To Recap or not: Good working Luxman R-1050

M

MyHeresyIsMe

Well-Known Member
I have a good working Lux R-1050 that I have spent hours upon hours on my 'bench' (an old table from the early 20th century that has seen a LOT of work done on it). I've changed rotary switches, changed the vol pot w/ the pc board on it, deoxit the controls. Everything sounds and functions well. I realize I'm working on a unit from 1978 and a couple of folks have urged me to to 'the next step,' recapping. Sounds adventurous, but my tools are limited and so is my experience in do 'recapping.' I use to do that on Fender Bassman amplifiers but there was a lot more room to work in those 1965-69 models. Another strike against me is that I have nothing other than a VOM ---not signal strenght meters, no signal generators, no oscilloscopes (sp?). But I am pretty good with a pencil iron and haven't burned through any pc boards yet. The recap job sounds daunting ----getting the right parts, the right Brand of parts, where to start, etc. I do have the HIFI Engine schematic and I've done electronic work for over 40 years --- a full recap is new to me though.
As I wrote earlier, the receiver is working fine at this point. But I know it is original and from what I've read in other threads and comments, a lot of folks 'take it on' to restore to restore to factory specs. I'm not exactly a novice but I'm not a journeyman on this. Any advice, pointers? Or should I just find a legit tech and let him do it? All comments are welcome! Thanks, all.
 
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I'm not mechanical and have no idea how long it would take nor what the cost would entail but it is a LUXMAN and if it is anything like my R-1040 I would say go for it or have someone do it.
 
if you'd replaced controls and switches, you can handle a re-cap. if you don't have easy access to a service manual, i'd suggest just looking at the boards and reading off the cap values to make your parts list (not a bad idea even if you do have the manual). you might have to partly diassemble it to read all of the cap sleeves.

i'm definitely in the pro-recap camp. you might be surprised at the difference it can make in sound. the older the amp, and the more electrolytics there are, the bigger the change.
 
It has more than 30 years,and already you cleaned it well.This would be the next step,and it's not hard at all(if I can do it so do you).You may hear some sound improvement or not,but it's a good service,like replacing all the filters and other stuff in your car.
Beeing this old it may more prone to electrical failure because the caps lose they original specs,they degrade with each year.
I would suggest checking the specs of the caps by reading what's on the caps inside the unit and not on the service manual.I've had a service manual for an amp(Sony TA-F570ES),and the values weren't the same.
 
I dont know this model .but on older solid state amps it is worth checking the main smothing caps ,if you have an analog meter monitor the voltage across them while playing music it should remain farely constant.
If there are any electrlitics in the signal path they should be changed maybe for audio grade ones .if thereis room try none electrlitics.
any leakage in coupling caps can cause a dc offset voltage at the speaker output.
as for test gear for audio work you have the best EARS!
good luck it will be well worh the effort
ps please dont use a scatter gun approach to changing caps do one and check.it's to easy to make a mistake if you change a lot at one time.
rob t
 
I recapped 5 amps now, including 2 Luxman, it has done wonders for the sound. I have used Elna Silmic II, Panasonic FM and FC and Mundorf M-lytic for the big main filter caps.
Recapping a tuner or the tuner part of a receiver might cause problems though with the tuner allignment.
 
cdfac said:
if you'd replaced controls and switches, you can handle a re-cap. if you don't have easy access to a service manual, i'd suggest just looking at the boards and reading off the cap values to make your parts list (not a bad idea even if you do have the manual). you might have to partly diassemble it to read all of the cap sleeves.

i'm definitely in the pro-recap camp. you might be surprised at the difference it can make in sound. the older the amp, and the more electrolytics there are, the bigger the change.
Click to expand...

I agree. Go for it. I just recapped my entire Pioneer SX 950 and the only soldering iron experience I had prior was recapping my Heresies - so you're probably already ahead of the game there. The trickiest part is desoldering - get a pump desoldering tool (I couldn't imagine doing it using desoldering braid). You'll find ways to detach the circuit board/components just enough to have enough room to get in there and replace what you need (which would only be electrolytic caps). Any questions and I'm sure it's already been addressed somewhere here.

Even if you did have the manual, the best way to recap IMO is to make a list of all the values on the board. I simply used all Nichichon PW or KL series with equal capacitances, and stepping up the voltage. You can go over some bill of materials from other recap lists (such as in the Pioneer forums) to study the decision-making process in selecting caps. Do one board at a time (protection relay and power supply boards first, followed by flat amp, tone amp, power amp, etc.) and listen to sonic differences as you progress. Your first board shouldn't take you more than a couple hours as you work up the technique, as you're probably replacing no more than 5 - 15 capacitors.

I have a Luxman R-1030 sitting here and from looking into the top cover looks quite spacious and the circuit boards look detachable and have enough room to maneuver (although the 1050 might be different). Go for it and good luck!
 
Here's what I would do, as I'm going through the same thing right now with my NAD 3020 amp.

Take the thing apart, and write down all the values of the electrolytic caps. You might need a small flashlight and a dentists mirror to see round the back of some of them. If you can see the cap number (ie. C100) on the board, then write this down as well. You can put them into an Excel spreadsheet with columns of cap number, value (uF), and voltage (V). If you spot a cap that is either an orange Elna brand, or a blue Sanyo brand, it is quite possibly a low leakage one, and you need to make a note of this. The first Kenwood KT-7500 I did, I just replaced all the caps with the same type. The second one I did, I was more knowledgeable, and used low-leakage where needed. If you have an electrolytic with no obvious negative stripe, it might be a bipolar, and you need to note this. The service manual may help with figuring out which are low-leakage and bipolar. Maybe add some more columns in your spreadsheet for later on.

Next, take your service manual, and compare your list to what's in the manual. If you have a good schematic in the manual, cross off each cap with a pencil as you check it. Any irregularities, go back and check it against what's already in your receiver. I always go with what's in the unit you're working on, since it has been working fine all these years.

Once you have a list of caps, go ahead an place an order with your favorite electronics supplier. I use Mouser, as do a lot of others on here. Caps are a personal choice, everyone has their favorite, and you'll drive yourself crazy trying to figure out which ones to use. Personally, I use Nichicon KLs for low leakage, ES for bipolar, and KWs for everything else except the main power supply caps. When you make your order, you might find that you can't get certain voltages. For example, you might need a 1uF, 25v cap, but they only stock a 50v one. This isn't too much of a problem, just trying and go with the lowest voltage ABOVE what you already have, so for our example a 1uF 35v cap would be fine. This is where it is useful to have that extra column in your spreadsheet, so you can note what you ordered to replace the original. Otherwise, you'll be left scratching your head thinking "where are my 1uf 25v caps?"

The main power supply caps are a law unto themselves, the last Kenwood KA-7100 I did, I used KWs, but I couldn't get them for the next one, so I used FWs. With these main caps, if they are mounted on the circuit board, you'll need to find some new ones with the same pin spacing. Sometimes, you will have to drill another hole in the board as there aren't any with the same spacing available, I did this with my Pioneer SA-7800. If your caps aren't mounted on the board, but bolted to the chassis and hard wired, things are a little easier. You may run into the problem of the new caps are a lot smaller, and you'll need to figure out some kind of bracket to mount them. When I did my Pioneer SX-535, I used some rubber lined P-clips. As with the smaller caps mentioned above, sometimes you might have to go with a slightly higher voltage, and maybe even capacitance. Just err on the size of just a little bit more. A 6800uF, 63v cap would be a good substitute for the original 5600uF, 50v cap if you can't get them. A 10,000uF, 100v cap would be overkill, it could stress the rectifier diodes, and may possibly be too big physically.

While you are inside the thing, you might consider replacing the trimmers for the amp offset and bias. These can and do go bad, and can lead to all kinds of nasties. On my Pioneer SX-626, they were the reason I kept blowing fuses. I had to change these, and also engineer some way of mounting new style trimmers. I would recommend Bourns multi-turn if you can fit them.

Before you start, TAKE LOTS OF PICTURES. That way, if you remove a cap, and it's not noted on the board which way round it went, you can refer to your pictures. Take your time, do one cap at a time, and you could even mark on the underside of the board with a sharp Sharpie which way round it went.

Be prepared to pay $6+ to ship a 32 cent capacitor when you find out you ordered the wrong one from Mouser. It always seems to happen to me, I usually order 47uF when I needed 4.7uF. See my comments above about checking your list against the service manual.

You'll see blue hyperlinks in the text above to various projects of mine. If you click on them, it will take you to the thread here in AK, which might be useful for you.

Hope this helps,

Lee.
 
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You can certainly handle a recap, but I disagree with most of the civilized world on this. First, read this. If you fall asleep, just go to the myths part at the end.

Bad caps need to be replaced. Period. Good caps, i.e., caps that measure good for both value and losses, don't. Unless they're in highly stressed locations, like poorly located in a hot tube amp, they are not about to fail.

Since the Lux is happy right now, I'd polish those soldering skills by building a simple cap bridge so you can actually measure and evaluate the condition of things. Or, if times are good, buy one. Then you can operate from a position of knowledge to make a sensible decision.
 
This particular model is one of the more difficult amps I've ever recapped. Lots of hard-to-reach places. Also, it yielded zero performance improvement (as is the case with most recaps, all mind tricks aside). Just FYI.

Don't expect it to sound better, but if you really want to keep this amp forever, it is necessary.
 
Every one of you, fellow Audiokarma-ers, has given me much in answer to my question about 'to recap or not.' Each has offered something I never thought of, or at least made me consider more seriously. Thanks for those references to other links and for the FYI (Ruxman) about the tiny quarters in there! I can definitely relate to that one I("Lots of hard-to-reach places."). I recently changed the Function rotary switched (yes, this is the one where the screwball EPOXIED the knobs onto most of the pots/switch shafts). The R-1050 is terribly cramped and I would not recommend going into one of those jobs of changing a rotary switch with 5 wafers without a bottle of aspirin or gin (or both). If it sounds good now, why do it? Hmmmmm---- I'll give it some thought while I listen to my Thorens through my Heresys. Thank you all very much!! You are all great listeners and communicators.
 
ConradH said:
Bad caps need to be replaced. Period. Good caps, i.e., caps that measure good for both value and losses, don't. Unless they're in highly stressed locations, like poorly located in a hot tube amp, they are not about to fail.
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Caps, or any other component should really be taken out of the circuit to test it correctly. If you're going to go to all the trouble to de-solder it, why not replace it with a brand new one that might only cost 50 cents or less? Sure, the cost adds up, but it's the main caps that are the expensive ones, especially in amps with 4 caps, like the KA-7100 and SA-7800. Not that I'm suggesting you don't replace the main caps.

Also, if you test one bad cap, and nine others test OK, how long do the others have before going bad?

Ruxman said:
This particular model is one of the more difficult amps I've ever recapped. Lots of hard-to-reach places. Also, it yielded zero performance improvement (as is the case with most recaps, all mind tricks aside). Just FYI.
Click to expand...

I had two scenarios where re-capping has fixed a problem and caused an audible improvement.

1) was with a Technics SL-230 turntable. This would not hold a constant speed despite cleaning and re-cleaning of the switches, trimmers and speed controls, and even replacing the belt. I eventually replaced the few caps inside, and it was solid as a rock after this.

2) was with an RCA Dimensia MPA-100 power amp. This amp had a low output on one channel. After verifying the power amp ICs were not at fault (by swapping them over), I read a thread on a similar MPA-120 where there was a bad capacitor in the feedback loop. After re-capping, it works fine now.

Lee.
 
leesonic said:
Caps, or any other component should really be taken out of the circuit to test it correctly.
Lee.
Click to expand...

The whole idea of testing and evaluation is not to have to take things apart and desolder components. There are certainly tests that can't be done in-circuit, full voltage leakage tests for example or a full range curve trace of a transistor, but that's rarely an issue in low voltage solid state electronics. The tests for value and loss (for caps) are the tests you can and should run. I have no trouble going through an amp or receiver and determining with a high degree of certainty, which parts are near or beyond their spec limits, rarely having to lift a lead to be sure. Now, if you do have to remove something, and it's cheap and available, sure, go ahead and replace it. That makes sense. OTOH, I have a huge parts stock and still run into all sorts of older parts where exact physical replacements (stuff that fits!) is hard to find or extremely expensive. I save time, I save money and I save degrading the value and originality of the unit, by determining which parts are good and don't need to be pulled or replaced. On caps, I've never seen an old cap that measured good for both value and loss (in-circuit) subsequently fail. Still, wait long enough and all caps will fail!
 
Conrad, you have answered another question I had: can caps be tested in circuit. Thank you. Now, as Robert Frost said, 'as way leads onto way,' I have yet another question: If I am not out to recap everything (the tuner section scares me if I change components that will alter the frequencies), is there a priority as to which caps go first, i.e., power supply, pre-amp, etc.? Or, are the caps stressed equally and it is all just a matter of time.....Thanks!
 
If you really like the 1050, I would practice on a receiver you won't care as much about first. To get a good feel of the process. If you have worked on electronics before, you know bad or unexpected things can happen when first starting out.
 
Where people get into trouble is going in and changing dozens of parts in one shot. What you want to do is change a limited area related to one function and then test. The fewer things you change prior to a problem, the easier it is to back track and fix it. Now, that has to be balanced with the amount of disassembly that needs to be done. Sometimes, in for a penny, in for a pound.

There will probably be filter electrolytics in the tuner section, but they shouldn't affect the RF- we hope! Don't mess with anything other than aluminum electrolytics, especially there.

If you're going to test, the big question is what to test with. A simple value-only C meter isn't going to tell you enough. In that case you still end up replacing everything to be on the safe side. An esr meter is, IMO, more useful. Some are cheap, some expensive or just DIY. There's very little in one. Best is to have both value and DF (or esr), but I haven't seen a decent (new) meter that reads both for much under $250. As should be obvious, I recommend testing, but without a suitable esr meter or LCR meter with loss, the only path is replacement.

The trick with in-circuit measurement is to concentrate on loss. There is nothing in surrounding circuitry that can make a lossy cap look good except another large cap in parallel. You'll know that because the value will be too high. The reverse isn't true; surrounding components can make a cap look lossy, but if the meter uses low voltages so as not to turn on associated semiconductors, you won't be fooled very often. Sometimes you'll see a cap in parallel with a low value resistor, less so in modern electronics, and that's a situation where pulling one lead is the only way to be sure. Of course they never seem to go bad in that situation.
 
ConradH said:
You can certainly handle a recap, but I disagree with most of the civilized world on this. First, read this. If you fall asleep, just go to the myths part at the end.

Bad caps need to be replaced. Period. Good caps, i.e., caps that measure good for both value and losses, don't. Unless they're in highly stressed locations, like poorly located in a hot tube amp, they are not about to fail.

Since the Lux is happy right now, I'd polish those soldering skills by building a simple cap bridge so you can actually measure and evaluate the condition of things. Or, if times are good, buy one. Then you can operate from a position of knowledge to make a sensible decision.
Click to expand...

My hat's off to you, Conrad. I'm a rookie in this field by most accounts so I wanted to check with the wise ones before I make any moves at all with my R-1050. Limiting the area, checking the replaced caps, following the test measurements from meters---all these are the things I need to know. Thank you very much. I may call on you again!! I appreciate your comprehensive knowledge in this area.
 
Well...I have a thread for MAC 1900...I am recapping and replacing all resistors...Talk about Crazy.

I have recapped a R-1070...Someone else said Hard to reach places..I agree.

I also just pick-up a R-1040...I will recap this as to a later time.

Get out the iron..Take your time...Check Check and Check...And learn.
 
MyHeresyIsMe said:
Thanks, terra1. I do have a few boards that I can practice on. They came to me as junk, so I can't do any harm! Good advice.
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I actually meant an actual working receiver so you can see results of what you are doing. That when you put it together you can still see it work.

The 1050 is such a nice receiver I would hesitate to work on that unless it had problems.

I have limited experience. I only replaced caps and relay and diodes on a Kenwood KA-7300 when it failed to power up.

I went through the process of ordering. Fortunately there was a thread with specific parts already. I used the schematic to plot where the parts would go. Keep in mind the schematic may be the bottom view so you have to keep in mind the orientation when looking at the actual board from the top. I drew a diagram map labeling values and + - positions. Caps will often identify the - side and usually when you remove the caps, you will see the polarity markings on the board as well.

I placed the new parts on the map. As I removed the old part, I placed the old part on the diagram map and the new part in place. In my case the glue holding the capacitors were more like taffy and unsoldering the caps was easy and they just pulled off. Some leads are hooked and you may need to straighten them to pull out easily.

I used plastic ice cube trays to hold the screws. It may be a good idea to take pictures along the way.

These are just some of the things you may come up with on your own as you go through the steps yourself and do what you need to feel comfortable about recapping.

A lot of it is just being organized.
 
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