Have to agree with Doug but that doesn't really answer your question. Your radio doesn't have electrolytic filter caps but rather 2 mf paper/oil type. They are located in the schematic by your 280 tube. Bad filter caps are what usually causes hum. They could be replaced by 10 mf @ 450 volt electrolytics but watch polarity. Positive connects toward your 280 tube filament.
Study the schematic and see if you can identify parts?
http://www.nostalgiaair.org/PagesByModel/901/M0013901.pdf
Norm
:Joe, I think you're starting with a set that is a little over your head. I'd recommend that you find somebody, possibly through a local anique radio club, that would be willing to coach you.
I agree that this might be something a bit over your head, but it sounds like you have motivation. Replacing condensers isn't hard. With the bakelite condenser banks, you melt all of the tar out with a 200 degree oven....windows open, people out of the house that might complain....you could also use a low fire charcoal grill, though there isn't much control to this.....you'd have to watch a lot. Then you replace the guts and wire per original. Ceramic caps fit well and do the job. Use spaghetti on the wires inside the bakelite blocks so that they can't short against eachother. Fill blocks with hot glue.
If you feel like you can do it, go for it. Do one block at a time and don't otherwise upset the wiring. Don't move on to another block until you've wired back in the previous one...this way you can keep track of wiring. Use ceramic condensers rated for at least 500 WVDC (500 working volts D.C.). Don't tamper with coils or trimmer condensers or anything like that. If the radio works, you don't need to play around with these, and until you're more of an expert, you don't want to play around with these. If your radio has any condenser banks other than the bakelite ones so common to Philco, or the big tin box found in my radio (my radio has a tin box and the bakelite units), ask about it. If you have something strange in there, this may or may not take you in over your head.
I don't really recommend leaving in all of the old paper condensers. Chances are they could work and chances are that they could fail. Unless you know what you're dealing with, you don't want random condenser failings. They are nightmares and can be dangerous to both you and the set.
So.....give this some thought and tell us what you think.
Thomas
Thanks for the info.I'v replaced a number of capacitors but when I looked at the chasis of the Philco 95 I was looking for the electrolitics and saw nothing that looked familiar.I do have a book on the bakelite caps. and have "by-passed" some, but there are none in the 95, just (4) Philco part#'s 3787A,(6)3788A and (1) 3584B (all paper caps.).A few ceramics and what I suspect are caps in (2) narrow rectangular
metal cases. Again thanks for the info.,at least I now know there are no elecrolitics.I'll still have to trace the 2.MFD you refered to. I do see them by the 80 tube in the schematic.
Early radios don't always have electrolytics because they were very new around 1930. Prior to this manufacturers who make AC sets worked around the problem of lacking a large filter condenser. Into the 1930s, manufacturers phased out the old filtering techniques (still using them somewhat in the early 1930s).
Good luck!
Thomas
Thanks for the positive response but I do consider myself an amatuer (an old one) but still an amatuer.I do enjoy working on old radios especially if I'm able to get them working again.As far as the 95 Philco is concerned, I'm able to see on the schematic where I would like to tie in the 10 x 450 capacitors but when looking at the actual 80 tube all I see are wires that are coming from the transformers? I don't plan on doing anything until I'm sure after all it still works even thou it has a hum. Thanks again...
Regarding your filter condensers, well, the main ones and many others are in an item numbered 48 in the schematic. You'll notice that all condensers in this item (probably a metal container of some sort that may look like a transformer) have numbers on each side corresponding to each lead. You'll probably see a bunch of numbered terminals on the actual device. A lot of these condensers share terminal 11. This terminal is connected to the chassis. Other condensers have terminals all of their own, since they connect to other parts of the radio. What you must do is either find out a way to open up this device so that you may replace all of the condensers with new ones, or simply disconnect all of the wires from this unit and then put replacement condensers under the chassis, wired to the same points as shown in the schematic. If you can figure out how to neatly open up the housing of this condenser block, I recommend that you stash new parts inside of this instead of putting them under the chassis. However, if this device is exposed above the chassis, and if opening it may ruin its appearance, simply disconnecting it and then inserting new parts where the old ones went is probably the better idea. I do not own this radio, so I do not know what the can, box, whatever looks like. If the device looks difficult to open, just disconnect it and wire in new components directly on the chassis.
You may use 10 MFD units to replace the 2 MFD units. For the 1 MFD unit you may use a 5 MFD unit. You could also change the first 10 MFD unit to a 15 or 20 MFD unit. The 5 MFD unit you could make a 10. These changes may reduce hum if it happens to be excessive. You could also leave all values original, though increasing the values to those listed above will give you more power. The original power supply was a tuned power supply. It was tuned to eliminate the hum. With larger condensers which are capable of holding a nice charge, tuning with specific values is no longer necessary. However, do not go above the values listed above. If you increase your electrolytics to excessively large sizes, you can overload the rectifier when the radio is first turned on. Those listed above are ideal. The .15 MFD condenser shown across the choke may be omitted. Try the radio with and without it. This was originally used for tuning the choke. Newer radios don't usually put condensers across chokes, as condensers will pass the hum that the choke cancels. When you tune a power supply, things are done differently. Special tank circuits, just like radio circuits, are made. I recommend using the larger values given above for the first three filter condensers. They'll yield better performance from the radio than if you use original values. For all other condensers, use non-electrolytic units of the same values as the originals. All must be rated for 450 volts or better, like Norm said. With the electrolytics, simply purchase 450 volt units. Higher rated ones are considerably more expensive. With the small value non-electrolytic units, use 450 to 600 volt units.
You may notice that the 1st schematic given for the model 95 radio does not have all of the values listed for all of the condensers found in the #48 part. If you go down to the 2nd sideways schematic, you'll find your values. Rotate using the tools in the upper right hand corner of the page.
Thomas
Once again thanks.I'v put the radio back together for the Holidays (it sits in our dining room)and the wife wants the room back together.In the mean time I'm going to search for a parts list. I believe the metal cans contain the 2 MFD. caps.but I want to be sure..Thanks again and enjoy the Holidays.
We all use different methods of repairing things, so if you don’t mind, I’d like to tell you my experience with the Bakelite condenser banks. Before I do though, I’d like to say that when these containers were used, the underside of a Philco chassis is easier to properly restore than any other AC powered radio that I know of. The main gripe I have is that a lot of servicemen cut the solder lugs off to bypass them.
First of all, the black substance that is used in these containers is different than the usual tar, and will dissolve in lacquer thinner. You can throw a handful of these things in a can of thinner and a few hours later all the stuff will be in solution. Additional thinner is required for a rinse, so this is somewhat wasteful unless done on a large enough volume. Gasoline may work, but I have never tried it. Maybe I did and forgot about it.
When repairing them one at a time, I use heat to get the stuff out. A hair dryer will soften it well enough in a minute or two so that it will easily dig out with a screwdriver. At this temperature, it has about the consistency of damp mud, so does not make much of a mess. After removing the contents, a small amount of thinner is good for cleanup. A final cleanup with Pledge will make them look like new.
If desired, metal film caps with axial leads will usually work for replacements. Pull the leads tightly through the eyelets with pliers, wrapping them around the solder lug. In most cases this will snug the body of the caps horizontally together well enough so that spaghetti is not required. Of coarse all different combinations are used in some of these things, so anything goes. Of all the ones that I recall doing, they pulled up tight and neat enough that I did not feel a need to fill the container afterwards. My idea has been that this would make it easier for someone in the future to replace them. But then, I have never used hot glue, so don’t know what its properties are for removal. It may be a useful product that I should try in the future.
As a general rule, I use something that melts at a low temperature when I feel a need to seal parts in a container. Paraffin melts at about the lowest and I occasionally use it because it is cheap and easily obtained. It was not used very often in old radios though, and I was surprised to see some a few weeks ago in a pair of condenser cans of the early 1920’s. If used to replace tar, a few drops of black pigment mixed with it gives an authentic look if desired. Beeswax is more common in old radios and melts at a higher temperature. I use it mostly for restoring tubular condensers, but a lot of other radio parts were impregnated with it. When beeswax was used, various parts were soaked in it for several hours to drive all the moisture out, then the temperature was reduced before removing some parts if a thick coating was needed for protection.
Here I am getting way off the subject, but I have even used beeswax as a mold for making radio knobs for old battery sets. Paraffin will not work for this if a catalyst is used in the mix, since too much heat is generated. Even with beeswax it is necessary to rapidly cool the pour by immediately curing it in the freezer. One advantage of using wax is that a mold release is not required.
Back to the subject of condensers. On rare occasions, I have found wet electrolytic condensers that were still good. If all the electrolyte is still inside, the condenser will usually reform in a few hours, or maybe overnight. You can tell if enough electrolyte is there by shaking it. If you don’t feel any movement, or maybe just a small amount inside, it is probably OK. If you hear it really sloshing inside, it is not enough. Here again, we have no way of knowing how long a good one will last, but I am willing to give them a chance, even though some of the early servicemen did not trust them. I have seen a few that were replaced with an under chassis type which had long gone bad, leaving a perfectly good original still mounted on the chassis. I expect some of these will still be good after I am dead and gone.
It is more difficult to predict a dry electrolytic when it comes to reforming. If it feels heavy enough, I may try it. If not, I no longer waste my time on one. But then, some collectors believe it is a complete waste of time to mess with any of these old caps, regardless of what type they are. They are probably right. It takes a sentimental old fool like myself to fiddle around with some of this old stuff.
Regarding Philco bakelite condensers, you probably have the right idea about not filling them with glue or anything. I think that method is best. You can't see whether they're filled or not, and filling them just makes life more difficult for any future repairmen. They were originally filled with tar, of course, because unsealed paper condensers were used. These, if left exposed, soak up moisture and become leaky (as they often do anyway).
Regarding coloring parafin black, what I do is melt in a black crayon. If only you could get a box of black crayons! I think that you can get those black wax marking pens, though--the type where you pull a string and peel away paper.
Thomas