> >
> > Was the failed IC marked '723' or some house number?
> >
> > -tony
>
> Hi Tony As I recall, it was marked LAS723-2.5Luckily, before I simply
> replaced it, I checked the
> feedbackresistor values. They didn't make sense for 7V.My guess is that it
> made using the 723
> for 5V supplies
> From: a...@p850ug1.demon.co.uk
>
> Was the failed IC marked '723' or some house number?
>
> -tony Hi Tony As I recall, it was marked LAS723-2.5Luckily, before I simply
> replaced it, I checked the feedbackresistor values. They didn't make sense
> for 7V.My guess is that it made using the 7
On Sun, Aug 2, 2015 at 10:56 PM, dwight wrote:
> Well, I had to look it up. The LAS723 comes with a 2.5V reference
> and not a 7V.
Cool! Thanks for the warning about it. Fortunately the Power-One
supply I'm dealing with only uses normal 723s, but I'll have to bear
that in mind when working on l
> > I've never found a 723 datasheet that gives a different values for
> > either reference.
> >
Nor have I
> The one I had to replace on my Nicolet oscilloscope was made by
> Lambda. I don't recall the reference voltage but I did have to change
> the feedback resistors to get it to work.
I se
Well, I had to look it up. The LAS723 comes with a 2.5V reference
and not a 7V.
Dwight
> From: space...@gmail.com
>
> On Sat, Aug 1, 2015 at 5:52 PM, dwight wrote:
> > There we two different reference voltages on 723s. I don't recall which
> > was which but one had to change the feedback resistors if you used the
> > wrong one.
>
> There's a reference with a built-in current sourc
Sounds just like the supply on my Altos. What a pain.
Eric Smith wrote:
>I previously wrote about the monitor of my Intel Series II MDS going
>out, which was because the +15V DC supply tripped the crowbar. The
>voltage adjust was all the way to the minimum, and the voltage was
>still about 17.4V
On Sat, Aug 1, 2015 at 5:52 PM, dwight wrote:
> There we two different reference voltages on 723s. I don't recall which
> was which but one had to change the feedback resistors if you used the
> wrong one.
There's a reference with a built-in current source and amplifier,
which outputs on pin 6 on
There we two different reference voltages on 723s. I don't recall which
was which but one had to change the feedback resistors if you used the
wrong one.
If seems there is only one ref voltage available today.
I think Jameco carries them. What package do you need. They
cam in cans and dips.
Dwight
On Sat, Aug 1, 2015 at 2:36 PM, Brent Hilpert wrote:
> Just a suggestion: you're sure there no ground reference problem on pin 7
> (V-) of the 723? (hence raising the Vref).
> I've seen small 723-based supplies with sense leads where the 723 V- is on
> the neg. sense lead rather than neg. output
On 2015-Aug-01, at 1:26 PM, Eric Smith wrote:
> On Sat, Aug 1, 2015 at 2:14 PM, tony duell wrote:
>>> The root cause of the failure appears to be that the internal voltage
>>> reference of the uA723, which is specified as 7.15V ±0.35V, is now
>>> 9.4V. The uA723 needs to be replaced. The uA723 i
On Sat, Aug 1, 2015 at 2:14 PM, tony duell wrote:
>> The root cause of the failure appears to be that the internal voltage
>> reference of the uA723, which is specified as 7.15V ±0.35V, is now
>> 9.4V. The uA723 needs to be replaced. The uA723 is still readily
>
> That's an unsual failure. I've ha
> The root cause of the failure appears to be that the internal voltage
> reference of the uA723, which is specified as 7.15V ±0.35V, is now
> 9.4V. The uA723 needs to be replaced. The uA723 is still readily
That's an unsual failure. I've had 723s go internally short-circuit and
then the output
I previously wrote about the monitor of my Intel Series II MDS going
out, which was because the +15V DC supply tripped the crowbar. The
voltage adjust was all the way to the minimum, and the voltage was
still about 17.4V with no load, and trips the crowbar with even a
small load. I think someone pr
The most common failures are the horizontal output transistor,
the flyback transformer and the dampening diode.
Dwight
> Date: Thu, 23 Jul 2015 20:10:21 -0600
> Subject: Re: diagnosing an Intel Series II MDS monitor failure
> From: space...@gmail.com
> To: cctalk@classiccmp.org
&
Al wrote:
> does it have a horizontal oscillator?
> some ball monitors require horizonal drive before the hv works
It doesn't appear to have a horizontal oscillator.
On 7/23/15 6:56 PM, Eric Smith wrote:
I'll test the
monitor on a lab power supply to see if it's drawing too much current.
does it have a horizontal oscillator?
some ball monitors require horizonal drive before the hv works
A few weeks ago, while I was testing a spare IPB-80 CPU card in an
Intel Series II MDS, the monitor stopped working, with the raster
collapsing to a very bright dot in the center of the screen. I hit the
power switch and pulled the line plug immediately, but the dot
persisted for several minutes, o
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