Forums :: NEW! Web Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives
Support This Site: Contributors :: Advertise


It is currently Oct Tue 19, 2021 4:41 pm


All times are UTC [ DST ]





Post New Topic Post Reply  [ 14 posts ] 
Author Message
 Post subject: Sprague TO-5 and Capacitor Color Chart
PostPosted: Sep Sat 18, 2021 4:34 am 
Member

Joined: Feb Sat 20, 2021 3:12 am
Posts: 107
Location: Bryson City, North Carolina
Hello everybody, good wishes to all.

I am trying to find a complete color code chart for sprague caps as I need to replace the bumblebee caps in a sprague TO-5 capacitor analyzer. I finally found a decent one that only needed the power cord replaced and I have done that, and while doing that I checked out its little guts. I found the bumblebees (4 I think) inside along with 2 sprague atoms that I'll be replacing.
I need the complete chart along the tolerance and working voltages. I think I remember 6 bands.
I searched and found plenty of references but no complete chart or only a placeholder for one.
I understand that the bumblebee and black beauty values are all in picofarads. Is that correct?
After checking it out, of course I did have to fire it up to test it out. The only potential problem I found is the voltage adjust, seemed wonky. I may have to pull it to try and fix or replace if deoxit does nothing for it.
Attachment:
20210917_230059.jpg
20210917_230059.jpg [ 154.47 KiB | Viewed 444 times ]

_________________
A complex machine that works evolved from a simple machine that works


Last edited by fixt on Sep Sun 19, 2021 1:42 am, edited 1 time in total.

Top
 Profile  
 
 Post subject: Re: Capacitor Color Chart
PostPosted: Sep Sat 18, 2021 5:40 am 
Member

Joined: Dec Sat 28, 2019 4:18 pm
Posts: 1079
Location: Corinth, TX
https://www.bing.com/images/search?view ... ajaxserp=0
https://www.bing.com/images/search?view ... ajaxserp=0

Google, Bing, or DuckDuckGo is your friend.

John


Last edited by KX5JSC on Sep Sun 19, 2021 12:07 am, edited 1 time in total.

Top
 Profile  
 
 Post subject: Re: Capacitor Color Chart
PostPosted: Sep Sat 18, 2021 6:02 am 
Member

Joined: Feb Sat 20, 2021 3:12 am
Posts: 107
Location: Bryson City, North Carolina
KX5JSC
Thank you very much for that.
For some reason with the google I couldn't find a comprehensive chart. Google has turned to junk for me and I may just swap search engines. It's so full of unrelated stuff that its become painful to use. It didn't use to be like that.

_________________
A complex machine that works evolved from a simple machine that works


Top
 Profile  
 
 Post subject: Re: Capacitor Color Chart
PostPosted: Sep Sat 18, 2021 9:35 pm 
Member
User avatar

Joined: Nov Sat 07, 2009 11:37 pm
Posts: 2914
Location: Sayreville, NJ 08872
From Google, anything and everything you wanted to know about Capacitor Color Code Charts:
https://www.google.com/search?q=capacit ... 9&dpr=1.25

_________________
Pete, WA2CWA - "A cluttered desk is a sign of genius"
https://www.manualman.com


Top
 Profile  
 
 Post subject: Re: Sprague TO-5 and Capacitor Color Chart
PostPosted: Sep Sun 19, 2021 2:48 am 
Member

Joined: Feb Sat 20, 2021 3:12 am
Posts: 107
Location: Bryson City, North Carolina
Alrighty, I'm having trouble figuring this out. I need some help please.
Edit: Serial number is 83102, less than 95001
Print here: http://bama.edebris.com/manuals/sprague/to5
I got the sprague chart and compared it to what I have and they are not matching.
I got 4 caps that are brown, gray, orange, white, yellow. 2 of these are C1 and C2
That's 1 8 000 10% 400 volts or .018 mfd
Another one with yellow, violet, red, white, yellow
That's 4 7 00 10% 400 volts or .0047 mfd
Trouble is there's nothing like that in the parts list when I tried to compare them. C1 and C2 show as .02 mfd 600 volt or 20000pf.
Am I reading this thing right?
Here is a picture so you can see what I'm saying
Attachment:
TO-5.jpg
TO-5.jpg [ 352.64 KiB | Viewed 347 times ]

_________________
A complex machine that works evolved from a simple machine that works


Last edited by fixt on Sep Sun 19, 2021 3:25 am, edited 1 time in total.

Top
 Profile  
 
 Post subject: Re: Sprague TO-5 and Capacitor Color Chart
PostPosted: Sep Sun 19, 2021 3:13 am 
Moderator

Joined: Jan Thu 01, 1970 1:00 am
Posts: 27847
Location: Detroit, MI USA
You are correct with your interpretation of the color bands on those capacitors.

The ones that are shown on the schematic as C8 and C9 and are a multiple factor involving 2 were hand selected to be matched tightly. Usually for C8 you find a .018 with another smaller value in parallel to tweak it up to exactly .02 within about 1% or less tolerance. Sometimes they found caps that did not need an added cap in parallel. Likewise, C9 consists of two caps in parallel to get exactly the multiple of the same value for that range.

Those are extremely cricital to be matched from one range to the other or you won't be able to calibrate the unit to be accurate when changing ranges. Today with a good digital meter and a handful or two of .02's and 1.0's , you can find a set of caps that match close enough to work. For example, if you are able to come up with .0201 for C8 then you must match it with a 2.01 for C9.

There has been plenty of discussion about matching the bridge caps in these units previously on ARF.

_________________
Dennis

Experience is what you gain when the results aren't what you were expecting.


Top
 Profile  
 
 Post subject: Re: Sprague TO-5 and Capacitor Color Chart
PostPosted: Sep Sun 19, 2021 3:19 am 
Member
User avatar

Joined: Feb Mon 22, 2021 1:29 am
Posts: 85
Location: Castro Valley CA
Sprague loved .018µf capacitors. If they are the line bypass, use safety caps. If they are in the bridge and you want to use your TO-5 to accurately measure capacitors be careful and understand the matching required and the % deviation matching between the ranges.
My TO-4 does not have bumblebees in the bridge, it is still working with surprising accuracy with the original matched bridge caps from the factory. My main use is leakage testing of SM capacitors and occasional testing of an electrolytic or two. Keeps me out of trouble!

_________________
Eric


Top
 Profile  
 
 Post subject: Re: Sprague TO-5 and Capacitor Color Chart
PostPosted: Sep Sun 19, 2021 3:21 am 
Member
User avatar

Joined: Feb Mon 22, 2021 1:29 am
Posts: 85
Location: Castro Valley CA
Mr. Detrola types faster than me; as well as providing a more complete answer!

_________________
Eric


Top
 Profile  
 
 Post subject: Re: Sprague TO-5 and Capacitor Color Chart
PostPosted: Sep Sun 19, 2021 4:55 am 
Member

Joined: Feb Sat 20, 2021 3:12 am
Posts: 107
Location: Bryson City, North Carolina
Thanks to both of you, Mr Detrola and Eric E
I don't know about using it to measure caps so much as I got it mainly for checking leakage. That said, I still want it to function as close to factory (or better maybe) as I can get it. That's what test equipment is all about to me. Accuracy.
When I checked a few after first getting it it seemed to be very close but I didn't check all ranges.

Would it be ok to use 1% polystyrene or metallized polypropylene to replace these (if I can find them)?
The .018 value just struck me as a weird value. Lacking experience I haven't seen any before.
Just Radios might have them, he has a lot of old strange values for the older sets. Its the tolerance that's hard to come by.

C8 parts list doesn't address the parallel capacitor though C9 does. I have put it back in the case so I can't check it right quick.
It's a new adventure for me in tracing this circuit.

_________________
A complex machine that works evolved from a simple machine that works


Top
 Profile  
 
 Post subject: Re: Sprague TO-5 and Capacitor Color Chart
PostPosted: Sep Sun 19, 2021 6:10 am 
Member

Joined: Jan Tue 10, 2012 8:39 am
Posts: 2806
0.018 is a standard value, and almost any decent capacitor should work. If it's 1% then put that in.


Top
 Profile  
 
 Post subject: Re: Sprague TO-5 and Capacitor Color Chart
PostPosted: Sep Sun 19, 2021 6:50 am 
Member

Joined: Feb Sat 20, 2021 3:12 am
Posts: 107
Location: Bryson City, North Carolina
That's one of the things that led to my confusion.
There is no .018 listed in the parts list anywhere. They are listed as .02 10% 600 vdc.

_________________
A complex machine that works evolved from a simple machine that works


Top
 Profile  
 
 Post subject: Re: Sprague TO-5 and Capacitor Color Chart
PostPosted: Sep Sun 19, 2021 6:11 pm 
Member

Joined: Dec Sat 28, 2019 4:18 pm
Posts: 1079
Location: Corinth, TX
I think Sprague used hand selected caps off their production line for the "standards" in the TO-5 except for the 200 pf cap in Ranges C1 and C2. There, they used a 180 pf silver mica in parallel with a 30 pf trimmer.

For a complete breakdown of the TO-5:
http://bama.edebris.com/download/spragu ... ersion.pdf

John


Top
 Profile  
 
 Post subject: Re: Sprague TO-5 and Capacitor Color Chart
PostPosted: Sep Sun 19, 2021 6:51 pm 
Member

Joined: Jan Tue 10, 2012 8:39 am
Posts: 2806
Here is how you find the proper value. Look at the dial and the value that is exactly in the center of rotation is the one to use.

It's a comparison bridge. The dial selects the ratio between the standard and the unknown. Center dial is 1:1 ratio.


Top
 Profile  
 
 Post subject: Re: Sprague TO-5 and Capacitor Color Chart
PostPosted: Sep Tue 28, 2021 11:05 pm 
Member

Joined: Feb Sat 20, 2021 3:12 am
Posts: 107
Location: Bryson City, North Carolina
Serial Number 83102 its less than 95001
Today I replaced capacitors in the sprague TO-5. It turned out very well with no calibration required. I had 3 or 4 1% caps to test and do calibration with. I don't have the 50, 80, 2000 mfd caps. I'll just trust it should I need to go that high I guess.
I used 1% 1mfd for C8 and C9 to replace the huge wax capacitors. A picture shows them for size comparison. I did have to slightly modify the capacitor hold down using some weatherstrip and slightly bending the tab that the screw goes in to. Its all good now. The machine was in very good condition, even better now.
I have replaced the leather handle, power cord, five bumblebee caps and two wax/paper 2% 1mfd caps with two 1% 1mfd caps, C8 and C9. The bumblebees were 10% tolerance, including one not shown for the 1629 tube. The 1629 tube is quite legible but you can tell its not as bright as it could be. I may have a couple in some other machines kicking around here. Which is good, they are outrageous on ebay.
I included some pictures of my machine including the replaced caps.
Its reading caps as on the money or so close it doesn't matter. So very glad I bid on this one; I'd been wanting one for a while but the price was always ridiculously high. I bought it as non working and it just needed a cord. It read ok but the new caps really brought out the accuracy these things are capable of.

When I printed out my manual I included the calibration sections by DavidK (I think it was) and Dr. Worry. Many thanks for that great work of information. Also thanks to David Cantelon of Just Radios for carrying such a wide variety of quality stuff for this hobby.

The TO-5
Attachment:
Sprague TO-5.jpg
Sprague TO-5.jpg [ 353.12 KiB | Viewed 141 times ]


The board has been cleaned of flux residue, Sorry didn't get that picture
Attachment:
Sprague Board.jpg
Sprague Board.jpg [ 592.97 KiB | Viewed 141 times ]


Difference in capacitor size is amazing. New ones are the width of the hold down, old ones shown for size comparison.
Attachment:
Sprague Capacitors.jpg
Sprague Capacitors.jpg [ 174.91 KiB | Viewed 141 times ]

_________________
A complex machine that works evolved from a simple machine that works


Top
 Profile  
 
Post New Topic Post Reply  [ 14 posts ] 

All times are UTC [ DST ]


Who is online

Users browsing this forum: xwarp and 16 guests



Search for:
Jump to:  


































Privacy Policy :: Powered by phpBB