Crossover Help Needed With ANOTHER Pair of ALTECS

[voice of the theater]

Wise choice, replacing the electrolytic, you don't want a potential failure point in your recapped networks, correct?

I'm guessing that you were able to identify the 470 uF capacitor as being of the electrolytic variety by the fact that it has such a high uF value for such a small capacitor?

I just read this from wikipedia:
"Electrolytic capacitors are capable of providing the highest capacitance values of any type of capacitor. However they have drawbacks which limit their use. The voltage applied to them must be polarized; one specified terminal must always have positive potential with respect to the other. Therefore they cannot be used with AC signals without a DC bias. They also have very low breakdown voltage, higher leakage current and inductance, poorer tolerances and temperature range, and shorter lifetimes compared to other types of capacitors."

It mentions one specific terminal must always have positive potential with respect to the other. Does this mean that there's a specific positive and negative terminal on it, or that there is not, but that electrolytic capacitors don't work with alternating current--one terminal must always be positive but it doesn't matter which terminal that is (as long as one of the terminals always stays positive)? Just want to be sure I wire these into the circuit correctly....

[aditya]

...................Does this mean that there's a specific positive and negative terminal on it, or that there is not, but that electrolytic capacitors don't work with alternating current--one terminal must always be positive but it doesn't matter which terminal that is (as long as one of the terminals always stays positive)? Just want to be sure I wire these into the circuit correctly..................................

Yes......there is a specific positive/negative terminal for an electrolytic capacitor (which also is mentioned on it with "+" & "-" like signs), and it should always be replaced with the same orientation as the original one was.....and this is very important......

If you look closely at this 470uF capacitor in discussion, you will find those markings. If it is not visible, then it must be facing downward and hence obscured from view. You can always see it if you just un-solder one of its ends and lift it up.

Many thanks for the "Thanks".

Aditya

[Earl K]

- The C3 outline ( for the 470 uF cap ) has a clear polarity marking on the PC board ( it's that "+" sign, top-right of the pin-hole, found on the left side of C3 outline ) .

- FYI, that 470 uF cap has markings that indicate the minus side, => (-) => .

- Electrolytic caps are always marked with a polarity indicator ( though sometimes the "pinch" in the metal can is all that denotes the + side ) .

- I think you better look up "Axial Capacitor" versus "Radial Capacitor" types, so that you order the electrolytic with the correct physical orientation .

- Also, look-up "heatsinking techniques for soldering delicate components" so that you avoid damaging your new parts when you install them ( from transmitted heat, stressing the caps ) .

- Please post a pic of your soldering iron !

[voice of the theater]

- The C3 outline ( for the 470 uF cap ) has a clear polarity marking on the PC board ( it's that "+" sign, top-right of the pin-hole, found on the left side of C3 outline ) .

- FYI, that 470 uF cap has markings that indicate the minus side, => (-) => .

- Electrolytic caps are always marked with a polarity indicator ( though sometimes the "pinch" in the metal can is all that denotes the + side ) .

Wow! You have good eyes. I zoomed in on my photo and sure enough, there is the + sign..... Good thing I asked--it would have been a disaster if I soldered that cap in backwards!! Thanks again for your answer Earl and aditya!!! Hopefully, once the 470 uF caps arrive, I'll be able to see which side is + on the caps. I'll be sure to post photos of the caps if I'm unsure......

- I think you better look up "Axial Capacitor" versus "Radial Capacitor" types, so that you order the electrolytic with the correct physical orientation .

The 470 uF caps I ordered lay on their side and have one lead coming out of each end--they are axial capacitors---I was pretty sure I ordered the correct ones--right?

- Also, look-up "heatsinking techniques for soldering delicate components" so that you avoid damaging your new parts when you install them ( from transmitted heat, stressing the caps ) .

I googled this and nothing came up. However, I was once instructed that when soldering capacitors, to keep the leads full length whenever possible and to apply heat only to the very tip of the lead (to minimize exposing the capacitor to heat). I was also taught to touch the tip of the lead to whatever you're trying to solder it to, apply heat for a few seconds (just long enough to warm up the lead and the piece of metal you're soldering it to--not long enough to fry the cap), and then melt the solder onto the connection because solder will stick better to a warm lead. Of course I was taught not to use a soldering iron that's too hot or you'll fry your caps as well. Not sure how much of the above is accurate/good advice. I've only used this advice once before (only recapped crossovers one time before). A couple of years ago I soldered new capacitors into my Heath/Altec AS 101's (with help from people here) and didn't fry anything (might have just gotten lucky!?). BTW, I thought I may have only noticed a very slight improvement in sound with that cap upgrade. I suspect that's because those 806-8A drivers (with 40 year old original diaphragms) just didn't have the high frequency extension/clarity to reveal much of an improvement in sound quality from a capacitor upgrade/replacement.....

- Please post a pic of your soldering iron !

OK, get ready to laugh (or cry)..... Here it is. It's old, the tip looks to be oxidized and it's also bent (this is NOT a Bill Clinton joke). It's looked this way since the 90's, and I've used it like this since then with no problems. It barely gets hot enough to melt solder. Once it's "warmed up", you really have to touch the tip of it to the solder to get solder to melt. If you touch the "side of the tip" to the solder, the solder won't melt--it has to be the exact "front of the tip"....... I feel that since this soldering iron gets BARELY hot enough to melt solder, that maybe that's a blessing in disguise with my lack of expertise--I'm less likely to fry anything with it (an amateur marksman is less likely to accidentally blow someone's head off with a tiny pistol than a semi-automatic?)...... (CLICK TO ENLARGE)





Time for a new soldering iron or "if it ain't broke, don't fix it"?


Earl, and everyone else here, I cannot adequately express my gratitude for all the assistance I've been receiving on these crossover upgrades for my Model 19's and 14's. I would never have known of the reasons to replace capacitors, and certainly would have never had the knowledge to pull this off successfully without all the help/knowledge I've gotten here. I really feel like I'm being coached by the best...... Not to mention, when I joined here--I'd never even heard of Model 19's or Model 14's. In fact, when I joined, I had only recently learned that my speakers (at the time) were called Valencias (846A) since they only said Iconic/Altec on the back. Up 'til then (for years and years) I'd been calling them what my brother who sold them to me called them "the home version of the voice of the theater" because that's what the guy who sold them to him called them. Quite a mouthful and not really accurate......

[Earl K]

Thanks for the pic !

Yes, I think you need a new iron . I usually use a 45 Watt Ungar/Weller iron .

I'll take a pic & then post it to show what I mean about "heat-sinking" a part ( be it on install or removal ) .

<> EarlK

[voice of the theater]

Thanks for the pic !

Yes, I think you need a new iron . I usually use a 45 Watt Ungar/Weller iron .

Yeah, I had a feeling it was time for a new soldering iron. I won't miss this one--you sometimes have to apply a little pressure on the solder just to get it to melt! My local hardware store only has 25 watt soldering irons. I called Harbor Freight (tool store located nearby) they have a 30 watt "Chicago Welding" soldering iron -- here's the link 30 Watt, 120 Volt Soldering Iron
Looks to be much better than what I have and I'm sure it's much hotter. Do you think this would be ok? I'm afraid to go much hotter/higher wattage -- just don't want to fry anything (should I consider the 25 watter for "safety"?).

I'll take a pic & then post it to show what I mean about "heat-sinking" a part ( be it on install or removal ) .

<> EarlK

Great!!

[Earl K]

Here's an example of heatsinking caps before desoldering . The "locking-pliers" are actually called "Kelly Forceps" . You can find them as surgical surplus .

The heat from the soldering iron is dissapated through them rather than being transmitted into the cap ( or device being soldered ) .

Do some research on YouTube for self-help vodeos on; how to solder, cleaning soldering irons, etc. before you do your work .

<> cheers

[voice of the theater]

Here's an example of heatsinking caps before desoldering . The "locking-pliers" are actually called "Kelly Forceps" . You can find them as surgical surplus .

The heat from the soldering iron is dissapated through them rather than being transmitted into the cap ( or device being soldered ) .

Do some research on YouTube for self-help vodeos on; how to solder, cleaning soldering irons, etc. before you do your work .

<> cheers

I found this video which shows heat sinking and seems pretty well done. I'm going to buy the forceps and a new soldering iron--maybe this one from my local Home Depot since it comes with a chisel tip (heats to 750 degrees).

http://www.amazon.com/Weller-SP23LK-.../dp/B0009ZD2AG

Actually feel like I know what I'm doing this time compared to when I recapped my AS-101's...... Thanks again!
YouTube - How and WHY to Solder Correctly

[RonSSS]

It takes a milliohm meter to measure this possible resistance. And even then, the connection of the leads can cause more resistance than might be present in the ground leads to the plate. Just connect the leads together with decent wire and solder. That's all it takes.

Ron

[QUOTE=westend9;1852555]An easy way to access the quality of the ground plane (lugs to plate) is to put a meter across varoius points and measure resistance. From the pictures, I think everything looks secure and no oxidation between metals. I have been known to give contact points like these a very quick squirt of Deoxit Gold or any other deoxidizing spray that is at my disposal.

[westend9]

You owe it to your self to get one of these adjustable temp statioms with a comfortable iron: Hakko 936.