Date   
Tek 468 with low bright, beam finder not working

Samuel Rocha <py1dkw@...>
 

DearRoger and the Group,

 Manythanks for your help. I have been trying to repair the 468 sinceJanuary, I had made the multiplier unit, which took me a lot of time and everyattempt which resulted in some sparks inside and outside the multiplier, componentsfailures and a new multiplier project!

Well, thebrightness control really reduce the intensity, and retrace is not seeing.


ChangingCRT bias does not affect much the tube brightness.

Assuggested, the tested voltages are:

Voltageacross C303: from 8,7 v to 55,4v

Voltageacross VR308: 73,4 v


TP84shows the waveform although is different from the 465 manual,  please see the photos.

But whenI press BEAM FINDER nothing appears on screen! TP84 shows no waveform pressingBeam Finder too. A intensified by B has no effect over the brightness.

 I thoughtin measuring the 15kv multiplier output, but I am afraid it can sparkeverywhere and burn half dozen components, as had occurred before.

 So, the-2450v is perfect, as -1700 v for pin 4 of the tube. I would like very much torepair this scope ! Any ideas? Thank youvery much!
Sam Rocha

PY1DKW

Brazil


I am repeating the message, since pictures are not allowed by Yahoo!

Re: 11403A as bench scope, how useful is it?

Chris Wilkson
 

Hi Dennis,

No not really. I'm just a lazy typist. I did imply that I was referring to non-repetitive signals and was content with that lever of "CYA". Of course if you're willing to wait "long enough" and the analog front end has enough bandwidth, then you can get quite good rise time performance for repetitive signals even with a low sample rate by using an equivalent time sampling. But or single shot events I think my math is accurate within the limitations of the under lying assumptions.


I agree with what you said. Thank you for expanding it out for me! :)


-Chris

Re: R7903 Intensity control and readout loss

Dave Hills
 

OK. If C1893 and C1897 are solid blobs then they are tantalum
electrolytic capacitors. I know of no tantalum capacitor that is not an
electrolytic. Search on "tantalum capacitor", there is a wealth of info
out there from manufacturers, NASA, and others. In this case, the "K47"
gives it away, definitely a solid-tantalum electrolytic capacitor.

The Tek parts lists and schematics can be confusing, as sometimes they
will call out "tantalum" and sometimes not and the schematic may be
missing the polarizing "+" symbol. Keep in mind that these documents
predate CAD and the originals were hand drawn with parts lists created
on a typewriter or rudimentary word processor. Errors are common, it's
something we lived with back then.

As to the 47/20, 100/25, 220/25v conundrum, in the mid 70's through
80's the massive growth of electronics technology created many shortages
of components, especially ceramic and tantalum electrolytic capacitors.
Parts were allocated by manufacturers and often different value parts
were substituted in order to keep production going. Changes were
coming so fast, documentation could not keep up. Using a much larger
aluminum electrolytic cap in place of a tantalum electrolytic was
necessary in many cases to maintain the required ESR value. Your axial
tantalum 47/35v caps should work just fine as long as you observe the
correct polarity orientation.

Tantalum electrolytics almost never fail for capacity or ESR change,
they either short or go completely open.

I believe your Fluke has you covered for capacitance measurements, so
next would be leakage current. All you need is a few 9v batteries, your
DMM or scope and a resistor. Create a series circuit with the
batteries, capacitor and resistor with the battery voltage close to the
circuit operating voltage and less than the capacitors spec voltage.
Measure the voltage across the resistor take a reading after it stops
decreasing. Apply Ohm's law and there you have your leakage current.
*Be very careful with polarity!! Even a brief moment of reverse polarity
can kill a tantalum electrolytic!!*

With a pulse/function generator ESR can be measured, but you don't have
that. Not likely a problem with tantalum electrolytic capacitors anyway.

Tick/burst mode is normal with no load.

Good Hunting!
Dave

Re: 7A13 shorted +15 rail

Jerry Massengale <jmassen418@...>
 

on the 15v lines they used 20v caps which is not enough. replace with
modern 35v aluminum caps. this should be a minimum effort. it would be wise
to replace all the old tants

jerry

On Tue, Jun 20, 2017 at 12:14 PM, Brent Watson brentleew2003@...
[TekScopes] <TekScopes@...> wrote:



So Jerry, are you saying just change the tants and eliminate any question
as to there condition.? I'm up against the same issue of Tantalums and
whether to just replace.Brent

From: "Jerry Massengale jmassen418@... [TekScopes]" <
TekScopes@...>
To: TekScopes@...
Sent: Tuesday, June 20, 2017 9:59 AM
Subject: Re: [TekScopes] 7A13 shorted +15 rail

It is best to replace all the tants.

jerry

On Tue, Jun 20, 2017 at 9:56 AM, Larry DeVito ldevito@...
[TekScopes]
<TekScopes@...> wrote:



Hello Everyone,
Does anyone have advice on troubleshooting procedure.I have a 7A13
plug-in
with +15V rail shorted. The mostlikely cause is tantalum cap. What is
best way to findthe errant component?

ThanksLarry




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SC501 parts location grid

EJP
 

All the SC501 service manuals I can lay my hands on are missing a parts location grid for either of the two boards. Was there one in the original paper manual? and if so any chance of a scan?

EJP

Re: New guy w/ 2-Teks... 2225 and early 465B

Marvin Kubaszewski
 

The problem is likely the rest of the aluminum electrolytic capacitors
especially including the power supply input capacitor C900 and the
preregulator output capacitor C914. But I would change all of the
aluminum electrolytic capacitors in the power supply whether they
tested good or not.


Great call! I finally got around to pulling the rest of the electrolytics from the PS and found both C900 and C914 to be sketchy... C900 had ESR about 3X what I'm seeing on its new replacement and C914 also had really high ESR and it measured down less than 50% of its specified capacitance. Between those and the bad ones I found in the 8.2v supply it's no wonder nothing wanted to work. The last of the replacement caps should be here tomorrow, so I'm excited to get them installed and see what happens. BTW, while I was digging around trying to pull C900 I also noticed a broken wire at the main board end of the W900 jumper, although I confess it might have been self-inflicted when I was moving the big xfrmr out of the way. Ah, the joys of poking around, eh? More to come.....

Re: Type 555 power supply with issues

Morris Odell
 

Hi David,

I'm also in Australia (Melbourne) and meant to reply to your original post but it got away from me.

My first comment is that if the supply really does have evidence of live contact on the case you should do absolutely nothing until you have dealt with the safety issue. There must also be a good solid reliable ground connection through the power cord. Do nothing else until you have fixed that!! Replace the US style power connector with an IEC plug if you need to. Check that the power transformers really are wired for 234 volts according to the manual. Make sure the fans spin freely.

Next, you should work on making the interconnecting cable. The 555 was designed to work as a unit with the power supply connected to the indicator unit and there's no point in doing anything (other than cleaning and carefully inspecting it) until you have the the two connected. Looking at the manual should give you some idea of the wire sizes required. I don't have the manual handy as I write this but obviously the mains and heater leads need to be adequate for the task. I can't remember whether the fan only runs if they are connected. The other power supply connections don't carry a lot of current in comparison. The chassis-to-chassis grounding also needs to be reliable (of course). I can help with advice if you need it.

Once you do have it together the only way to go is to fire it up at full voltage. Using a variac will put unnecessary strain on some circuits and will delay or even prevent the thermal relay closure. You should connect voltmeters to certain power supplies, especially the -150 and +100, make sure you have plugins and the right size fuses installed and let 'er rip. Be prepared to flick the switch quickly if you need to. My experience with many Tek tube scopes is that they usually come up OK. While it's warming up you can check that all the tubes light up and the fans are running. The 45 second time delay is a loooong anxious time the first time you do that.

Once it's running and the power supplies are within spec you can work on getting it set up properly. Even after 50 years the 555 is an amazingly beautiful and reliable scope and well worth restoring..Fortunately they don't have the HV transformer problem.

Good luck!

Morris

----------------------------------------------
Re: Type 555 power supply with issues
Posted by: firielnxd@... firielnxd
Date: Mon Jun 19, 2017 9:45 pm ((PDT))

Hello, Thank you for the cable description. I assume the cable is the same if running off 240V (what the scope is wired for, according to its plate on the back, and what is available down here in Australia)?
When I bought the scope, the seller emphatically told me not to bring it up with a variac. Is there a reason for this (other than the usual 'stuff builds up in the tubes' thing, which seems to usually be a decent tradeoff for the short periods of time usually required)?
Thanks,
David

Re: 11403A as bench scope, how useful is it?

ArtekManuals
 

I have service manuals for both the 11301 and 11403A ...sadly neither
has schematics which would be in something entitled "Extended Service
manual" ..which I have never been able to find ( though I do have the
extended manual for the 11401 ...go figure)

Dave
manuals@...

On 6/20/2017 8:18 PM, jerry@... [TekScopes] wrote:

make sure you can get the operating and service manuals. I recently
was given a 11301 which has some issues and I haven't been able to
find the service manual. I have it working, it must have a ROM problem
as I have to play with the focus/astig and the brightness of the
various traces every time I power it on.

No big deal. Oh, and by the way, the 11301 heats my garage nicely and
I suspect the 1140x will do the same.

[Non-text portions of this message have been removed]

--
Dave
Manuals@...
www.ArtekManuals.com

Re: 11403A as bench scope, how useful is it?

Jerry
 

make sure you can get the operating and service manuals. I recently was given a 11301 which has some issues and I haven't been able to find the service manual. I have it working, it must have a ROM problem as I have to play with the focus/astig and the brightness of the various traces every time I power it on.

No big deal. Oh, and by the way, the 11301 heats my garage nicely and I suspect the 1140x will do the same.

Re: 11403A as bench scope, how useful is it?

Tom Gardner
 

Not only digitising scopes, of course.

As an extreme example, the Tek 1502 TDR has a sampling
rate of ~10kS/s, but can display 140ps risetimes since its
front-end bandwidth is >2.5GHz. That's why it is beneficial
to specify both the sampling rate and the front-end bandwidth.

And the first sampling scope I saw used a XY pen plotter
as an output device :)

Note that for digital signals the period/frequency is irrelevant.
All that matters is the transition time, since that's the principal
influence on the "signal integrity".

On 20/06/17 23:53, 'Dennis Tillman' @Dennis_Tillman_W7PF [TekScopes] wrote:

Hi,

You are taking Nyquist too literally. If all you had was one chance to
sample a waveform the Nyquist Criteria would apply but if the waveform is
repetitive then you have an infinite amount of time to sample it or to build
up a set of samples. This is like the difference between a waveform that is
a single shot or a waveform that repeats.

These were the early days of digital scopes and many clever schemes were
needed to achieve excellent bandwidth (1GHz to 3Ghz) with the relatively
slow sampling speed available in those days. The 11403A is capable of GHz
bandwidth on several channels as long as you are measuring repetitive
signals.

A single shot waveform only gives you one chance to sample it (or one chance
to display it on the CRT of an analog scope). Your eye has to be really fast
to see the entire one shot waveform or to study any part in detail. A
repetitive waveform refreshes the phosphor of the CRT over and over and you
eye has a chance to study any part of it in detail for as long as you like.

Dennis Tillman W7PF

-----Original Message-----
Sent: Tuesday, June 20, 2017 2:00 PM
Subject: [TekScopes] Re: 11403A as bench scope, how useful is it?

The biggest weak spot is the 20MSPS maximum sample rate. The short
record length is not so great either.

Is it really that low? Wow.
Using my typical rules of thumb that gives you a good look at square
waves up to about 2MHz (5th harmonic is 10MHz, Nyquist rate -> 20MSPS).

Not great at all. Surely it has some tricks to be better for non
repetitive signals?

Re: 11403A as bench scope, how useful is it?

 

Hi,

You are taking Nyquist too literally. If all you had was one chance to
sample a waveform the Nyquist Criteria would apply but if the waveform is
repetitive then you have an infinite amount of time to sample it or to build
up a set of samples. This is like the difference between a waveform that is
a single shot or a waveform that repeats.

These were the early days of digital scopes and many clever schemes were
needed to achieve excellent bandwidth (1GHz to 3Ghz) with the relatively
slow sampling speed available in those days. The 11403A is capable of GHz
bandwidth on several channels as long as you are measuring repetitive
signals.

A single shot waveform only gives you one chance to sample it (or one chance
to display it on the CRT of an analog scope). Your eye has to be really fast
to see the entire one shot waveform or to study any part in detail. A
repetitive waveform refreshes the phosphor of the CRT over and over and you
eye has a chance to study any part of it in detail for as long as you like.

Dennis Tillman W7PF

-----Original Message-----
Sent: Tuesday, June 20, 2017 2:00 PM
Subject: [TekScopes] Re: 11403A as bench scope, how useful is it?

The biggest weak spot is the 20MSPS maximum sample rate. The short
record length is not so great either.

Is it really that low? Wow.
Using my typical rules of thumb that gives you a good look at square
waves up to about 2MHz (5th harmonic is 10MHz, Nyquist rate -> 20MSPS).

Not great at all. Surely it has some tricks to be better for non
repetitive signals?
------------------------------------
Posted by: cwilkson@...
------------------------------------

Re: New member introduction...

Vincent Trouilliez
 

---In TekScopes@..., <fabio.tr3visan@...> wrote :
> Just answering you about the "relative" closeness of Brazil to the US...
> Indeed, would it be just the distance I'd say I'd be a happy man.

Wow.... thanks for the briefing, quite enlightening indeed !
Didn't think that Brazil was THIS bad !

Well I am really sorry to hear that you have to put up with that much crap every day ! :-/

You really must be motivated/passionate about electronics then, no doubt... glad you managed to finally get a scope, you sure deserve it !

Here is crossing fingers that the situation in Brazil improves... some day.... the sooner the better... be strong Fabio... :-/


Regards,


Vince

Re: New member introduction...

Fabio Trevisan
 

Hey Vince,

Nice curriculum! I love aircrafts in general and Helicopters are indeed a
fascinating thing (with the rotational collective control... that's an
ingenious idea!).
Nice to know about the A350... It was about time for Airbus to come up with
something!

Just answering you about the "relative" closeness of Brazil to the US...
Indeed, would it be just the distance I'd say I'd be a happy man.

But Brazil, since I was young has been a country that raised or sustained A
LOT of importation barriers, banning or heavily taxing the importation of
pretty much everything that is or could be manufactured in Brazil, with the
excuse of protecting the Brazilian manufacturers and allow our "wannabe"
hi-tech industry to flourish (Bah... bulls...t!).
Any semi-educated Brazilian know, however, that this market protection only
served 3 purposes.
1, Make Customs officers rich (who would get bribes to look to the other
side when smugglers were passing, but smugglers were more interested in
consumer electronics, not scopes).
2. To make some Brazilian industry big shots richer, allowing them to
manufacture lousy stuff and sell them for absurd prices, without risk of
competition.
3. Ultimately, to prevent Brazilian entrepreneurs and scientists from
having access to 1st grade R&D lab equipment, which eventually condemned 3
generation of technology students of all kinds to change profession or to
be workforce to multi-national industries which eventually had some branch
here, to do mostly unintelligent work (after all, multi-national R&D is
always at the headquarters).

In the nineties, a progressive president (who was, granted, a crook, and
was impeached) eventually withdrawn most of the importation bans, allowing
stuff to be at least imported legally... But with such high importation
duties that it remained prohibitive to buy imported stuff.
Once again, well established industrial big shots took advantage of the -
now legal - importation, and fired their manufacturing employees and
started buying everything from China. even with high importation duties, it
was still cheaper than paying the local worker (and no hassle... who wants
to deal with a worker, with all his rights?).
I was caught by that wave in 1991. The computer manufacturer I worked for,
started importing motherboards from Taiwan and sliced 90% of their
workplaces.

Add to this the rate of exchange, of about 3.3 BRL : 1 USD and you have an
ugly picture.

If I want to buy, say, a 60 bucks UNI-T multimeter from e-bay or even from
AliExpress, it will knock my door at roughly R$ 500,00.

So, all the Hi-tek equipment from the 70s, 80s and 90s, that could be
affordable nowadays to the hobbyist, are very rare (because they didn't
make it to Brazil back at the time) and whoever have them, still sell it
for big money (or they ask for big money without ever selling it, I don't
understand!)...

Regards,

Fabio


2017-06-20 17:01 GMT-03:00 vincent.trouilliez@... [TekScopes] <
TekScopes@...>:



Hi Fabio,



By the way, you said you're on Aircraft maintenance business... I can't
refrain from asking... Do you work for Air France?
Nope.. I don't work in maintenance, sadly.. I was TRAINED for that.. but I
found out that MRO companies do'nt waste time/money on newbies like me...
they hire only seasoned people...
A week before passing my final exam, I got recruited by a company that
does Quality Control. So that's what I have been doing for the past 5
years. I work at a major Airbus site (in Saint-Nazaire), mostly on the new
airbus programe, thee A350 XWB (carbon plane, competition for the Boeing
787 "Dreamliner").
I also worked for 6 month on the A400M, the new military Aircraft,
supposed to free Europe from buying american C130... but it's doesn't quite
work so we keep buying C130 until the A400M finally can be made to work...

Hell I DID work in maintenance... for 3 weeks only, as part of our one
year training program we had to do a 3 week mini-placement. I love
helicopters, especially off-shore/oil and Gas, and luckily I managed to be
accepted at "Heli-Union", a French company that's one of the world wide
leaders in oil and gas heli transportation. In northern America the
equivalent would be the famous 'CHC'. Inthe UK 'Bristow'. In Belgium 'NHV'
is very young in this market but with great ambitions and growing fast

http://www.heli-union.com/ http://www.heli-union.com/

My 3 weeks there were very intense, I loved every minute of it. I got the
chance to work mostly on one of my favorite heli, the military version of
the "Dauphin"/Dolphin Helicopter (from Aérospatiale/Eurocopter/ Now "Airbus
Helicopter."). That heli is quite well know in the USA too, as we sold
quite a few there, for coast guard/search and rescue missions, known
there/rebadged as the " HH 65"

https://www.youtube.com/watch?v=mmVwzNfVj9g https://www.youtube.com/watch?
v=mmVwzNfVj9g


As for your collection, for someone who's (only) 39 and not working
directly on the electronics / R&D or Repair / business, you have quite an
impressive assortment!
They are old and not very expensive (compared to what the equivalent would
cost new...)


I wish I could say the same. I'm 53 and only one year ago I managed to
get
my first Tek...this stuff is hard to get by in Brazil and when they show
up, it's always expensive.
Brazil is much closer to the US than I am... shipping should be more
reasonable I would think ? Can't you just buy stuff on-line on Ebay USA and
get it shipped to your country ??


Just realized... in my first message, replace "TDS 360" with "TDS 310" , I
got mixed up ! Yeah I admit, I don't know my TDS3XX family tree by heart
just yet... I wish it were a 360 though, 310 is only 200MS/s, 360 has 1GS/s
it appears, and a floppy drive to boot (pun intended..). But who cares, now
that I have the 544A.


--
Vince


[Non-text portions of this message have been removed]

Re: 11403A as bench scope, how useful is it?

Chris Wilkson
 

The biggest weak spot is the 20MSPS maximum sample rate. The short
record length is not so great either.


Is it really that low? Wow.
Using my typical rules of thumb that gives you a good look at square waves up to about 2MHz (5th harmonic is 10MHz, Nyquist rate -> 20MSPS).


Not great at all. Surely it has some tricks to be better for non repetitive signals?

Re: New member introduction...

Vincent Trouilliez
 

Hi Siggy,


the service manuals are like a master class in analog engineering.
Yeah I love these old comprehensive manuals, so much to learn from them. I am still watching at the schematics of the pre-regulator of my 2232 scope in bed at night, while trying to find sleep. I am trying to figure out exactly how the "start-up"/boot-strap mechanism works exactly... am getting there but slowly, but not 100% clear just yet.... :-/
Having the GROUND power pin of the PWM chip, connected to the 40V OUTPUT rail of the regulator, is a bit disconcerting at first...


I'm now at 2*7834 (one still has PSUproblems), 485 (oooh, what a beauty!),
a 2465, 2467 (oooh!), 2340, TDS684A (broken, probably not fixable),
Well not bad ! :-)

and a TDS784D.
Oh, my dream TDS, I want it ! LOL :-))))

All bought in various state of disrepair for the pleasure of repairing them.
Yep, I am finding it more and more fun to troubleshoot stuff. My 2232 however puts me under some pressure though, because unlike all the other gear I am trying to fix, this scope is my main scope, so I really would like / need to fix it ASAP. Almost there though... maybe I won't even need to post about it here in the end, but will anyway.. a short thread just to describe what I did... might still help other newbies like me.


Vince

Re: R7903 Intensity control and readout loss

Dave Hills
 

Re: New member introduction...

Vincent Trouilliez
 

Hi Fabio,



>By the way, you said you're on Aircraft maintenance business... I can't
refrain from asking... Do you work for Air France?
Nope.. I don't work in maintenance, sadly.. I was TRAINED for that.. but I found out that MRO companies do'nt waste time/money on newbies like me... they hire only seasoned people...
A week before passing my final exam, I got recruited by a company that does Quality Control. So that's what I have been doing for the past 5 years. I work at a major Airbus site (in Saint-Nazaire), mostly on the new airbus programe, thee A350 XWB (carbon plane, competition for the Boeing 787 "Dreamliner").
I also worked for 6 month on the A400M, the new military Aircraft, supposed to free Europe from buying american C130... but it's doesn't quite work so we keep buying C130 until the A400M finally can be made to work...

Hell I DID work in maintenance... for 3 weeks only, as part of our one year training program we had to do a 3 week mini-placement. I love helicopters, especially off-shore/oil and Gas, and luckily I managed to be accepted at "Heli-Union", a French company that's one of the world wide leaders in oil and gas heli transportation. In northern America the equivalent would be the famous 'CHC'. Inthe UK 'Bristow'. In Belgium 'NHV' is very young in this market but with great ambitions and growing fast

http://www.heli-union.com/ http://www.heli-union.com/

My 3 weeks there were very intense, I loved every minute of it. I got the chance to work mostly on one of my favorite heli, the military version of the "Dauphin"/Dolphin Helicopter (from Aérospatiale/Eurocopter/ Now "Airbus Helicopter."). That heli is quite well know in the USA too, as we sold quite a few there, for coast guard/search and rescue missions, known there/rebadged as the " HH 65"

https://www.youtube.com/watch?v=mmVwzNfVj9g https://www.youtube.com/watch?v=mmVwzNfVj9g


As for your collection, for someone who's (only) 39 and not working
>directly on the electronics / R&D or Repair / business, you have quite an
> impressive assortment!

They are old and not very expensive (compared to what the equivalent would cost new...)


>I wish I could say the same. I'm 53 and only one year ago I managed to get
my first Tek...this stuff is hard to get by in Brazil and when they show
>up, it's always expensive.

Brazil is much closer to the US than I am... shipping should be more reasonable I would think ? Can't you just buy stuff on-line on Ebay USA and get it shipped to your country ??


Just realized... in my first message, replace "TDS 360" with "TDS 310" , I got mixed up ! Yeah I admit, I don't know my TDS3XX family tree by heart just yet... I wish it were a 360 though, 310 is only 200MS/s, 360 has 1GS/s it appears, and a floppy drive to boot (pun intended..). But who cares, now that I have the 544A.


--
Vince

Re: 7A13 shorted +15 rail

TomC
 

A tantalum in a 7A26 shorted so I set it aside to be worked on later. Then a couple of weeks later another shorted tantalum in another 7A26. Seeing a pattern here, I ordered a bag of tantalum capacitors with a somewhat higher voltage rating and replaced all of them in my 7A26 plugins. I think there are 3 or 4 in each plugin.

Replacement goes quick once you have the parts and get set up to go through them all.

Tom

On 6/20/17 10:14 AM, Brent Watson brentleew2003@... [TekScopes] wrote:
So Jerry, are you saying just change the tants and eliminate any question as to there condition.? I'm up against the same issue of Tantalums and whether to just replace.Brent
From: "Jerry Massengale jmassen418@... [TekScopes]" <TekScopes@...>
To: TekScopes@...
Sent: Tuesday, June 20, 2017 9:59 AM
Subject: Re: [TekScopes] 7A13 shorted +15 rail
It is best to replace all the tants.
jerry
On Tue, Jun 20, 2017 at 9:56 AM, Larry DeVito ldevito@... [TekScopes]
<TekScopes@...> wrote:

>
>
> Hello Everyone,
> Does anyone have advice on troubleshooting procedure.I have a 7A13 plug-in
> with +15V rail shorted. The mostlikely cause is tantalum cap. What is
> best way to findthe errant component?
>
> ThanksLarry
>
>
>
>
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Re: R7903 Intensity control and readout loss

Ed Breya
 

Just to clarify - Ta caps ARE electrolytic - just a different kind compared to Al and others, so in any parts description of them it is appropriate. Ed

Re: 7A13 shorted +15 rail

Brent Watson <brentleew2003@...>
 

So Jerry, are you saying just change the tants and eliminate any question as to there condition.? I'm up against the same issue of Tantalums and whether to just replace.Brent


From: "Jerry Massengale jmassen418@... [TekScopes]" <TekScopes@...>
To: TekScopes@...
Sent: Tuesday, June 20, 2017 9:59 AM
Subject: Re: [TekScopes] 7A13 shorted +15 rail

  It is best to replace all the tants.

jerry

On Tue, Jun 20, 2017 at 9:56 AM, Larry DeVito ldevito@... [TekScopes]
<TekScopes@...> wrote:



Hello Everyone,
Does anyone have advice on troubleshooting procedure.I have a 7A13 plug-in
with +15V rail shorted. The mostlikely cause is tantalum cap. What is
best way to findthe errant component?

ThanksLarry

[Non-text portions of this message have been removed]


[Non-text portions of this message have been removed]

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