Electrolytic Cap Substitute Close enough?

1/7/2007 1:25:43 PMBob Elbert

I am replacing an E Cap that is labeled 2 X 8 @ 475 wv
Both leads on the postive end connect to same wire.
Must have been a replacement? I cannot seem to find/ identify this cap on the scehmatic so I am trying to decide if the cap I have on hand would be close enough. I have a 22 mfd @ 450. Should I gopher it?
bob

1/7/2007 3:02:50 PMMark

:I am replacing an E Cap that is labeled 2 X 8 @ 475 wv
:Both leads on the postive end connect to same wire.
:Must have been a replacement? I cannot seem to find/ identify this cap on the scehmatic so I am trying to decide if the cap I have on hand would be close enough. I have a 22 mfd @ 450. Should I gopher it?
:bob
Hi Bob
Perhaps you could tell us what make and model radio your working with, as to be able to look at the schematic and determine which capacitor is in question.
Mark

1/7/2007 3:18:12 PMBob

Near as I can figure it is an RCA V210 or V209 radio.
This Cap is connected to pins 1,2,3, and 5 of RF 6SG7 and the other side goes to Pin 4 of the 1st det/Osc 6SA7. The schematic I am looking at is not real easy for me to read...but thats not unusual...

::I am replacing an E Cap that is labeled 2 X 8 @ 475 wv
::Both leads on the postive end connect to same wire.
::Must have been a replacement? I cannot seem to find/ identify this cap on the scehmatic so I am trying to decide if the cap I have on hand would be close enough. I have a 22 mfd @ 450. Should I gopher it?
::bob
:Hi Bob
: Perhaps you could tell us what make and model radio your working with, as to be able to look at the schematic and determine which capacitor is in question.
:Mark
:

1/7/2007 3:54:21 PMMark

:Near as I can figure it is an RCA V210 or V209 radio.
:This Cap is connected to pins 1,2,3, and 5 of RF 6SG7 and the other side goes to Pin 4 of the 1st det/Osc 6SA7. The schematic I am looking at is not real easy for me to read...but thats not unusual...
:
:
:
:::I am replacing an E Cap that is labeled 2 X 8 @ 475 wv
:::Both leads on the postive end connect to same wire.
:::Must have been a replacement? I cannot seem to find/ identify this cap on the scehmatic so I am trying to decide if the cap I have on hand would be close enough. I have a 22 mfd @ 450. Should I gopher it?
:::bob
::Hi Bob
:: Perhaps you could tell us what make and model radio your working with, as to be able to look at the schematic and determine which capacitor is in question.
::Mark
::HI Bob
In looking at the schematic I think the capacitor your refering too is C16? if this is so it is a 120Pf
Mark

1/7/2007 3:57:48 PMMark

:Near as I can figure it is an RCA V210 or V209 radio.
:This Cap is connected to pins 1,2,3, and 5 of RF 6SG7 and the other side goes to Pin 4 of the 1st det/Osc 6SA7. The schematic I am looking at is not real easy for me to read...but thats not unusual...
:
:
:
:::I am replacing an E Cap that is labeled 2 X 8 @ 475 wv
:::Both leads on the postive end connect to same wire.
:::Must have been a replacement? I cannot seem to find/ identify this cap on the scehmatic so I am trying to decide if the cap I have on hand would be close enough. I have a 22 mfd @ 450. Should I gopher it?
:::bob
::Hi Bob
:: Perhaps you could tell us what make and model radio your working with, as to be able to look at the schematic and determine which capacitor is in question.
::Mark
::Hi Bob
Which C Number is this capacitor?

1/7/2007 4:18:41 PMBob

::Near as I can figure it is an RCA V210 or V209 radio.
::This Cap is connected to pins 1,2,3, and 5 of RF 6SG7 and the other side goes to Pin 4 of the 1st det/Osc 6SA7. The schematic I am looking at is not real easy for me to read...but thats not unusual...
::
::
::
::::I am replacing an E Cap that is labeled 2 X 8 @ 475 wv
::::Both leads on the postive end connect to same wire.
::::Must have been a replacement? I cannot seem to find/ identify this cap on the scehmatic so I am trying to decide if the cap I have on hand would be close enough. I have a 22 mfd @ 450. Should I gopher it?
::::bob
:::Hi Bob
::: Perhaps you could tell us what make and model radio your working with, as to be able to look at the schematic and determine which capacitor is in question.
:::Mark
:::Hi Bob
: Which C Number is this capacitor?

After studying the schematic I *think* it is C21 but that was my problem...trying to find the C number to find the value. C21 is a 16 which this dual 8 in parallel would equal to, right? So my question remains will the 22 work since it is 450 wv rather than a 475? OR should I look for something closer?

1/7/2007 4:55:44 PMMark

:::Near as I can figure it is an RCA V210 or V209 radio.
:::This Cap is connected to pins 1,2,3, and 5 of RF 6SG7 and the other side goes to Pin 4 of the 1st det/Osc 6SA7. The schematic I am looking at is not real easy for me to read...but thats not unusual...
:::
:::
:::
:::::I am replacing an E Cap that is labeled 2 X 8 @ 475 wv
:::::Both leads on the postive end connect to same wire.
:::::Must have been a replacement? I cannot seem to find/ identify this cap on the scehmatic so I am trying to decide if the cap I have on hand would be close enough. I have a 22 mfd @ 450. Should I gopher it?
:::::bob
::::Hi Bob
:::: Perhaps you could tell us what make and model radio your working with, as to be able to look at the schematic and determine which capacitor is in question.
::::Mark
::::Hi Bob
:: Which C Number is this capacitor?
:
:After studying the schematic I *think* it is C21 but that was my problem...trying to find the C number to find the value. C21 is a 16 which this dual 8 in parallel would equal to, right? So my question remains will the 22 work since it is 450 wv rather than a 475? OR should I look for something closer?
HI Bob
Thanks for clearing that up for me, a 22uf will work ok, but you need an equal or higher working voltage than 450vdc, at least 475vdc or higher, I Have some 10uf at 500vdc, if you would like to try a couple of those, they are axial lead, let me know.
Mark

1/7/2007 5:38:05 PMBob

::::Near as I can figure it is an RCA V210 or V209 radio.
::::This Cap is connected to pins 1,2,3, and 5 of RF 6SG7 and the other side goes to Pin 4 of the 1st det/Osc 6SA7. The schematic I am looking at is not real easy for me to read...but thats not unusual...
::::
::::
::::
::::::I am replacing an E Cap that is labeled 2 X 8 @ 475 wv
::::::Both leads on the postive end connect to same wire.
::::::Must have been a replacement? I cannot seem to find/ identify this cap on the scehmatic so I am trying to decide if the cap I have on hand would be close enough. I have a 22 mfd @ 450. Should I gopher it?
::::::bob
:::::Hi Bob
::::: Perhaps you could tell us what make and model radio your working with, as to be able to look at the schematic and determine which capacitor is in question.
:::::Mark
:::::Hi Bob
::: Which C Number is this capacitor?
::
::After studying the schematic I *think* it is C21 but that was my problem...trying to find the C number to find the value. C21 is a 16 which this dual 8 in parallel would equal to, right? So my question remains will the 22 work since it is 450 wv rather than a 475? OR should I look for something closer?
:HI Bob
: Thanks for clearing that up for me, a 22uf will work ok, but you need an equal or higher working voltage than 450vdc, at least 475vdc or higher, I Have some 10uf at 500vdc, if you would like to try a couple of those, they are axial lead, let me know.
:Mark
Mark,
Thanks a lot for offering. I see AES actually has a 16@475 Sprague Atom Cap listed in their catalog and I need a few other things so I can order them tomorrow.
But stayed tuned I am sure I will have more questions with this radio before I finish. Too bad there is not a parts listing with this schematic info I got here.
I have a Riders Cd too and it did not have a parts list.
I am curious if original equip really was 475 wv since this cap is a dual 8 mfd. Do you think RCA would have used a dual when they manufactured it? Looks like someone just used what they had to fit the repair. YaThink? Anywhere else to find out if the voltage is really originally 475?
Bob

1/7/2007 6:39:17 PMBob

::::Near as I can figure it is an RCA V210 or V209 radio.
::::This Cap is connected to pins 1,2,3, and 5 of RF 6SG7 and the other side goes to Pin 4 of the 1st det/Osc 6SA7. The schematic I am looking at is not real easy for me to read...but thats not unusual...
::::
::::
::::
::::::I am replacing an E Cap that is labeled 2 X 8 @ 475 wv
::::::Both leads on the postive end connect to same wire.
::::::Must have been a replacement? I cannot seem to find/ identify this cap on the scehmatic so I am trying to decide if the cap I have on hand would be close enough. I have a 22 mfd @ 450. Should I gopher it?
::::::bob
:::::Hi Bob
::::: Perhaps you could tell us what make and model radio your working with, as to be able to look at the schematic and determine which capacitor is in question.
:::::Mark
:::::Hi Bob
::: Which C Number is this capacitor?
::
::After studying the schematic I *think* it is C21 but that was my problem...trying to find the C number to find the value. C21 is a 16 which this dual 8 in parallel would equal to, right? So my question remains will the 22 work since it is 450 wv rather than a 475? OR should I look for something closer?
:HI Bob
: Thanks for clearing that up for me, a 22uf will work ok, but you need an equal or higher working voltage than 450vdc, at least 475vdc or higher, I Have some 10uf at 500vdc, if you would like to try a couple of those, they are axial lead, let me know.
:Mark

Mark,
Next question...maybe this should be a new string but...I am replacing the Can Cap to this unit. there are 3 caps in the can. Square (15-400) no problem on where to hook up replacement, Triangle (10-400) no problem where to hook up replacement and the 3rd cap with no marking C39 (10-25) connects directly to the punch-out chassis ground terminal and nothing else as far as I can see...so both ends are grounded? Wish I could show you a picture but maybe you understand.
Bob

1/7/2007 6:39:24 PMBob

::::Near as I can figure it is an RCA V210 or V209 radio.
::::This Cap is connected to pins 1,2,3, and 5 of RF 6SG7 and the other side goes to Pin 4 of the 1st det/Osc 6SA7. The schematic I am looking at is not real easy for me to read...but thats not unusual...
::::
::::
::::
::::::I am replacing an E Cap that is labeled 2 X 8 @ 475 wv
::::::Both leads on the postive end connect to same wire.
::::::Must have been a replacement? I cannot seem to find/ identify this cap on the scehmatic so I am trying to decide if the cap I have on hand would be close enough. I have a 22 mfd @ 450. Should I gopher it?
::::::bob
:::::Hi Bob
::::: Perhaps you could tell us what make and model radio your working with, as to be able to look at the schematic and determine which capacitor is in question.
:::::Mark
:::::Hi Bob
::: Which C Number is this capacitor?
::
::After studying the schematic I *think* it is C21 but that was my problem...trying to find the C number to find the value. C21 is a 16 which this dual 8 in parallel would equal to, right? So my question remains will the 22 work since it is 450 wv rather than a 475? OR should I look for something closer?
:HI Bob
: Thanks for clearing that up for me, a 22uf will work ok, but you need an equal or higher working voltage than 450vdc, at least 475vdc or higher, I Have some 10uf at 500vdc, if you would like to try a couple of those, they are axial lead, let me know.
:Mark

Mark,
Next question...maybe this should be a new string but...I am replacing the Can Cap to this unit. there are 3 caps in the can. Square (15-400) no problem on where to hook up replacement, Triangle (10-400) no problem where to hook up replacement and the 3rd cap with no marking C39 (10-25) connects directly to the punch-out chassis ground terminal and nothing else as far as I can see...so both ends are grounded? Wish I could show you a picture but maybe you understand.
Bob

1/7/2007 8:06:05 PMRadiodoc

Bob,

The can cap you are referring to is probably special. If you note on the schematic, C37 & C38 have their minus tied to the power transformer HV secondary center tap and on to the chassis thru a 270 Ohm and a 15 Ohm resistor (providing negative bias voltage for the audio output tube, etc). C39 probably has its plus connected to the cap can internally and its minus brought out to a connection tab. Without looking at the radio directly the centertap wire and the 270 Ohm resistor probably connect to the C39 cap terminal (the one not marked). Some radios had the can of the cap insulated on a fibre mounting washer, some had the caps insulated from the can with an extra solder terminal. You could probably use a two section cap rated 450 volts or better (using a fibre mounting washer) and use a separate axial cap underneath the chassis for C39.

Radiodoc

:::::Near as I can figure it is an RCA V210 or V209 radio.
:::::This Cap is connected to pins 1,2,3, and 5 of RF 6SG7 and the other side goes to Pin 4 of the 1st det/Osc 6SA7. The schematic I am looking at is not real easy for me to read...but thats not unusual...
:::::
:::::
:::::
:::::::I am replacing an E Cap that is labeled 2 X 8 @ 475 wv
:::::::Both leads on the postive end connect to same wire.
:::::::Must have been a replacement? I cannot seem to find/ identify this cap on the scehmatic so I am trying to decide if the cap I have on hand would be close enough. I have a 22 mfd @ 450. Should I gopher it?
:::::::bob
::::::Hi Bob
:::::: Perhaps you could tell us what make and model radio your working with, as to be able to look at the schematic and determine which capacitor is in question.
::::::Mark
::::::Hi Bob
:::: Which C Number is this capacitor?
:::
:::After studying the schematic I *think* it is C21 but that was my problem...trying to find the C number to find the value. C21 is a 16 which this dual 8 in parallel would equal to, right? So my question remains will the 22 work since it is 450 wv rather than a 475? OR should I look for something closer?
::HI Bob
:: Thanks for clearing that up for me, a 22uf will work ok, but you need an equal or higher working voltage than 450vdc, at least 475vdc or higher, I Have some 10uf at 500vdc, if you would like to try a couple of those, they are axial lead, let me know.
::Mark
:
:Mark,
:Next question...maybe this should be a new string but...I am replacing the Can Cap to this unit. there are 3 caps in the can. Square (15-400) no problem on where to hook up replacement, Triangle (10-400) no problem where to hook up replacement and the 3rd cap with no marking C39 (10-25) connects directly to the punch-out chassis ground terminal and nothing else as far as I can see...so both ends are grounded? Wish I could show you a picture but maybe you understand.
:Bob

1/8/2007 12:15:31 AMBob

Doc,
See photo http://img452.imageshack.us/my.php?image=cancapag4.jpg
C37 (10uf450) and C38 (substitute 22uf-450 for 15-450) minus ends will twist together and connect to post that connects to
center tap of Pwr TX.
C37 positive will connect to post that goes to Rectifier 5Y3 filament pin 8.
C38 positive will connect to three connections, one of which goes to the 1st IF TX, another goes to R11, (12K), and the third goes to a terminal board mounted on side of chassis and goes "somewhere".
I think the above is correct?
It is C39 I am not clear where the physical connections should be.
C39 (47uf-50 substitute for 40uf-25) minus end goes to ??? Center Tap also??
Positive goes to ???
Bob

:Bob,
:
:The can cap you are referring to is probably special. If you note on the schematic, C37 & C38 have their minus tied to the power transformer HV secondary center tap and on to the chassis thru a 270 Ohm and a 15 Ohm resistor (providing negative bias voltage for the audio output tube, etc). C39 probably has its plus connected to the cap can internally and its minus brought out to a connection tab. Without looking at the radio directly the centertap wire and the 270 Ohm resistor probably connect to the C39 cap terminal (the one not marked). Some radios had the can of the cap insulated on a fibre mounting washer, some had the caps insulated from the can with an extra solder terminal. You could probably use a two section cap rated 450 volts or better (using a fibre mounting washer) and use a separate axial cap underneath the chassis for C39.
:
:Radiodoc
:
:
::::::Near as I can figure it is an RCA V210 or V209 radio.
::::::This Cap is connected to pins 1,2,3, and 5 of RF 6SG7 and the other side goes to Pin 4 of the 1st det/Osc 6SA7. The schematic I am looking at is not real easy for me to read...but thats not unusual...
::::::
::::::
::::::
::::::::I am replacing an E Cap that is labeled 2 X 8 @ 475 wv
::::::::Both leads on the postive end connect to same wire.
::::::::Must have been a replacement? I cannot seem to find/ identify this cap on the scehmatic so I am trying to decide if the cap I have on hand would be close enough. I have a 22 mfd @ 450. Should I gopher it?
::::::::bob
:::::::Hi Bob
::::::: Perhaps you could tell us what make and model radio your working with, as to be able to look at the schematic and determine which capacitor is in question.
:::::::Mark
:::::::Hi Bob
::::: Which C Number is this capacitor?
::::
::::After studying the schematic I *think* it is C21 but that was my problem...trying to find the C number to find the value. C21 is a 16 which this dual 8 in parallel would equal to, right? So my question remains will the 22 work since it is 450 wv rather than a 475? OR should I look for something closer?
:::HI Bob
::: Thanks for clearing that up for me, a 22uf will work ok, but you need an equal or higher working voltage than 450vdc, at least 475vdc or higher, I Have some 10uf at 500vdc, if you would like to try a couple of those, they are axial lead, let me know.
:::Mark
::
::Mark,
::Next question...maybe this should be a new string but...I am replacing the Can Cap to this unit. there are 3 caps in the can. Square (15-400) no problem on where to hook up replacement, Triangle (10-400) no problem where to hook up replacement and the 3rd cap with no marking C39 (10-25) connects directly to the punch-out chassis ground terminal and nothing else as far as I can see...so both ends are grounded? Wish I could show you a picture but maybe you understand.
::Bob

1/8/2007 3:14:57 AMPeter G Balazsy

Bob:
The photo shows the connection of C39 + positive end exactly correct as the print clearly shows it should be. Positve end to metal chassis and neg end to the CT.

C37 and c39 each have the positive end connecting to the field coil. C37 on the input of the field coil and c38 to the other side. Both C37 and c38 have their negative leads connected to the CT of the power transformer
( which is NOT the metal chassis ground )
C39 , if you look closely on the print, is shown with it's positive end schematic symbol drawn in opposite direction as c37 and c38. And the C37 + positive terminal goes directly to the metal chassis ground and it's negative (internal neg lead is connected in common inside the can and it connects to the CT of the transformer too.
So to summerize.
You have a CT that is more negative than the chassis ... so that makes the chassis more positive and therefore C39's postive end must connect to the more positive metal chassis.

So connect c37 + pos term to the input of the field coil and c37's negative connects to the CT.
Then connect the + pos end of C38 to the other end of the field coil and connect it's neg end to the CT as well.
Then connect c39's negative to the CT also and the + pos end to the metal chassis.
All three have their negative leads connected in common to the CT and the photo of the old part clearly shows this is exactly how it is connected. The can has all three negative leads tied together inside the can commonly.
Therfore

1/8/2007 3:20:47 AMPeter G Balazsy

CORRECTION OF TYPO:
:Bob:
: The photo shows the connection of C39 + positive end exactly correct as the print clearly shows it should be. Positve end to metal chassis and neg end to the CT.
:
:C37 and c38 each have the positive end connecting to the field coil. C37 on the input of the field coil and c38 to the other side. Both C37 and c38 have their negative leads connected to the CT of the power transformer
: ( which is NOT the metal chassis ground )
:C39 , if you look closely on the print, is shown with it's positive end schematic symbol drawn in opposite direction as c37 and c38.
And the C39 + positive terminal goes directly to the metal chassis ground and it's negative (internal neg lead is connected in common inside the can and it connects to the CT of the transformer too.
:So to summerize.
:You have a CT that is more negative than the chassis ... so that makes the chassis more positive and therefore C39's postive end must connect to the more positive metal chassis.
:
: So connect c37 + pos term to the input of the field coil and c37's negative connects to the CT.
:Then connect the + pos end of C38 to the other end of the field coil and connect it's neg end to the CT as well.
:Then connect c39's negative to the CT also and the + pos end to the metal chassis.
:All three have their negative leads connected in common to the CT and the photo of the old part clearly shows this is exactly how it is connected. The can has all three negative leads tied together inside the can commonly.
:C39's + Positive end connects to the metal chassis ground. C39's negative lead connects to the CT.

1/9/2007 9:53:08 PMBob

:CORRECTION OF TYPO:
::Bob:
:: The photo shows the connection of C39 + positive end exactly correct as the print clearly shows it should be. Positve end to metal chassis and neg end to the CT.
::
::C37 and c38 each have the positive end connecting to the field coil. C37 on the input of the field coil and c38 to the other side. Both C37 and c38 have their negative leads connected to the CT of the power transformer
:: ( which is NOT the metal chassis ground )
::C39 , if you look closely on the print, is shown with it's positive end schematic symbol drawn in opposite direction as c37 and c38.
:And the C39 + positive terminal goes directly to the metal chassis ground and it's negative (internal neg lead is connected in common inside the can and it connects to the CT of the transformer too.
::So to summerize.
::You have a CT that is more negative than the chassis ... so that makes the chassis more positive and therefore C39's postive end must connect to the more positive metal chassis.
::
:: So connect c37 + pos term to the input of the field coil and c37's negative connects to the CT.
::Then connect the + pos end of C38 to the other end of the field coil and connect it's neg end to the CT as well.
::Then connect c39's negative to the CT also and the + pos end to the metal chassis.
::All three have their negative leads connected in common to the CT and the photo of the old part clearly shows this is exactly how it is connected. The can has all three negative leads tied together inside the can commonly.
::C39's + Positive end connects to the metal chassis ground. C39's negative lead connects to the CT.
:
I am getting close to getting this to a test run.
I want to be sure of the last hook up. Can you tell me where the junction of R23 (270 ohm) and the wire that goes to between R20 and R21 (390 ohmers) gets connected to? Originally they are the two connections to the post that comes through the fiber washer of the can. Does it also go to the CT?
Bob

1/10/2007 11:33:04 AMPeter G Balazsy

Yes They go the the CT

1/12/2007 9:30:52 AMBob

:
:
:Yes They go the the CT
:
Peter, Mark, Radiodoc,
Thanks for you input. I powered it up and it speaks!
I have started on the cabinet now. Needs veneer around the bottom where there is water damage as well as some rotting supports, refinishing, etc but that should go smoothly...(famous last words) Bob

1/7/2007 7:36:46 PMRadiodoc

Bob,

C21 on the schematic is shown connected to the screen grid B+ circuit. The schematic shows 95 volts on the screen B+ so the 22 MFD @450 should be sufficient.

Radiodoc

:I am replacing an E Cap that is labeled 2 X 8 @ 475 wv
:Both leads on the postive end connect to same wire.
:Must have been a replacement? I cannot seem to find/ identify this cap on the scehmatic so I am trying to decide if the cap I have on hand would be close enough. I have a 22 mfd @ 450. Should I gopher it?
:bob

1/7/2007 8:37:20 PMBob

:Bob,
:
:C21 on the schematic is shown connected to the screen grid B+ circuit. The schematic shows 95 volts on the screen B+ so the 22 MFD @450 should be sufficient.
:
:Radiodoc
:
:
Thanks doc! I will change it out with the 22 450.
This Forum is great! :O)
::I am replacing an E Cap that is labeled 2 X 8 @ 475 wv
::Both leads on the postive end connect to same wire.
::Must have been a replacement? I cannot seem to find/ identify this cap on the scehmatic so I am trying to decide if the cap I have on hand would be close enough. I have a 22 mfd @ 450. Should I gopher it?
::bob

1/7/2007 11:37:24 PMMike McCarty

:I am replacing an E Cap that is labeled 2 X 8 @ 475 wv
:Both leads on the postive end connect to same wire.
:Must have been a replacement? I cannot seem to find/ identify this cap on the scehmatic so I am trying to decide if the cap I have on hand would be close enough. I have a 22 mfd @ 450. Should I gopher it?
:bob

The rule I apply is that the actual voltage across an electro should be not less than 1/3 of the rated voltage, nor more than 3/4 of the rated voltage. The former ensures that the cap gets more or less formed, and the latter prevents stress. So see what the actual voltage is, and pick a rating between 4/3 and 3x the actual.