Sounds like a plan. It would also help if you give us an idea of your level of experience with electronics. If you are a novice, we can provide more detailed directions vs. assuming you know what we mean.
Help Sansui QRX 7500 Powers on but no sound!
- Thread starter Matt Timson
- Start date
Matt Timson
New Member
Fairly Novice My father was keeping up ok but I even just asked him and he was like yup this was pretty much his point so I would say novice as well
Matt Timson
New Member
Pic 1 is the two blown caps, pic two is the 4 fuses more up close especially the winged one, and out of the second two pics where is that relay
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petehall347
the brandy coffee man
that is glue from the factory
fuse appears a replacement and just not done neatly ..if its blown i guess someone kept blowing fuses and left the wires long to change the fuse more easily .
fuse appears a replacement and just not done neatly ..if its blown i guess someone kept blowing fuses and left the wires long to change the fuse more easily .
Rey1
Super Member
Well, it looks to me that someone has messed with all of the fuses. They should all be in very neatly sitting in fuse holders. If they check good, then you have a bigger problem as someone was obviously messing around in there. If a previous owner was repeatedly blowing fuses and replacing them, he probably ruined the holders. If fuses are repeatedly blowing, then there is a bigger issue. If you can't check the fuses then just get their rating and get 4 new ones and see what happens.
kevzep
Its all about the Music
Thats glue the factory used to secure the caps, they are not "blown".
I think since someone has already had a go at replacing the fuses, the issue probably lies within the output section of the power amps...
kevzep
Its all about the Music
This amp doesn't have fuse holders for the rail fuses, they are pigtail style which solder in....
But anyway, agreed, someone has been there messing around, so its safe to say the power-amps have issues....
I have restored a couple of these and they are easy enough to work on, especially in the power-amp section...
Matt Timson
New Member
We opened it back up the relay itself is humming o the board itself not from the speakers the speakers still produce no sound.
kevzep
Its all about the Music
What do you mean by the "relay is humming"?
Another thought I had was that I noticed the regulated supply board (the one with the fuses on it) has been running incredibly hot as they do.
There could be an issue here on this board and one of the supplies, maybe the front end of the power-amp is getting power....
There could be any number of issues like this.......You need to make a plan for working through the unit, finding out where the signal is getting lost.
You need a scope or signal tracer, and a signal generator.
Then you can logically work the problem, at the moment its all guesswork looking for a magic bullet.
petehall347
the brandy coffee man
could be a few things ..
i would start with checking the relay power supply for correct voltage and if any AC present ..if ok then i would check out the relay driver circuit voltages .
its called relay chatter when it makes constant noise something is telling it to do it .
i would start with checking the relay power supply for correct voltage and if any AC present ..if ok then i would check out the relay driver circuit voltages .
its called relay chatter when it makes constant noise something is telling it to do it .
kevzep
Its all about the Music
Yes at this point anything is a guess.
Signal tracer or scope will tell him where to look.
Assumption, need more information, pointless guessing...
petehall347
the brandy coffee man
just throwing ideas out there .... it is only educated guesses on my behalf .
kevzep
Its all about the Music
All good man, but there is now two pages of "just throwing ideas out there" which ultimately ends up in confusion and no clear path and plan to solve the problem.
petehall347
the brandy coffee man
best bet is check out the power supply first . without that working properly all bets are off .
i would try to help more if i had a decent schematic . one i have has missing parts .
i would try to help more if i had a decent schematic . one i have has missing parts .
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kevzep
Its all about the Music
The signal path in these units is incredibly complex, makes your head spin....
petehall347
the brandy coffee man
its one of those big jobs that is made up of little jobs ...one of my old bosses told me that many years ago about any so called big job . he said firstly no such thing as big job .