Hi all.
Wondering if anyone can give me some steps to try to ensure I don't mess this up.
I've always had separates but I wouldn't say I have any knowledge of the inner workings of the amp and stereos in general, but I'm also (hopefully) not an idiot... I'll try explain as best I can.
Back story, I got a Sansui AU-101 off ebay, apparently working.
I bought Sansui S-23 speakers off a total hifi nut, I heard them working before I took them.
I had the amp unplugged.
Wired up the speakers and rca inputs.
Had the speaker switch on the amp set to 'off'.
The volume turned down.
Then plugged in and turned on the amp.
Turned on the speaker switch and slowly faded it up.
Only sound from the right channel, perfect and clear.
Left totally dead.
So unplugged and opened it up and one of the two fuses is blown.
Now, if I get a new fuse what sort of steps should I take, well.. was my previous procedure just wrong?
I was thinking on replacing the fuse and testing with the headphones before wiring up the speakers.
If i have both signals at that stage (hopefully) I'll go ahead and wire up the speakers with the amp off & unplugged for a while.
If the fuse goes again maybe that indicates a speaker fault causing the fuse to go?
If it was the speakers causing the initial fuse to go why would that be? Maybe lose wires in the speakers.
But I know they both work as I tried switching the inputs on the amp and they both work fine, just not no left speaker sound.
So to me that indicates amp issue, and as I have discovered a blown fuse could that be a transit issue or the way I turned it on.
Is there also a chance the problem went deeper and caused other issues?
I guess wont know that until I eliminate the blown fuse and replace that.
So mainly any thoughts on a systematic procedure I can take whan I get the new fuse. Did I do anything glaringly wrong the first time...
Thanks for any input, check my set up hopefully sweet when its going.
Turntable SR-222
Amplifier AU-101
Speakers S-23 8ohms
Sansui cabinet.
One final thought its not blown because of the speaker choice right? I know the AU101 amp is just 15wts. Are the 8ohms S-23's too big and caused the problem maybe?
Wondering if anyone can give me some steps to try to ensure I don't mess this up.
I've always had separates but I wouldn't say I have any knowledge of the inner workings of the amp and stereos in general, but I'm also (hopefully) not an idiot... I'll try explain as best I can.
Back story, I got a Sansui AU-101 off ebay, apparently working.
I bought Sansui S-23 speakers off a total hifi nut, I heard them working before I took them.
I had the amp unplugged.
Wired up the speakers and rca inputs.
Had the speaker switch on the amp set to 'off'.
The volume turned down.
Then plugged in and turned on the amp.
Turned on the speaker switch and slowly faded it up.
Only sound from the right channel, perfect and clear.
Left totally dead.
So unplugged and opened it up and one of the two fuses is blown.
Now, if I get a new fuse what sort of steps should I take, well.. was my previous procedure just wrong?
I was thinking on replacing the fuse and testing with the headphones before wiring up the speakers.
If i have both signals at that stage (hopefully) I'll go ahead and wire up the speakers with the amp off & unplugged for a while.
If the fuse goes again maybe that indicates a speaker fault causing the fuse to go?
If it was the speakers causing the initial fuse to go why would that be? Maybe lose wires in the speakers.
But I know they both work as I tried switching the inputs on the amp and they both work fine, just not no left speaker sound.
So to me that indicates amp issue, and as I have discovered a blown fuse could that be a transit issue or the way I turned it on.
Is there also a chance the problem went deeper and caused other issues?
I guess wont know that until I eliminate the blown fuse and replace that.
So mainly any thoughts on a systematic procedure I can take whan I get the new fuse. Did I do anything glaringly wrong the first time...
Thanks for any input, check my set up hopefully sweet when its going.
Turntable SR-222
Amplifier AU-101
Speakers S-23 8ohms
Sansui cabinet.
One final thought its not blown because of the speaker choice right? I know the AU101 amp is just 15wts. Are the 8ohms S-23's too big and caused the problem maybe?
Attachments
Nothing wrong with your procedure , is there a chance that you shorted the speaker out put as they are bare wire connectors maybe the same could apply at the speakers . Take the fuse out and examine it , is there any sign of the fuse wire ( sometimes they just break ) or are there signs of wire splattering ( instant current overload ) or a neat burnt hole in the wire ( sustained load near the fuse rating limit ).
If the fuse is a 'speaker fuse' then it is VERY important that you make sure that there is no DC voltage across the speakers terminals after replacing that fuse.
Measure with a meter and no speakers connected. There should be no voltage across either set of speaker terminals.
Your choice of speaker should not cause any issue.
Measure with a meter and no speakers connected. There should be no voltage across either set of speaker terminals.
Your choice of speaker should not cause any issue.
probably one or two volts at startup that must go down to +/- 50 mv or less after a few seconds.
it is possible that an output capacitor is dead.
now you have to test the rest too ...
it is possible that an output capacitor is dead.
now you have to test the rest too ...
Huggygood the visible part of the schematic suggests the headphones are fed from the output of the amps and from a photo I have seen on Ebay you can select between phones or speakers , is this correct.
yes, by default it is the speakers that are connected, and if you introduce the jack, it short cut's the output through resistances
Ignore my post 6 when I first looked at the schematic it was very large and I couldn't see the far right hand side .
Huggys circuit shows the amp is AC coupled to the speaker which means it is essentially 'speaker safe'.
Disregard my earlier comment on checking for voltage in this case if checked with no load attached.
Disregard my earlier comment on checking for voltage in this case if checked with no load attached.
Yes, the fuses are in the single rail power supply leads to the amp. If one is blown, its likely that amplifier channel is damaged. The amp. is around 45 years old now and if it's anything like my example, it is long overdue for full replacement of the electrolytic capacitors.
Re-capping should have been done before powering up but I guess with Ebay purchases, you only have the seller's word that "it works" means it works properly, not just when last used 20 years ago or "sort of works" on occasion. I don't blame people for wanting to try out their purchases immediately but this is likely an example of why you should resist and take precautions. I rushed in too, but only after checking that someone had already done the urgent repairs and only a small wisp of smoke arose from a resistor. That was easily fixed without further damage but there were still a lot of very leaky and even a shorted cap. to replace.
If you'd like to see the schematic in larger format and read the full manual, sign up and download the service manual here: Sansui AU-101 - Manual - Solid State Stereo Amplifier - HiFi Engine
Re-capping should have been done before powering up but I guess with Ebay purchases, you only have the seller's word that "it works" means it works properly, not just when last used 20 years ago or "sort of works" on occasion. I don't blame people for wanting to try out their purchases immediately but this is likely an example of why you should resist and take precautions. I rushed in too, but only after checking that someone had already done the urgent repairs and only a small wisp of smoke arose from a resistor. That was easily fixed without further damage but there were still a lot of very leaky and even a shorted cap. to replace.
If you'd like to see the schematic in larger format and read the full manual, sign up and download the service manual here: Sansui AU-101 - Manual - Solid State Stereo Amplifier - HiFi Engine
- Status
- Not open for further replies.