Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Posted to sci.electronics.repair,rec.antiques.radio+phono
external usenet poster
 
Posts: 411
Default Painting a Bakelite radio cabinet

I picked up a RCA Victor 66X2 Radio from 1946-47. It's a very unusual
radio. It is AM broadcast band and one Shortwave band. Amazingly this
radio worked right away, except for the broken dial string and a power
cord that needs to be replaced soon. All the tubes appear to be
original, and all capacitors appear to be original too. Even the filter
cap appears original, and there is no hum.

Other than replace the cord and dial string, I dont plan to do anything
with the components for now, except add a fuse.

The bakelite case is solid, but badly scratched. The bakelite under the
Ivory paint is black. This radio sold in black (unpainted - model 66X1),
Painted Ivory - Model 66X2, and two additional woodgrain models.

My plan is to remove the case from the chassis, remove or tape up the
grill cloth and trim. Then spray paint it with an Ivory colored spray
paint. (after sanding it with some very fine sandpaper to clean up all
scratches).

My question is whether I can use a common spray paint on bakelite, such
as Rustoleum? I may not get the exact color as original, but I dont see
any way to get the original paint.

Have any of you painted bakelite? Will common spray paint work on it?

One other thing, the dial bulbs are burned out. Bayonette base, wired in
series, two 3.2 volt bulbs. A schematic shows them as Mazda 1490. ( I
never heard of Mazda bulbs). Anyhow, where can I get such bulbs?
The bayonette base is the same as a #47 bulb.

BTW: The 6 volt feeding them comes from the filament center tap in the
35Z5 rectifier tube. How they get 6volts from that center tap evades me,
but that's how it is.....



Thanks

  #3   Report Post  
Posted to sci.electronics.repair,rec.antiques.radio+phono
external usenet poster
 
Posts: 201
Default Painting a Bakelite radio cabinet

In article ,
wrote:

The bakelite case is solid, but badly scratched. The bakelite under the
Ivory paint is black. This radio sold in black (unpainted - model 66X1),
Painted Ivory - Model 66X2, and two additional woodgrain models.

My plan is to remove the case from the chassis, remove or tape up the
grill cloth and trim. Then spray paint it with an Ivory colored spray
paint. (after sanding it with some very fine sandpaper to clean up all
scratches).

My question is whether I can use a common spray paint on bakelite, such
as Rustoleum? I may not get the exact color as original, but I dont see
any way to get the original paint.


http://www.radiomuseum.org/forum/vin...abinets. html
has a good discussion of this.

He doesn't mention any specific sort of paint being required, but does
recommend spraying on a coat of primer after a thorough
cleaning... probably a good idea to help ensure good adhesion.

I recall that Rustoleum makes some paint varieties which are specified
as being suitable for use on plastics. This sort of multi-surface
paint might give you some additional defense against peeling, if you
decide to omit the primer step.
  #4   Report Post  
Posted to sci.electronics.repair,rec.antiques.radio+phono
external usenet poster
 
Posts: 399
Default Painting a Bakelite radio cabinet

Dave Platt wrote on 9/26/2017 3:42 PM:
In article ,
wrote:

The bakelite case is solid, but badly scratched. The bakelite under the
Ivory paint is black. This radio sold in black (unpainted - model 66X1),
Painted Ivory - Model 66X2, and two additional woodgrain models.

My plan is to remove the case from the chassis, remove or tape up the
grill cloth and trim. Then spray paint it with an Ivory colored spray
paint. (after sanding it with some very fine sandpaper to clean up all
scratches).

My question is whether I can use a common spray paint on bakelite, such
as Rustoleum? I may not get the exact color as original, but I dont see
any way to get the original paint.


http://www.radiomuseum.org/forum/vin...abinets. html
has a good discussion of this.

He doesn't mention any specific sort of paint being required, but does
recommend spraying on a coat of primer after a thorough
cleaning... probably a good idea to help ensure good adhesion.

I recall that Rustoleum makes some paint varieties which are specified
as being suitable for use on plastics. This sort of multi-surface
paint might give you some additional defense against peeling, if you
decide to omit the primer step.


It all depends on the details. I used a paint for plastic to use on a
plastic container and it did not work well at all. I cleaned the surface
well, but did not rough it up and did not use a primer. It was not too long
before the paint started to peel. I don't know the type of plastic. It was
a food storage container with a seal ring commonly available in stores.
Just a data point for what it is worth.

--

Rick C

Viewed the eclipse at Wintercrest Farms,
on the centerline of totality since 1998
  #5   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 12,364
Default Painting a Bakelite radio cabinet

On Tuesday, 26 September 2017 22:14:42 UTC+1, rickman wrote:

It all depends on the details. I used a paint for plastic to use on a
plastic container and it did not work well at all. I cleaned the surface
well, but did not rough it up and did not use a primer. It was not too long
before the paint started to peel. I don't know the type of plastic. It was
a food storage container with a seal ring commonly available in stores.
Just a data point for what it is worth.


Nothing sticks to polythene.


NT


  #6   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 12,364
Default Painting a Bakelite radio cabinet

On Tuesday, 26 September 2017 20:42:20 UTC+1, Dave Platt wrote:
In article ,
wrote:

The bakelite case is solid, but badly scratched. The bakelite under the
Ivory paint is black. This radio sold in black (unpainted - model 66X1),
Painted Ivory - Model 66X2, and two additional woodgrain models.

My plan is to remove the case from the chassis, remove or tape up the
grill cloth and trim. Then spray paint it with an Ivory colored spray
paint. (after sanding it with some very fine sandpaper to clean up all
scratches).

My question is whether I can use a common spray paint on bakelite, such
as Rustoleum? I may not get the exact color as original, but I dont see
any way to get the original paint.


http://www.radiomuseum.org/forum/vin...abinets. html
has a good discussion of this.

He doesn't mention any specific sort of paint being required, but does
recommend spraying on a coat of primer after a thorough
cleaning... probably a good idea to help ensure good adhesion.

I recall that Rustoleum makes some paint varieties which are specified
as being suitable for use on plastics. This sort of multi-surface
paint might give you some additional defense against peeling, if you
decide to omit the primer step.


I've seen seasoned restorers use car spray paint, vauxhall brazil brown for bakelite.

When getting a colour match I always give the sample a good clean first, otherwise the wrong colour is inevitable.


NT
  #8   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 12,364
Default Painting a Bakelite radio cabinet

On Tuesday, 26 September 2017 23:43:46 UTC+1, rickman wrote:
tabbypurr wrote on 9/26/2017 6:31 PM:
On Tuesday, 26 September 2017 22:14:42 UTC+1, rickman wrote:

It all depends on the details. I used a paint for plastic to use on a
plastic container and it did not work well at all. I cleaned the surface
well, but did not rough it up and did not use a primer. It was not too long
before the paint started to peel. I don't know the type of plastic. It was
a food storage container with a seal ring commonly available in stores.
Just a data point for what it is worth.


Nothing sticks to polythene.


Are you in the UK? Is that what we call polyethylene? How does it happen
that we end up with different names for things like common plastic?


Yes, yes, it's easier to say. Polythene is the next best thing to ptfe when you want to keep friction low. Handy for moving heavy loads. Food storage containers are most commonly polythene.


NT
  #9   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 201
Default Painting a Bakelite radio cabinet

In article , rickman wrote:
wrote on 9/26/2017 6:31 PM:


Nothing sticks to polythene.


Are you in the UK? Is that what we call polyethylene? How does it happen
that we end up with different names for things like common plastic?


Tradition. It dates back at least as far as the day when we Americans
decided we couldn't afford to spell the new metal "aluminium" due to a
severe shortage of printers' slugs for the letter "i". :-)






  #10   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 12,364
Default Painting a Bakelite radio cabinet

On Wednesday, 27 September 2017 00:16:44 UTC+1, Dave Platt wrote:
In article , rickman wrote:
tabbypurr wrote on 9/26/2017 6:31 PM:


Nothing sticks to polythene.


Are you in the UK? Is that what we call polyethylene? How does it happen
that we end up with different names for things like common plastic?


Tradition. It dates back at least as far as the day when we Americans
decided we couldn't afford to spell the new metal "aluminium" due to a
severe shortage of printers' slugs for the letter "i". :-)


Pedant mode on. Most plastics have a short common name for obvious reason. IIRC Mr. Webster's rewrite of American spelling occurred well before plastics in the 1800s.


NT


  #11   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 1,625
Default Painting a Bakelite radio cabinet

On Tuesday, September 26, 2017 at 7:16:44 PM UTC-4, Dave Platt wrote:

Actually, consider the additional i in Aluminium, and all those Us such as colour, behaviour an more, going on since the days of Shakespeare and before.

If you allow a cost of GBP 0.01/100 such extra letters, and for round figures consider that the average number of printed & written such letters is around two billion per year, that comes to GBP 200,000 per year. Since about 1590. Consider the miracle of compound interest - and what that would be worth today, not including all the additional years. What a waste!

That initial 200,000 would be worth GBP 807,434,220 +/- today. Boggles the mind.

http://www.angelfire.com/va3/timshenk/codes/meihem.html

Peter Wieck
Melrose Park, PA
  #13   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 1,625
Default Painting a Bakelite radio cabinet

On Wednesday, September 27, 2017 at 3:39:23 PM UTC-4, rickman wrote:


The question is what is the cost of conversion? Tell you what. If the UK
converts from colour to color and aluminium to aluminum and a few incidental
others, the US will convert fully to metric. I think both are equally
likely unfortunately.


There is no cost to delete letters in future printings. There are massive costs associated with retooling. Emphasis on "Future". Engraved plates, and so forth may be left as-is. It would be new plates and so forth that would realize the savings.

Peter Wieck
Melrose Park, PA
  #14   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 12,364
Default Painting a Bakelite radio cabinet

On Wednesday, 27 September 2017 20:52:51 UTC+1, wrote:
On Wednesday, September 27, 2017 at 3:39:23 PM UTC-4, rickman wrote:


The question is what is the cost of conversion? Tell you what. If the UK
converts from colour to color and aluminium to aluminum and a few incidental
others, the US will convert fully to metric. I think both are equally
likely unfortunately.


There is no cost to delete letters in future printings. There are massive costs associated with retooling. Emphasis on "Future". Engraved plates, and so forth may be left as-is. It would be new plates and so forth that would realize the savings.

Peter Wieck
Melrose Park, PA


the imagined savings were based on 1p per letter, which has nothing to do with reality.


NT
  #15   Report Post  
Posted to sci.electronics.repair,rec.antiques.radio+phono
external usenet poster
 
Posts: 3
Default Painting a Bakelite radio cabinet

In article ,
wrote:

One other thing, the dial bulbs are burned out. Bayonette base, wired in
series, two 3.2 volt bulbs. A schematic shows them as Mazda 1490. ( I
never heard of Mazda bulbs). Anyhow, where can I get such bulbs?
The bayonette base is the same as a #47 bulb.

BTW: The 6 volt feeding them comes from the filament center tap in the
35Z5 rectifier tube. How they get 6volts from that center tap evades me,
but that's how it is.....

This looks to be the schematic for the set. It's an AA6, with an RF
amplifier ahead of the converter.
http://www.nostalgiaair.org/pagesbym...6/M0015076.pdf

We used to use schematics of sets like these back in the 1950's and
'60's as interview questions for EE and technician canditates. One very
good one was "talk to me about the rectifier circuit."

Understanding the circuit starts with understanding basic electricity,
particularly Kirchoff's current law and Thévenin's theorem. What you
are calling a "center tap" between pins 2-3 of a 35Z5 is at the 21.5%
point of the heater, not the center. According to the RCA data sheets,
with 35 volts between pins 2 and 7, you'll see 7.5 volts across pins
2-3. Now add a #47 (6.3v 150 ma.) bulb across pins 2 and 3, and feed
the plate from pin 3. RCA claims that the voltage across pins 2-3 (and
the bulb), with a 60 ma. draw on the cathode is now 5.5 volts and
between pins 2-7, 32 volts.

That, of course, doesn't "add up." Assuming RMS values, a 150 ma.
heater plus 60 ma. of DC is only 210 ma. RMS, which should explain the
lower voltage between pins 2-3. However, also consider that current
flow in the plate circuit, with a 40 mike cap connected to the cathode
is a pulse, not a full half sine wave, and that RCA measurements were
made with a VTVM, which isn't a "true RMS instrument." Those pulses,
and the low thermal inertia of the pilot lamp filament(s) explains why
the bulb is at full brilliance when the set is warmed up and playing.

Another "trick" to the series circuit is that during warmup, the series
filaments are a voltage divider that is essentially constant for any
current passing through the heater string. These heaters have a steep
positive temperature (heat/ohms) coefficient, so the startup current is
more like 1.5 amps. If you are going to fuse the radio, you need to
measure the resistance of the filament string cold, and work from there.

That's for starters.

Now, as to the rest of the set, take a look at the B+ circuit and
voltages. The tube data sheets give 100 volts on both plate and screen
as "typical operation" points for AA5 tubes. However, this set says 76
volts. Also note that "typical operation" specs an initial bias (-1
volt for 12SK7), while this set has the cathodes of the RF tubes
grounded.

Yes, that schematic is a very good interview subject.

Don't get foxed by "Mazda." That was a GE trademark from around 1910 to
denote "tungsten filament," and was licensed by other bulb
manufacturers. GE dropped using it in 1945. If you need bulbs, a 1490
is a 1490, readily available today.

If you are going to play the radio without recapping, the critical caps
are the coupling caps between stages, particularly the cap feeding the
audio power amp. Also, check the value of the grid leak resistor(s).
You should see zero volts DC at the grid of the 35L6.

The AA5 (and AA6) are, with the DC-3 airplane, and the GG-1 locomotive,
standout classics of American design. They look "simple" but there's a
lot of thinking that made them robust and reliable without being
complicated.

Hank



  #16   Report Post  
Posted to sci.electronics.repair,rec.antiques.radio+phono
external usenet poster
 
Posts: 12,924
Default Painting a Bakelite radio cabinet

rickman wrote:

It all depends on the details. I used a paint for plastic to use on a
plastic container and it did not work well at all. I cleaned the
surface well, but did not rough it up and did not use a primer. It
was not too long before the paint started to peel. I don't know the
type of plastic. It was a food storage container with a seal ring
commonly available in stores. Just a data point for what it is worth.



If you are talking about 'Tupperware' type containers, that plastic
is the lowest grade available. It won't hold paint, and common adhesives
won't stick to it.

--
Never **** off an Engineer!

They don't get mad.

They don't get even.

They go for over unity! ;-)
  #17   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 12,364
Default Painting a Bakelite radio cabinet

On Thursday, 28 September 2017 11:55:48 UTC+1, Michael Terrell wrote:
rickman wrote:


It all depends on the details. I used a paint for plastic to use on a
plastic container and it did not work well at all. I cleaned the
surface well, but did not rough it up and did not use a primer. It
was not too long before the paint started to peel. I don't know the
type of plastic. It was a food storage container with a seal ring
commonly available in stores. Just a data point for what it is worth.



If you are talking about 'Tupperware' type containers, that plastic
is the lowest grade available. It won't hold paint, and common adhesives
won't stick to it.


They're food grade. Nothing sticks to polythene unless you torch it first or weld it.


NT
  #18   Report Post  
Posted to sci.electronics.repair,rec.antiques.radio+phono
external usenet poster
 
Posts: 411
Default Painting a Bakelite radio cabinet

On Thu, 28 Sep 2017 06:27:49 -0000 (UTC),
(Hank) wrote:

In article ,
wrote:

One other thing, the dial bulbs are burned out. Bayonette base, wired in
series, two 3.2 volt bulbs. A schematic shows them as Mazda 1490. ( I
never heard of Mazda bulbs). Anyhow, where can I get such bulbs?
The bayonette base is the same as a #47 bulb.

BTW: The 6 volt feeding them comes from the filament center tap in the
35Z5 rectifier tube. How they get 6volts from that center tap evades me,
but that's how it is.....

This looks to be the schematic for the set. It's an AA6, with an RF
amplifier ahead of the converter.
http://www.nostalgiaair.org/pagesbym...6/M0015076.pdf

We used to use schematics of sets like these back in the 1950's and
'60's as interview questions for EE and technician canditates. One very
good one was "talk to me about the rectifier circuit."

Understanding the circuit starts with understanding basic electricity,
particularly Kirchoff's current law and Thévenin's theorem. What you
are calling a "center tap" between pins 2-3 of a 35Z5 is at the 21.5%
point of the heater, not the center. According to the RCA data sheets,
with 35 volts between pins 2 and 7, you'll see 7.5 volts across pins
2-3. Now add a #47 (6.3v 150 ma.) bulb across pins 2 and 3, and feed
the plate from pin 3. RCA claims that the voltage across pins 2-3 (and
the bulb), with a 60 ma. draw on the cathode is now 5.5 volts and
between pins 2-7, 32 volts.

That, of course, doesn't "add up." Assuming RMS values, a 150 ma.
heater plus 60 ma. of DC is only 210 ma. RMS, which should explain the
lower voltage between pins 2-3. However, also consider that current
flow in the plate circuit, with a 40 mike cap connected to the cathode
is a pulse, not a full half sine wave, and that RCA measurements were
made with a VTVM, which isn't a "true RMS instrument." Those pulses,
and the low thermal inertia of the pilot lamp filament(s) explains why
the bulb is at full brilliance when the set is warmed up and playing.

Another "trick" to the series circuit is that during warmup, the series
filaments are a voltage divider that is essentially constant for any
current passing through the heater string. These heaters have a steep
positive temperature (heat/ohms) coefficient, so the startup current is
more like 1.5 amps. If you are going to fuse the radio, you need to
measure the resistance of the filament string cold, and work from there.

That's for starters.

Now, as to the rest of the set, take a look at the B+ circuit and
voltages. The tube data sheets give 100 volts on both plate and screen
as "typical operation" points for AA5 tubes. However, this set says 76
volts. Also note that "typical operation" specs an initial bias (-1
volt for 12SK7), while this set has the cathodes of the RF tubes
grounded.

Yes, that schematic is a very good interview subject.

Don't get foxed by "Mazda." That was a GE trademark from around 1910 to
denote "tungsten filament," and was licensed by other bulb
manufacturers. GE dropped using it in 1945. If you need bulbs, a 1490
is a 1490, readily available today.

If you are going to play the radio without recapping, the critical caps
are the coupling caps between stages, particularly the cap feeding the
audio power amp. Also, check the value of the grid leak resistor(s).
You should see zero volts DC at the grid of the 35L6.

The AA5 (and AA6) are, with the DC-3 airplane, and the GG-1 locomotive,
standout classics of American design. They look "simple" but there's a
lot of thinking that made them robust and reliable without being
complicated.

Hank


Thanks for the detailed explanation. I had a suspicion that the "center
tap" of the rectifier tube was not actually CENTER. The more I work on
these old sets, the more I notice that they are all pretty much the
same, particularly if it's the same brand. One website I looked at, said
that the chassis is a number -xxxx-. (I forget the number, but it was a
4 digit number 10__). I guess that means this same chassis was used in
other RCA radios, not just these 66X_ (1 thru 4) models. But considering
the years they were made, that makes sense. They produced the chassis
and made numerous cabinets to fit around them.

I have to say that I am highly impressed that this 70 year old radio
still works, with it's old caps and all. I have considered recapping it,
or at least the critical caps and the power supply filter caps. But then
again, "if it works, dont fix it". Having it power up with no hum, was
what impressed me most, since the electrolytics are usually bad.

Thanks for explaining that "Mazda". That had me puzzled. In all the
years I have worked on this stuff, that is the first time I saw that
word used. I should have suspected it was a trademark....

That schematic is clearer and better than the one I had, so that will
help too.

  #19   Report Post  
Posted to sci.electronics.repair,rec.antiques.radio+phono
external usenet poster
 
Posts: 164
Default Painting a Bakelite radio cabinet

On 9/28/2017 10:44 AM, wrote:
I have to say that I am highly impressed that this 70 year old radio
still works, with it's old caps and all. I have considered recapping it,
or at least the critical caps and the power supply filter caps. But then
again, "if it works, dont fix it". Having it power up with no hum, was
what impressed me most, since the electrolytics are usually bad.


Are you stupid, or do you just try to appear to be stupid?

"It works."
Yeah, right up until it doesn't and fries an IF transformer or something
else like one of the vacuum tubes.

A couple of examples:
1. A late '40s vintage Artone AM/FM/Phono console my parents bought new.
It was working when I left home in 1972. I pulled the chassis around
2001 and turned it on. I worked for about 10 minutes and paaaf! one of
the paper caps self-destructed. I replaced that one and tried it again.
This time it lasted 3 minutes and pafff! another paper cap went away.
After I changed the 4th one, I just replaced the remaining ones.'
After another 15 minutes the one of the filter caps self destructed.
I replaced all of them.
The radio sits in my living room and has been working fine for the past
16 years.
2. A Hallicrafters SX-110 general coverage receiver. It looked like new
and had the matching speaker. I set it on the work bench at the shop in
2007. Turned it on, and it worked perfectly. After 20 minutes the audio
slowly dropped to zero. I turned it off to checked what happened. The
filter can was hot enough to fry eggs.
I recapped the radio and gave it to a friend of mine. It's still working
perfectly and is one of his favorite radios.

But, by all means, do whatever you want.
Solid technical advice is wasted on you.



--
Jeff-1.0
wa6fwi
http://www.foxsmercantile.com
  #20   Report Post  
Posted to sci.electronics.repair,rec.antiques.radio+phono
external usenet poster
 
Posts: 35
Default Painting a Bakelite radio cabinet

On Thu, 28 Sep 2017 16:10:58 -0500, Foxs Mercantile wrote:

On 9/28/2017 10:44 AM, wrote:
I have to say that I am highly impressed that this 70 year old radio
still works, with it's old caps and all. I have considered recapping
it,
or at least the critical caps and the power supply filter caps. But
then again, "if it works, dont fix it". Having it power up with no hum,
was what impressed me most, since the electrolytics are usually bad.


Are you stupid, or do you just try to appear to be stupid?

"It works."
Yeah, right up until it doesn't and fries an IF transformer or something
else like one of the vacuum tubes.

A couple of examples:
1. A late '40s vintage Artone AM/FM/Phono console my parents bought new.
It was working when I left home in 1972. I pulled the chassis around
2001 and turned it on. I worked for about 10 minutes and paaaf! one of
the paper caps self-destructed. I replaced that one and tried it again.
This time it lasted 3 minutes and pafff! another paper cap went away.
After I changed the 4th one, I just replaced the remaining ones.'
After another 15 minutes the one of the filter caps self destructed.
I replaced all of them.
The radio sits in my living room and has been working fine for the past
16 years.
2. A Hallicrafters SX-110 general coverage receiver. It looked like new
and had the matching speaker. I set it on the work bench at the shop in
2007. Turned it on, and it worked perfectly. After 20 minutes the audio
slowly dropped to zero. I turned it off to checked what happened. The
filter can was hot enough to fry eggs.
I recapped the radio and gave it to a friend of mine. It's still working
perfectly and is one of his favorite radios.

But, by all means, do whatever you want.
Solid technical advice is wasted on you.


Jeff was lucky, his capacitors failed quickly while he still had the
radio apart. My experience was different, each one lasted months, so I
ended up taking the set apart numerous times to replace one capacitor
each time. I learned from that, now I replace them all at one go. But
if you like taking things apart repeatedly, that's up to you.

--
Jim Mueller


To get my real email address, replace wrongname with eggmen.
Then replace nospam with expressmail. Lastly, replace com with dk.


  #21   Report Post  
Posted to sci.electronics.repair,rec.antiques.radio+phono
external usenet poster
 
Posts: 164
Default Painting a Bakelite radio cabinet

On 9/28/2017 5:09 PM, Jim Mueller wrote:
Jeff was lucky, his capacitors failed quickly while he still had the
radio apart. My experience was different, each one lasted months, so I
ended up taking the set apart numerous times to replace one capacitor
each time. I learned from that, now I replace them all at one go.

The Artone was the third set I worked once I decide I was going to play
with old radios. The first was a Signatone code practice oscillator and
every cap and resistor was bad in it. The second was a Columbia phono,
AC/DC/Battery portable with a wind up clockwork mechanism.

After about ten years of playing with vintage tube gear, I opened a shop
to do this for profit. This means when you fix a radio, it has to stay
fixed once it goes out the door.

But if you like taking things apart repeatedly, that's up to you.


"You can't fix stupid."

--
Jeff-1.0
wa6fwi
http://www.foxsmercantile.com
  #22   Report Post  
Posted to sci.electronics.repair,rec.antiques.radio+phono
external usenet poster
 
Posts: 411
Default Painting a Bakelite radio cabinet

On 28 Sep 2017 22:09:50 GMT, Jim Mueller wrote:

Jeff was lucky, his capacitors failed quickly while he still had the
radio apart. My experience was different, each one lasted months, so I
ended up taking the set apart numerous times to replace one capacitor
each time. I learned from that, now I replace them all at one go. But
if you like taking things apart repeatedly, that's up to you.


Considering my age, it probably dont matter, but I bet all the modern
caps will fail in far less time than those old paper caps. Nothing these
days is made as well as in the old days. Caps that are still working
after 70 years were not poorly made. I think a lot of that was because
in those days, people had respect for their customers, anad wanted the
name of their company to stand out. That was before our "throw away
society". That is no longer the case.

Add to that, the fact that most caps are now made in China, and I know
they wont last. I try to get all NOS Orange Drop caps. They were made in
the USA and were top of the line. They cost more, but are the only ones
I consider worth buying.

  #23   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 12,364
Default Painting a Bakelite radio cabinet

On Friday, 29 September 2017 03:31:04 UTC+1, wrote:
On 28 Sep 2017 22:09:50 GMT, Jim Mueller wrote:

Jeff was lucky, his capacitors failed quickly while he still had the
radio apart. My experience was different, each one lasted months, so I
ended up taking the set apart numerous times to replace one capacitor
each time. I learned from that, now I replace them all at one go. But
if you like taking things apart repeatedly, that's up to you.


Considering my age, it probably dont matter, but I bet all the modern
caps will fail in far less time than those old paper caps. Nothing these
days is made as well as in the old days. Caps that are still working
after 70 years were not poorly made. I think a lot of that was because
in those days, people had respect for their customers, anad wanted the
name of their company to stand out. That was before our "throw away
society". That is no longer the case.

Add to that, the fact that most caps are now made in China, and I know
they wont last. I try to get all NOS Orange Drop caps. They were made in
the USA and were top of the line. They cost more, but are the only ones
I consider worth buying.


Capacior reliability is another topic to learn about. The 3 unreliable types are electrolytic, paper and multilayer ceramic. Other types are extremely reliable. Unfortunately most 1950s or earlier small caps are paper, and most are well & truly shot now. Replacing old papers with new plastic film is a big reliability & longevity upgrade.


NT
  #24   Report Post  
Posted to sci.electronics.repair,rec.antiques.radio+phono
external usenet poster
 
Posts: 164
Default Painting a Bakelite radio cabinet

On 9/28/2017 8:29 PM, wrote:
Considering my age, it probably dont matter, but I bet all the modern
caps will fail in far less time than those old paper caps. Nothing these
days is made as well as in the old days. Caps that are still working
after 70 years were not poorly made. I think a lot of that was because
in those days, people had respect for their customers, anad wanted the
name of their company to stand out. That was before our "throw away
society". That is no longer the case.


Of for ****'s sake.
You are one ignorant son of a bitch.

Caps made "back then" were made with non-archival, i.e. acid bearing
paper. They were sealed with bee's way which was hygroscopic. Moisture
reacted with the acid in the paper and that was the end of that.

Modern capacitors are made with a metalized mylar film and have a
service life measured in hundreds if not thousands of years.

Modern electrolytic capacitors have improved 10 fold over the years.

Add to that, the fact that most caps are now made in China, and I know
they wont last. I try to get all NOS Orange Drop caps. They were made in
the USA and were top of the line. They cost more, but are the only ones
I consider worth buying.


"A fool and his money are soon parted."

While you're at it, why not buy NOS Black Beauty capacitors.


--
Jeff-1.0
wa6fwi
http://www.foxsmercantile.com
  #25   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 446
Default Painting a Bakelite radio cabinet

On Thursday, September 28, 2017 at 10:31:04 PM UTC-4, wrote:


Add to that, the fact that most caps are now made in China, and I know
they wont last.




LOL! You *are* one stupid son of a bitch. There, I said it.

Even the worse plastic caps will outlast any paper and wax cap (one exception for another thread). I've been using these Chinese caps to restore old radios for 20 years and not one has failed. But by all means, keep using those paper caps and destroy tubes and transformers that are no longer in production - in *any* country...

And even if you were to believe your own bull****, do you really think caps that are already 70 years old have any reliability left in them, more than a brand new Chinese plastic cap?

Jeff says you can't fix stupid. My older brother says you can fix stupid but you can't fix *really* stupid. I think you qualify as the latter.




  #26   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 1,625
Default Painting a Bakelite radio cabinet

A bit of history might help you understand things. Once upon a time, light switches and receptacles were designed to be able to handle AC and DC. What happens when switching DC? Arcing. So, switches and receptacles, and switches in everything from lamps to toaster had to be arc-resistant. In addition, manufacturers did not have 100 years of historical data to design from. So, things were over-designed (by modern standards), heavy (by modern standards) and many have withstood the test of time and survive to this day. Today, switches are either AC or DC, designed to very specific standards, and as long as they are used within those standards, will also last indefinitely.

Capacitors started as foil-and-glass devices, evolving to foil-and-paper (cheap) sealed with paraffin wax + some bees wax for workability (cheap), and some were potted in tar (even then, manufacturers understood that the materials had self-decay problems) and various other methods were tried - and discarded over time. BUT, remember, EVERYTHING WAS NEW back in those days. Nobody had 100+ years of data to use, and what we understand today as being very short blind alleys were enticing options. So, there is a LOT of crap out there that was perfectly functional when made. Electrolytics evolved similarly and improved similarly. As did resistors, even tubes. Nuvistors, developed about the same times as reliable transistors, were thought then, and perhaps still, to have a pretty-much indefinite service-life as compared to a standard tube.

So, now the evolution of consumer-grade electronic components, caps, resistors, transistors, and so forth, has made them into commodities based on unprotected (no patent protection) technology using cheap-as-hell materials and largely automated manufacturing processes operating at a precision that was not possible back-then. Meaning that a Visay-Sprague has no competitive advantage over the Grace L. Furgeson storm-door and capacitor company, or the Wa-Chen capacitor company operating out of a garage in Shanghai. But that Wa-Chen capacitor is superior in every way to the Sprague wax-paper cap produced in 1947. Or that plastic-encapsulated cap produced by Philco in 1961.

You really need to step back and take a 20,000 view of this hobby. Don't plant your feet 'back in the day' as you *DO* have 100 years of data to pull from, and you *DO* have the opportunity to bypass the mistakes of others and go directly to the proper solution. There is not one person in 20 that understands the sequence of events necessary for the lamp in their ceiling fixture to light up at the flick of a switch. They take it for granted. Back in the day, that simple result was the nearest thing to magic the world had ever experienced. If you understand how we got here, you need not repeat the mistakes, or duplicate the errors, or repeat the learning process as experienced over the last 100 years. Save yourself the pain.

Otherwise the appearance of idiocy you seem to cultivate so carefully may, in fact, be your reality. That would be sad.

Peter Wieck
Melrose Park, PA
  #27   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 524
Default Painting a Bakelite radio cabinet

Thursday, Sept. 28, 2017 at 10:31PM, wrote:

Add to that, the fact that most caps are now made in China, and I know
they wont last.


Can you tell where the rest are made?
  #28   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 142
Default Painting a Bakelite radio cabinet

On Sat, 30 Sep 2017 09:43:03 -0700, Jeff Liebermann wrote:

The supply of white space is limited and in danger of extinction.
When we run out of white space, allthewordswillruntogether.


Entropy's effect would seem to create just the opposite -- whitespace
ever expanding until e v e n l e t t e r s w i l l b e
t o o f a r a p a r t t o
r e l a t e t o e a c h
o t h e r .

Jonesy
--
Marvin L Jones | Marvin | W3DHJ.net | linux
38.238N 104.547W | @ jonz.net | Jonesy | FreeBSD
* Killfiling google & XXXXbanter.com: jonz.net/ng.htm
  #29   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 4,045
Default Painting a Bakelite radio cabinet

On 30 Sep 2017 20:47:43 GMT, Allodoxaphobia
wrote:

On Sat, 30 Sep 2017 09:43:03 -0700, Jeff Liebermann wrote:
The supply of white space is limited and in danger of extinction.
When we run out of white space, allthewordswillruntogether.


Entropy's effect would seem to create just the opposite -- whitespace
ever expanding until e v e n l e t t e r s w i l l b e
t o o f a r a p a r t t o
r e l a t e t o e a c h
o t h e r .

Jonesy


That's not entropy, which is the tendency for all attempts to organize
this newsgroup to turn into randomized rubbish. It's also not the
expansion of the universe, which would increase the font size along
with the inter-character spacing. After all the great ideas are
eliminated, whatever is left, no matter how dumb, must be the cause.
In this case, it's caused by authors being paid by the page. In the
distant past, authors were paid by the word. This resulted in
numerous abrevs, contractions, and hypenations to increase the word
count.

However, it was tedious to count words. So, publishers changed to
counting pages instead. That changed the style sheet to gigantic
fonts, absurdly wide margins, margin notes, double and triple spaced
lines, two spaces between sentences, a heading on every page, and
footnotes that nobody reads. What's important is that the tool to
make all this happen is the white space character. Prior to these
changes, the worlds supply of white space was adequate for all forms
of publication. Afterwards, the supply of white space began to
diminish. That happened to me, when I pressed the space bar, and
nothing happened. I quickly inserted a flash drive full of empty
space, which allowed me to continue writing. However, that's only
temporary as AGW alarmists are already proclaiming impending doom.
Little wonder that NASA is trying to resurrect the space program, so
that we can replenish our supply of white space from outer space.

Unfortunately, I do not have an answer to the white space depletion
problem. Conservation is only a temporary measure. Eventually, we
will run out of white space resulting in the implosion of all written
text and the rationing of white space. It might be possible to use
black paper and white printing because unlike the supply of white
space, there's plenty of black space available inside the nearest
black hole.

--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #32   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 4,045
Default Painting a Bakelite radio cabinet

On Tue, 26 Sep 2017 18:43:35 -0400, rickman wrote:

wrote on 9/26/2017 6:31 PM:
On Tuesday, 26 September 2017 22:14:42 UTC+1, rickman wrote:

It all depends on the details. I used a paint for plastic to use on a
plastic container and it did not work well at all. I cleaned the surface
well, but did not rough it up and did not use a primer. It was not too long
before the paint started to peel. I don't know the type of plastic. It was
a food storage container with a seal ring commonly available in stores.
Just a data point for what it is worth.


Nothing sticks to polythene.


That should be poly-mumble-ene.

Are you in the UK? Is that what we call polyethylene? How does it happen
that we end up with different names for things like common plastic?


There are naming standards for chemicals and compounds which I believe
includes plastics. Chemists are amazingly human (and childish) in
their naming of various compounds. There are enough examples to fill
a Wikipedia article:
https://en.wikipedia.org/wiki/List_of_chemical_compounds_with_unusual_names

Should you ever be in a position to assign a name, please resist the
temptation to be excessively clever. I didn't. Because I had one
foot in engineering and the other in marketing, I was honored with the
task of assigning a model number of a marine radio that I helped
design. Most of the other radios followed the pattern COM1, COM3,
COM21, etc (this was before the IBM PC serial ports used the same
designation). Without the slightest hesitation, I proclaimed that
COM1C will be the next model number. It was about a week before
anyone noticed the obvious. I soon became a candidate for immediate
execution by those who had to rewrite the product releases and hastily
retrieve those had been mailed.



--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #33   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 4,045
Default Painting a Bakelite radio cabinet

On Sat, 30 Sep 2017 19:22:29 -0700, Jeff Liebermann
wrote:

There are naming standards for chemicals and compounds which I believe
includes plastics.


Polyethylene isn't the only plastic with some naming confusion. See
table 2:
https://books.google.com/books?id=wmohBQAAQBAJ&pg=PR26


--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #34   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 74
Default Painting a Bakelite radio cabinet

On Fri, 29 Sep 2017 05:23:32 -0700 (PDT), "
wrote:

A bit of history might help you understand things. Once upon a time, light switches and receptacles were designed to be able to handle AC and DC. What happens when switching DC? Arcing. So, switches and receptacles, and switches in everything from lamps to toaster had to be arc-resistant. In addition, manufacturers did not have 100 years of historical data to design from. So, things were over-designed (by modern standards), heavy (by modern standards) and many have withstood the test of time and survive to this day. Today, switches are either AC or DC, designed to very specific standards, and as long as they are used within those standards, will also last indefinitely.

Capacitors started as foil-and-glass devices, evolving to foil-and-paper (cheap) sealed with paraffin wax + some bees wax for workability (cheap), and some were potted in tar (even then, manufacturers understood that the materials had self-decay problems) and various other methods were tried - and discarded over time. BUT, remember, EVERYTHING WAS NEW back in those days. Nobody had 100+ years of data to use, and what we understand today as being very short blind alleys were enticing options. So, there is a LOT of crap out there that was perfectly functional when made. Electrolytics evolved similarly and improved similarly. As did resistors, even tubes. Nuvistors, developed about the same times as reliable transistors, were thought then, and perhaps still, to have a pretty-much indefinite service-life as compared to a standard tube.

So, now the evolution of consumer-grade electronic components, caps, resistors, transistors, and so forth, has made them into commodities based on unprotected (no patent protection) technology using cheap-as-hell materials and largely automated manufacturing processes operating at a precision that was not possible back-then. Meaning that a Visay-Sprague has no competitive advantage over the Grace L. Furgeson storm-door and capacitor company, or the Wa-Chen capacitor company operating out of a garage in Shanghai. But that Wa-Chen capacitor is superior in every way to the Sprague wax-paper cap produced in 1947. Or that plastic-encapsulated cap produced by Philco in 1961.

You really need to step back and take a 20,000 view of this hobby. Don't plant your feet 'back in the day' as you *DO* have 100 years of data to pull from, and you *DO* have the opportunity to bypass the mistakes of others and go directly to the proper solution. There is not one person in 20 that understands the sequence of events necessary for the lamp in their ceiling fixture to light up at the flick of a switch. They take it for granted. Back in the day, that simple result was the nearest thing to magic the world had ever experienced. If you understand how we got here, you need not repeat the mistakes, or duplicate the errors, or repeat the learning process as experienced over the last 100 years. Save yourself the pain.

Otherwise the appearance of idiocy you seem to cultivate so carefully may, in fact, be your reality. That would be sad.

Peter Wieck
Melrose Park, PA


I agree with everything you say except for nuvistor reliability. We
were constantly replacing them in RCA tuners back in the early 70s.

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

  #35   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 1,625
Default Painting a Bakelite radio cabinet

On Monday, October 2, 2017 at 9:52:23 AM UTC-4, Chuck wrote:


I agree with everything you say except for nuvistor reliability. We
were constantly replacing them in RCA tuners back in the early 70s.


Agreed that the very earliest did suffer from poor QC. But after a pretty short shakedown, they became exceedingly reliable. The biggest problem with them was either a poor vacuum (no getters, no way to draw out air by individual tube) or loss of vacuum. As the technology progressed, these were solved to the point that were they as inexpensive as contemporary transistors, they may have survived in volume production to this day. They were very costly as compared to solid-state devices, however.

Peter Wieck
Melrose Park, PA


  #36   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 4,045
Default Painting a Bakelite radio cabinet

On Sat, 30 Sep 2017 20:38:11 -0400, rickman wrote:

Mike Coon wrote on 9/30/2017 7:11 PM:
In article ,
says...

In this case, it's caused by authors being paid by the page. In the
distant past, authors were paid by the word. This resulted in
numerous abrevs, contractions, and hypenations to increase the word
count.


That reminds me of my invention of logarithmically-lined paper because
there is always just a few extra lines of writing which (when we used to
do long-hand) just needed to be fitted in to that last page...


That one was pretty good! You should get that patented. lol


Yep. I like it. I did some searching through various online patent
search databases and did not find anything even close. Plenty of
semi-log paper graphs, but nothing suitable for writing. They all
have the necessary semi-log horizontal lines, but they also have
equally spaced vertical lines, which makes it difficult to use as
writing paper.

I think it just might be patentable. No clue how you're going to sell
the idea to a manufacturer of rules writing paper. It's far too easy
to clone and steal:
https://www.google.com/search?q=ruled+writing+paper&tbm=isch
http://objective.restrictions.us/lined-paper

In honor of the cats that like to plant themselves at the center of
attention:
https://static.boredpanda.com/blog/wp-content/uploads/2014/10/lined-paper-doodles-art-interactive-4__605.jpg

--
Jeff Liebermann

150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #38   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 1,625
Default Painting a Bakelite radio cabinet

The issue is not the number of letters/symbols in an alphabet.
The issue is not the amount of white space on a page.
The issue is all about clarity of communication.

Symbols that increase clarity or reduce the potential for confusion are good.
Symbols that are there based merely on form or tradition do neither.

The additional i does nothing for Aluminium.
The additional u does nothing for Colour, Behaviour et.al.

Tongue firmly in cheek.

By the way, Surveyors have been using a decimal scale for hundreds of years (since 1620) - the Chain Scale. In the US, the Ramsden Scale (1785) divided feet into 10ths, and Chain Scale tapes are still used by surveyors to this day -those not using GPS devices, that is. Note that most surveyor measurements are in decimals.

Ain't history fun?

Peter Wieck
Melrose Park, PA
Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Emerson black bakelite radio w/tubes- works- $10 Dwight D. Eisenhower Electronics Repair 0 October 28th 08 11:33 PM
Cabinet, Furniture Design Software, Autodesk QuickCAD v8.0, Punch Software Home Design Architectural Series 18 v6.0, SOLID V3.5 - CABINET VISION, Cabinet Design Centre v7.0 - Cubit, 20-20 Kitchen Design V6.1,Cabinet Vision Solid, Planit Millennium II athens.gr. Woodturning 0 September 3rd 04 08:45 AM
Cabinet, Furniture Design Software, Autodesk QuickCAD v8.0, Punch Software Home Design Architectural Series 18 v6.0, SOLID V3.5 - CABINET VISION, Cabinet Design Centre v7.0 - Cubit, 20-20 Kitchen Design V6.1,Cabinet Vision Solid, Planit Millennium II athens.gr. Home Repair 0 September 3rd 04 08:44 AM
Cabinet, Furniture Design Software, Autodesk QuickCAD v8.0, Punch Software Home Design Architectural Series 18 v6.0, SOLID V3.5 - CABINET VISION, Cabinet Design Centre v7.0 - Cubit, 20-20 Kitchen Design V6.1,Cabinet Vision Solid, Planit Millennium II athens.gr. Home Ownership 0 September 3rd 04 08:43 AM
Cabinet, Furniture Design Software, Autodesk QuickCAD v8.0, Punch Software Home Design Architectural Series 18 v6.0, SOLID V3.5 - CABINET VISION, Cabinet Design Centre v7.0 - Cubit, 20-20 Kitchen Design V6.1,Cabinet Vision Solid, Planit Millennium II athens.gr. Woodworking 0 September 3rd 04 08:13 AM


All times are GMT +1. The time now is 12:44 PM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"