开云体育

Loading, finding, looking up, bla bla bla, why not just put the image here ? Too bad Dropbox turned into garbage.

As for how you described the symptom, I would look at all voltages on the CRT, including the blanking electrode if it has one, and whatever else.

Just to eliminate it as a cause maybe you should short the vertical deflection plates together. Look at the manual and make sure it won't fry the amp, of in doubt disconnect one and run both plates off one or the other.

There is a possibility you have cathode damage but I have no idea how it could have happened. there is also the possibility the CRT is simply weak.

Sounds like you have something to investigate. Be careful not to
electrocute yourself when finding the source of the arc, it's not
supposed to arc! Try sticking plastic, move things apart, etc. to see
if you can get the arcing to stop.

The voltage on the base is fine when the HV isn't actually running -
it's both a symptom and a result but not a cause. I would suspect the
voltage is around -4.4V (or much lower than 11V) when you have the line
voltage turned down. At that point it's actually running and you're
getting HV. When the HV is not operating, the only way to get things
going is to turn that transistor on, and at -4.4V it may not be enough
to get things going.

The presence/operation of HV is what causes the voltage to go down to
-4.4V, if that would help explain what's going on here.

I recently acquired a 465 in rather good condition, and have been cleaning it up over the weekend. Power supply rails have been checked to be within spec, including the -2450V one. CRT bias adjusted according to service manual as well.

Having just finished converting the volts/div indicator lights to LEDs, I unfortunately stumbled onto a more serious seeming trace issue. At a low intensity setting, the trace is as one would expect, albeit not particularly sharp, but still quite usable. However, at the intensities required at faster sweeps (50u/div and above), the trace takes a very peculiar appearance of doubling itself! This can be controlled at will with the intensity knob, and the two "traces" appear when the focus is at sharpest. Here are some pictures of the issue:

The issue was not present just a day or two ago, so is it possible that the CRT has given up the ghost over the ~10 hours or so of power-on time during testing and adjustments? Hoping someone can shed light on this oddity.

Hi Tony,

Glad to hear that your PSU is functional. The diode that you are referring
to is VR1297 (9V zener) right? Not CR1297?

In regard to the Read Out, I believe that I read somewhere in the manual
that there is a way to turn off the readout via a switch inside the unit -
maybe yours has been turned off?

Are the switches lighting up on time base plugin when you put it in the
horizontal A slot? If not, it could be something with the power on the main
board. Or, is there a problem with the triggering?

Best,
John

On Sun, Apr 29, 2018 at 12:24 PM, Yiu On Tony C via Groups.Io <
tonycheung_hk@...> wrote:

Hi John :
Now the PSU had no problem , after find the zener open ( CR1297 ) , and
reference the uploaded file by Robert.
CR1311 and CR1312 is not fast recovery , TEK parts reference is 1N5823
,which is schottky barrier diode, after change it to 1N5820 , 3A 20V , 5V
light now return to 5V .
On the other hand , remove the short at front interface board by shield
panel of mode switches , find the trace open ( -15V ) C60 to P12-pin3 and
J1, J2, J3, J4 . ( it become R1541 and all plug in no -15V supply ). I did
check other supply voltages to main interface board, and find the pin
numbers for J1 , J2, J3, J4 at schematic are different for connected power,
error or not sure at schematic ?
After all the above repair completed , front panel return normal ,included
button's light, GRAT ILLUM, INTENSITY and FOCUS.
Still have problems on my 7904 :
1. Horizontal A plug in slot ,function issue -- position problem. Same
plug had no problem at Horizontal B slot ! It may be Main interface board
again ? anyone know J1, J2, J3 and J4 pin-out ? it is 38 pin but it seem
more pins ?
2. CRT read out no function, R2124 Readout Intensity no function at all .
RegardTony CheungAPR 30 2018


From: JJ <jajustin@...>
To: [email protected]
Sent: Friday, April 27, 2018 1:21 AM
Subject: Re: [TekScopes] 7904 Mainframe damaged

Tony, does the value of 5V lights fall below 4.5V when you increase the
load to the point that the PSU shuts off? 5V lights is monitored by the
Inverter Control IC U1275. A fraction of the 5V lights voltage is fed into
the BAL Sense input of U1275. I would monitor TP1302 on the rectifier board
and 5V lights. There is also a sense current from T1310 that enters that
Bal sense node and can shut down the PSU.

On page 3-58 of the manual, it discusses the Balance Sense input.

Best,
John

On Thu, Apr 26, 2018 at 12:05 PM, Yiu On Tony C via Groups.Io <
tonycheung_hk@...> wrote:

Hi JJ:
TP1625 are normal 40V +/-3V ! ( it must be connected to maim unit , it is
related to CRT HV CKT !
If PSU alone , such voltage reading will more positive ( + 130V ) ).
On the other hand , I did measure the value of R1286 and 1287 , it is OK

!

When PSU connected to main unit , I do not understand ,for CR1311 and

1312

, I use HSR208 ( 2A 1KV CJ=14pF ) will shut down PSU . but use FR607 ( 6A
1KV CJ= 80pF ) will not shut down the PSU ! both setting are Control
ILLUM must OFF, and GRAT ILLUM are always turn on ( not controllable ! ).
Still finding the problem !
RegardTony CheungAPR 27 2018

From: JJ <jajustin@...>
To: [email protected]
Sent: Wednesday, April 25, 2018 7:04 PM
Subject: Re: [TekScopes] 7904 Mainframe damaged

Tony, did you do the Power Supply test on page 5-8 of the manual :

Adjust

Inverter Control R1293 for a meter reading on TP1625 of +40V? Maybe your
operating point for the Inverter Controller is way off. Mine was way off

in

the negative range until I adjusted it.

Best,
John

On Tue, Apr 24, 2018 at 10:52 PM, Yiu On Tony C via Groups.Io <
tonycheung_hk@...> wrote:

Hi John :
It is overall power handling issue for the PSU , U1275 is the

controller

for the shut down action, 5V light is NOT only output, there is

feedback

to R1304 to controller too !
On the other hand the total current sampling from T1235 to U1275.
I did check C1316, C1317 and C1318 are normal .
My PSU was damaged by miss-align one pin of SENS input on LV Board (

P1483

) :
pin 1 ------- Beam I Sens input on LV board NO Connection.
pin 2 ------- GND Sens input on LV board connected to P83 pin 1
-------Beam I sens. --------------- Beam I sens short to GND.
pin 3 ------- +5V Sens input on LV board connected to P83 pin 2 -------
GND sens, -------------means +5V short to GND !
pin 4 ------- -50V Sens input on LV board connected to P83 pin 3

--------

+5V sens, ------------- short -50V to +5V !
pin 5 ------- +50V Sens input on LV board connected to P83 pin 4

--------

-50V sens -------------- short +50V to -50V
pin 6 -------- -15V Sens input on LV board connected to P83 pin 5

--------

+50V sens ------------- short -15V to +50V
pin 7 ------- +15V Sens input on LV board connected to P83 pin 6

-------

-15V sens ------------ short +15V to -15V

The results is all ( +5V, -50V, +50V, -50V, -15V, +5V and Beam I sens
short to GND ). may be serious damage for the PSU or main unit ?
Anyway it is under repair for the damage !
RegardTony CheungAPR 25 2018



From: JJ <jajustin@...>
To: [email protected]
Sent: Wednesday, April 25, 2018 5:26 AM
Subject: Re: [TekScopes] 7904 Mainframe damaged

Tony,
If all you can draw is 100ma on 5v lights, you could have a problem

with

that power supply's pi section filter - I had to change C1318 to get my

PSU

up. It measured 40uf instead of 100uf. That cap may be right on the

edge

of

failure at certain loads. There are also 2 other caps in that filter -
C1316, C1317. Note that 5v lights is not regulated on the LV regulator
board - it just goes through the board to the connectors - so the

problem

is localized to the cap rectifier board.

I would first change C1318 with any 100uf cap (doesn't have to be

tantalum

to just test). And, do the same sequentially for the other two - swap

out

then test. They're pretty easy to change.

Best,
John



On Tue, Apr 24, 2018 at 2:35 PM, Yiu On Tony C via Groups.Io <
tonycheung_hk@...> wrote:

Hi John :
Yes, I did put it back to 7904 , but find something NOT working !
1. Graticule Light always on ----------- I did check NO -15V at

R1451,

but

PSU was tested with full loading pass .2. Front panel push button's

light

not function.3. For Horizontal Mode Switch ALT , CHOP will shut down

the

PSU. A or B is OK !
Regard
Tony Cheung


From: JJ <jajustin@...>
To: [email protected]
Sent: Wednesday, April 25, 2018 1:21 AM
Subject: Re: [TekScopes] 7904 Mainframe damaged

Tony, have you tried putting the PSU back into the mainframe to see

if

it

works in its normal load and interaction environment? You may be

chasing

the proverbial wild goose! :)

Best,
John

On Tue, Apr 24, 2018 at 12:16 PM, Yiu On Tony C via Groups.Io <
tonycheung_hk@...> wrote:

Hi:
It is a good idea ! But I leave my workshop already ! May check day

after

tomorrow. It is midnight in Hong Kong !
One thing I find at least, I disconnect-15 V loads, it become

normal.

So

that my next step to check the resistor!
Regard
Tony Cheung


從我的 iPhone 傳送

dadhills@... 於 2018年4月24日 下午11:40 寫道：

Have you checked R1286, 1K, 5%? It is a carbon composition

resistor

and

if it has drifted high in value, it will lower the "total" load

current

limit threshold.

Dave

On Tue, Apr 24, 2018 at 07:59 am, Yiu On Tony C wrote:


Hi Harvey :
My PSU are test alone and connected to Loading resister and "

sens "

return to

LV board.
For the current limiter was controlled by U1275 , and I find the

zener

VR1297

---- 9V are opened , I replace it and now always shut down

again ,

even

I open

the zener again , still shut down ! It means cannot return as

before ,

I did

check all the diodes on A12 , but no defective !
There may be something wrong again !
RegardTony CheungAPR 24 2018

From: Harvey White <madyn@...>
To: [email protected]
Sent: Tuesday, April 24, 2018 9:41 PM
Subject: Re: [TekScopes] 7904 Mainframe damaged

On Tue, 24 Apr 2018 13:27:01 +0000 (UTC), you wrote:

Hi :
My 7904 still have problem for PSU !
+/-50V, +/-15V, +5V , +130V are normal with loading power on !
Once I connect the loading to +5V light , it cannot load even

0.1A

!

it will

shut down PSU. ( If normal , It can output up to 3.5A ! )

The diode for +5V lights are defective ( shorted ) and replaced

by

fast

recovery diode FR607 ( junction Cap 80pF )or HER208 ( junction

cap

14pF ).

Sounds as if the supply is working normally for regulation, but

the

shutdown circuitry is too sensitive. There's a current sense

resistor

in there, and some associated parts. Could the current sense

resistor

be too high in value? That will certainly cause this supply to

shut

down on a lower current. I'd also check the amplifier for that

sense,

to make sure it is working properly.

Harvey

Who cares about or or of ....
I need to remove / reinstall SWEEP (!) generator board.
Let me start with
since it is "older" technology - does the board "pulls-up" from "mother board"?
Or is it something different? Like sideways etc. instead of straight up.
It looks there is only one pair of wires which is soldered in, everything else is "plug in".

I like the idea of disabling the "delay sweep" time electronically - since I have no idea about the setting of presumably broken pot wafer.
And yes - if you pull the delay time knob on normally working scope it DOES change something even when the delay sweep levers are not used.

Hi John :
Now the PSU had no problem , after find the zener open ( CR1297 ) , and reference the uploaded file by Robert.
CR1311 and CR1312 is not fast recovery , TEK parts reference is 1N5823 ,which is schottky barrier diode, after change it to 1N5820 , 3A 20V , 5V light now return to 5V .
On the other hand , remove the short at front interface board by shield panel of mode switches , find the trace open ( -15V ) C60 to P12-pin3 and J1, J2, J3, J4 . ( it become R1541 and all plug in no -15V supply ). I did check other supply voltages to main interface board, and find the pin numbers for J1 , J2, J3, J4 at schematic are different for connected power, error or not sure at schematic ?
After all the above repair completed , front panel return normal ,included button's light, GRAT ILLUM, INTENSITY and FOCUS.?
Still have problems on my 7904 :
1. Horizontal A? plug in slot? ,function issue -- position problem. Same plug had no problem at Horizontal B slot ! It may be Main interface board again ? anyone know J1, J2, J3 and J4 pin-out ? it is 38 pin but it seem more pins ?
2. CRT read out no function, R2124 Readout Intensity no function at all .
RegardTony CheungAPR 30 2018?
?

From: JJ <jajustin@...>
To: [email protected]
Sent: Friday, April 27, 2018 1:21 AM
Subject: Re: [TekScopes] 7904 Mainframe damaged

Tony, does the value of 5V lights fall below 4.5V when you increase the
load to the point that the PSU shuts off? 5V lights is monitored by the
Inverter Control IC U1275. A fraction of the 5V lights voltage is fed into
the BAL Sense input of U1275. I would monitor TP1302 on the rectifier board
and 5V lights.? There is also a sense current from T1310 that enters that
Bal sense node and can shut down the PSU.

On page 3-58 of the manual, it discusses the Balance Sense input.

Best,
John

On Thu, Apr 26, 2018 at 12:05 PM, Yiu On Tony C via Groups.Io <
tonycheung_hk@...> wrote:

Hi JJ:
TP1625 are normal 40V +/-3V ! ( it must be connected to maim unit , it is
related to CRT HV CKT !
If PSU alone , such voltage reading will more positive ( + 130V ) ).
On the other hand , I did measure the value of R1286 and 1287 , it is OK !
When PSU connected to main unit , I do not understand ,for CR1311 and 1312
, I use HSR208 ( 2A 1KV CJ=14pF ) will shut down PSU . but use FR607 ( 6A
1KV? CJ= 80pF ) will not shut down the PSU ! both setting are? Control
ILLUM must OFF, and GRAT ILLUM are always turn on ( not controllable ! ).
Still finding the problem !
RegardTony CheungAPR 27 2018

? ? ? From: JJ <jajustin@...>
? To: [email protected]
? Sent: Wednesday, April 25, 2018 7:04 PM
? Subject: Re: [TekScopes] 7904 Mainframe damaged

? Tony, did you do the Power Supply test on page 5-8 of the manual : Adjust
Inverter Control R1293 for a meter reading on TP1625 of +40V? Maybe your
operating point for the Inverter Controller is way off. Mine was way off in
the negative range until I adjusted it.

Best,
John

On Tue, Apr 24, 2018 at 10:52 PM, Yiu On Tony C via Groups.Io <
tonycheung_hk@...> wrote:

Hi John :
It is overall power handling issue for the PSU , U1275 is the controller
for the shut down action, 5V light is NOT only output,? there is feedback
to R1304 to controller too !
On the other hand the total current sampling from T1235 to U1275.
I did check C1316, C1317 and C1318 are normal .
My PSU was damaged by miss-align one pin of SENS input on LV Board (

P1483

) :
pin 1 ------- Beam I Sens? input on LV board? NO Connection.
pin 2 ------- GND Sens input on LV board connected to P83 pin 1
-------Beam I sens. --------------- Beam I sens short to GND.
pin 3 ------- +5V Sens input on LV board connected to P83 pin 2 -------
GND sens, -------------means +5V short to GND !
pin 4 ------- -50V Sens input on LV board connected to P83 pin 3 --------
? +5V sens, ------------- short -50V to +5V !
pin 5 ------- +50V Sens input on LV board connected to P83 pin 4 --------
-50V sens? -------------- short +50V to -50V
pin 6 -------- -15V Sens input on LV board connected to P83 pin 5

--------

+50V sens ------------- short -15V to +50V
pin 7 ------- +15V Sens input on LV board connected to P83 pin 6 -------
-15V sens? ------------ short +15V to -15V

The results is all ( +5V, -50V, +50V, -50V, -15V, +5V and Beam I sens
short to GND ). may be serious damage for the PSU or main unit ?
Anyway it is under repair for the damage !
RegardTony CheungAPR 25 2018



? ? ? From: JJ <jajustin@...>
? To: [email protected]
? Sent: Wednesday, April 25, 2018 5:26 AM
? Subject: Re: [TekScopes] 7904 Mainframe damaged

Tony,
If all you can draw is 100ma on 5v lights, you could have a problem with
that power supply's pi section filter - I had to change C1318 to get my

PSU

up. It measured 40uf instead of 100uf. That cap may be right on the edge

of

failure at certain loads. There are also 2 other caps in that filter -
C1316, C1317. Note that 5v lights is not regulated on the LV regulator
board - it just goes through the board to the connectors - so the problem
is localized to the cap rectifier board.

I would first change C1318 with any 100uf cap (doesn't have to be

tantalum

to just test). And, do the same sequentially for the other two - swap out
then test. They're pretty easy to change.

Best,
John



On Tue, Apr 24, 2018 at 2:35 PM, Yiu On Tony C via Groups.Io <
tonycheung_hk@...> wrote:

Hi John :
Yes, I did put it back to 7904 , but find something NOT working !
1. Graticule Light always on ----------- I did check NO -15V at R1451,

but

PSU was tested with full loading pass .2. Front panel push button's

light

not function.3. For Horizontal Mode Switch ALT , CHOP will shut down

the

PSU. A or B is OK !
Regard
Tony Cheung


? ? ? From: JJ <jajustin@...>
? To: [email protected]
? Sent: Wednesday, April 25, 2018 1:21 AM
? Subject: Re: [TekScopes] 7904 Mainframe damaged

Tony, have you tried putting the PSU back into the mainframe to see if

it

works in its normal load and interaction environment? You may be

chasing

the proverbial wild goose! :)

Best,
John

On Tue, Apr 24, 2018 at 12:16 PM, Yiu On Tony C via Groups.Io <
tonycheung_hk@...> wrote:

Hi:
It is a good idea ! But I leave my workshop already ! May check day

after

tomorrow. It is midnight in Hong Kong !
One thing I find at least, I disconnect-15 V loads, it become normal.

So

that my next step to check the resistor!
Regard
Tony Cheung


從我的 iPhone 傳送

dadhills@... 於 2018年4月24日 下午11:40 寫道：

Have you checked R1286, 1K, 5%?? It is a carbon composition

resistor

and

if it has drifted high in value, it will lower the "total" load

current

limit threshold.

Dave

On Tue, Apr 24, 2018 at 07:59 am, Yiu On Tony C wrote:


Hi Harvey :
My PSU are test alone and connected to Loading resister and "

sens "

return to

LV board.
For the current limiter was controlled by U1275 , and I find the

zener

VR1297

---- 9V are opened , I replace it and now always shut down again ,

even

I open

the zener again , still shut down ! It means cannot return as

before ,

I did

check all the diodes on A12 , but no defective !
There may be something wrong again !
RegardTony CheungAPR 24 2018

? ? ? From: Harvey White <madyn@...>
To: [email protected]
Sent: Tuesday, April 24, 2018 9:41 PM
Subject: Re: [TekScopes] 7904 Mainframe damaged

On Tue, 24 Apr 2018 13:27:01 +0000 (UTC), you wrote:

Hi :
My 7904 still have problem for PSU !
+/-50V, +/-15V, +5V , +130V are normal with loading power on !
Once I connect the loading to +5V light , it cannot load even

0.1A

!

it will

shut down PSU. (? If normal , It can output up to 3.5A ! )

The diode for +5V lights are defective ( shorted ) and replaced

by

fast

recovery diode FR607? ( junction Cap 80pF )or HER208 ( junction

cap

14pF ).

Sounds as if the supply is working normally for regulation, but

the

shutdown circuitry is too sensitive.? There's a current sense

resistor

in there, and some associated parts.? Could the current sense

resistor

be too high in value?? That will certainly cause this supply to

shut

down on a lower current.? I'd also check the amplifier for that

sense,

to make sure it is working properly.

Harvey

It worked both times.

-Chuck Harris

David M wrote:

Well, it happened again. I made sure to click the little "Quote Whole Post" icon before replying, but the quoted text didn't make it into my reply. Groups.io gone bonkers, or is it me? What am I doing wrong?

Dave M

Wasn't because I didn't try... I made sure to quote the original post in my reply, but I guess groups.io scrubbed it. I replied by "Reply to Group" at the bottom of the original message (I get the digest format), and made sure to copy the original message text into my reply..
Anyway, sorry for the confusion.

Cheers,
Dave M

On Sat, Apr 28, 2018 at 05:45 pm, Phillip Potter wrote:

Wow, what a nice clean up job you did... makes mine look like a mess, by
comparison!? Congratulations.

Phil


On 4/28/2018 4:51 PM, lop pol via Groups.Io wrote:

Here it is cleaned up and running.

Thanks. On scopes with no button labels I use Innerclean by Chemical Guys. Its for cleaning car interiors but works good for other stuff (like scope faces).

Many thanks for what ? Relevant prior post not included ????

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

Many thanks for that; I'll look it up..... might even have some in the transistor collection :).

Nigel Pritchard

-----Mensaje original-----
De: [email protected] [mailto:[email protected]] En nombre de Chuck Harris
Enviado el: domingo, 29 de abril de 2018 6:19
Para: [email protected]
Asunto: Re: [TekScopes] Nuvistors

The tunnel diode indeed does have the V/I curve shown in the books, but only if the load resistance is zero, or very near zero. The slope of that load resistance's load line has to be so steep that it only touches the negative resistance curve at a single point, as I recall.

I think of that as swamping out the diode, or forcing it.

The magically weird part of TD's is almost impossible to miss. If you pick a load resistor that is high enough that its load line intersects the TD's characteristic curve at only two points, it will demonstrate something to you that is seemingly impossible.

A two point intersection puts the load line intersection very near the first current peak, and somewhere on the second current rise.

As you raise the voltage across the series diode and resistor, the current will rise up from zero along the characteristic curve of the TD, until it reaches the point where the load line touches the curve near the peak, and it will suddenly snap over to the other intersection point of the load line.

If you continue raising the voltage, the current will then follow the TD curve up to infinity, or the diode burns out.

Because the theoretical maximum switching frequency of a TD is something greater than a million megacycles, this switch will be too fast to see.

Hard to describe, pictures would make it easier, but I am not up for drawing, scanning, and posting the pictures right now. You can easily find the info elsewhere with a search.

If you have your curve tracer set to any resistance load that is higher than the just about zero, you will see this switching phenomenon in your curve, which is what I was describing earlier.

We were talking about TD switches, after all.

-Chuck Harris

OBTW, I think my Dad gave me that GE manual back in the mid 1960's. By gave, I mean that it got put on a shelf that I could reach without asking... so I did...
A lot.

Ed Breya via Groups.Io wrote:

The tunnel diode indeed does have the V/I curve shown
in the books, but only if the load resistance is
zero, or very near zero. The slope of that load
resistance's load line has to be so steep that it
only touches the negative resistance curve at a
single point, as I recall.

I think of that as swamping out the diode, or forcing it.

The magically weird part of TD's is almost impossible
to miss. If you pick a load resistor that is high
enough that its load line intersects the TD's characteristic
curve at only two points, it will demonstrate something
to you that is seemingly impossible.

A two point intersection puts the load line intersection
very near the first current peak, and somewhere on
the second current rise.

As you raise the voltage across the series diode and
resistor, the current will rise up from zero along the
characteristic curve of the TD, until it reaches
the point where the load line touches the curve near
the peak, and it will suddenly snap over to the other
intersection point of the load line.

If you continue raising the voltage, the current will
then follow the TD curve up to infinity, or the diode
burns out.

Because the theoretical maximum switching frequency
of a TD is something greater than a million megacycles,
this switch will be too fast to see.

Hard to describe, pictures would make it easier, but
I am not up for drawing, scanning, and posting the
pictures right now. You can easily find the info
elsewhere with a search.

If you have your curve tracer set to any resistance
load that is higher than the just about zero, you
will see this switching phenomenon in your curve,
which is what I was describing earlier.

We were talking about TD switches, after all.

-Chuck Harris

OBTW, I think my Dad gave me that GE manual back in
the mid 1960's. By gave, I mean that it got put on
a shelf that I could reach without asking... so I did...
A lot.

Ed Breya via Groups.Io wrote:

Hi GeorgeP,

I'm over in Toronto, Ont., I don't mind driving over for big items.
I only saw 5 items on Ebay, can you post a list we could look at?
Thanks,

Peter

Hi Dennis,

On Sat, 28 Apr 2018 18:59:06 -0700
"Dennis Tillman W7PF" <dennis@...> wrote:

That's not all...

there is much more Tektronix manuals, catalogs, app notes, etc on
this site.

I've used archive.org a lot - but wasn't aware of using the "search
metadata" tool to create a compilation of an subject such as
"tektronix".

Good stuff...

Lyle

Dennis Tillman W7PF

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of
Lyle Bickley
Sent: Saturday, April 28, 2018 6:46 PM
To: HankC, Boston, WA1HOS via Groups.Io
<hankc918@...> Cc: [email protected]
Subject: Re: [TekScopes] 700 Pages of Tekscope, back to 1959,
searchable, PDF download:

_Sep_1971/Service_Scope_Oct_1959_-_Sep_1971.pdf

On Sun, 29 Apr 2018 01:36:22 +0000 (UTC) "HankC, Boston, WA1HOS via
Groups.Io" <hankc918@...>
wrote:

HankC, Boston WA1HOS

Thank you, Hank!!!

Lyle

--
Lyle Bickley
AF6WS '73

"Black holes are where God is dividing by zero"

--
Lyle Bickley
AF6WS '73

"Black holes are where God is dividing by zero"

That's not all...

there is much more Tektronix manuals, catalogs, app notes, etc on this site.


Dennis Tillman W7PF

On Sun, 29 Apr 2018 01:36:22 +0000 (UTC)
"HankC, Boston, WA1HOS via Groups.Io" <hankc918@...>
wrote:

?HankC, Boston WA1HOS

Thank you, Hank!!!

Lyle

--
Lyle Bickley
AF6WS '73

"Black holes are where God is dividing by zero"

The original mask is unscathed.? But I am surprised that Tek did not cover the guard traces with mask.? They are just traces after all and covering them with mask would simplify repairs like this.? I understand the need for a good liquid flux, preferably no-clean which I clean after anyway.? But the pitch on these pins is so tight that, in most cases, any trace passing between would be masked.? These are not.? I wonder why. ?
I don't usually make a big deal of soldering a simple part to a board, done it many times.? But I have never cooked a part with my heat wand before and it has me a bit skittish.? So, I am being extra careful (some might say obsessed) so I know the part isn't damaged.? Then if the MUX doesn't work I can confidently look elsewhere for the problem.
Thanks again for your advice and help.

HankC, Boston WA1HOS