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 Post subject: RCA RE-57 condenser bank HELP!!!!!!
PostPosted: Jul Sun 07, 2019 4:15 am 
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Joined: Sep Mon 24, 2018 5:30 am
Posts: 257
Location: Wilmington Ca
Hey Fellas.
After 2 months of research and YouTube I finally got the courage to take
the old RCA RE-57 on.
3 of the 6 caps tested O.L. On my meter so I opened up the bank.
To my surprise, there’s 7 caps in there. I’ve never worked on a bank before so am I missing something??? I really am lost here guys so if anyone has done this before, can you please help me out. Thanks


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 Post subject: Re: RCA RE-57 condenser bank HELP!!!!!!
PostPosted: Jul Sun 07, 2019 4:47 am 
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Joined: Jan Tue 31, 2012 1:55 am
Posts: 8795
Location: Mountains of Mourne. Ireland.
The six capacitors in the filter block can be seen here...
C26
C27
C28
C29
C30
C31

viewtopic.php?p=2986097#p2986097

------------

On pdf-page-576 of this linked service manual, there is an additional capacitor C34 2μF shown (dotted line) - when using a 25 Hz (hertz) aka 25 cycle power transformer.

Maybe that's your guy. lol

RCA-Victor-Service-Notes-1929-1930.pdf 31.7MB
viewtopic.php?p=3051875#p3051875

Greg.
oh... 25 Hz power transformers are considerably larger in (physical) size.


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 Post subject: Re: RCA RE-57 condenser bank HELP!!!!!!
PostPosted: Jul Sun 07, 2019 8:51 pm 
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Joined: Sep Mon 24, 2018 5:30 am
Posts: 257
Location: Wilmington Ca
But there’s still a 7th Cap in there.
I thought the #5 terminal was just for ground but it goes into a cap.
My 2nd picture is the caps in order.
The small one is 1-2 then 8-3-7-6-4-5


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 Post subject: Re: RCA RE-57 condenser bank HELP!!!!!!
PostPosted: Jul Sun 07, 2019 9:25 pm 
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Joined: Jun Sun 15, 2014 11:04 pm
Posts: 1042
Location: Coos Bay, Oregon
Check if two of the caps are paralleled to each other. Some of those are different physical sizes though your diagram indicates they are all the same value (except the smallest one).


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 Post subject: Re: RCA RE-57 condenser bank HELP!!!!!!
PostPosted: Jul Sun 07, 2019 9:47 pm 
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Joined: Jan Tue 31, 2012 1:55 am
Posts: 8795
Location: Mountains of Mourne. Ireland.
Just restuff it according to the schematic.
Image
and... yes, tab five connects to chassis ground.

new capacitors, different radio. lol
viewtopic.php?p=2775663#p2775663

Greg.


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 Post subject: Re: RCA RE-57 condenser bank HELP!!!!!!
PostPosted: Jul Sun 07, 2019 9:55 pm 
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Joined: Apr Sun 01, 2012 9:55 pm
Posts: 10246
Location: Seattle, WA
SpiderLovesBeer wrote:
3 of the 6 caps tested O.L. On my meter so I opened up the bank.
Without knowing what type of meter you were using or what setting you were measuring on, I don't know what the reading should be.

On a modern DVM using an auto-ranging Resistance setting (i.e. Ohms), I would expect to read O.L. with any modern film or mica cap, and that's the 'correct' reading. [Modulo a discussion of whether you should be testing caps with a resistance setting.] The way to interpret the reading is that the internal resistance of the capacitor is so high (i.e. the internal leakage of the capacitor is so low) that the meter can't measure a resistance through the cap, even on the Megohm range.

If the meter does read a resistance, it means the capacitor is leaking enough that it allows the meter to make a reading. It's possible you opened that can up because 3 of the capacitors were good. When you should have been opening it because the other 3 were bad. ;-)

SpiderLovesBeer wrote:
But there’s still a 7th Cap in there.
Are you saying, "It's not the 25Hz model, but there are 7 caps anyway." ???

Can you draw a schematic snippet like your 1st picture, showing the 7th cap in addition to the known 6? What terminal(s) is it connected to, and is it connected to any of the other caps internally?

startgroove wrote:
Some of those are different physical sizes though your diagram indicates they are all the same value
Spider, this can be due to different working voltage ratings on the different caps. I.e. if one is 2µF - 200V, and another is 2µF - 400V. The one with the higher voltage rating will be a larger cap, even though the capacitance is the same.

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Rodney -- KG7EPW
Measure it with a micrometer, mark it with chalk, cut it with a chainsaw.


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 Post subject: Re: RCA RE-57 condenser bank HELP!!!!!!
PostPosted: Jul Sun 07, 2019 10:07 pm 
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Joined: Mar Sun 11, 2007 6:55 am
Posts: 10727
Location: Mission Viejo, southern California
Easy. Just put the new capacitors in the container, connected as indicated. I would use film capacitors. I've not had any problems using the regular yellow 1 and 2 MFD 630VDC unital for such radios.

For larger values needed in other radios, such as 8 MFD, I buy the AC rated film capacitors, many also with a ripple rating on the specifications sheet (see Mouser's web site, and especially the DC-link capacitors).

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 Post subject: Re: RCA RE-57 condenser bank HELP!!!!!!
PostPosted: Jul Mon 08, 2019 1:25 am 
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Joined: Sep Mon 24, 2018 5:30 am
Posts: 257
Location: Wilmington Ca
#4 is in parallel with #5
Then all are connected to #5 except 1&2
Maybe they used two 1mfd for #4 & #5 to make the 2mfd so everything will fit tight in the Bank?
That kind of makes sense.

I’m not sure if it’s a 25Hz or not. I’m new to this.


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 Post subject: Re: RCA RE-57 condenser bank HELP!!!!!!
PostPosted: Jul Mon 08, 2019 2:56 am 
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Joined: Sep Mon 24, 2018 5:30 am
Posts: 257
Location: Wilmington Ca
Thank you guys for all the info.
I’m going to install the caps exactly like that diagram.
#5 will be just a tie point for all the ground leads (except for 1&2)

I’ll be back with an update once I’ve accomplished the mission


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 Post subject: Re: RCA RE-57 condenser bank HELP!!!!!!
PostPosted: Jul Mon 08, 2019 4:01 am 
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Joined: Jan Sun 18, 2015 5:01 am
Posts: 1385
Location: Waxahachie Texas
Here's a link of my RE-57 restoration. It has a lot of detail you'll find interesting.

viewtopic.php?f=6&t=342260

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Crist


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 Post subject: Re: RCA RE-57 condenser bank HELP!!!!!!
PostPosted: Jul Mon 08, 2019 5:19 am 
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Joined: Sep Mon 24, 2018 5:30 am
Posts: 257
Location: Wilmington Ca
Holy Smokes Christ....
WOW!!!!!!!!!!!!!!
I think I might’ve bit off more than I can chew on this one.
Outstanding job on that one.
You made my day with all that info but ruined my day at the same time.
Hahahaha
You know what though, I’m going to give it my all. Not sure if I can pull
It off like what you did but I’ll try.
Thank you so much for that.
Thank you all... May The Radio Gods be with me on my journey.


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 Post subject: Re: RCA RE-57 condenser bank HELP!!!!!!
PostPosted: Jul Mon 08, 2019 5:31 am 
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Joined: Sep Mon 24, 2018 5:30 am
Posts: 257
Location: Wilmington Ca
one more thing Christ..
What did you do with that 7th CAP???


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 Post subject: Re: RCA RE-57 condenser bank HELP!!!!!!
PostPosted: Jul Mon 08, 2019 5:32 am 
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Joined: Sep Mon 24, 2018 5:30 am
Posts: 257
Location: Wilmington Ca
Sorry. Crist


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 Post subject: Re: RCA RE-57 condenser bank HELP!!!!!!
PostPosted: Jul Mon 08, 2019 2:41 pm 
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Joined: Jan Sun 18, 2015 5:01 am
Posts: 1385
Location: Waxahachie Texas
SpiderLovesBeer wrote:
one more thing Christ..
What did you do with that 7th CAP???


IIRC, looking at my picture, I think one of the "caps" was just a spacer. Most likely the 2nd one from the left.

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Crist


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 Post subject: Re: RCA RE-57 condenser bank HELP!!!!!!
PostPosted: Jul Mon 08, 2019 7:53 pm 
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Joined: Sep Mon 24, 2018 5:30 am
Posts: 257
Location: Wilmington Ca
Ok cool. Thanx
I’m just waiting on the new caps now


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 Post subject: Re: RCA RE-57 condenser bank HELP!!!!!!
PostPosted: Jul Sun 14, 2019 12:01 am 
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Joined: Sep Mon 24, 2018 5:30 am
Posts: 257
Location: Wilmington Ca
Not as clean as yours Crist but I think It’ll work just fine.
No one will ever see it anyway right. Thanx for your outstanding attention to detail on your restoration.


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 Post subject: Re: RCA RE-57 condenser bank HELP!!!!!!
PostPosted: Jul Sun 14, 2019 5:38 am 
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Joined: Jan Sun 18, 2015 5:01 am
Posts: 1385
Location: Waxahachie Texas
Thanks. Getting there. Just take your time and enjoy the experience.

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Crist


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