Assessment/advice on a sx-727

33&athird said:

Alright, later today or tommorow i'll send it out or attach it here, if mark doesn't mind, since the mouser list is the most helpful I belive. If you just need to know what it may have, the word attachment on up the page is a visual of what my unit had...though they differ. I'll try to get it up sooner than later:yes:.

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You have my permission to post both of what I sent you, the spreadsheet and the word document. The idea was that you post them, my attachment list is rather cluttered from when I posted schematic fragments, before the pdf manuals became more widely available, and may be pruned soon.

Oh, and since I had done Maddart's sx-1010, I had his email address, and already sent him a copy of both....

Alright...soory it took so long, but here is the cap list in both excel and word formats. I hope the word one works since on the old computer when I drug it in, word 2007 goes into fits, and it didn't want to open in word97. If it needs to be fixed up, just ask and i'll find a way.

Both are the attachments down below; the part numbers are for mouser. And I can't for the life of me remember the number, but the main filter caps at 50v (stock) are on backorder till febuary 1st (2010) , Mark mentioned a 63v caps of the same uF rating.

[ I will edit in the excel version...it doesn't want to upload :scratch2:]

EDIT: It won't let me upload the excel file at all, maybe the file type isn't supported? i'll look into it...:headscrat

Okay-lets see if this works

It Verks! thanks markthefixer...didn't even think of zipping it.

It will support .zip's so you could zip it up....

The Re-cap is in progress, and I think I have cleaned up the pots nicely. However, when working on the pot board (AWK-010) I looked over to the power supply and saw something new (not brand new-just haven't noticed before);



Should I be concerned about this? I don't know if it was caused by the heat-sink, or more likely the resistor. Last time I powered it on, it worked fine, and wasn't on long enough for that to happen, unless it was a very major problem. Should the resistor be replaced?...I don't think any of the traces were effected, just the surface. Any ideas would be appreciated...I would hate to go through all this trouble (though it's kinda fun) just to have the power supply blow:sigh:.

What are you using for these? I'm trying to order
now (Mouser) but cant find solid aluminum caps...

33&athird said:

Uh...i'll have to check the list again

Those are a form of electrolytic that are solid aluminum. Typically in old pioneers they are sanyo caps, with, as you noticed, weird markings for a capacitor. The ones mentioned earlier in the topic are sanyo, but are non-polarized, and used on the protection board, which some units lack. The way sanyo marked them is, in your case 1/25, or 1uF at 25volts. I belive the rest are polarized, just not the standard electrolytic. In the manual they will be listed as CSSA, where most caps are marked as CEA...these are just standards, and indicate different caps.

I'll try to find them in the list, but I'll have to swap computers...maybe markthefixer will have it off the top of his head:yes:.

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Mine is exactly the same way and look-
replaced it with a flameproof 2w (crap colored resistor).

33&athird said:

The Re-cap is in progress, and I think I have cleaned up the pots nicely. However, when working on the pot board (AWK-010) I looked over to the power supply and saw something new (not brand new-just haven't noticed before);

Should I be concerned about this? I don't know if it was caused by the heat-sink, or more likely the resistor. Last time I powered it on, it worked fine, and wasn't on long enough for that to happen, unless it was a very major problem. Should the resistor be replaced?...I don't think any of the traces were effected, just the surface. Any ideas would be appreciated...I would hate to go through all this trouble (though it's kinda fun) just to have the power supply blow:sigh:.

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33&athird said:

The left channel appears to be working (as far as amplifing), since when switched to mono, both play through the speakers...but in normal mode, the left channel is absent. I had some luck moving buttons and switchs around to get the left working, but even then it was intermittant. ,

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I had the EXACT same problem with my 980. Did the same you tried. No success. I sold it.

Sorry to go off track, here. Didn't notice we were 4 pages in.

Rockmore said:

Mine is exactly the same way and look-
replaced it with a flameproof 2w (crap colored resistor).

Click to expand...

Sounds like a good idea, it's just weird...seems like it still works. Almost like the resistors heat was stuck in the area because of that heatsink . Flameproof would be good, and perhaps a higher wattage. Just worrysome is all.

Also; i'll check the cap list (in the middle of replacing now), by marks list, the solid aluminum CSSA style caps are replaced with electrolytic. I would double check with him, however, since something may be special about them.

Dave1384 said:

I had the EXACT same problem with my 980. Did the same you tried. No success. I sold it.

Sorry to go off track, here. Didn't notice we were 4 pages in.

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...we'll see how this turns out, i'm hoping for the best:yes:...sorry to hear about the 980, those are pretty nice...


And a extra note to Markthefixer; on the fm/am board, there were .47uF caps, in the mouser list these were non-polarized...is this correct? I don't want to come off as doubting, all I can assume is in this section, for that value, that polarity isn't important?:scratch2:.

33&athird said:

Sounds like a good idea, it's just weird...seems like it still works. Almost like the resistors heat was stuck in the area because of that heatsink . Flameproof would be good, and perhaps a higher wattage. Just worrysome is all.

Also; i'll check the cap list (in the middle of replacing now), by marks list, the solid aluminum CSSA style caps are replaced with electrolytic. I would double check with him, however, since something may be special about them.



...we'll see how this turns out, i'm hoping for the best:yes:...sorry to hear about the 980, those are pretty nice...


And a extra note to Markthefixer; on the fm/am board, there were .47uF caps, in the mouser list these were non-polarized...is this correct? I don't want to come off as doubting, all I can assume is in this section, for that value, that polarity isn't important?:scratch2:.

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They ARE flameproof wattage types guy.. by the size and shape. Mark didnt seem to take a care about them- blackened board or not. Hard thing is, KNOWING exactly what the stock wattage is since they are NOT marked or on the schematic either. I just did a comparison to the other wattage flameproofs I had on my amp board. Size of them were only 2w and they were bigger than this one. You're right about being OK to go up a watt or two. Read that before. Just for info, here is the link to one of one of them I ordered:
http://www.mouser.com/Search/Produc...4virtualkey61300000virtualkey71-CPF3-G-390-E3

Read the data sheet on them, and they seem to be the same type flameproof.

Rockmore said:

They ARE flameproof wattage types guy.. by the size and shape. Mark didnt seem to take a care about them- blackened board or not. Hard thing is, KNOWING exactly what the stock wattage is since they are NOT marked or on the schematic either. I just did a comparison to the other wattage flameproofs I had on my amp board. Size of them were only 2w and they were bigger than this one. You're right about being OK to go up a watt or two. Read that before. Just for info, here is the link to one of one of them I ordered:
http://www.mouser.com/Search/Produc...4virtualkey61300000virtualkey71-CPF3-G-390-E3

Read the data sheet on them, and they seem to be the same type flameproof.

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D'oh, sleeping on the job...flameproof, should have known. 2 watts sounds about right, though it could be less, unlike caps, resistors haven't changed much in size between then and now (unless you count surface mount). looking at it, I may just see how it does, since the charring is only on the surface. Just seems like a weird that it would happen...almost one of those known faults, only it still works. Thanks for the link, next time I put a order in I may pick one up for the 727 and 525 (should probably check that one).

I DO "give a care"...
edit: I posted yesterday at 4:16pm about posting the .zip, that picture was posted yesterday at 4:34 pm, that comment was posted at 11:19 pm - less than 7 hours later
but I don't live on here....

I just saw ALL this new stuff in the thread.

there's somebody here on this forum whose secondary mission seemed to be to criticize, find fault and knock me whenever I interacted with them. I could do nothing right, never had the answers they wanted, so I sadly STOPPED trying. I was saddened by doing so, I had actually WANTED to maintain a good relationship with them, because they let slip their day job, and I someday hoped I might be able to seek THEIR insights in THEIR area of expertise.... Now I'm criticized for my silence, or absence.... sigh.....

The 0.47's may have been originally polarized - (in the past that's how they got a lot of capacitance in a small package) and I specified newer non-polarized - generally all round superior stacked film capacitors that should last "forever". Back then the stacked film capacitors didn't exist, and the other types were HUGE... now they're smaller and relatively inexpensive.

I was "tossed up" by the solid aluminum caps:
1. did Pioneer Engineers want the small size in their design?
2. did Pioneer Engineers want the "low leakage" in their design?

So I believe I have been specifying low leakage caps (ukl) in those locations.
It is general knowledge that tantalum caps don't have any business carrying "high quality audio". Solid aluminum caps are made like tantalum caps, sintered slugs of metal, so I figured they have similar unwanted audio characteristics. Thus I class tantalum and solid aluminum caps together, as a low leakage replacement. Safest that way, and the price differential isn't a deal killer.

Now to resistors....:

as to that "cooked picture", that is long term radiant heat damage, not flame damage... also those power transistor heat sinks are held on with nylon screws that will break at the slightest provocation (ask me how I know - answer: an sx-828 taught me...) , so you will want to get some new mounting kits:
532-4990M @ $0.77 with mica insulator, screw, washer, lock washer, insulating shoulder washer & nut.
from mouser. I routinely remount them - actually I remount NEW transistors for reliability - and if I can increase that heatsink size I do so.

When you buy the mounting kits, you may want to get some more power resistors, that's fine. Mount them wayyy up in the air with their leads to allow air circulation.

Resistors HAVE CHANGED, they're smaller and are expected to hit even HIGHER temperatures during normal operation. Get wattage greater than what is called for, the physical sizes are 50% smaller than what's there - thus they will run EVEN HOTTER, because there's less heat dissipation area for the same amount of energy, and they're made of materials that can withstand the heat - but the solder joints mounting them to the board will not do well with the increased temperature!!! And when near a PC board it will bake them even worse.

When you mount the resistor you want to make a "kink" in the wire before it goes into the hole, and bend it over onto the foil on the other side of the hole, so there is a secure mechanical mount holding it all together before soldering it - this is to save the solder pattern from being lifted because the glue between the foil and the board will be the only thing holding it up otherwise. And the previous high temperatures as well as the current high temperatures will compromise that glue quickly. In other stuff, I see eyelets mounted into the PC board to provide mechanical support.

As for the cooked appearance - Pioneer was learning to get the resistors up in the air away from the PC board - thus a cooked to death, brittle board is a normal experience - and it IS somewhat better to just leave it be, because stuff could break during the replacement that would have continued to function had they been left alone.

Without that resistor, the transistor would have to dissipate both it's heat and the resistors' heat. Pioneer was TRYING to get a handle on heat - it just took them a long long time.

MAn, that is alot of great information:yes: I figured the caps were sized/typed that way for capacitance rating, but wanted to double check. I hadn't thought much of resistors, and honestly, its quite funny that as they get smaller,the heat dissapation is actually worse. Haven't seen many resistors that differ much, except for older comp ones, though there are some weird ones floating around these units. I think i'll leave it be, unless it does something unexpected...and thanks for the link to the mounting unit, as I have heard these are somewhat brittle and easy to screw up. Thanks again for everything, I may save chunks of it to go with my schematics, for when I eventually do my 525...the recap should be done very soon, and I have high hopes it comes out sounding great.

Actually- for the main filter caps (and on a side note; the 1000uF one) they are now physically smaller (to be expected), whats the best way to accomidate the smaller size. I've heard of tape, and various other means...any particular suggestion from your experiance?

It always seems to work out differently for each one. Sometimes on the medium size ones that downsized to snap in's, I come up with a pc board that mounts the cap and affixes to the holes where the old clamps mounted.

Sort of oval shaped like a to-3 case.

Geeze Mark... chill. Thinks you spend too much time here.
When I told 33 you didnt take a care about the resistors in question, it was from other threads where you stated it wouldnt make a difference and the resistor probably already worked. Just clean the board and test it.

TOO MUCH INFORMATION, worded vaguely.

33- I (and come to find out) many others, just like the other threads in the last couple weeks youve been in, use anything thats uncompressiable (wont squish) and probably heat resistant to fit and mod the smaller caps in those bigger clamps. Its going to be pretty simple and easy to mod if a guy needed to use the stock clamps. You could rig something easily. Its only a holding/mounding clamp.

I personally plan on trying some weatherstripping at first with the stock clamps, just like some of the other thread's suggestions. Might not be enough unflamable and heat resistant for me though.. If it doesnt work, I've got 10 other simple common ideas. Like heat proof automotive goop or silicone.

Dont need 15 paragraphs full of fluff and almost vague rantings to figure that out, even for me! LOL

Did you decide on exactly what your going to use for those "solid aluminum powder blue caps" (third time)? I just went with good standard electrolytics and be done with it.

The ONLY thing hard about any of this and recapping, Ive found, is just to get or come up with a simple parts list for whatever a guy needs or is recapping. Not 3 weeks worth of million word discussions on the mundane that dont deal with simple part numbers and specific parts merely listed in a bullet format.

(kid tech here and at Digikey and Mouser havent helped either lol).

Let me know how your recapping is going. I'll do the same. PM's are FINE with me.

Rockmore said:

Did you decide on exactly what your going to use for those "solid aluminum powder blue caps" (third time)? I just went with good standard electrolytics and be done with it.

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straight answer: nichicon UKL caps for the best possible performance, your use of "good standard electrolytics" is fine....
(psuedo EchoWars style - nothing wrong with it...)

long winded crap from a windbag:
(markthefixer style)

markthefixer said:

<snip>
I was "tossed up" by the solid aluminum caps:
1. did Pioneer Engineers want the small size in their design?
2. did Pioneer Engineers want the "low leakage" in their design?

So I believe I have been specifying low leakage caps (ukl) in those locations.

It is general knowledge that tantalum caps (also "solid") don't have any business carrying "high quality audio". Solid aluminum caps are made like tantalum caps, with sintered slugs of metal, so I figured they have similar unwanted audio characteristics. Thus I class tantalum and solid aluminum caps together, as a low leakage replacement. Safest that way, and the price differential isn't a deal killer.

<snip>

Click to expand...

that's
nichicon UKL caps
from mouser - low leakage, unfortunately 85 degrees c.

for example, the 1uf 25v power blue would be:
647-UKL1H010KDDANA 1uF 50v

in mousers search engine I type in:

1uf UKL

and start the search
and then select which voltage I want from what comes up.


The only real difference between a general purpose UPW and a low leakage UKL is when there is no audio coming through and the volume is turned all the way up, some "hiss" might be heard with the UPW's in very sensitive amplifiers. I verified that in a sa-9500 I was working on. I first thought the "hiss" was the transistors. I proved it was the caps.


as an explanation about requesting the "list", based on the sheer amount of time it takes, I refuse to take the additional time to look up and enter the caps in a unit for somebody else, if they care enough to recap their unit and want parts numbers from me, they can post a list that they have visually verified as present in their unit.

Then I can quickly put it into a spreadsheet, in a form I can easily insert parts numbers into.

As a "consolation prize", I've been adding the list of parts numbers in a form that can be cut and pasted into the Bill Of materials entry tool on Mousers site - saving the OP from having to type in many many iterations of critical alphabet soup. Just copy, paste, enter and look for out of stock items....

The "extra" information of component and board designation I request is so that the OP can tell where to put the few low leakage 1uf 50v UKL caps instead of the general purpose 1uf 50v UPW caps. The "other extra information" of css, cea, cza, ceanl and bipolar is what I need to tell which caps are special.

You said it yourself, I spend too much time here, but it's what I have done, and how I have done it for a long time.

Am I "handing out fish"? Or "trying too TEACH how to fish"? For some I am wasting my words, for others they may eventually make sense.

Anyone is free to say "oh, more stuff from that long winded esso bee " and just scroll down the page.

Rockmore said:

TOO MUCH INFORMATION, worded vaguely.

Dont need 15 paragraphs full of fluff and almost vague rantings to figure that out, even for me! LOL

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If your mearly getting the job done, then alot of it is not immediately useful...but I really like reading and finding out everything about my amp, or others as possible, since alot of his insight into the design and repair is unavailable anywhere else. There's nothing really vague about it, there is a logical flow...and too be honest, he helps with a tremendous amount of projects at the same time, so the fact that he can keep it straight is impressive to some degree. If one is interested in electronics (i'm majoring in it) then just about everything mark has to say is both interesting and has practical uses, if I read IEEE magazine (I do), i'm probably never going to build a atom collider (or other such device), but reading a post of his has alot of information I can use for later amps or projects...the resistor size thing, for example.

I guess what i'm getting at is, while I don't mean to offend, give the guy a break...he provides a service not available anywhere else and he does it for free...there is alot of work behind the scenes that he does to make it easier for other members, and he doesn't really have to do it. He takes valuable time to assist anyone who needs it, and sticks with it through the end, I appreciate it, and so do many others...cut him a some slack, okay?

The ONLY thing hard about any of this and recapping, Ive found, is just to get or come up with a simple parts list for whatever a guy needs or is recapping. Not 3 weeks worth of million word discussions on the mundane that dont deal with simple part numbers and specific parts merely listed in a bullet format.

Click to expand...

It couldn't be that easy...just not possible. You have to relize that the pioneer people probably never thought anyone would ever have to re-cap the equipment, why would they? many times, a visual check must be done, and then compared to the service manual...that's the easy part. When you try to order it, many times products from a year ago won't be around, or be on backorder months long. Also, alot of the discussion about this stuff helps to make sure everything else is correct in the amplifier...a recap won't solve any other problems than its supposed to.

Did you decide on exactly what your going to use for those "solid aluminum powder blue caps" (third time)? I just went with good standard electrolytics and be done with it.

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There are technically two sets of these. The directional ones in mine are replacable by standard electrolytics. They should be blue sanyos with a negative marking, common value seems to sit around 2.2uF, 3.3uF, and 1uF...any of those can be replaced by same value electrolytics. On my model there are two that look similar, but are non-directional, these would be replaced with film caps...however, in your case it isn't (or shouldn't) be an issue, since these were only used on the protection board, which the 525 lacks. Seems like the solid aluminum caps were used because of what was available at the time, and small value electrolytics weren't as common.

...

Here's something i've been wondering, should I check the offset? From reading Echowars topic on the subject, if its cap coupled, you can't read it on a multimeter (admittidly, I need to check it again). Should I be concerned and check the offset, as well as the bias current? and if so, how would I go about this...seems just as important as re-capping and such. I just don't know where to start measuring:scratch2:...

33&athird said:

...

Here's something i've been wondering, should I check the offset? From reading Echowars topic on the subject, if its cap coupled, you can't read it on a multimeter (admittidly, I need to check it again). Should I be concerned and check the offset, as well as the bias current? and if so, how would I go about this...seems just as important as re-capping and such. I just don't know where to start measuring:scratch2:...

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A cap coupled amp's output IF adjustable is set to half the B+ voltage to avoid asymmetrical clipping. Idle current is set and measured just the same as a non-cap coupled amp.

Usually you can read B+ on a collector of the outputs, and the other output's collector should be half that.

markthefixer said:

A cap coupled amp's output IF adjustable is set to half the B+ voltage to avoid asymmetrical clipping. Idle current is set and measured just the same as a non-cap coupled amp.

Usually you can read B+ on a collector of the outputs, and the other output's collector should be half that.

Click to expand...

huh...alright, i'll check up on the manual and see how to check it on the 727. I find it somewhat funny that the term "b+" is still used in solid state, since I associate it with tubes. Thanks for the information, i'll check it later today, or tomorrow, when i'm done re-capping and testing. Only have the power amp, power supply, general, and am/fm boards left...

Alright, got another board done, and was starting the am/fm board...however, I am having a complete dog of a time getting to the bottom to de-solder. I loosened the wires coming in from the left, and the board on the right, and was carefully pulling, trying to keep it neat at the bottom (where a large majority of the solder-stick plug things are).

Is there any way to get better acess than this, or any wires that could be carefully documented and de-soldered to more easily replace the caps? Seems like pioneer kinda jumbled up the order of the wires near the board as well, they all tend to go through one another, not making this any easier.