleaning this switch with deoxit.

Sometimes it works fine, but mostly there is no sound at all on the right channel at low volumes. But when you turn the volume up a good halfway, both channels kick in and it works fine. Just I don't always want it that loud. So you turn it back down and both channels will work fine for awhile, then the right one will disappear. Turn it back up, it kicks in.

I did actually take this one apart and cleaned it as best as I could. There's no scratchy at all, anywhere. BBRN - I've done several passes with the deoxit, thought that would help, but didn't really help.

Another note: In the pic you can see the knobs are missing. I'm just wondering if that may have had a hand in why it doesn't work. Like it was hit there or took some trauma. Perhaps pushed something? There's no visible damage to the pot, even on the inside. But I don't know.

http://www.audiokarma.org/forums/attachment.php?attachmentid=451781&d=1377707603

 

[Phase700b]

I have a two 7065s a 7055, and a 6055.

On the 7065/55 check your speaker selector switch has been thoroughly cleaned with Deoxit . I had issues with the same problem you are having on one 7065 and the sound would get through after cranking the volume up as you indicate. The rotary speaker selector operates an internal slide switch.
It may help to turn the 7055 onto its left side (front of 7055 facing you) as you spray the Deoxit into the speaker selector slide switch. Those contacts are very hard to get at. Just spray. .. rotate the switch. . spray some more. . . . rotate it many times through all positions.


This will happen if there is oxidation on the speaker selector contacts because a higher signal level (more voltage) will sometimes "spike" through the oxidation and work temporarily.

Using the "B" speaker connections and see if you are having the same issue? Otherwise, rotate the heck out of the speaker selector switch AS you spray Deoxit into ALL the contacts inside of the switch. The switch could also have damaged or loose contacts.

One other thought. . .. check the wires and connections coming from the board area near the speaker selector switch that run to the back panel. These are all bundled together and a bit of a mess and difficult to trace. . . but there could be a wire with a poor or broken connection especially where they get soldered onto the board or onto the terminals on the rear panel. tug and check all of them to see if any feel loose or flimsy. Sotimmees a wire looks like it is connected but broken inside it's insulation.

 

[HiFi in WYO]

Thanks Phase. I may be doing some toy cleaning this weekend, I'll give this a try.

One more thing, since you have the others. Are the clear plastic balance knob and the volume knob the same on the 7065 as on the 7055? I need both and it seems to be easier to find them from a 7065.

 

[iamthejeff]

I had this problem and after cleaning everything to no avail, it turned out to be an oxidized contact within the relay switch. Had to remove the clear plastic cover to clean it.

 

[HiFi in WYO]

I had this problem and after cleaning everything to no avail, it turned out to be an oxidized contact within the relay switch. Had to remove the clear plastic cover to clean it.

Great. Thanks!

 

[Phase700b]

I had this problem and after cleaning everything to no avail, it turned out to be an oxidized contact within the relay switch. Had to remove the clear plastic cover to clean it.

This is often a problem on receivers that have a "protection relay". If I recall correctly, there is no relay in a Sony 7055 or 7065. They use an electronic muting circuit that shunts audio output during power up.

But I had that same issue with a Pioneer and Technics receiver and oxidized protection relay contacts were the culprit as you said.

 

[Phase700b]

Thanks Phase. I may be doing some toy cleaning this weekend, I'll give this a try.

One more thing, since you have the others. Are the clear plastic balance knob and the volume knob the same on the 7065 as on the 7055? I need both and it seems to be easier to find them from a 7065.

The balance knob from a 7065 will work, however, the volume control knob may stick out a bit more than then using the original 7055 knob. I tried swapping them and it works, but you may like swapping the balance and volume knob as a pair from a 7065. At least, that's the way it is on the units I have. . . unless someone swapped knobs in the past form some other model. But it does not appear so.