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philco bakelite blocks
#1

How many of you restuff them versus bypass them(jump them)?

Also I have a 0.09 twin cap. Can I use 0.15 caps in place of them?
thanks
Chris
#2

"Jumping" them is not a good idea. It still leaves the old bad part in the circuit, unless you are cutting all the internal leads to the terminals.

I recommend ALWAYS re-building. I assume you've seen this section on my site regarding the bakelite block rebuilding?

BAKELITE BLOCK RE-BUILDING
Easy Steps to Re-building
#3

Chuck,
Yes I did. I rebuild them. I just read somewhere that you could cut the terminals and jump over them t save the digging out the tar. Is the cap sub okay?
thanks
Chris
#4

Chris

When I was young and foolish, I removed every bakelite block in a Model 18 and replaced them with terminal strips and new Orange Drops.

Soon after, I learned that the bakelite blocks could be rebuilt - but not usually with Orange Drops. That's when I started using the smaller metalized film capacitors and never looked back.

Chuck is right; they should always be restuffed with new caps.

If I still had that 18 lowboy, I would do it over again, the right way. (I have a small stash of bakelite blocks now for when I have one missing or broken in a set.)

Regarding your second question, 0.15 uF would probably be O.K. but 0.1 uF would be a better (closer) sub.

--
Ron Ramirez
Ferdinand IN
#5

Just like Ron, I did a lot of foolish things with radios many years ago. But we live and learn.

I ALWAYS restuff the bakelite blocks and keep them in the radio. This usually does not take any longer than removing them and mounting terminal strips, and it keeps the Philco original. Also, it avoids the possibility of potential problems in certain stages of the radio from re-directing the original lead dress.

Poston
#6

Not only does it keep it looking original, it also makes it a neater, cleaner, more organized electronic restoration job.
Ed M.
#7

Ron..Chuck..I have to ask this in the name of safety, then. One of the more common Bakelite Condensers was the line bypass unit with two .015 capacitors. Are the caps that could be re-stuffed into the bakelite tubs as safe as the newer X/Y caps, such as available from justradios.com.??
#8

Tubenutt...can't you use the X/Y safety caps in the block? I do...mine come from Mouser, and look like ceramic discs except they are blue. I use .01 uF, and they fit.

I've never bought anything from Just Radios - nothing against them, I'm just used to buying from Mouser and Allied - so I don't know how big the Just Radios X/Y safety caps are.

Edit: The counter guy at the local electronics distributor, where I occasionally buy a few parts when I'm in a hurry, insists that a metalized film capacitor rated at 630v DC is safe to use on AC; they don't carry the X/Y caps. But I use the X/Y units anyway. Better safe than sorry, especially when they're going into radios that aren't mine (customers' sets).

--
Ron Ramirez
Ferdinand IN
#9

Regular film caps can fail SHORTED, that's why X/Y caps are safety types - they fail OPEN. On the A/C line bypasses, X/Y's are safer.
#10

Thanks for adding that, Chuck; a very important point. I forgot to mention it in my post.

--
Ron Ramirez
Ferdinand IN
#11

Ron,
I get my X/Y caps from Dave at justradios; they are also blue in color and are most likely identical to yours from Mouser. I always use .01 mfd for line bypass regardless of what was originally in the radio. As you mentioned, they fit fine into the bakelite blocks.

As far as metallized film caps in this application, most of us used them for many years with no problems. They are thousands of times better and safer than the original paper ones. But since the X/Y type are now readily available at a fairly low price, there is no reason not to use them for the added safety factor.

The only problem with these safety disc caps is in non-Philco radios where you are re-stuffing the original paper cap shells. The disc caps of course won't fit inside. In these cases I admit that I still sometimes use a film cap, 630v rating. That is DC rating of course; as I recall AC rating on most of these 630v film caps is 200v. Most 400v film caps also have a 200v AC rating, but I only keep 630v in stock.

Poston

NOTE: Ron, you are very lucky to still have a good electronics jobber in your area. All of ours here are now gone, the closest is in Huntington, about 50 miles from me. Unless it is a dire emergency, considering current gasoline prices and the driving time it is more practical for me to order by mail.
#12

Poston

Yes, I too used metalized film caps rated at 630V for many, many years. It wasn't until recently (within the last couple of years) that I began to use the X/Y safety caps.

Your comment on the AC rating of metalized film caps is what the guy at the counter at Hutch & Son was trying to convey to me when I inquired whether they carried them (they don't). As you say, they do have that 200 volt or so AC rating - but they fail shorted (as Chuck mentioned), making the X/Y a far better choice for line-to-ground and line-to-line applications.

In regard to local jobbers. When I was a teenager and in my early years as an antique radio collector, living in western Kentucky at the time, I used to drive up here to Evansville and get most of my parts. Back then (mid-late 1970s) there were three distributors in town - Hutch & Son, Ohio Valley Sound and WESCO Radio Parts. Back in the day, WESCO was the GE distributor; Ohio Valley Sound was an RCA distributor, and I think Hutch & Son had been a Sylvania distributor but even then had moved into industrial electronics, which they continue to specialize in.

Back then, WESCO was pretty much on its last legs; anytime I went in there, more often than not I was their only customer. I bought more from them than the other two as they were usually the cheapest of the three.

WESCO went out of business in the 1980s as their building was scheduled to be razed to make way for a new east-west highway. As they went into their "quitting business" sale, I found out that they still had some parts from as far back as the 1930s in their inventory; I bought a few electrodynamic speakers and a very old RCA tube tester from them before they closed their doors.

Ohio Valley Sound closed its doors about 10 years ago.

Hutch & Son had a devastating fire about 15 years ago, but they rebuilt on the same site and are still in business, Evansville's last electronics distributor. I frequently buy heat shrink tubing from them for the 1939-42 Philcos I work on, and the occasional odd resistor or capacitor when I don't want to wait for a mail order.

--
Ron Ramirez
Ferdinand IN




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