Concept 11.0

[t j]

Bought a nice looking one that had no fuse or cap. Was told that it works by someone that I somewhat trust. He said that he blew the fuse and had the cap, and I bought it and got a fuse and cap at Frys. When I plugged it in it lit up momentarily and then died without any sound. The fuse did not blow.
Can anyone advise me on the best plan of action. Is there an internal fuse or protection circuit? Should I sell it for parts? Any and all advice is appreciated...

 

[mjstriker5]

Ummm where to start. Sounds like you were taken for a ride by this person you sort of trust. Second, fuses blow for a reason and shouldn't just be replaced as whatever is wrong will just blow it again. Third, there are probably a ton of caps inside that receiver so you will need to be a bit more specific on what was replaced.

If you are serious about trying to fix it you will first need a schematic and some basic tools (DMM and dim bulb tester) at minimum. Takes some pics of the amp and upload here. Do the same with the schematic. Show us the cap that was messed up and try to correlate it on the schematic.

That should be enough to get the ball rolling. On a side note if you are looking to sell, shoot me a PM. I might be interested.

 

[t j]

Ummm where to start. Sounds like you were taken for a ride by this person you sort of trust. Second, fuses blow for a reason and shouldn't just be replaced as whatever is wrong will just blow it again. Third, there are probably a ton of caps inside that receiver so you will need to be a bit more specific on what was replaced.

If you are serious about trying to fix it you will first need a schematic and some basic tools (DMM and dim bulb tester) at minimum. Takes some pics of the amp and upload here. Do the same with the schematic. Show us the cap that was messed up and try to correlate it on the schematic.

That should be enough to get the ball rolling. On a side note if you are looking to sell, shoot me a PM. I might be interested.

Slow down hot rod. I said nothing of a messed up or replaced cap and I can probably get my money back. Answer these questions if you can:
1. Is there an internal fuse or protection circuit?
2. Is there a reset function?
3. What's it worth to you?

 

[mjstriker5]

What do you mean by cap? Like the cap to the fuse holder? Slang for capacitor is to just say cap so I was confused. How do you know the fuse is still good? If it is a big lead inside it is obvious but I have been fooled a few times when the burnt part is hiding under the metal end. A continuity tester is the best way.

Offhand I know nothing of this particular receiver's circuitry but if you find a schematic I could answer your first two questions. The third question is purely based on my googling what it looked like. The receiver is cool looking. I know nothing of its value.

 

[t j]

What do you mean by cap? Like the cap to the fuse holder? Slang for capacitor is to just say cap so I was confused. How do you know the fuse is still good? If it is a big lead inside it is obvious but I have been fooled a few times when the burnt part is hiding under the metal end. A continuity tester is the best way.

Offhand I know nothing of this particular receiver's circuitry but if you find a schematic I could answer your first two questions. The third question is purely based on my googling what it looked like. The receiver is cool looking. I know nothing of its value.

That makes sense. I always hope that someone has had a similar experience that they can share, but that's probably not realistic. The cap that I spoke of is the screw in fuse cap. It and the fuse were missing but have been replaced. I'll try another fuse. That's great advice...

 

[mjstriker5]

Looks like audiokarma has the schematic in their repository here. Took a peek (curiosity got the best of me). There is a AC mains fuse (probably the one that is external) and 4 internal fuses. There is also a speaker output relay (aka speaker protection).

If you are blowing the AC fuse then you are drawing too much current and a common reason but not the only reason is bad output transistors. I say that but just repaired an amp that had a shorted bridge rectifier. Anyways, the receiver can be tough to work on without test equipment if it is blowing the main fuse. Really need a DMM, dim bulb tester and a variac to begin narrowing down the problem.

The dim bulb is a must cause it limits current and will help prevent the fuses from blowing and other arts from getting fried during the repair process.

Also there is no reset function.

Lastly, upload some pics!!! We want some eye candy.

 

[t j]

Looks like audiokarma has the schematic in their repository here. Took a peek (curiosity got the best of me). There is a AC mains fuse (probably the one that is external) and 4 internal fuses. There is also a speaker output relay (aka speaker protection).

If you are blowing the AC fuse then you are drawing too much current and a common reason but not the only reason is bad output transistors. I say that but just repaired an amp that had a shorted bridge rectifier. Anyways, the receiver can be tough to work on without test equipment if it is blowing the main fuse. Really need a DMM, dim bulb tester and a variac to begin narrowing down the problem.

The dim bulb is a must cause it limits current and will help prevent the fuses from blowing and other arts from getting fried during the repair process.

Also there is no reset function.

Lastly, upload some pics!!! We want some eye candy.

Awesome Thanks! Eye candy coming tomorrow....

 

[blhagstrom]

Those are great units.

My bet is a blown amp. Last owner blew the fuse. I'm betting you blew a new fuse.

If you don't set up a dim bulb tester and use it, you are just going to keep blowing fuses.

Since you don't know the things I just listed, I recommend you either find a vintage tech to work on it or sell it as is.

If we knew where you are, we may know someone capable of working on it.

I work on them but not I do not know if any of the other techs or fixers here do. They are sort of rare.

 

[mjstriker5]

Looking at the schematic, doesn't seem overtly complicated. I would like to think any competent repair tech could handle this one. Albeit I didn't look closely to see if there were any specialty or unobtanium parts.

Unfortunately, techs nowadays can be pretty suspect. I had a guy bring a marantz receiver that a tech recapped and did some other stuff to eliminate some scratching in one channel. When it didn't fix it he took the guy's money and said good luck. Took all of 5 seconds to clean some selectors.

Reminds me of auto parts store workers. They know nothing about cars anymore. They are just there to look up parts for you and pull them from the back. You should have seen the guy when I walked in and asked about a 1960 international scout 4x4. He looked at me like I was talking in tongues.

 

[t j]

Looking at the schematic, doesn't seem overtly complicated. I would like to think any competent repair tech could handle this one. Albeit I didn't look closely to see if there were any specialty or unobtanium parts.

Unfortunately, techs nowadays can be pretty suspect. I had a guy bring a marantz receiver that a tech recapped and did some other stuff to eliminate some scratching in one channel. When it didn't fix it he took the guy's money and said good luck. Took all of 5 seconds to clean some selectors.

Reminds me of auto parts store workers. They know nothing about cars anymore. They are just there to look up parts for you and pull them from the back. You should have seen the guy when I walked in and asked about a 1960 international scout 4x4. He looked at me like I was talking in tongues.

Pierced tongues...

 

[blhagstrom]

It's a vintage receiver.

Power supply, pre-amp and tone section, phone pre-amp, tuner and a pair of output amps. Lots of Japanese transistors, capacitors, resisters, diodes, etc. mostly discrete components that can be replaced. The tuner may have an IC or three.

A competent old school tech can fix it.

Finding a competent old school tech is the trick.

The stereo shop in my home town couldn't fix a vintage Pioneer 40 years ago when the original parts were still available. I fixed it myself 5 years ago.

I have seen some serious hack jobs by people claiming to be vintage techs. Business card type business and all.

 

[t j]

It's a vintage receiver.

Power supply, pre-amp and tone section, phone pre-amp, tuner and a pair of output amps. Lots of Japanese transistors, capacitors, resisters, diodes, etc. mostly discrete components that can be replaced. The tuner may have an IC or three.

A competent old school tech can fix it.

Finding a competent old school tech is the trick.

The stereo shop in my home town couldn't fix a vintage Pioneer 40 years ago when the original parts were still available. I fixed it myself 5 years ago.

I have seen some serious hack jobs by people claiming to be vintage techs. Business card type business and all.

Yeah man, I don't look forward to shopping techs. I have some leads, one of which is Tom Ishimoto here in SoCal. But I'm not gonna lie, of late, my faith in man is shaken...

 

[blhagstrom]

I think there are some good vintage techs around SoCal.
People here have spoke well of some.

Worst case, ship it up here.

Concept gear has some magical goodness in the sound.
It was a house brand for Pacific Stereo and very little documentation is available, but we have knowledge.

 

[KingBubba]

Another issue is that Pacific Stereo never made service manuals for the Concept line.

 

[t j]

 

[mjstriker5]

Very nice!!

 

[SoCal Sam]

Yeah man, I don't look forward to shopping techs. I have some leads, one of which is Tom Ishimoto here in SoCal. But I'm not gonna lie, of late, my faith in man is shaken...

Tom is an ace. Your faith will be restored. He has taken care of countless of my items. He also serviced the receiver collection of former AK member Vintagestereo.

 

[jdurbin1]

Nothing against Tom BUT there are a couple other very strong techs in SoCal for Concept pieces - Jeff, who runs the tapeheads.net forum (goes by Pacific Stereo and was the manager of the Pacific Stereo repair center in a previous life - Concept was developed for that company) and Tinman who you can reach thru AK or TH. Both are extremely solid techs and very familiar with the 11.0.

John

 

[blhagstrom]

There you go.
I knew there were some down there.

Spend some coin and do it right and you'll smile a long long time.

 

[KingBubba]

I have been on the fence of getting my malfunctioning Concept 5.5 done over or not. I will have to remember this thread in case I do decide. It will probably be the malfunctioning Sansui Model 8 that will go out first. At this point I am paying for the new lenses that were put in my eyes. Medicare pays for some but not all types of lenses and they are expensive. I could have bought a couple of SX-1250s instead.