Sansui qrx 7001 keeps blowing rear leff fuses

QuadraphonicQuad

Help Support QuadraphonicQuad:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

lev

Member
Joined
Apr 10, 2016
Messages
28
Location
Mexico
Hi,

Finally I got a chage to hook up my 7001 yesterdad both left back outputs are blown

I found a thread in this forum about the speakers fuses, checked them and they were blown, today I went and bought some, it keeps blowing them.

If I put only one of the 2 fuses, it doesn't burn when I turn it on, but if I put both,they burn as soon as I turn the unit on.

I appreciate any help.

Thanks
 
At a guess they are push-fit wires for your speakers, and it could be that your speaker cable is shorting to the chassis by the speaker sockets, or you have internal shorts in the Sansui.
 
Thank you DuncanS


The speaker cables aren't shorting because they're the same I have been using with another reciever,actually, I am listening to them now.

Will check the sansui for any shortings,
 
Hi,

Finally I got a chage to hook up my 7001 yesterdad both left back outputs are blown

I found a thread in this forum about the speakers fuses, checked them and they were blown, today I went and bought some, it keeps blowing them.

If I put only one of the 2 fuses, it doesn't burn when I turn it on, but if I put both,they burn as soon as I turn the unit on.

I appreciate any help.

Thanks

Since it works with either of the fuses in but not both, that suggests that wiring is not the problem or else the problem would be specific to one fuse. Unfortunately whether the specifics of the qrt 7001, so please take the following as a guess.

This suggests some type of overall impedance issue, total power issue or thermal issue. All three of those are related in a way.

What is the impedance of the speakers you are trying to use? Are the Sansui air vents covered or open? Can you try with different speakers?

Unfortunately without testing the unit, it's hard to provide more than guesses about a cause.

Andy
 
Thank you very much Andy,

I tried it with infinity sm115 (8ohms)

But it burns the fuses even without speakers.

It is well ventilated,I also tried on top of the rack, and with the sansui's top off.

Ivan
 
That is very strange, as I wouldn't expect the fuses to blow if the speakers aren't connected as I would expect the fuse to be between the amp output and the speaker. Do you get a circuit diagram with the Sansui?

Thank you very much Andy,

I tried it with infinity sm115 (8ohms)

But it burns the fuses even without speakers.

It is well ventilated,I also tried on top of the rack, and with the sansui's top off.

Ivan
 
I had one thought which is to verify that you have the right rating of fuses. Also, try to verify if you need regular fuses or delay action ones.

If it is happening with an infinity ohm load (open load), then that eliminates the speakers as the cause. It makes me think there is a short in the unit. Maybe a cap has shorted?

Andy
 
That is very strange, as I wouldn't expect the fuses to blow if the speakers aren't connected as I would expect the fuse to be between the amp output and the speaker. Do you get a circuit diagram with the Sansui?
I don't have a diagram,but will try to get one.

Thank you very much
 
I had one thought which is to verify that you have the right rating of fuses. Also, try to verify if you need regular fuses or delay action ones.

If it is happening with an infinity ohm load (open load), then that eliminates the speakers as the cause. It makes me think there is a short in the unit. Maybe a cap has shorted?

Andy

Thank you very much Andy, I will check that.
Ivan
 
There is often whats known as a Zoebel network (just Resistors & Capacitors) to modify the load seen by the amplifier as speakers will present a mainly inductive load (though this is modified by the cross-over filters in the speaker), so if this is post fuse it could be the problem.

I had one thought which is to verify that you have the right rating of fuses. Also, try to verify if you need regular fuses or delay action ones.

If it is happening with an infinity ohm load (open load), then that eliminates the speakers as the cause. It makes me think there is a short in the unit. Maybe a cap has shorted?

Andy
 
Thank you Duncan,

I was about to start packaging the 7001 to send it for guarantee, the seller told me he knew a technician who is really good, he has sold me a few more things and I have never had any issues, but the idea of someone I know nothing about tinkering with it gave the creeps haha,

I will contact the QRX store to get it fixed, recapped, etc, I think sending it from Mexico is going to cost me a kidney :( , but I am sure it will be worth it :)

In the mean time I bought a Sansui QR1500, and now I need t get at least one quad tape haha


P.S.
I removed the lower cover? today to see if there were any cables or hairs shorting something, everything looked ok, put 2 new fuses and now it blew 1 !!, I replaced it 3 times and it again blew only one...strange isn´t it?

Kind regards,
Ivan
 
Hi Ivan

I think it would be best if you can let a Audio teck look at your QRX7001 as the saying goes a little knowledge is a dangerous thing, to keep putting fuses in can bring other problems in play.
I bought a Sansui QRX80001 about 6? years ago and sent it to Jim Showker in the US. he has a web site ( qrxrestore.com ) he done a fantastic job I got him to do the full restore it cost me a leg & arm but the results are first class. So have a look at his web site I`m not saying send it to him just there is good information there to see.
A locale man near where you live is the best..
Bill..


Thank you Duncan,

I was about to start packaging the 7001 to send it for guarantee, the seller told me he knew a technician who is really good, he has sold me a few more things and I have never had any issues, but the idea of someone I know nothing about tinkering with it gave the creeps haha,

I will contact the QRX store to get it fixed, recapped, etc, I think sending it from Mexico is going to cost me a kidney :( , but I am sure it will be worth it :)

In the mean time I bought a Sansui QR1500, and now I need t get at least one quad tape haha


P.S.
I removed the lower cover? today to see if there were any cables or hairs shorting something, everything looked ok, put 2 new fuses and now it blew 1 !!, I replaced it 3 times and it again blew only one...strange isn´t it?

Kind regards,
Ivan
 
Hi Ivan

I think it would be best if you can let a Audio teck look at your QRX7001 as the saying goes a little knowledge is a dangerous thing, to keep putting fuses in can bring other problems in play.
I bought a Sansui QRX80001 about 6? years ago and sent it to Jim Showker in the US. he has a web site ( qrxrestore.com ) he done a fantastic job I got him to do the full restore it cost me a leg & arm but the results are first class. So have a look at his web site I`m not saying send it to him just there is good information there to see.
A locale man near where you live is the best..
Bill..

Thanks Bill, I will do it.

I will contact the QRXstore, I am sure it will be worth every penny.

Kind regards,
Ivan
 
Hi. Ivan

I think you want regret it, but it will be up to your budget as how far you go to repair the 7001 unit.
And remember the Sansui is a QS matrix unit so it will play QS LP`s better than SQ although it is still pretty good compared with other Quad units, the synth control on the 7001 does a great job on stereo music converting to Surround Quad really good most people have stereo LP`s or CD`s

Thanks Bill, I will do it.

I will contact the QRXstore, I am sure it will be worth every penny.

Kind regards,
Ivan
 
Hi. Ivan

I think you want regret it, but it will be up to your budget as how far you go to repair the 7001 unit.
And remember the Sansui is a QS matrix unit so it will play QS LP`s better than SQ although it is still pretty good compared with other Quad units, the synth control on the 7001 does a great job on stereo music converting to Surround Quad really good most people have stereo LP`s or CD`s



Thanks Bill, I have checked the price for restoring the 7001, and it´s all right I can afford it, just need to go sell a kidney haha,

I need to talk to the UPS guys to see if it will go through customs without any problems from Mexico to the U.S., and if everything is ok, make a big sturdy box.
 
Hi. Ivan

Well I hope everything works out for you .
And remember when you get it back if you don't have any Quad LP`s just plug your CD or DVD stereo player into the front Auxiliary input press the Surround Synthesize Mood, of course you need 4 speakers connected to the 7001 & instant Surround Music you will be surprised ......:51banana:.......surprised
Bill.....


Thanks Bill, I have checked the price for restoring the 7001, and it´s all right I can afford it, just need to go sell a kidney haha,

I need to talk to the UPS guys to see if it will go through customs without any problems from Mexico to the U.S., and if everything is ok, make a big sturdy box.
 
You have a shorted transistor in the output stage of that channel. It's either one of the heat sinked output transistors or one of the board mounted driver transistors. They will pull down the B+ voltage even without speakers connected and blow the fuses. If you can figure out which transistor is bad, you can order a replacement online for a few dollars, de-solder the bad one and solder in the new one.
 
You have a shorted transistor in the output stage of that channel. It's either one of the heat sinked output transistors or one of the board mounted driver transistors. They will pull down the B+ voltage even without speakers connected and blow the fuses. If you can figure out which transistor is bad, you can order a replacement online for a few dollars, de-solder the bad one and solder in the new one.

Thank you very much, I hadn't seen you reply till now

Kind regards,
 
I wanted to send my 7001 to the qrx store but it would be too expensive.

Some months ago a friend of mine who likes hi-fi gear told me he knew a guy who es really good, he even makes his own tube amps,so 2 weeks ago I sent him the 7001, I received it today, and just plugged it ,

I don´t know if he reads this forum but I want to thank Pedro Muñoz for fixing and give it maintenance.

Now I am listening to some music, I got a mild flu today, but I think it it would be a sin not to open a beer or two, what the hell ...a six pack :)

20170815_213758.jpg
 
OMG this thing sounds great !

I think my onkyo(recent model) is going for sale :)
 
Back
Top