Sony STR-7035 Power Capacitors

Aethelstan

Aethelstan

Active Member
What say ye, Audiokarma?

I just recapped a Sony STR-7035 and changed the STKs. It is working much better, but I think the big power capacitors (5600/35v) need to be changed. The problem is that the originals are huge and I can't seem to find any new ones that have lead spacing more than 10mm. Is there a decent-fitting option out there or am I going to have to make do with bending the leads on a smaller sized capacitor?
 
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Aethelstan said:
One is bulging a bit and the left speaker occasionally cuts out with some distortion. When it isn't cutting out, it sounds good..
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Make sure it is not the plastic cover that is bulging and not the can itself.

Capacitors don't usually cause cut outs and distortion. Tape monitor and other dirty switches do.
 
Schematic for STR-7045 (model above) calls for 4700uF/50V filter capacitors. So this is a model below with 5600uF filters... I doubt they are originals. Looks sketchy.
 
Mr. Nick said:
Schematic for STR-7045 (model above) calls for 4700uF/50V filter capacitors. So this is a model below with 5600uF filters... I doubt they are originals. Looks sketchy.
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The original PS filtering caps on the STR-7035, C805, C806, are 5600 uF, 35V, 4-pin radial caps.

2 of the pins are only for mounting - no electrical connection - so 2-pin caps could be substituted. (It's also possible to go higher on the voltage to get wider pin spacing, if needed.)
 
Thanks for the responses. A few notes. The cutout/distortion problem is in the left channel. It affects the A & B speakers and the headphones. It affects the tape monitor and the FM. It was occurring before I replaced the original Sony STKs with some surplus Raytheon STKs I got off of eBay.

By the way, recapping and replacing the STKs each helped other issues and the receiver sounds great when the left channel isn't cutting out. (Digable Planets are great for testing the bass response :-))
 
If you haven't done so yet, clean your volume and balance pots and especially the function switch using deoxit, liberal exercise followed by faderlube. Volume/Balance is a 4-gang pot. Be sure to get all 4.

The function switch in these units can often be a cause of cutout. The rotary knob controls multiple sliders in two housings. It is difficult to get the deoxit/faderlube where it needs to go. You will need to tip the unit around until you find holes for access and you need to position the sliders so the fluids actually get to the contacts. It can be a bit of a challenge but if done correctly, may be exactly the solution you're looking for.
 
Having to deal with a little component noise on switch on, Vol way down, and a Thumpth noise when turning off, any thoughts , Cheers *
 
50 Green said:
If you haven't done so yet, clean your volume and balance pots and especially the function switch using deoxit, liberal exercise followed by faderlube. Volume/Balance is a 4-gang pot. Be sure to get all 4.

The function switch in these units can often be a cause of cutout. The rotary knob controls multiple sliders in two housings. It is difficult to get the deoxit/faderlube where it needs to go. You will need to tip the unit around until you find holes for access and you need to position the sliders so the fluids actually get to the contacts. It can be a bit of a challenge but if done correctly, may be exactly the solution you're looking for.
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I realize this is an older thread, but I was just searching for how to clean those selector-switch slider-style pots. So I hope my question is appropriate here. Where exactly, or which end, is the critical contact point inside the slider that needs the contact cleaner applied to it? I can see the white-toothed gear slide something back-and-forth, so I assume it’s underneath the slider piece. Or is it on top? I’m not sure. I assume then I’ll have to stand the unit on its side and try to get the fader lube to make its way down in there by gravity. Thanks for your thoughts.

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Puddintane said:
I realize this is an older thread, but I was just searching for how to clean those selector-switch slider-style pots. So I hope my question is appropriate here. Where exactly, or which end, is the critical contact point inside the slider that needs the contact cleaner applied to it? I can see the white-toothed gear slide something back-and-forth, so I assume it’s underneath the slider piece. Or is it on top? I’m not sure. I assume then I’ll have to stand the unit on its side and try to get the fader lube to make its way down in there by gravity. Thanks for your thoughts.

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The contacts are under the piece that slides, and there are several contacts in each slider. A look at the schematic will give an idea of what they are, and viewing the locations of the pins on the solder side of the board will give an idea of where they are in each slider.

The trick is to find a hole that - when the unit is tipped up appropriately - will allow the cleaner, and then the lube, to flow down and over the contacts. You may have to use more than one hole and various angles to get the fluids to flow where needed. You also may need to tip the unit around in several directions after applying the cleaner / lube, to get them to flow to all of the contacts.

It takes some care and patience to get enough cleaner and lube in without flooding it with too much. Be sure to exercise the knob thoroughly, once you have the cleaner on the contacts.

It's a bit of work, but far less than removing and disassembling then reassembling the sliders, and finally soldering them back in.
 
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