Sony STR V4 repair in MPLS Mn

[specialx1]

can someone recommend a repair shop in the Mpls Mn area for my sony receiver, STR-V4 Bad hum as volume goes up when i use turntable, looking for good shop to repair it, THX
Specialx1

[markallen]

Since you specifically identify a turntable problem, might this have something to do with improper/lack of grounding? I could be way off, but that's what jumps to my mind.

[specialx1]

yes sounds like it to me but i cant find the problem,looked inside everyhting looks good, put turn table on different receiver and it works fine, so i am thinking something is wrong in the receiver,althought visually everything looks ok to me,just gets louder as i increase volume till it sounds like speakers are gonna blow, but yet works fine on am/fm/and casette,only when tt is used, so was hoping to find someone on my area to work on it,!
Thx
maybe i could try a preamp in cassette jacks to hookup tt

[Arkay]

How are you grounding the turntable to the receiver? How is the receiver itself grounded? I would investigate that ground connection first. A grounding problem is extremely likely to be the source of the hum, not a defective receiver... although it is just possible (but much less likely) that something in the receiver's phono stage is causing it.

Since you say that the problem gets worse as volume is increased, you might be getting some kind of feedback loop. Have you tried to better isolate the turntable, and tried changing the relative positions of the receiver and the turntable? Have you tried a different turntable (with diferent cart) through the same receiver?

Your idea of trying a different preamp and routing the signal through a different input is worth trying. If you STILL get a hum, then you'll know it isn't something in the receiver's phono stage.