Re: Sprague capacitors variants
A couple of other thoughts: The metal cased caps the ad refers to are
probably the Vitamin-Q caps I mentioned. These are metal cases with
glass seals on the ends. I would guess from the description of the
Telecap that they were filled with oil after being molded. The lead on
one side of the cap is tubular and was used for filling, then a wire
lead was soldered into it to seal it and act as the lead on that side.
One mode of failure is that the heat of installing melts out the
sealing solder and allows the oil to leak out. I think the oil filling
was applied only to 600 volt caps, not to the lower voltage ones.
I have dissected a number of these caps. Often the cases are cracked
and sometimes have disintegrated. The cap windings are distorted. Its
possible that might have been done to adjust their values but I doubt
it, I think it is due to mechanical force applied by the casing as it
shrunk or, perhaps, from the oil filling process. In any case, the ads
for the later Telecap indicate they were NOT oil filled.
BB caps with RMA coding seem to have been quite widely used but
don't seem to have come apart in equipment other than the SP-600
suggesting that it was partly due to manufacturing technique at Hammarlund.
FWIW, the Mica-Mold paper caps did not fall apart nor have signs of
mechanical damage. I have no idea how long their lives were. The ones I
replaced in my RCA AR-88 were at least seventy years old. In the AR-88
the caps specified in the original handbook were RCA made mica caps.
Because mica was a strategic material during the war the paper caps were
substituted. Evidently, they performed well enough for RF use. The
original RCA caps, where found, are all good but the Mica-Mold caps must
all be replaced. I was warned about Mica-Mold by my engineering mentor
but that was when they were very old. Mica-Mold made a wide range of
caps, they disappeared around 1948 along with Solar, I have not been
able to find out what happened to either.
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On 4/29/2024 2:45 PM, don Root wrote: Richard, also Jacques and all
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
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Re: Sprague capacitors variants
This is about when molded paper caps were introduced although one
can consider the Mica-Mold flat caps that look like mica to be molded
paper. Those evidently date from the early 1940s since they are found in
WW-2 vintage receivers.
I don't know when Sprague began to use the name Black Beauty for
its caps but must have been about 1950, that is about when the first
SP-600 receivers were built (although advertised earlier). Telecap seems
to have been a replacement trade-name for the former Black Beauty, I
suspect after the BB caps began to fail rapidly. Since the trade
journals made their living off of advertising I suspect there won't be
much about this in them.
Not all molded paper caps had problems, in fact, the BB seems to
have been unique. There were many brands. All paper caps eventually
degrade although some have very long lifetimes. For instance, oil filled
transmitting paper caps can last for decades, but the resin molded ones
and wax paper ones probably had lives of about ten years.
Sprague was a well established company with a reputation for good
quality so the failure of the BB caps must have been a blow to them.
Of course the name Bumble Bee was a nick name given to them long
after they were made, never used by Sprague, and inspired by the RMA
color stripes on them, which were also used on other brands for a time.
Its interesting that Sprague also made the Vitamin-Q paper caps
which have a very good reputation for reliability and long life.
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On 4/29/2024 2:45 PM, don Root wrote: Richard, also Jacques and all
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
|
Re: Sprague capacitors variants
Richard, also Jacques and all re…..The early one does not list any molded paper caps Here is the first ad I found for the molded caps , no telecap or black beauty yet ??? ? ^^ 1948-02? Radio-Maintenance- pdf? 21 --- ? …and the first telecap ad ? ? ^^? 1949-04 RSD- Pdf?? 12 ? ? ? ? And telecaps are referred to by the expression ?[These "Black Beauties"] ?? ^^ 1950-04 Radio-News- pdf?? 16??? -----?? ? then two month later? =? Sprague Black Beauty Telecap? Tubulars ?? ?????????? ???? ^^?? 1950-06 Radio-Maintenance- pdf???? 4? -----? ? ? ? RE ?In any case, I believe these are the replacements for the Black Beauty caps I don’t understand this. ???Black Beauty began in 1950, and ran in ads to 1967. but the construction changed first brought in HCX and later Difilm ? ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Richard Knoppow
Sent: Sunday, April 28, 2024 10:42 PM
To: [email protected]
Subject: Re: [HallicraftersRadios] Sprague capacitors variants? FWIW, I have a couple of hard copy "Radio's Master" catalogues.
Others are on the worldradiohistory.org site. The ones I have are 1947
and 1953. The early one does not list any molded paper caps, the 1953
edition shows Sprague Telecap, called Black Beauty in quotes but without
RMA code striping. These are described as "dry process" caps with the
same qualities as oil filled ones. In any case, I believe these are the
replacements for the Black Beauty caps. I am too lazy to look at the
on-line catalogues but, from memory, it seems to me that BB was used as
a trademark about 1950.
The 1953 catalog also shows Sprague Vitamin-Q caps.
Some older Hewlett-Packard instruments, like early 400D and similar,
have molded sprague caps with RMA coding on them. These do not seem to
have failed and don't show the mechanical disintegration of the caps in
the Hammarlund receivers. I don't know if they are the same caps or not.
The signal corps issued modification work orders to replace all
paper caps in the SP-600 about the mid 1950's, I don't know the exact
date. The caps were replaced with disc ceramic types.
The Black Beauty caps were advertised as "deluxe quality at no
higher price" for use in locations with high heat. Telecaps were
advertised for similar applications especially, as the name implies, in
television sets. Other manufacturers made similar molded caps, for
instance, Cornell-Dublier made Blue Cubs. Paper caps of all types have
limited lives but the Black Beauty seems to have had a special problem.
On 3/25/2024 1:17 PM, Richard Knoppow wrote: Sprague began using the trade name "Telecap" after the Black Beauty
was discontinued. I don't know for certain but think they were the same
capacitor with whatever was wrong fixed. These look like their
advertising illustrations, no stripes, values marked in numerals. Again,
I don't know the exact dates but think the BB problems happened about
the mid or late 1950s.
On 3/25/2024 11:43 AM, Jacques_VE2JFE wrote:
Hi all, I still had, until recently, few “Bumblebee-coded” 0.01?F, 600V
Sprague capacitors that passed all the leakage tests with flying colors.
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998 -- don??? va3drl
|
Re: WTB: 1N3487, NTE506, or equivalent for my PS-150-120
I replaced them with BY133s.? Rating 1.3 kV, 1.0A.? $1.64 for 10 pieces at DK.
Halden VE7UTS
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Re: 5T restoration - IF cans and R4 toasting
Thank-you.? I appreciate your response as I do all feedback I receive.? I've gained a terrific amount of knowledge on these radios from this group and all of its contributors.?
Those caps had been replaced.? The loud "hum" cutting in and out turned out to be one of the rusty trimmers on top of the 2nd IF transformer.? Just touching that one screw could cause the "hum" to come or go, ?I suppose actually a low pitched out of tune IF squeal/motor-boating.? Removal and a good cleaning of the trimmer resolved that issue.? The oddball ohm rating on the coils seems to make no difference to operation.? Replacing the 6AF made no difference to operation despite how the original tube tests. ?I replaced the power transformer with a Stancor P8306 I had on the shelf and although it's a low 40ma supply where I think a 70ma is needed, the radio is alive and working all three bands.? R4 I changed to a 2W resistor and it seems OK at that wattage.? The 1500ohm dummy load for the open field coil will stay.? Since it's going to be more of a mantle type piece rather than a daily player I may leave it that way.? Played the chassis for an hour yesterday and was pleased with it's resurrected performance.? The BFO works too.? I'll get the reworked chassis final assembled and that spring loaded belt drive tuning in working order this week.
Now for the cabinet....
--
Dan
K1DTS
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Re: WTB: 1N3487, NTE506, or equivalent for my PS-150-120
Thank you to all who replied. The diodes have been sourced and purchased.
73,
Jeff
W8KZW
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Re: WTB: 1N3487, NTE506, or equivalent for my PS-150-120
Hi Jeff,
You can find the NTE506's on eBay,? 20 for $20
Or
Otherwise, if it were me replacing diodes in my PS-150-120,? since I have a box of 1N4007's, ? I would double them up (2-per leg in the bridge) if it bothered me to use single 1000V diodes 1 per leg.
--
73/Rick
W4XA
__________________________________
All posts are created using OpenSuSE Leap 15.5 x64 Linux
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Re: Sprague capacitors variants
FWIW, I have a couple of hard copy "Radio's Master" catalogues.
Others are on the worldradiohistory.org site. The ones I have are 1947
and 1953. The early one does not list any molded paper caps, the 1953
edition shows Sprague Telecap, called Black Beauty in quotes but without
RMA code striping. These are described as "dry process" caps with the
same qualities as oil filled ones. In any case, I believe these are the
replacements for the Black Beauty caps. I am too lazy to look at the
on-line catalogues but, from memory, it seems to me that BB was used as
a trademark about 1950.
The 1953 catalog also shows Sprague Vitamin-Q caps.
Some older Hewlett-Packard instruments, like early 400D and similar,
have molded sprague caps with RMA coding on them. These do not seem to
have failed and don't show the mechanical disintegration of the caps in
the Hammarlund receivers. I don't know if they are the same caps or not.
The signal corps issued modification work orders to replace all
paper caps in the SP-600 about the mid 1950's, I don't know the exact
date. The caps were replaced with disc ceramic types.
The Black Beauty caps were advertised as "deluxe quality at no
higher price" for use in locations with high heat. Telecaps were
advertised for similar applications especially, as the name implies, in
television sets. Other manufacturers made similar molded caps, for
instance, Cornell-Dublier made Blue Cubs. Paper caps of all types have
limited lives but the Black Beauty seems to have had a special problem.
toggle quoted message
Show quoted text
On 3/25/2024 1:17 PM, Richard Knoppow wrote: Sprague began using the trade name "Telecap" after the Black Beauty
was discontinued. I don't know for certain but think they were the same
capacitor with whatever was wrong fixed. These look like their
advertising illustrations, no stripes, values marked in numerals. Again,
I don't know the exact dates but think the BB problems happened about
the mid or late 1950s.
On 3/25/2024 11:43 AM, Jacques_VE2JFE wrote:
Hi all, I still had, until recently, few “Bumblebee-coded” 0.01?F, 600V
Sprague capacitors that passed all the leakage tests with flying colors.
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
_._,_._,_
------------------------------------------------------------------------
Groups.io Links:
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
|
Paul
There is a tiny bit of backlash but not bad at all. The piano string on this one is in really good shape. I am thankful it did not need replacing. I do need to align the dials properly. They were off a small amount when I began this project. Good thing thats an easy task now that I have longer spline tools. Now to finish painting the cabinet and reassemble.?
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indispensable, is BASS FIDDLE ROSIN. I treat those pesky dial cords with
it, and they NEVER slip thereafter.? Violin and Cello are too hard a
compound... use the BASS stuff.
Tom - W?EAJ
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Re: 5T restoration - IF cans and R4 toasting
Dan:
?I would check the following capacitors? C4, C6 , C8. These all appear to be bypass capacitors going from B+ to ground. I am just thinking if they were leaky or shorted they might cause the problems you are having.
Just my 2 cents worth, and I hope it helps.
Howard, N9KTW
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Excellent - now let's hear WWV on 2.5, 5, 10, 15 and 20?? :o)? My SX-100 still struggles a bit with this task.
I do know I need a better antenna for sure.
After much patience, the SX100 is working nicely. Very pleased with the results. Pays to not rush. Thank you all for the pointers. Still working on final tweaks, but it’s playing now where before, it was nothing.
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WTB: 1N3487, NTE506, or equivalent for my PS-150-120
Looking to purchase subject diode for my power supply. Maybe 1 or 2 extra just to have around.
Please reach me off list.
Thanks, & 73,
Jeff
W8KZW
|
Keith, ? How much main tuning and bandspread tuning dial backlash do you notice?? I need to dig into my SX-100 and replace several bad caps.? Then to try and disengage the anti-backlash gears which had seized together long ago. Anyone have any luck with that?? If possible, I would really like to avoid restringing the steel “piano string.” ? Paul, W9AC ??? ?
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From: [email protected] <[email protected]> On Behalf Of Bob
Sent: Sunday, April 28, 2024 7:15 PM
To: [email protected]
Subject: Re: [HallicraftersRadios] SX100? ? After much patience, the SX100 is working nicely. Very pleased with the results. Pays to not rush. Thank you all for the pointers. Still working on final tweaks, but it’s playing now where before, it was nothing.
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After much patience, the SX100 is working nicely. Very pleased with the results. Pays to not rush. Thank you all for the pointers. Still working on final tweaks, but it’s playing now where before, it was nothing.
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After much patience, the SX100 is working nicely. Very pleased with the results. Pays to not rush. Thank you all for the pointers. Still working on final tweaks, but it’s playing now where before, it was nothing.
|
On Fri, Apr 26, 2024 at 03:35 PM, Richard Knoppow wrote:
I have lost track here. Have you just shorted the mic connector to
see what happens? If you have does the noise continue?
Yes, that was an early test.? Yes, the noise was still there.? I previously had biased off the first mic stage and the noise disappeared, so I concluded that it wasn't coming from the audio strip.? But, tonight I just removed the mic line at the grid of the second mic amp and the noise was still there.? Not sure why it wasn't there when the first stage was biased off.? Maybe I made an error.? At any rate, it now appears that the noise could be coming from the audio strip at the third mic amp or the audio modulator.? If I pull V5, the 12AT7 audio modulator, the noise is gone.? Next will examine the phase shift network between the third mic amp and the audio modulator.? I know the audio outputs from V5 are equal as I previously had a bad bypass cap in the output and one channel was way down.?? Flyd
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On Fri, Apr 26, 2024 at 03:31 PM, waltcates wrote:
How and where are you sampling when you see the noise.
The noise if being observed (visual and audible) on an external transceiver spectrum scope.? The signal is being sampled at a sampling port on the dummy load and is applied to the monitoring transceiver at a receive-only antenna port. Floyd
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he is talking about the shield on the cable.
Walt Cates, WD0GOF
?
A majority of acceptance is not proof of correctness.
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I have lost track here. Have you just shorted the mic connector to
see what happens? If you have does the noise continue?
On 4/26/2024 12:23 PM, Floyd - K8AC wrote:
Well, the AALC idea didn't pan out.? I disconnected one end of the
diodes and also removed the plate supply from the AALC amplifier stage.
No change whatever.? Also played with the mic? connector lead and there
was no difference in the noise level or pattern with both ends of the
cable grounded vs. just one end.
Floyd
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
|
I have lost track here. Have you just shorted the mic connector to
see what happens? If you have does the noise continue?
toggle quoted message
Show quoted text
On 4/26/2024 12:23 PM, Floyd - K8AC wrote: Well, the AALC idea didn't pan out.? I disconnected one end of the
diodes and also removed the plate supply from the AALC amplifier stage.
No change whatever.? Also played with the mic? connector lead and there
was no difference in the noise level or pattern with both ends of the
cable grounded vs. just one end.
Floyd
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
|
don Root
Rick W7IMM
Donald J
Paul Christensen
Bob
Floyd - K8AC
waltcates