Ahh.. Carl Carl Carl...lol
I didn't think you were the type that throws stones like this...
So why is it? Why do you do that? ... tsk tsk.

I think that keeping things at a nice discussion level of theory and supporting documentation is much better.

Y''know Carl.. The major difference between you and me is that ...at least I am WILLING to and CAN support what I claim...

Why do you want to see my NON AA5 work? .. Don't you believe me?
Be careful what you ask for.. just a small sample of them may choke up your screen...

Obviously you don't follow the restoration threads here much to see any of these radios that have all been there as each was completed.
So here's just a few.. Mr. "doubting Thomas"
But ok here goes...

( BTW ...I expect YOU now, to show your schematics and supporting info now too ok?)...lol

Remember you asked! .... lol
Here's just the first TEN or so radios... how many more do you need to see, Carl?...lol

BTW.. Since I don't bother to re-stuff the old electrolytic can-caps, you'll see that I have (mostly) also used radial-lead electrolytic caps in all these radios ... but you'll find them all neatly placed.. and maybe even a little hard to find mounted vertically.

So I asked and I see way too many shots of the same radio and way too many AA5's and other basic sets without a tuned RF stage which confirms my prior premise. I dont need to see any more.
As far as following threads I have little enough free time as is and looking at all the basic "See Me" threads of the you see a few you see them all variety, except for some interesting cabinets.

Some of mine have been shown in the Communications Receiver forum as well as others and usually as part of a restortation discussion. Im not a show off type. Others I prefer to keep private.

You rarely ever have done anything but want to argue with those who offer help so why should I bother.
If you want assistance then ask.

If you want theory read a book, I dont have time to play instructor to a know it all student.....did that in the Navy Reserves and industry for decades and they werent very happy after I got thru with them

Or just live with your reputation and keep up your rants. As far as Im concerned the thread has run its course.

This is an example of what Im often involved with and is a before view of a customers 1965 version HRO-500 (yes it is SS and synthesized; the first of its kind) which I just finished today before coming up here to grab the camera. Thats just the bottom view. There were 25 electrolytics and 27 resistors, and 16 silver micas changed plus numerous leaky transistors and diodes, poor grounds, switch problems, prior repair messes and other typical things involved with these sets. Alignment was a two day affair. It will soon be going to Spain and is considered a high end collector item.

Carl

This may work in most radios, but in electronics in general, this certainly is not a good rule to live by. I have done a bit of work where single point grounds were almost mandatory. Ever hear of ground loops? They can play havoc. Anyway, if it works for you, fine. But I personally like keeping my grounds similar to what the factory layout was. And you are right, the radial leads can make a neat job in a lot of cases.

I like your radios Peter. Very nice job.

I agree with you as far as "single point" or "star" grounds..
But we weren't talking about that per se.

The point was that if and old radio had a big-long old-fashioned type paper caps that were grounded at that far end of itself... it was mostly because it was just too long to reach a closer ground point.

All I said .. and my only point ....was that I like to use radial lead caps because you don't need leads that are as long as the old ones and finding the nearest chassis ground is best anyway.

That's just simple basic electronic radio and circuit theory and plain common sense!

For the usual AM set what Peter does is fine, I do it myself all the time. I have found those little green radial caps to be very reliable, I don't know what Dave means when he says they are not as good as the yellow axials. They are very accurate value wise and can take a lot more voltage than they are rated for, price is great. When it comes to the higher frequency sets such as communications gear and VHF and FM lead dress is very critical and was taken into account in the design with the components available at the time. Most the time alignment will compensate for the work done in a recap. But even the lowly TO will be affected by moving around wires going to the coil tower on the highest bands.

While I enjoy disagreeing with Pbpix in general, lol, his point here is valid, at least AFA AA5's and the like are concerned.

Naturally, a much more complex receiver requiring closer tolerances, such as what burnt fingers displayed, would demand stricter adherence to the original wiring paths.

So I guess it would be safe to say that those green Mylar caps are ok.
Vin

Still being somewhat of a noob in cap selection myself, Ive found myself diving into cap spec sheets. I've learned that each project calls for differing quality. I mostly like sets that cover anywhere from VLF up to VHF. There's quite a bit of build quality in that range. Initially I thought that just about the worst mylars we make today are better than the best papers we made 50 years ago. Re considering the source of this info it's 'usually' a website hawking capacitors that says their cheap caps will get up and dance for you too. Those 60s Japanese S-120 knock offs should be ok with just about any cap. The better receivers and test gear should get better parts. It's frustrating reading data sheet after data sheet for cap offerings from sometimes many manufacturers, whose charts don't compute the same thing and you have to get out your scientific calculator, but in the end, I feel better knowing that I've selected at least an educated guess based on the numbers in front of me.

There's lots of things to consider with caps (resistors too!). Will it fit? Are you trying to keep as close to voltage rating specs just for the sake of it, or is all 600V ok because they're smaller anyway? Do you want them all to look the same, or taste the rainbow? What other properties is this newer style cap going to introduce, or have a lack of for the circuit? Is it more or less inductive? Are you trying to improve the circuit with tighter tolerances? Will changing the lead length and dress screw with things?

Mouser makes the spec sheets available. I say google the old part number specs. Compare them with the new.
If the parts list just says .01 @ 200V paper then I wouldn't worry so much.

At the end of the day, I've learned (fairly recently too!) that cap selection is job specific.

You all have probably scared off the original poster by now with all this infighting. I don't see any need for high tolerance caps in a broadcast set for use in coupling and bypassing, beyond the original tolerances. If you are talking like disc or mica caps in RF circuits, that is different. He should be concerned with voltage ratings, though. Safety margins.

I go along with Peter on the idea that using the shortest lead length for bypass caps is generally the best practice.

EDIT:
Salval,
I also recommend Bob's Capacitors http://www.radioantiques.com/supplies.html
His prices are great, and shipping is very fast. Bob has been a long time member of the Antique Radio Club of IL http://www.antique-radios.org/

It's a good idea to remember the original layout when you do a restoration or repair. That way you have some reference if you wind up with a howler or a motorboater.

RRM

I think the best aid to that memory would be "snapping a picture", as we used to say, of the chassis before doing any surgery.

Short ground leads are good, but modern caps can have much lower ESR losses and may improve
stage gain at the operating frequency and at unexpected UHF and VHF frequencies.
Choosing an alternate shorter ground path and deciding to share it for grid and plate bypass caps
can setup an unexpected feedback path in the stage. Nothing is as simple as it looks.

Pete

I know you mean well Pete.. but geez...
lol...
Talk about s-t-r-e-t-c-h-i-n-g a point that's beyond the pale ... OMG.

Oh yeah I must have missed the chapter.

"Hey do ya hear oscillations in your antique AM radio Bucky?
Did ya put one of them there NEW-type "modern" radial-lead capacitors in there?
And did you relocate one end to a nearby ground?
You did?
Ah hah!!
Well ya see Bucky... that's yer whole darned problem!
.... it's caused by that well-known old problem called: "The classic improved ESR, increased gain, unexpected feedback, syndrome"
Didn't ya know that? ... ya dummy."

Peter....

Priceless.

The best advice for newbies, is to replace the 'Lytics first, which should then get the radio operating.

I don't think anyone would argue that for these, the shortest path to ground for the negative leads is operative.

After that, plug it in and test it after each succeeding wax/paper/plastic encapsulated cap has been replaced. Don't forget to unplug it from AC before doing the next replacement.

As you become more familiar with this kind of circuitry, perhaps check after every several cap replacements. That's pretty much what I do.

Well.. at least you're a good sport about it Pete.

... And a very good and interesting story it is too!

I'm reminded here of a story about the most difficult troubleshooting story we ever had when I was a field service tech for a computer type-setting & micro-film system company.
Our big systems had a very high resolution CRT that displayed text which was filmed by a big camera mounted above the CRT... That film was made for Micro-film data storage.

We had just re-located one of those systems for RR Donnelly Printing company to their other building on the fifth floor somewhere along Broadway in mid-town Manhattan.

The customer was complaining that "at random times of the day"... the text characters on the micro-film were all "wiggly" and noisy-like.

We tried every possible trouble shooting technique to localize the problem.. all to no-avail. The home office even sent out their top service engineers to help solve it... nothing helped.

I was there one Saturday while we were all huddled around the system doing tests.... one guy was looking down at the face of the screen with a micro-scope looking at the test text characters reporting to us everything he could detect as we were testing various test patterns etc.

Suddenly he yelled out... " I see it.. I see it" .... then it stopped and was clean again...
about 3 minutes later it was back again.... but this time... as he yelled out that he saw the noise on the screen we all noticed it was simultaneous with the freight elevator going by our floor about 20 feet away!

Yep... that giant electric motor on the freight elevator had a big magnetic field around it and as it passed by our system the magnetism screwed up all the text on the CRT...
Who would EVER have anticipated that?

We re-positioned the machine another 40 feet away.. and the problem was gone for good! ...lol
Now ....how weird and random was that?