New member. Sansui 4000 "projector" light issue.

[weareno_one]

Hello all, I hope everyone is having a lovely Monday.

I am very new to vintage audio and receivers. I did a somewhat steady amount of research before buying a Sansui 4000 receiver.
Purchased as working with no known flaws.
I have had it in my possession for a little over a month now, but have just finish wiring and testing.

I have 16ga copper wiring from the receiver to the Klipsch R-41M bookshelf speakers. Then I have red/white RCA cord from the Phono 2 input to my U-Turn Audio custom turn table.
When I got everything hooked up, it sounded awful. Then I realized it was because I had the pre-amp turned on the turn table.
Turned that off and it worked amazing that first night.
At least for about one full side A playthrough.
I changed the record when that started to sound a bit fuzzy, or like the sound was slowly dying out. However, I didn't think much of it because the record was pressed in 1978.
I put on a heavyweight 180 gram record and this was also a tad fuzzy, but not nearly as bad as before.

A few days later, because we were having new built-in shelving installed, I was finishing hiding the wiring, etc. I also changed the input to Phono 2, just because I had to plug in a different RCA cord at that time. Or rather, a better quality RC cord.

While moving and organizing my albums on the same shelf, I had 3 different albums playing during that time. The very first one is an orchestral ambient album that is very, very quiet. It played flawlessly. Dead silence with full-body flourishes. I was thrilled that it sounded this good.

By the 3rd album, side C maybe, nearly an hour or so of play-time later, the sound starts getting fuzzy and hollow again.
Similar to before. Almost like it was overheating or something and just slowly dying out.
I was sitting on the floor, but looked up and noticed the dashboard lights that had "Phono 2" lit up this whole time, now it also says in red "Projector".
I found absolutely no information for what that means when googling this.
The same fizzling out sound started and so I moved the tone arm on my turn table. It isn't the turn table.
It's almost like the unit is overheating or something, but I can't really find any info about this.

It seems like everything else works great. I played around with the bass, loudness, high and low filter buttons, etc. Nothing made any difference with what it was doing.

I appreciate anyone taking the time to read this.
I guess my question is more along the lines of understanding this receiver and what I could or should do differently -- or if I'm doing something wrong myself.

Could it just be as simple as it being an older unit and it's normal for them not to play for a very long time?

 

[Robisme]

Google Sansui 4000 protector light, instead of projector.

Sounds like you may be losing voltage somewhere. This is both channels?

Rob

 

[weareno_one]

Hey Rob, thanks.
I will google that and see if it gives me anything different.
Googling "Sansui 4000 projector" was only bringing up listings for a projector to buy...

The channel that was doing this was the Phono 2, but I have not tried it using different inputs, speaker inputs, or anything else yet.
I could troubleshoot that way, but I guess I thought I'd go ahead and figure out what the "projector" light meant on the front.

 

[Beez1965]

ProTector. Try hooking up a signal source to the "aux" input and see if it does the same thing.
If it does, I'd suspect power supply issues. If it does not, perhaps the phono input board.

 

[weareno_one]

Thanks Beez,
I was going to play around with it when I get home. The first thing I considered was to use AUX and see if that made any different.
So far I HAVE used both Phono 1 and 2 when using this and only Phono 2 did what it did in my first post above.
I did not play anything long enough on Phono 1.

Are you saying that it says "ProTector" instead of "projector" or did I misunderstand that?

Sansui 4000 "protector" light always on

I recently rescued a Sansui 4000 from storage in my basement. I'd never opened it up before, but somebody had. (There's a little spring jerry-rigged to hold up the tuner indicator wires.) The first thing I noticed as I was about to do a little cleaning inside was that the PROTECTION lamp was...

audiokarma.org

This post here shows the same red projector light, but that doesn't seem to be the same issue that mine has.

 

[DB-7]

The proctector light comes on when there is an issue with the reciever.
Does it ever come on while on am or fm?
It may be a fault in your phono stages.
If you only have vinyl, try using your pre-amp to AUX

 

[weareno_one]

Wow, I literally did NOT realize that says "proTector" until just now. Even going back to look at the image in the other post it still didn't click.
Sorry. Kept glancing through and just assumed it said projector each time.

SO, I have a red PROTECTOR light that was lighting up after being on and used for around an hour.

The FM was being used at first to test the speakers before I hooked up the turn table later.
No issues there.

When it first started trailing off and/or fizzling out, the protector light came on. I turned off the unit with the power button.
I let it sit for about 2 minutes and turned it back on. It did not light up immediately, but did after a few seconds.
That's what made me think it overheated or something. I have not tested anything since then.

 

[DB-7]

There are alot of Sansui 4000 fans on this forum. I personally don't own one.
Those members will have a better idea of what is happening with yours . You will just have to wait until they check in.

Welcome to AK. And the Sansui world.

 

[weareno_one]

No worries, thank you!

I will add some more details after playing with the inputs and channels to see if I can pinpoint what may be the issue.

 

[Robisme]

Probably going to be TR001. 2SC971.

Or maybe TR002, but I think that's only for tuner power.

Check the supply voltage on the phono board and see if you lose it when the sound gets fuzzy. Then check the outputs of the power supply.

Rob

 

[Jefft91]

Maybe this will help. You should check your offset voltage and, as the second picture says, shorted outputs. I have not looked at the protect circuit in this receiver, but others more familiar with the 4000 may have something to add. Finally, you may want to avoid powering up on full line voltage until you get the problem fixed.

 

[weareno_one]

Thank you for the advice on that.
I do not have any necessary tools or knowledge to test any voltage.

I will add, now that I’m home, that I immediately tested the unit again using AUX input.
Couldn’t hear anything. I turned up the volume a bit and could make out the song playing.
I started to turn the input knob again and could hear the volume blast out before I changed the input. Almost like the knob wasn’t perfectly tuned to that input or something.

I then plugged in the RCA to Phono 1, 2, and AUX again. Not right away, just for a few seconds of the songs.
Every one of those are not working even remotely close to how well they were working a few day ago.
Fuzzy, static, generally unclear.
I went through 3 songs while testing this, but the best, clearest channel was Phono 2.
Still has what I would define as static though. And nowhere close to as balanced and clear as it was.

I did touch the speaker wires where those are plugged in and I DID get a bit of clarity from that, but it barely lasted. That made me think they weren’t plugged in all the way, but they definitely are.

No protector light at this time.

The FM and other radio inputs seem to work fine, but there is static on those too, likely because I am not perfectly tuned to the station though.

I will have a look at the above “manual” and see if anything that changes what I’m dealing with.
I am modern tech savvy, but this is a new thing for me.
I purchased because of the aesthetic for our decor and I wanted something that was still a great pair with the newer speakers and turn table.

 

[Beez1965]

Thanks Beez,
I was going to play around with it when I get home. The first thing I considered was to use AUX and see if that made any different.
So far I HAVE used both Phono 1 and 2 when using this and only Phono 2 did what it did in my first post above.
I did not play anything long enough on Phono 1.

Are you saying that it says "ProTector" instead of "projector" or did I misunderstand that?

Sansui 4000 "protector" light always on

I recently rescued a Sansui 4000 from storage in my basement. I'd never opened it up before, but somebody had. (There's a little spring jerry-rigged to hold up the tuner indicator wires.) The first thing I noticed as I was about to do a little cleaning inside was that the PROTECTION lamp was...

audiokarma.org

This post here shows the same red projector light, but that doesn't seem to be the same issue that mine has.

Yes, it says protector. The protection circuit is part of the power supply board.

 

[DB-7]

It seems like your 4000 is original and is in need of freshing up.
Where are you located? Someone may know of a reliable Tech in your area or maybe there will be a AK member close to you that does work on the side.

 

[Jefft91]

@weareno_one I reviewed the scematics for the 4000. The protect circuit monitors the output current for each channel. If it senses excess current, it will reduce the supply to the input stage of the amplifier sections, which is what you are likely experiencing as fuzzy sounding (and reduced amplitude) outputs. This will affect all inputs similarly. Excess current can damage output transistors, so you sould not try to run your unit until the cause of the fault is found. It can cause more damage.

One clarification. I mentioned checking output offset. This does not apply to your receiver, as it is a capacitor coupled design, which as capacitors that block DC voltage at the speaker outputs.

 

[Guido57]

@weareno_one: as you "...do not have any necessary tools or knowledge to test any voltage..."
DB-7 provided good advice.
IMAHO you need to find someone who can help you, in person, with this unit, or find someone to do it, or learn how to test/fix it yourself which means buying at least a digital multi meter (DMM) and building a dim bulb tester (DBT). The DBT can help mitigate damage if something is not right, but no guarantees of absolute protection. Which path you take involves decisions of time and money. The less cash you can put into it means the more time you may need for it.

 

[CrSens]

Thank you for the advice on that.
I do not have any necessary tools or knowledge to test any voltage.

I will add, now that I’m home, that I immediately tested the unit again using AUX input.
Couldn’t hear anything. I turned up the volume a bit and could make out the song playing.
I started to turn the input knob again and could hear the volume blast out before I changed the input. Almost like the knob wasn’t perfectly tuned to that input or something.

I then plugged in the RCA to Phono 1, 2, and AUX again. Not right away, just for a few seconds of the songs.
Every one of those are not working even remotely close to how well they were working a few day ago.
Fuzzy, static, generally unclear.
I went through 3 songs while testing this, but the best, clearest channel was Phono 2.
Still has what I would define as static though. And nowhere close to as balanced and clear as it was.

I did touch the speaker wires where those are plugged in and I DID get a bit of clarity from that, but it barely lasted. That made me think they weren’t plugged in all the way, but they definitely are.

No protector light at this time.

The FM and other radio inputs seem to work fine, but there is static on those too, likely because I am not perfectly tuned to the station though.

I will have a look at the above “manual” and see if anything that changes what I’m dealing with.
I am modern tech savvy, but this is a new thing for me.
I purchased because of the aesthetic for our decor and I wanted something that was still a great pair with the newer speakers and turn table.

You have to be absolutely sure you do not have unintended shorts in speaker connections. Check and double check all wires at both amplifier and speaker ends, that there are not touching, even a little hard to see litz wire can cross over and touch the wrong side. That would cause symptoms you are having.

 

[weareno_one]

Sorry to reply so late to this. I was looking a bit further into this and testing the unit to better pinpoint what I was dealing with.

Thank you to everyone for this, you've all made this a very simple and friendly first experience here.


So, in short:
I am in north Florida. I did a few google searches for vintage audio repair and found that someone is close where I am located. I had a few-minutes-long phone call explaining what is happening.

He said this can be repaired and he knows what it needs. Didn't really add anything about possibly having a short in the speak wire or the connections. I did double-check those after the above recommendations.
He also added that this could have happened before I purchased it and that it may likely be caused from the humidity down here. Oxidized copper wires, for one.

I used the receiver for a total of about an hour, possibly less. I did NOT solder the tips of the copper wiring, which he said this would need for him to warranty any repair he makes.
I watched multiple videos with a similar set-up to mine and NONE of those videos, how-to, or reviews, mentioned anything about soldering the copper wires before plugging those into the receiver or the speakers.
In fact, one video showed the creator spreading out the copper wire before twisting it into the speaker inputs.

The "likely minimum" for the repair was at least $300. That seems quite steep of a repair at first glance, though I can also understand since it's probably around 50 years old.

Anyway, he did explain how this likely happened and gave me a short explanation of what it needs, basically that the damage has been done and it will continue to have this problem until it's fixed.

If anyone here has any further comments on what a repair should likely cost, I am happy to have any advice on that. I understand my information was vague at best, so it's difficult to put a price on something that is mostly unknown here. But, thank you all the same.

 

[Guido57]

Soldering the tips of the wires helps prevent loose strands from sticking out and causing a short. I have done this at times after twisting the strands together as it can make the wire easier to handle.
Repair techs can be expensive. Would this $300 mean fixing the one problem and leaving the rest of the 50 year old stuff as is? In other words what is he proposing to do? Replace wires and clean contacts? Hard to say from this distance if putting money into this unit is worth it. Might be, might not be. Perhaps paying a bench fee so the tech can give a more precise estimate, though the cost to just put it on the bench may be pretty high.
Your decision on whether to fix this unit should depend on what it would cost vs the value of the unit after repair. Whatever you've already paid is a sunk cost and should not be considered in whether or not to proceed with repair.

 

[DB-7]

There is absolutely no way that Tech you called, no matter how good he is could possibly know what is wrong with your 7000 without looking at it first! Almost impossible!
They could have a rough idea but cannot know for sure.

The Tech I use requires a non-refundable diagnostic deposit fee of $50 that goes towards the repair if you choose to let him repair.

The only reason the Tech wants you to solder the speaker wire ends is to save you from shorting it out with stray wire.
The reason you dont see many other people soldering the speaker ends is because soldering them does not make the best connection especially with spring clip type connectors like your 7000 has. If you solder the wires you are only making connection on the hard outside edge of the solder.
When you dont solder the spring clips can dig into the copper wire and spread it a bit for a better connection.
I never solder my wires. I only twist them enough to get them in the hole and once they are in and clamped, I gently pull on them with a slight wiggle to seat them good.

$300 seems very high unless he is doing a complete refresh.