[Milsurplus] Sandy Coolness for Our BAs

Sun May 14 08:14:19 EDT 2017

I did play with the device a little yesterday, I loaded a 125v regulator
with 31ma using a 4K resistor and 150v input from a Heath HV regulated
suppley. It regulated at 125.4v. If I removed the base resistor the
regulator shuts down consistantly. Thinking the same thing would happen if I
grounded the base I tried it and was surprised what happened. The output
dropped to 6v and current flow from the 150v supply went up to over 150ma.
If I quickly removed and reattached the ground sometimes it would shutdown
but sometimes it would not and I'd get the high supply current and 6 volts
out. So putting a ground on the base pin to shut it down is unstable. I
beleive it's because once you have output voltage there is now voltage on
the output and initially throwing a ground on the base pin still momentarily
provides a current path through the pass transistor internal base resistors
to a positive voltage on the output.

I also tested it with a ground on the base pin before supplying 150v input
and it remained shutdown repeatedly no problems. But I don't think it's a
good idea to try and control it by normally having a ground on the base pin
and then lifting it when you want the regulator to turn on. Reason being if
for some reason that ground gets reapplied after the regulator has started
the risk is there to draw significant amounts of current from the supply
which could cause damage. Therefore I would rule out using the base pin to
try and control the regulator.

Cool device though

John Schmitz

-----Original Message-----
From: Milsurplus [mailto:milsurplus-bounces at mailman.qth.net]On Behalf Of
Bruce Gentry
Sent: Saturday, May 13, 2017 12:17 PM
To: Milsurplus at mailman.qth.net >> Milsurplus
Subject: Re: [Milsurplus] Sandy Coolness for Our BAs

Could these inputs on  regulators serve as part of the power on/off
switching circuitry? The line power could be rectified and keeping a
filter condensor charged at all times, supplying power to the regulator
and also powering a small switching power supply  for the logic
circuitry. Upon command from the remote or power button, a turn on
signal to the regulator(s)  would power up the rest of the receiver.
It  would eliminate the cost, space, reliability, and possible safety
issues of using relays to do the switching.

       Bruce Gentry  KA2IVY

On 5/13/17 9:55 AM, John Schmitz wrote:
> After further studying the internals scat it occurs to me there is no
start
> up to start the regulator working. I'm betting the base pin needs a
resistor
> to the input to get the regulator started when voltage is first applied.
> Looking at the specs it appears to should maybe be a 10-12K resistor
between
> the base pin and the input pin. This is kind of interesting. I have some
> STR's and now I'm really tempted to play with it a little.
>
> John Schmitz
>
> -----Original Message-----
> From: John Schmitz [mailto:cjs004 at comcast.net]
> Sent: Saturday, May 13, 2017 8:10 AM
> To: David Stinson; ARC-5; milsurplus at mailman.qth.net;
> boatanchors at mailman.qth.net
> Subject: RE: [Milsurplus] Sandy Coolness for Our BAs
>
>
> These types of regulators were very popular in TV's for awhile. These NTE
> regulators are replacements for the the orginal STR series of regulators.
> I'm going to try and attach a data sheet for the STR3110 thru STR3130
series
> of regulators. Manufacturer is Japanese Sanken and the attachment is in
> Japanese but it does have a scat of the internals. Looks like you may not
> have to connect anything to the base pin it may work with nothing
connected
> but not sure. Perhaps this additional base pin was a way to cut the
> regulator off. Possibly used by the saftey circuits in the TV that shut
the
> TV down if HV gets to high. But at least with a scat you can play with it.
> If the attachment doesn't come through google STR3125 regulator and you
> should find the scat I tried to attach.
>
> -----Original Message-----
> From: Milsurplus [mailto:milsurplus-bounces at mailman.qth.net]On Behalf Of
> David Stinson
> Sent: Friday, May 12, 2017 7:28 PM
> To: ARC-5; milsurplus at mailman.qth.net; boatanchors at mailman.qth.net
> Subject: [Milsurplus] Sandy Coolness for Our BAs
>
>
> New devices that make reviving our loved radios
> simplier and less expensive are appearing regularly.
> The mass marketing of large LCD and Plasma
> TVs have birthed some pretty cool devices.
> Just found this honey today, an NTE1743.
>
> https://goo.gl/photos/iXzL1SaXKNczYTQi7
>
> The little wonder was soooo expensive: $9 ;-)
> It's a high-voltage regulator similar to the little
> LM317 things for low voltage, but this one
> takes DC under 200V peak and delivers
> 135 V +/- 0.8V; just right for "reduced B+"
> projects.  NTE1776, 1777, 1778, 1743
> deliver 120, 130, and 135 Volts fixed,
> good for an Amp (if you can source that much).
> Originally designed to follow the AC-line-
> bridge rectifier-regulator architecture.
> I'm going to use it with a transformer.
>
> So I'm building what is, I think, going
> to be the easiest regulated receiver supply
> ever.  B+/Fil transformer, bridge rectifier,
> 47 uFd filter cap and the regulator.
> Should work a treat and be rock stable.
> Will let ya know.
>
> 73 DE Dave AB5S
>
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