Hi all:I have a navy model RCH military receiver that I have to change the filters.The parts sheet shows then as:4mf 600v paper. Can I use electrolytics instead?

not unless they are paper electrolytic.
are they polarized + or a - on one end.
if not you need orange drop caps.
look this over. http://antiqueradio.org/recap.htm#types

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Hi all:I have a navy model RCH military receiver that I have to change the filters.The parts sheet shows then as:4mf 600v paper. Can I use electrolytics instead?

:not unless they are paper electrolytic.
:are they polarized + or a - on one end.
:if not you need orange drop caps.
:look this over. http://antiqueradio.org/recap.htm#types
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:Hi all:I have a navy model RCH military receiver that I have to change the filters.The parts sheet shows then as:4mf 600v paper. Can I use electrolytics instead? av1:Thanks for your reply.I cannot find a + or - on the capacitors.I probably did not give a proper description.these are metal cans on top of the chassis and are the power supply filters,1 1/2" in diameter & 4" tall.The metal cans (there are four of them) go through a hole in the chassis & are retained by a large nuts.Protruding from the bottoms are pieces of black phenolic from which two metal solder terminals protrude.there are no + or - marks on this phenolic,so I beleive there is no polarity.So can I replace these with electrolytics or do I have to find paper filters of the same value?

Metal cans are quite often polarized. And most are electrolytic.
Typically the outside body is negative and the terminal in the phenolic area is positive.

But basically it does not matter whether you decide to use a polarized electrolytic or a non-polar capacitor.
What matters is that you replace the old capacitor with a new one of similar value capacitance and voltage rating.

So for instance if your equipment used 4 uf @ 300vdc electrolytic caps... you do not need to replace them specifically with electrolytic caps... you can just replace it with ANY 4 uf @ 300-400vdc

If you ever find a non-polar, non-electrolytic cap in a DC circuit area (such as a power supply filter)....you could replace it with a polarized electrolytic cap.. you just need to place the positive terminal in the most positive part of the circuit.... such as the cathode of the rectifier.

So any cap can usually replace any other cap as long as the size and voltage are appropriate... and when using electrolytics.. just observe proper polarity.

Peter:Thanks for the information.I was hoping thats what someone would say as I already ordered electrolytic caps.Thanks again for clearing it up. SCOTTY.

EDD:Thanks for your reply & interest.If these are oil filled I dont want to lose them.The tops of the cans are not rolled.Stamped into the top of the can is--"INDUSTRIAL COND CORP CHICAGO ILL,4MFD 600VDC WORKING,CIE 5070".On side of can stamped in ink is--"CIE 481080".Can closest to front of chassis has slight indentation on top & was slightly out of line with the others by about 1/8".when I tried to straighten it,the can loosened from its base but did not come off.Also I noticed a thin sticky substance around this can on the chassis which had been there for some time.Later today I will remove the condenser & investigate.If it is the only bad one,can I replace it only with an electrolytic?I will perform surgery & report back!
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: Sir Scotty:
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: Might I pose question or two and give some info on that unit which might prove to be an impressive receiver for you. . . . .after all . . . .GREAT SCOTT. . . . .its a SCOTT.
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:I think that I remember that unit sort of being up on a slight pedestal base and being finished in a black crackle, not the typical Naval battleship grey, and being for AC power shore use.
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:You also might confirm if the 4 ufd caps are having a rolled seam at the tops. . . .like a tin can. . . and some used two bolts for mounting while others used a round clamp for mounting. The rolled seam units were oil filled paper capacitors for sure, while the other configurations were conventional paper caps. WHICHEVER type used, I usually expect a lifetime of “ ‘til the twelfth of never” from them. . . unless proven otherwise.
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:I enclosed a thumbnail of the shema of portions of interest:
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:Firstly, there is the power supply, which you can see did not skimp on its capabilities, initially there is the output of raw DC taken from the 5Y3 and then the first filter section and then a series choke filter in the order of a hefty 12 henry choke and then the intermediate 4 ufd filter capacitor.
:At that point, the B+ is pure enough for being the main B+ supply for primarily the audio output stage.
:That initial B+ level is then being passing on to the even heftier 32 henry final choke and being followed
:by the final 4 ufd filter, that results in the production of the sub B+.
:Now here is the kicker to check out, note that the center tap winding of the HV winding is NOT going to
:ground, instead, it is routed to a 50 ohm resistor before it can complete its ground loop thru that resistor. That will result in a negative voltage being developed across that resistor, which you can see at the top that is being routed to other circuitry in the set for biasing uses.
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:Also take note of capacitor C119 and note that it is the filtering capacitor for that bias supply, and also take note of its polarity of installation.
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:Looking at the parts list for that receiver I am seeing that C119 capacitor, along with C117 and C118 as being 25 ufd at 25VDC electrolytic capacitors, the other , C101-102-103 being paper type capacitors.
:The C117 and C118 are cathode bypass capacitors and with their failure mode, the effect is mainly the loss
:of audio gain and a peripheral altering of overall audio tonal response.
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:If you have a failure of the C119 . . . .WHOAAAA. . . .somewhat of a different effect, note that it is shunting the
:50 ohm resistor , so that means that the DC component of the power supply is going to pass thru it and be complete, less that small voltage drop for the bias supply.
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:Now what you also need to see that if that C119 deteriorates in capacitance or opens up, that opens up the, otherwise, very low impedance path of the AC component of the first and second 4 ufd caps on getting to ground, just visualize them trying to copmlete a path tru an electrolytic that has deteriorated to .1 ufd. . . . .Hummmmm...city .
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:Look over to the third and final 4 ufd and you can see, it just doesn’t care, since it IS connected to ground, BUT the two prior stages were NOT providing their normally, fully filtered B+ to it.
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:Soooooo. . . . check out the three electrolytic and see what their conditions are. I think that they were bathtub units and mounted near the chassis lips edges.
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:In accordance to supplier, some are stamped with their polarity, some have it almost engraved into the metal, while others have a splash of red and black paint on the solder blobs of the connector terminals.
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:If this does happen to be your filter situation, I would sort of hate to see you casting your three 4 ufd diamonds aside and replacing them with Cubic Zirconias.
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:Thumbnail Schemas:
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:73's de Edd
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