MessageView 421F schematic

[TekMan]

Jim Yanik <jyanik@abuse.gov> wrote in message news:<Xns9475D11F643D3jyanikkuanet@204.117.192.21>...

Joerg Hau <joergREMOVETHIS.hau@swissonline.ch> wrote in
news:ksmhub.os1.ln@54693.user.dfncis.de:

....
Any idea what might be wrong here (better yet: how to fix it ?)

Well,getting the service manual is the first step.Read the circuit
description,it's very helpful in understanding how the scope works.

Hi,

I've send him a Service Manual, see PM.

hope this helps.

Heike

 

[Robert Lacoste]

Hi,
I don't have this manual, but I do have the same equipment. So if you find
it I am really intested !!!

On the "filter/6x9" button as far as I understand it adds a slow loss pass
filter/averaging filter on the readings, drastically smoothing the readings
but adding one more digit.

Sorry, I can't help on the GPIB side. Have you tried just to read from it ?

Friendly yours,

Robert Lacoste - ALCIOM : The mixed signals experts
http://www.alciom.com

"Joerg Hau" <joergREMOVETHIS.hau@swissonline.ch> a écrit dans le message de
news:7g3hub.u32.ln@54693.user.dfncis.de...

Hi,

Does anyone have a reference/service/maintenance manual available for
the 6-digit DMM "Solartron 7150" (Schlumberger, ca. 1989)?

Specifically, I'm looking for the following information:

(1) function of the "special" keys on the keypad
("Filter"/"6x9" etc),
(2) instructions on re-calibration (yes, I opened it, but it's
not that obvious ;-)
(3) command set of the integrated GPIB/IEEE/HBIB bus (I want
to use it under Linux),

A simple copy or a pdf would of course be sufficient.

Please feel free to contact me either via the newsgroup, or per direct
mail.

Thanks in advance for any help,
and greetings from Lausanne!

- Joerg


[ xpost to s.e.equipment & s.e.repair, f'up to s.e.e. ]


--
joerg dot hau at swissonline dot ch * Lausanne, Switzerland
http://www.mysunrise.ch/users/joerg.hau/
"All standard disclaimers apply".
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(this became necessary due to increasing SPAM)

 

[Jim Yanik]

Joerg Hau <nospam.joerg.hau@swissonline.ch> wrote in
news:m76jub.4ob.ln@54693.user.dfncis.de:

Hi,

Yet another scope in trouble ...

HP 1222A. Has always been working fine, but recently (after a longer
pause) it suddenly has developed a "sawtooth" baseline.

- periodicity ~9 ms, int'y ~1 graticule
- both channels are equally concerned
- A/B gain setting or grounding does not change amplitude
- both channels can be moved up/down w/o problems
- input signal overlays the "sawtooth"
- sawtooth reacts on trigger (or vice versa ;-)
- sawtooth becomes "steeper" if moved beam is moved to the
lower part of the CRT

Power supplies:
+95 V adjusted, OK
+210 V reads +219.5 V
+12 V reads +14.20 V, -12 V reads -14.25 V (at least symmetrical ;-)

I suspect that the input channels are OK and that the problem is
probably related to the vertical deflection (or sweep?).

Before diving into the circuit ... does that ring a bell ... anybody?

Please feel free to contact me either via the newsgroup, or per direct
mail.

Thanks in advance for any help,
and greetings from Lausanne!

- Joerg


[ xpost to s.e.equipment & s.e.repair, f'up to s.e.e. ]

Did you check for ripple on those DC supplies? Are the regulated supplies
actually regulating when you vary mains voltage with a Variac?

Also,do you have a service manual or schematics?

--
Jim Yanik
jyanik-at-kua.net

 

[Joerg Hau]

On Tuesday 20 January 2004 12:26, TekMan wrote:

I've send him a Service Manual, see PM.

Hi Heike,

That's truly kind ), but I got a bounce on your mail address ("This
account is not allowed"). Could you contact me via PM please?

Best regards (and sorry for the bandwidth),

- Joerg


--
joerg dot hau at swissonline dot ch * Lausanne, Switzerland CHANGED
URL: http://homepage.sunrise.ch/mysunrise/joerg.hau/
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[Joerg Hau]

Hi Jim

HP 1222A. Has always been working fine, but recently (after a
longer pause) it suddenly has developed a "sawtooth" baseline.

- periodicity ~9 ms, int'y ~1 graticule
- both channels are equally concerned
- A/B gain setting or grounding does not change amplitude
- both channels can be moved up/down w/o problems
- input signal overlays the "sawtooth"
- sawtooth reacts on trigger (or vice versa ;-)
- sawtooth becomes "steeper" if moved beam is moved to the
lower part of the CRT

Power supplies:
+95 V adjusted, OK
+210 V reads +219.5 V
+12 V reads +14.20 V, -12 V reads -14.25 V (at least symmetrical
;-)

Did you check for ripple on those DC supplies?

Admittedly I did not even think of this before (the values were
"approximatively correct" and steady) ... and indeed, there is a fat
ripple of about 2.2 Vss on everything except the +95 V supply. Now
I've really got something to start with

BTW, I've put a picture of the patient showing its symtoms at
<http://homepage.sunrise.ch/mysunrise/joerg.hau/test/hp1222a.jpg>.
The different slope of the two traces is only is due to the different
position on the screen.

Are the regulated supplies actually regulating when you vary
mains voltage with a Variac?

I don't have a Variac :-(

Also,do you have a service manual or schematics?

Yes, but I thought I'd ask here first ... I'm pretty well used to work
_with_ a scope, but much less _inside_ of it ;-)

Thanks!

- Joerg


--
joerg dot hau at swissonline dot ch * Lausanne, Switzerland CHANGED
URL: http://homepage.sunrise.ch/mysunrise/joerg.hau/
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[Joerg Hau]

Hi again,

Check to see if external trigger input works.

No, it doesn't.

Ah ... I got a copy of the circuit diagrams

Scope to see if the trigger signal picked off
from the vertical is getting to the input FETS on the trigger
board.One or both of those FETs could have failed(matched pair).You
can swap the pair from B trigger.

For the measurements I split the input via a "T" connector to both
channels & set the display to CHOP mode:

- Signal comes through the input stage, up to to TPS26 (U520 Pin 3).
- Yes, in both channels.
- Channel A, output of U520 (Pin 8+9) does not carry any AC component.
- Channel B, output of U520 (Pin 8+9) has the trigger signal.

Scope input then grounded, measured DC voltages at the output of U520
(should be 14.7 V according to circuit diagram):

Channel B, pin 8+9 = 14.58 V both.
Channel A, pin 8 = 14.20 V, is influenced by R542
Channel A, pin 9 = 15.03 V, NOT influenced by R542

.... is that now "just" a problem of DC voltages around U520 in Ch A,
or is that IC "shot"?

Any ideas?
(... pleeeease say it ain't that IC ;-)

- Joerg


--
joerg dot hau at swissonline dot ch * Lausanne, Switzerland CHANGED
URL: http://homepage.sunrise.ch/mysunrise/joerg.hau/
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[Emanuele Girlando]

For a free 475A service manual go to http://bama.sbc.edu and look for
Tektronix. Quality is not high, but it is for free!
I used it to fix my 475..
Good luck.

Joerg Hau <joergREMOVETHIS.hau@swissonline.ch> wrote in message
ksmhub.os1.ln@54693.user.dfncis.de...

Hi,

I'm looking for a copy of the repair/maintenance manual, or at least
the circuit diagrams, for the Tektronix 475A/DM44 scope.

The trigger for channel A does not work; the corresponding LED (or is
that a lamp?) does not light up as it should. I can only obtain a
stable display if _all_ the four buttons of the HORIZ DISPLAY kerys
(to the right of the CRT) are out & I use the "B" trigger button to
adjust ... ?!

Any idea what might be wrong here (better yet: how to fix it ?)

Please feel free to contact me either via the newsgroup, or per direct
mail.

Thanks in advance for any help,
and greetings from Lausanne!

- Joerg


[ xpost to s.e.equipment & s.e.repair, f'up to s.e.e. ]
--
joerg dot hau at swissonline dot ch * Lausanne, Switzerland
http://www.mysunrise.ch/users/joerg.hau/
"All standard disclaimers apply".
remove ".nospam" from my address to reply
(this became necessary due to increasing SPAM)

 

[Crcard53762]

Sounds like Ripple on one of the power supplys. Check with another scope, or
with your meter on AC mode. Check the supplys for ripple. Probably a bad
filter cap in a power supply.

 

[Jim Yanik]

Joerg Hau <nospam.joerg.hau@swissonline.ch> wrote in
news:44tmub.2n9.ln@54693.user.dfncis.de:

Hi again,

Check to see if external trigger input works.

No, it doesn't.

Ah ... I got a copy of the circuit diagrams

Scope to see if the trigger signal picked off
from the vertical is getting to the input FETS on the trigger
board.One or both of those FETs could have failed(matched pair).You
can swap the pair from B trigger.

For the measurements I split the input via a "T" connector to both
channels & set the display to CHOP mode:

- Signal comes through the input stage, up to to TPS26 (U520 Pin 3).
- Yes, in both channels.
- Channel A, output of U520 (Pin 8+9) does not carry any AC component.
- Channel B, output of U520 (Pin 8+9) has the trigger signal.

Scope input then grounded, measured DC voltages at the output of U520
(should be 14.7 V according to circuit diagram):

Channel B, pin 8+9 = 14.58 V both.
Channel A, pin 8 = 14.20 V, is influenced by R542
Channel A, pin 9 = 15.03 V, NOT influenced by R542

... is that now "just" a problem of DC voltages around U520 in Ch A,
or is that IC "shot"?

Any ideas?
(... pleeeease say it ain't that IC ;-)

- Joerg

I'm not sure what U520 is,are you checking signals on the -vertical- assy.?

I don't have any schematic to reference,but you may want to check the metal
film resistors around that IC,one could have changed value or opened.

--
Jim Yanik
jyanik-at-kua.net

 

[Joerg Hau]

On Thursday 22 January 2004 01:52, Jim Yanik wrote:

Scope to see if the trigger signal picked off
from the vertical is getting to the input FETS on the trigger
board.One or both of those FETs could have failed(matched
pair).You can swap the pair from B trigger.

For the measurements I split the input via a "T" connector to both
channels & set the display to CHOP mode:

- Signal comes through the input stage, up to to TPS26 (U520 Pin
3). - Yes, in both channels.
- Channel A, output of U520 (Pin 8+9) does not carry any AC
component. - Channel B, output of U520 (Pin 8+9) has the trigger
signal.

Scope input then grounded, measured DC voltages at the output of
U520 (should be 14.7 V according to circuit diagram):

Channel B, pin 8+9 = 14.58 V both.
Channel A, pin 8 = 14.20 V, is influenced by R542
Channel A, pin 9 = 15.03 V, NOT influenced by R542

... is that now "just" a problem of DC voltages around U520 in Ch
A, or is that IC "shot"?

I'm not sure what U520 is,are you checking signals on the -vertical-
assy.?

No, I'm still inside the "A" trigger generator. U520 is the TEK-made
input preamp just after the FET stage.

I don't have any schematic to reference,but you may want to check
the metal film resistors around that IC,one could have changed value
or opened.

Been there, done that, no avail ... well, as the voltages were not
that much off and all the transistors were OK, I finally swapped this
preamp IC with its partner from the "B" channel: Indeed, U520 is
shot. One of those - as you said - "TEK-made IC's which aren't
available from TEK anymore,just from parts scopes" :-((

(If anyone has a spare to give away: it's labelled with the TEK logo,
then "155 0032 01" and in the second row "621 366 USA").

At least Ch A triggers now, which is the most important channel

Thanks a lot to all those that provide input!

- Joerg


--
joerg dot hau at swissonline dot ch * Lausanne, Switzerland CHANGED
URL: http://homepage.sunrise.ch/mysunrise/joerg.hau/
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(this became necessary due to increasing SPAM)

 

[news2020pp]

Subject : Where is news2020 ? re: lasers/radar/beacons/serious-injuries

That's me. Lots of injuries and more than 6 months after the last post on
this newsgroup !

My old account is blocked by the ISP due to frivolous reasons. The last I
heard last month they were going to re-connect everything at $9.95 /month or
something like that. However, it is still not up.

Has anyone kept track of posts related to the
radiation/lasers/radar/serious-injuries etc. issues he had raised (news2020
aliias).
I have just been able to reconnect via a different
account after a total blockage for over 6 months in this age of instant
communications !!! (virtual imprisonment in wide open view of everyone).
This connection has also had its share of problems with various disconnects
already. I have told them that this is the equivalent of a llife line (jobs,
contacts, email, web, news, etc.) now that everyone has plugged into the
internet.

< My thanks to all those who provided feedback from all these newsgroups.
Since the issue is not restricted to me, the outcome of these posts is
useful to everyone in these newsgroups as well as outside. Therefore, either
everyone stands to gain or lose equally. Everyone is on the same boat,
perpetrators and victims ! Today's perpetrators will be tomorrow's victims.
>

 

[Winfield Hill]

news2020pp wrote...

I have just been able to reconnect via a different account after a total
blockage for over 6 months in this age of instant communications !!!
(virtual imprisonment in wide open view of everyone).

This is nonsense 2020. We know it and you know it. There's no need
for you to troll with a non-issue, when you have so many substantive
"issues" to put in front of us.

When my mother-in-law had trouble with AOL, and after that Earthlink,
I went to her aid looking for a new ISP. Google searches (which you
can do at your local library) reveal hundreds, if not thousands, of
eager ISPs. Several web sites rate them according to various criteria.
All of these ISP have national phone POP (point of presence) coverage
using several competing POP networks, and most of these will have one
or more local phone numbers to insure no long distance charges. This
means if you're unhappy with your ISP, get a change! I selected one
and changed my mom and now she's reasonably happy on her third ISP.

Furthermore, there are hundreds of internet domain providers and for a
modest cost you can own your own domain and have your own private email
address and email server. (For example, I own picovolt.com) This is
independent from your ISP, and it means you can change ISPs at will,
as often as you like, without affecting access to your email address.
In my case AT&T trashed 750000 long-standing MediaOne email addresses
and I could see that Comcast would soon trash all the AT&T addresses,
and escaping the rein of ISP-owner insanity became mandatory for me.
Other people achieve the same result with a web-based email accounts,
such as yahoo, hotmail, etc.

Thanks,
- Win

whill_at_picovolt-dot-com

 

[Fred Bloggs]

news2020pp wrote:
{...snip...]

!PLONK!

 

[CWatters]

"news2020pp" <user121@peoplepc.com> wrote in message
news:101477q19viikb6@corp.supernews.com...

Has anyone kept track of posts related to the
radiation/lasers/radar/serious-injuries etc. issues he had raised
(news2020
aliias).

I'm confused. You say "issues he had raised" rather than "Issues I raised".
That slip suggests you aren't the real news2020. How can we be sure it's the
real news2020 back after all this time?

 

[Ken Taylor]

"CWatters" <colin.watters@pandoraBOX.be> wrote in message
news:6IzQb.3689$jf4.33826@phobos.telenet-ops.be...

"news2020pp" <user121@peoplepc.com> wrote in message
news:101477q19viikb6@corp.supernews.com...

Has anyone kept track of posts related to the
radiation/lasers/radar/serious-injuries etc. issues he had raised
(news2020
aliias).

I'm confused. You say "issues he had raised" rather than "Issues I
raised".
That slip suggests you aren't the real news2020. How can we be sure it's
the
real news2020 back after all this time?

Yeah, we want to ignore the right people.

Ken

 

[news2020pp]

Thanks for the moral support.

While you are squarely straddling the fence with colorful terminology, your
alternative seems to be 'pack up and leave (to another ISP,etc.)' rather
than 'try to solve the underlying issue'. Yet, the 'avoid the problem'
attitude seems to be viable now though it was not very viable earlier on. I
bet it would not be viable at all in a different or totalitarian country.
Even now there seem to be software hangs and virus type of activity shutting
down or disabling my connection every other time.

If you do not 'try' when you are right, you not only set yourself up for a
downhill path, but you also set a bad precedent for all the others that are
watching you and hoping for their own sakes that you succeed. There is
nothing wrong in failing after trying. However, you can only blame yourself
if you do not 'try'. The bad guys cannot be blamed if you give up and agree
to be raped.

So, for the record, my position is clear. I am trying. Not only for myself,
but also for everyone that depends on this. I am not surpirsed by your
resigned acceptance, though. I have seen many many people who have given up
either because the 'machine' seems all powerful and invincible or because
they have been prostituted and implicated by the 'machine' already. An
illegal action (or complicity in rape/.torture, etc.) calls for appropriate
punishment. Torturing the victim further, as was done quite openly with
everyone participating, is not okay. That is why 'avoiding' or 'moving away'
is also not really a solutiion. It just postpones and intensifies the
activity.


"Winfield Hill" <Winfield_member@newsguy.com> wrote in message
news:butso0017un@drn.newsguy.com...

news2020pp wrote...

I have just been able to reconnect via a different account after a
total
blockage for over 6 months in this age of instant communications !!!
(virtual imprisonment in wide open view of everyone).

This is nonsense 2020. We know it and you know it. There's no need
for you to troll with a non-issue, when you have so many substantive
"issues" to put in front of us.

When my mother-in-law had trouble with AOL, and after that Earthlink,
I went to her aid looking for a new ISP. Google searches (which you
can do at your local library) reveal hundreds, if not thousands, of
eager ISPs. Several web sites rate them according to various criteria.
All of these ISP have national phone POP (point of presence) coverage
using several competing POP networks, and most of these will have one
or more local phone numbers to insure no long distance charges. This
means if you're unhappy with your ISP, get a change! I selected one
and changed my mom and now she's reasonably happy on her third ISP.

Furthermore, there are hundreds of internet domain providers and for a
modest cost you can own your own domain and have your own private email
address and email server. (For example, I own picovolt.com) This is
independent from your ISP, and it means you can change ISPs at will,
as often as you like, without affecting access to your email address.
In my case AT&T trashed 750000 long-standing MediaOne email addresses
and I could see that Comcast would soon trash all the AT&T addresses,
and escaping the rein of ISP-owner insanity became mandatory for me.
Other people achieve the same result with a web-based email accounts,
such as yahoo, hotmail, etc.

Thanks,
- Win

whill_at_picovolt-dot-com

 

[news2020pp]

You can never be sure. Anonymity is offered by rape shield laws for
protection from rapists/ etc. Remember good old Bob Dole referring to
himself in third person as 'Bob Dole' during his election campaign ?

"CWatters" <colin.watters@pandoraBOX.be> wrote in message
news:6IzQb.3689$jf4.33826@phobos.telenet-ops.be...

"news2020pp" <user121@peoplepc.com> wrote in message
news:101477q19viikb6@corp.supernews.com...

Has anyone kept track of posts related to the
radiation/lasers/radar/serious-injuries etc. issues he had raised
(news2020
aliias).

I'm confused. You say "issues he had raised" rather than "Issues I
raised".
That slip suggests you aren't the real news2020. How can we be sure it's
the
real news2020 back after all this time?

 

[John Gilmer]

This is nonsense 2020. We know it and you know it. There's no need
for you to troll with a non-issue, when you have so many substantive
"issues" to put in front of us.

When my mother-in-law had trouble with AOL, and after that Earthlink,
I went to her aid looking for a new ISP. Google searches (which you
can do at your local library) reveal hundreds, if not thousands, of
eager ISPs. Several web sites rate them according to various criteria.
All of these ISP have national phone POP (point of presence) coverage
using several competing POP networks, and most of these will have one
or more local phone numbers to insure no long distance charges.

Well, for MOST of you out there you can reach most of the national ISPs with
local calls but for folks in semi-rural or rural areas the nationals don't
bother providing a local number so you are sometimes stuck with only ONE or
maybe two local ISPs. That's my situation. The local ISP is OK but even
if it weren't I would still be using them.

Were my ISP to turn flaky, I would have to sign up for one of those
unlimited long distance plans.

Out in the sticks you just don't have cable or DSL or any of that stuff.
The technology is used to benefit the telco which means that we often have
"concentrators" between us and the local Central Office. In practice, this
means that out connection speed is about 25 kbs rather than 57 kbs.

This
means if you're unhappy with your ISP, get a change! I selected one
and changed my mom and now she's reasonably happy on her third ISP.

Furthermore, there are hundreds of internet domain providers and for a
modest cost you can own your own domain and have your own private email
address and email server.

Yes but ... even if you get your own domain you have to comply with the
TOS of the hosting company. They may let you "get away" with more than
your typical ISP but if you get carried away with yourself the hosting
service might decide you are more trouble that your are worth!

 

[Keith R. Williams]

In article <6IzQb.3689$jf4.33826@phobos.telenet-ops.be>,
colin.watters@pandoraBOX.be says...

"news2020pp" <user121@peoplepc.com> wrote in message
news:101477q19viikb6@corp.supernews.com...

Has anyone kept track of posts related to the
radiation/lasers/radar/serious-injuries etc. issues he had raised
(news2020
aliias).

I'm confused. You say "issues he had raised" rather than "Issues I raised".
That slip suggests you aren't the real news2020. How can we be sure it's the
real news2020 back after all this time?

Bingo! ...too lucid. Nice try there NEWSIEpp.

--
Keith

 

[Winfield Hill]

John Gilmer wrote...

This is nonsense 2020. We know it and you know it. ...

Well, for MOST of you out there you can reach most of the national
ISPs with local calls but for folks in semi-rural or rural areas
the nationals don't bother providing a local number ...

I know this sad scene very well, as my brother on the ranch in
Nevada has been struggling with it for years. However, I know
exactly where news2020 lives, and this is not a problem for him.

Thanks,
- Win

whill_at_picovolt-dot-com