Toshiba TV29C90 problem; Image fades to black...

In article <ac61acb6-9240-49c1-a7df-c0f815b748d7@googlegroups.com>,
73km0k@gmail.com wrote:

On Wednesday, May 14, 1997 at 2:00:00 AM UTC-5, Bob Wilson wrote:
I have an Astron RS-35M with a shorted output transisitor. It uses 4
2N3771's
made by Motorola in parallel. My question is: does Astron match output
transistors or will any Motorola 2N3771 balance out OK with the other 3
output
transistors? Thanks
Bob
Click to expand...

This is a little old, but Astron power supplies are still around. I
have had a couple of the regulator IC's go bad, but never a pass
transistor. I would first suspect a short external to the transistor!

The original 2N3771 transistors may come out of the same batch, but
probably are not matched. Each one has an emitter resistor to help
equalize current. Therefore you should not have a problem with un-equal
current due to replacement transistors.

The current meter measures voltage drop across one of the 4 emitter
resistors. It may need slight re-calibration, but you should have no
trouble with a replacement 2N3771.

Fred
 
On Fri, 14 Apr 2017, Fred McKenzie wrote:

In article <ac61acb6-9240-49c1-a7df-c0f815b748d7@googlegroups.com>,
73km0k@gmail.com wrote:

On Wednesday, May 14, 1997 at 2:00:00 AM UTC-5, Bob Wilson wrote:
I have an Astron RS-35M with a shorted output transisitor. It uses 4
2N3771's
made by Motorola in parallel. My question is: does Astron match output
transistors or will any Motorola 2N3771 balance out OK with the other 3
output
transistors? Thanks
Bob

This is a little old, but Astron power supplies are still around. I
have had a couple of the regulator IC's go bad, but never a pass
transistor. I would first suspect a short external to the transistor!

Then why reply to it?
Click to expand...

The guy who restarted this thread didn't even bother to say anything, just
took a 20 year old post and reposted it.

There was no question or comment.

Michael
 
In article <alpine.LNX.2.02.1704142350410.7080@darkstar.example.org>,
Michael Black <et472@ncf.ca> wrote:

On Fri, 14 Apr 2017, Fred McKenzie wrote:

In article <ac61acb6-9240-49c1-a7df-c0f815b748d7@googlegroups.com>,
73km0k@gmail.com wrote:

On Wednesday, May 14, 1997 at 2:00:00 AM UTC-5, Bob Wilson wrote:
I have an Astron RS-35M with a shorted output transisitor. It uses 4
2N3771's
made by Motorola in parallel. My question is: does Astron match output
transistors or will any Motorola 2N3771 balance out OK with the other 3
output
transistors? Thanks
Bob

This is a little old, but Astron power supplies are still around. I
have had a couple of the regulator IC's go bad, but never a pass
transistor. I would first suspect a short external to the transistor!

Then why reply to it?

The guy who restarted this thread didn't even bother to say anything, just
took a 20 year old post and reposted it.

There was no question or comment.
Click to expand...

Michael-

Surely someone is interested in the discussion. As I mentioned, there
are a lot of the Astron analog power supplies around. The design has
only slightly evolved since the 1980's, and they are still being
produced.

Fred
 
On 16/04/17 23:33, lometon592@gmail.com wrote:
Mine does that too. I just set the fan speed to 4 so it doesn't overheat
Click to expand...

Responding to a 17yr old post.



Nothing to see here, move along ....

--
Adrian C
 
On Monday, April 17, 2017 at 4:34:47 AM UTC-4, Adrian Caspersz wrote:
On 16/04/17 23:33, lometon592@gmail.com wrote:
Mine does that too. I just set the fan speed to 4 so it doesn't overheat


Responding to a 17yr old post.



Nothing to see here, move along ....

--
Adrian C
Click to expand...

Other than the fact that when a microwave oven starts to act out in this manner, the only safe 'next stop' is the knacker's yard.

Peter Wieck
Melrose Park, PA
 
On Thu, 27 Apr 2017 14:29:07 -0700, tabbypurr wrote:

I have an old EHT PSU to repair. There are 2 capacitors, one paper, one
plywood! The paper cap, which is uncased, tests as: 420nF 11 ohms ESR,
5% loss. I've not yet done a dc leak test, which it needs. What do you
think of those figures? IME pre-war paper caps are highly suspect. I'd
rather establish what I can before subbing it, as the construction of
the whole thing is rather characterful.
Click to expand...

I've a few boxes full of oil/paper metal-cased capacitors I could test
for comparison purposes if needs be, Tabby, but I've added s.e.r in case
some kind soul there will know the answer off the top of their heads
first.
 
On Thu, 27 Apr 2017 14:29:07 -0700, tabbypurr wrote:

I have an old EHT PSU to repair. There are 2 capacitors, one paper, one
plywood! The paper cap, which is uncased, tests as: 420nF 11 ohms ESR,
5% loss. I've not yet done a dc leak test, which it needs. What do you
think of those figures? IME pre-war paper caps are highly suspect. I'd
rather establish what I can before subbing it, as the construction of
the whole thing is rather characterful.
Click to expand...

What, if anything, are the markings on the caps themselves?

You ought to be able to screen a modern film cap to within a very few percent of the OEM values, go high on the voltage parameters, and go from there.

Peter Wieck
Melrose Park, PA
 
In <news:590545ec$0$40425$c3e8da3$b280bf18@news.astraweb.com>, JF Mezei
suggested:

Yet, any Android phone that runs the Google camera app has the same
portrait mode. It's just done differently but the end result is the same.

This is where "qualitative" comes into play. Often, the Apple side of
the fence has a less "amazing" implementation but what it does, it does
it better. Android tends to be first with many features but implemented
with less quality.
Click to expand...

That is a reasonable statement.
But is it correct?

I only speak facts.
And I'm very reasonable since I'm a logical thinker.

Most iOS users appear to be so inextricably emotionally attached to
whatever the Apple Marketing Machine tells them to think, that their own
words indicate that they can't even think facts on their own.

Contrary facts seem to befuddle them.
But the Apple Marketing Machine message soothes them.

So, maybe it is true that the Apple portrait mode ends up with superior
results in the final form (that is, in the photo itself).

Maybe it is true.
But maybe it's not true.

Has *anyone* shown facts either way in this thread (or in the thread
dedicated to this topic)? Nope.

So everyone is just guessing.

What we need is very simple, since it's a fact that both Android and Apple
iOS phones have portrait mode.

We need to find a reference that does a blind test of the results.
It's pretty easy to do the test.

1. Person 1 shoots a set of portrait mode photos with iOS.
2. They shoot the same set using Android under the same conditions.
3. A different person, a digital photo expert, compares the results

It's a simple test to run, and, depending on the conditions and the
expertise of the digital photo expert, they can pronounce whether there is
any meaningful difference in the quality of the results.

It's a valid question.
Does anyone have a pointer to such a reference?
 
On Friday, 28 April 2017 19:58:41 UTC+1, pf...@aol.com wrote:
On Thu, 27 Apr 2017 14:29:07 -0700, tabbypurr wrote:

I have an old EHT PSU to repair. There are 2 capacitors, one paper, one
plywood! The paper cap, which is uncased, tests as: 420nF 11 ohms ESR,
5% loss. I've not yet done a dc leak test, which it needs. What do you
think of those figures? IME pre-war paper caps are highly suspect. I'd
rather establish what I can before subbing it, as the construction of
the whole thing is rather characterful.

What, if anything, are the markings on the caps themselves?
Click to expand...

the cap doesn't have a case, let alone markings.

You ought to be able to screen a modern film cap to within a very few percent of the OEM values, go high on the voltage parameters, and go from there.

Peter Wieck
Melrose Park, PA
Click to expand...

Of course I can replace it, and probably will need to, I just wanted to know if this thing might still be serviceable, if so I'll let it stay.


NT
 
On Monday, 17 April 2017 21:49:08 UTC+1, pf...@aol.com wrote:
On Monday, April 17, 2017 at 4:34:47 AM UTC-4, Adrian Caspersz wrote:
On 16/04/17 23:33, lometon592@gmail.com wrote:
Mine does that too. I just set the fan speed to 4 so it doesn't overheat


Responding to a 17yr old post.



Nothing to see here, move along ....

Other than the fact that when a microwave oven starts to act out in this manner, the only safe 'next stop' is the knacker's yard.

Peter Wieck
Melrose Park, PA
Click to expand...

It's many years since I saw a microwave capable of cooking with the door opened. Any such machine should be got rid of even if working ok, because one day it won't be. Since teh early 80s all machines (here at least) have had an interlock system that can't fail unsafely. Well almost, unfortunately. Always check the shorting resistor if there's any question at all of the interlock system's reliability.


NT
 
On Sunday, April 30, 2017 at 6:53:02 PM UTC-4, tabb...@gmail.com wrote:

> Of course I can replace it, and probably will need to, I just wanted to know if this thing might still be serviceable, if so I'll let it stay.

The short answer is No.

Peter Wieck
Melrose Park, PA
 
On 20/05/17 19:06, gilman080566@gmail.com wrote:
> Tv gives black screen and no sound

Hideous. Can you sue?

--
Adrian C
 
On 5/20/2017 2:06 PM, gilman080566@gmail.com wrote:
> Tv gives black screen and no sound

What type of TV is this? Is it an old CRT set, with tubes? Or is it a
modern set with an LCD or plasma display?

--

Rick C
 
On 5/20/2017 4:16 PM, rickman wrote:
On 5/20/2017 2:06 PM, gilman080566@gmail.com wrote:
Tv gives black screen and no sound

What type of TV is this?
Click to expand...

Broken apparently.


--
Jeff-1.0
wa6fwi
http://www.foxsmercantile.com

---
This email has been checked for viruses by AVG.
http://www.avg.com
 
On Saturday, 20 May 2017 19:06:08 UTC+1, gilman...@gmail.com wrote:
> Tv gives black screen and no sound

Some do that. If you want information on fixing it you'd need to give a whole heap more information than that. Since you haven't it seems unlikely you'd be able to do much more than check the mains plug.
 
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