Discovering a Sony STR-DH750 A/V Receiver - Part 2: Inside

In the first part of this series, I discovered that a Sony STR-DH760 A/V receiver I had bought at an estate sale has some problems, notably in its display. In this second of a three-part series, I test some of the receiver's other functions and take a look around inside it. In the third part, I will attempt to repair it.

[@francisco5434]

I own one of these. From power off to power on, there is an initial click of a relay enabling what I believe to be the power board. There is an immediate and deep-toned “brrrr” sound as some high voltage system is charged, possibly those large electrolytic capacitors. That sound is absent on yours. This should be followed about 2-3 seconds later by the de-bounce (anti pop) circuitry to null out or wait out the electric noise signal as the circuits settle down and prevent the destructive and annoying “pop from reaching the speakers. After that relay kicks in, normal operation is possible. Your digital circuits appear operational. I believe most, if not all, are logic voltage: 5V (My guess). I would also guess the analog signal voltage/s, are absent (the missing second relay sound) Maybe test power supply out voltages. Maybe check for a bad relay not powering some daughter boards and/or sections of the motherboard. That black monolithic unit on the main power-board might be a relay. You could try a few random test leads on the boards to see if voltage is even present, just stay away from those large capacitors. Good luck

[@francisco5434]

Also, I believe the Op-amp and signal voltages would probably be in the 12V range. They are probably absent or not latched in. Maybe bad power supply, power board or power control circuitry.

[@rudypj30]

I still got mine and works great still, but plan on upgrading to a onkyo TX-NR6100 soon since I upgraded the rest of my surround sound

[@-SDegirmenci]

I have same reciever. Bluetooth and hdmi dosn't work. Only I'm getting sound on the optical cable.

[@trainrick1]

I have one. I got it from my scrapper friend. Seems it got thrown away because no display. Bluetooth works good. Fm works. RCA input works. On your first video you were going through the input choices too fast. Me I switch input wait a couple seconds then switch again. It rocks using no remote or app. Great sound. I'll get a remote maybe. I like your video. I can't believe I got this free. 125 watts x 7!.... Hehe

[@SomeDisassemblyRequired]

Thanks! It's been sitting on the shelf since I made the video but I hope to dust it off again and maybe fix it some day.

[@trainrick1]

​@@SomeDisassemblyRequired right on! Mine now won't Bluetooth, the Bluetooth button won't work so I cannot pair my new phone....crazy

[@trainrick1]

​@@SomeDisassemblyRequired I got Bluetooth to pair!

[@jasongomez5344]

I have one of these. I have it in a cabinet with glass sliding doors at the front and I am worried that it may be getting too warm. Does heat make these things fail prematurely?

[@WHOHATESTOWORK]

Always on top unless you have a fan in the back i say

[@88mtellez]

Mine powers on but shuts off 10 seconds later and the display isn’t working.

[@va1872]

We’re you able to fix it or see what was wrong with it?

[@SomeDisassemblyRequired]

I haven't gotten back to fixing it yet. I hope to do that eventually, but my Steinway piano project (see other videos( is my priority for now.

[@trainrick1]

If you don't get it to work I'll take it!

[@trainrick1]

Hey where's part 3? Hehe don't salvage it I'll take it I bet I'll hafta pay shipping

[@stevenljohnson867]

I just purchased the Sony str-dh740 from a Thrift store!? And I'm a day late a dollar short ($37.00)😢 Please give me some suggestions to who I would give this to for parts. I can't afford to have it fix🤡