• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

How far gone is TOO far gone?

Blue Shadow said:
Well let's put some reason to read page 2 of this thread so someone will need to follow this post with that good post.

Not knowing baglory's skill level, using the fact that he needs to buy soldering equipment, I'm with roger2 on the issue of whether this amp is too much for a first-timer. This is something the OP can respond to or consider.

The L-100 is a great amp. Very old, from the mid-70s and needing some work. I'm interested in what parts Steve believes are unobtanium or very-rareium that would make the choice of this working amp* a problem. I believe the unit is just discrete components and not really an issue finding the electronic parts. As will many units today, finding the knobs, switches, buttons and dials for vintage will be much harder. But this unit isn't using a bunch of IC chips that can't be replaced.

The faceplate is engraved so you can clean it without losing the wording.

*Blaze said the amp works. If it comes out of protection and does in fact work, the rebuild is just a matter of swapping out all the recommended components for some new parts. This involves some disassembly that is more difficult than many and less difficult than some units. But with it working, diagnostics will be kept to a minimum and will occur when the project is in it last stages, the turn-on after the work.

This unit has a couple boards that are additional to the standard amps. There is a winker circuit to flash the on indicator and a mute circuit that is done with a touch switch for muting the signal by 20dB or so. Just a bit more work to do but the unit is worth the trouble.
Click to expand...

Ive wired new construction (homes), built hundreds of computers (well maybe a couple dozen), wired hundreds of systems (nothing high end but I get the idea) and basically fixed every electrical problem in my house...SO with that in mind ( by means I am no expert), I havent really worked on circuitry "per say" using a soldering iron but I have seen it done. I am familiar with how electricity flows through systems and know the basics of what each component does but I would need help on EXACT items and how/when to fix them using which methods.

Thats what you guys are here for right ;-) If you see me with a fork close to any electrical outlets just shout "step away from the electricity"!!!

I own a mutli meter, so that is a start no?
 
Last edited:
A few more thoughts...

Get a good soldering station. It makes a difference. There is no point in trying to overcome lack of experience AND inferior gear when trying to make good solder joints. And every joint has to be good.

Hakko FX888 is what I have. Around $80. There may be a new model number for it now I don't know, mine was purchased a couple years back. It is excellent compared to the cheap stuff I had been using. A similarly priced Weller would be fine as well. There are many, many threads discussing soldering stations, tips, solder, wick, flux, technique, etc. Google search of AK works well...

It is good to learn soldering on junk PCBs. Something thrown out or, where I live, you can get VHS players for around $5 at Goodwill. Your soldering ability will improve in phases, not all at once. The first steps in that process are better left out of any gear that is intended to last long term.

If you are going to consider an alternative to this Luxman for a first project, I would suggest a smaller, simple integrated amp that is in working order ( i.e. no blown transistors to worry about). Kenwood KA-3700, KA-3500, etc., or any similar Pioneer/Marantz/Sansui, would be so much easier than the L-100U. If you choose one of these brands you would also be able to post in its dedicated AK forum and receive input from people familiar with whatever model you are working on. But even a simpler Luxman or other brand, whatever happens to come your way, would be something to consider.
 
roger2 said:
A few more thoughts...

Get a good soldering station. It makes a difference. There is no point in trying to overcome lack of experience AND inferior gear when trying to make good solder joints. And every joint has to be good.

Hakko FX888 is what I have. Around $80. There may be a new model number for it now I don't know, mine was purchased a couple years back. It is excellent compared to the cheap stuff I had been using. A similarly priced Weller would be fine as well. There are many, many threads discussing soldering stations, tips, solder, wick, flux, technique, etc. Google search of AK works well...

It is good to learn soldering on junk PCBs. Something thrown out or, where I live, you can get VHS players for around $5 at Goodwill. Your soldering ability will improve in phases, not all at once. The first steps in that process are better left out of any gear that is intended to last long term.

If you are going to consider an alternative to this Luxman for a first project, I would suggest a smaller, simple integrated amp that is in working order ( i.e. no blown transistors to worry about). Kenwood KA-3700, KA-3500, etc., or any similar Pioneer/Marantz/Sansui, would be so much easier than the L-100U. If you choose one of these brands you would also be able to post in its dedicated AK forum and receive input from people familiar with whatever model you are working on. But even a simpler Luxman or other brand, whatever happens to come your way, would be something to consider.
Click to expand...

Thank you! That is very good advice!

I think if I can get the Luxman for a good price, I will grab it but put it away until I do as you said. Thank you so much for that, I never thought of that. I have alot of old VCR's that I can open up to mess around with!

I think you just saved me alot of headache and a possible screw up on the Luxman. I will keep those other amps in mind as well...What makes those amps "similar" to each other as you say and less advanced than the Luxman? Just so I have an idea
 
Last edited:
Another question...

If these older amps, if they DO NOT power on, is that usually an easy fix? Or is that a question that has a complicated answer?
 
blazeaglory said:
Another question...

If these older amps, if they DO NOT power on, is that usually an easy fix? Or is that a question that has a complicated answer?
Click to expand...
It can potentially be easiest thing to fix - power supply problem. But keep in mind that power regulator failure can take large portion of circuit with it. In that case it can become not worth to fix, as repair cost will exceed value of the unit.
 
for_p1 said:
It can potentially be easiest thing to fix - power supply problem. But keep in mind that power regulator failure can take large portion of circuit with it. In that case it can become not worth to fix, as repair cost will exceed value of the unit.
Click to expand...

I see. So it could be nothing (or something small like a blown fuse) but it could be that the power supply, or something, fried much of the circuitry?

Also, why are amps like a Marantz 4230 so sought after and pricey but yet they only produce 30w per channel?
 
Last edited:
If they do not power on that could mean a blown fuse...which could mean blown main output transistors. Blown fuses usually don't happen for no reason. Or, occasionally, it could be that the pre-main jumpers are missing. Or it could mean something else.

Something that is very common, and likely to be be fixable, is scratchy controls, where static is heard when turning a knob or moving a switch, or intermittent channel drop-outs. That is likely to be corrosion and can usually be fixed with Deoxit...

I am trying to be careful in qualifying my statements here, using words like "could" , "likely", "usually", etc.

A first rebuild project will, at minimum, entail: obtain Service Manual for the unit, recapping, comprehensive Deoxit job, and setting of bias and DC offset (if the unit has trimmers for these settings). It is good to also replace the trim pots. If the unit has a relay, again, best practice is to replace it. Also, if the particular unit has any known defects, those should be addressed.

There is just a lot to learn first time. Restoring and troubleshooting are two different things. A first project is easier if the troubleshooting can be avoided or at least minimized.
 
Last edited:
blazeaglory said:
I see. So it could be nothing (or something small like a blown fuse) but it could be that the power supply, or something, fried much of the circuitry?

Also, why are amps like a Marantz 4230 so sought after and pricey but yet they only produce 30w per channel?
Click to expand...

Sound quality. Build quality. Perceived quality in both areas.
 
No I havent got it yet, Im looking at a Kenwood as well.

Are new amps worth fixing or is it usually just better to find a working one..Like average ONKYO and DENON. Once $1200 dollars in 2001-3 but now has problems...
 
robertokray said:
Did you get it?
Click to expand...

No I havent got it yet, Im looking at a Kenwood as well.

Are new amps worth fixing or is it usually just better to find a working one..Like average ONKYO and DENON. Once $1200 dollars in 2001-3 but now has problems...(Just a quick question, dont mean to get off topic)
 
The topic is actually you exploring options I think, which is a smart thing to do.

I'd say get the Luxman if the price is reasonable. It is an impressive amp. You may decide to work on it later. Or maybe you could do limited work on it like fixing the feet, get the SM and adjust bias and DC offset, etc.

I need to add to something I posted earlier. I remembered that KA-3500 does not have a removable bottom cover. May not be absolutely ideal as a 1st project candidate as that will make working on it a bit more challenging. Still it is a simple amp with few components and ample spacing between components on the PCB. Not sure about the KA-3700 bottom cover, but there is a recent thread in the Kenwood forum on a KA-3700 (still on the first page I believe, Kenwood forum moves slow :) )
 
roger2 said:
The topic is actually you exploring options I think, which is a smart thing to do.

I'd say get the Luxman if the price is reasonable. It is an impressive amp. You may decide to work on it later. Or maybe you could do limited work on it like fixing the feet, get the SM and adjust bias and DC offset, etc.

I need to add to something I posted earlier. I remembered that KA-3500 does not have a removable bottom cover. May not be absolutely ideal as a 1st project candidate as that will make working on it a bit more challenging. Still it is a simple amp with few components and ample spacing between components on the PCB. Not sure about the KA-3700 bottom cover, but there is a recent thread in the Kenwood forum on a KA-3700 (still on the first page I believe, Kenwood forum moves slow :) )
Click to expand...


So I am looking at another "backup" amp haha

A Kenwood KR-6400... Thoughts?
 
Last edited:
Also, if I do gt the Luxman, could I route that through the outs on my DENON 3805? So I could listen to CD's, tuner, etc? While using the Luxman as a dedicated 2 channel power amp?
 
blazeaglory said:
So I am looking at another "backup" amp haha

A Kenwood KR-6400... Thoughts?
Click to expand...


I have no experience with KR-6400, but there are lots of AK threads about it which could be found using Google search of AK. It is a MOTL, very nice looking '70s receiver. Kenwood is a popular and generally well regarded brand, its receivers are known for having good tuners.

Whether you should get it? Who can say? I am not crystal clear on what your reasons are for considering buying vintage, the Luxman or any other piece.

To have just because you like it, or maybe dabble a bit in repairs? Hell yes! (assuming the price/condition ratio is reasonable)

To do a 1st time, comprehensive restore project, maybe not either piece would be ideal IMO. The Lux has been discussed in this regard. As for the KR-6400, ANY receiver will be more complex than a similarly powered integrated. The receiver will have more functions/circuitry/PCBs/lights/switches, etc. And the tuner part of a receiver may need sophisticated knowledge and gear to be brought to optimum performance. I am out of my league here, having only rebuilt integrated amps.

blazeaglory said:
Also, if I do gt the Luxman, could I route that through the outs on my DENON 3805? So I could listen to CD's, tuner, etc? While using the Luxman as a dedicated 2 channel power amp?
Click to expand...

If both the Denon and the LUX have pre-in/main-out RCA jacks then yes. Or, technically, the Denon would only need pre-outs, but not sure how likely that is. I am not familiar with either unit.
 
Last edited:
roger2 said:
I have no experience with KA-6400, but there are lots of AK threads about it which could be found using Google search of AK. It is a MOTL, very nice looking '70s receiver. Kenwood is a popular and generally well regarded brand, its receivers are known for having good tuners.

Whether you should get it? Who can say? I am not crystal clear on what your reasons are for considering buying vintage, the Luxman or any other piece.

To have just because you like it, or maybe dabble a bit in repairs? Hell yes! (assuming the price/condition ratio is reasonable)

To do a 1st time, comprehensive restore project, maybe not either piece would be ideal IMO. The Lux has been discussed in this regard. As for the KR-6400, ANY receiver will be more complex than a similarly powered integrated. The receiver will have more functions/circuitry/PCBs/lights/switches, etc. And the tuner part of a receiver may need sophisticated knowledge and gear to be brought to optimum performance. I am out of my league here, having only rebuilt integrated amps.



If both the Denon and the LUX have pre-in/main-out RCA jacks then yes. Or, technically, the Denon would only need pre-outs, but not sure how likely that is. I am not familiar with either unit.
Click to expand...

Yes the DENON has pre outs!! It is a fairly decent surround sound amp from what I hear and my IL10's sound really good hooked up to it...I think it pushes 125w per channel if Im not mistaken.


http://www.crutchfield.com/S-ZWuAQiTspbF/p_033AV3805B/Denon-AVR-3805-Black.html

Well I missed out on the Kenwood and the Luxman has now shot up to over $200 so I dont know how comfortable I am in buying it now. I was willing to pay $100-$150 for it...If I had more experience, I would buy it.

Thanks for the help and I am still on the lookout for old equipment!!
 
You must log in or register to reply here.
Back
Top Bottom