Topics

Tek 2215

Tothwolf
 

On Sun, 24 Jan 2016, David @DWH [TekScopes] wrote:
On Sun, 24 Jan 2016 22:11:50 -0600 (CST), you wrote:
On Sun, 24 Jan 2016, David @DWH [TekScopes] wrote:
On Sun, 24 Jan 2016 18:56:02 -0600 (CST), you wrote:
On Sun, 24 Jan 2016, jasontucker70@... [TekScopes] wrote:

I used new manufacture carbon comp resistors for the 1M ohm resistors, however after the discussion on the list, I picked up some high voltage rated film parts that I plan to replace those with the next time I have the scopes opened up.
The Vishay VR25 and VR35 series high voltage film resistors are very similar if not identical to the high voltage film resistors which Tektronix used to replace the carbon composition resistors originally used in the 22xx series focus chain. They are readily available and inexpensive.
That's what I'm planning to install. I picked up 100 Vishay VR37000001004FR500 for $13.60.
Lol. How many 22xx oscilloscopes are you rebuilding?
So far I've done 3 but I might rebuild one or two more 22xx scopes if I manage to find them cheaply enough. At 6ea for the 3x 2213 scopes I have that's already 18 out of the 100, and as useful as these resistors seem to be, I plan to keep some stock of them in my parts cabinets. For whatever reason the 1% parts were cheaper than the 5% too.

 

On Sun, 24 Jan 2016 23:02:56 -0600 (CST), you wrote:

On Sun, 24 Jan 2016, David @DWH [TekScopes] wrote:
On Sun, 24 Jan 2016 22:11:50 -0600 (CST), you wrote:
On Sun, 24 Jan 2016, David @DWH [TekScopes] wrote:
On Sun, 24 Jan 2016 18:56:02 -0600 (CST), you wrote:
On Sun, 24 Jan 2016, jasontucker70@... [TekScopes] wrote:

I used new manufacture carbon comp resistors for the 1M ohm
resistors, however after the discussion on the list, I picked up some
high voltage rated film parts that I plan to replace those with the
next time I have the scopes opened up.
The Vishay VR25 and VR35 series high voltage film resistors are very
similar if not identical to the high voltage film resistors which
Tektronix used to replace the carbon composition resistors originally
used in the 22xx series focus chain. They are readily available and
inexpensive.
That's what I'm planning to install. I picked up 100 Vishay
VR37000001004FR500 for $13.60.
Lol. How many 22xx oscilloscopes are you rebuilding?
So far I've done 3 but I might rebuild one or two more 22xx scopes if I
manage to find them cheaply enough. At 6ea for the 3x 2213 scopes I have
that's already 18 out of the 100, and as useful as these resistors seem to
be, I plan to keep some stock of them in my parts cabinets. For whatever
reason the 1% parts were cheaper than the 5% too.
I only have the later 2230 and 2232 models and Tektronix used film
resistors for the focus resistor chain in them.

I would have expected there to be a clean cutoff date for when they
changed resistors in the focus resistor chain but that apparently is
not the case. The 2235, released in 1984, used carbon composition
resistors but the 2236 which was released at the same time used film
resistors and the 2213A and 2215A which were released later, both in
1986, used carbon composition resistors.

There was another resistor change Tektronix made and I think it was
for reliability. The 2213 and 2215 use two 1/2 watt 1% metal film
resistors in series for the collector loads at the output of the
vertical amplifier. These resistors run hot making them unreliable
and were the first 2213/2215 repair that I made and I know of two
other instances where they had to be replaced. The later models used
3 resistors in series for each collector load to distribute the heat
better.

The collector load resistors are not difficult to replace so I would
change them also.

Tothwolf
 

On Mon, 25 Jan 2016, David @DWH [TekScopes] wrote:

I only have the later 2230 and 2232 models and Tektronix used film resistors for the focus resistor chain in them.

I would have expected there to be a clean cutoff date for when they changed resistors in the focus resistor chain but that apparently is not the case. The 2235, released in 1984, used carbon composition resistors but the 2236 which was released at the same time used film resistors and the 2213A and 2215A which were released later, both in 1986, used carbon composition resistors.
Tektronix revised the type of resistors used in the high voltage divider in the 2213/2215 at least several times too. All of my 2213 scopes are late model scopes which already had the preregulator option installed. None of the scopes appeared to have ever been serviced and these are the resistors I found installed:

B0228xx [scope #2]
R877 - 18K 1/4W carbon film (in spec)
R878, R879, R880, R881, R882, R884 - 1M 1/2W carbon film [red dot on body]

B0229xx [scope #1]
R877 - 18K 1/4W carbon comp (in spec, measured dead on 18K)
R878, R879, R880, R881, R882, R884 - 1M 1/2W carbon comp [standard]

B0233xx [scope #3]
R877 - 18K 1/4W carbon comp (out of spec, measured as 22K)
R878, R879, R880, R881, R882, R884 - 1M 1/2W carbon comp [mil spec]

The B0228xx and B0229xx scopes are only 21 digits apart on their serial
numbers.

There was another resistor change Tektronix made and I think it was for reliability. The 2213 and 2215 use two 1/2 watt 1% metal film resistors in series for the collector loads at the output of the vertical amplifier. These resistors run hot making them unreliable and were the first 2213/2215 repair that I made and I know of two other instances where they had to be replaced. The later models used 3 resistors in series for each collector load to distribute the heat better.

The collector load resistors are not difficult to replace so I would change them also.
Are those the 4 resistors mounted to the board plus the two inline with V+ and V- on the left side of the board in this photo? One of my scopes has one carbon comp and one carbon film for the two inline resistors. I'm planning to replace the two inline resistors with Vishay CCF6015R0FKE36 and the 18K R877 with a Vishay CCF0718K0GKE36. I hadn't planned to replace the 4 resistors on the board, but they look like they might be 1W parts. I've seen photos of these boards where the board is discolored badly from heat around those 4 resistors.

http://strudel.ignorelist.com/~tothwolf/photos/Tektronix_2213/Tektronix_2213_3/1600/IMG_9288.1600.jpg

 

On Mon, 25 Jan 2016 01:36:53 -0600 (CST), you wrote:

On Mon, 25 Jan 2016, David @DWH [TekScopes] wrote:

There was another resistor change Tektronix made and I think it was for
reliability. The 2213 and 2215 use two 1/2 watt 1% metal film resistors
in series for the collector loads at the output of the vertical
amplifier. These resistors run hot making them unreliable and were the
first 2213/2215 repair that I made and I know of two other instances
where they had to be replaced. The later models used 3 resistors in
series for each collector load to distribute the heat better.

The collector load resistors are not difficult to replace so I would
change them also.
Are those the 4 resistors mounted to the board plus the two inline with V+
and V- on the left side of the board in this photo? One of my scopes has
one carbon comp and one carbon film for the two inline resistors. I'm
planning to replace the two inline resistors with Vishay CCF6015R0FKE36
and the 18K R877 with a Vishay CCF0718K0GKE36. I hadn't planned to replace
the 4 resistors on the board, but they look like they might be 1W parts.
I've seen photos of these boards where the board is discolored badly from
heat around those 4 resistors.

http://strudel.ignorelist.com/~tothwolf/photos/Tektronix_2213/Tektronix_2213_3/1600/IMG_9288.1600.jpg
Sorry for taking so long to respond. Those are the ones.

The parts list says they are 1/2 watt 1% film 340 ohm resistors (and
metal film based on the part number) and since there was only one
modern choice matching that available, I was not picky. I bought 10
from Mouser, replaced the 4, and left the remaining 6 inside a bag
taped to the inside of the chassis with a note.

The originals in my case were visibly discolored and cracked and once
removed, their coating flaked off. I was able to replace them without
removing the CRT using needle nose pliers. The original parts were
spaced above the printed circuit board so I used the shaft from a
Q-tip as a temporary spacer during installation.

The replacements were physically smaller than the original parts. I
thought Tektronix might have selected the originals for good RF
performance but other than size, they are the same series of film
resistors used throughout the rest of the oscilloscope and a transient
response test showed that the new physically smaller replacements
worked fine.

I did not check it before since I did not have more than one resistor
to select from but the Dale MFF series datasheet says "very good high
frequency characteristics" for whatever that is worth:

http://www.33audio.com/enter/data/DaleFilmpart2.pdf

Tothwolf
 

On Mon, 25 Jan 2016, David @DWH [TekScopes] wrote:
On Mon, 25 Jan 2016 01:36:53 -0600 (CST), you wrote:
On Mon, 25 Jan 2016, David @DWH [TekScopes] wrote:

There was another resistor change Tektronix made and I think it was for reliability. The 2213 and 2215 use two 1/2 watt 1% metal film resistors in series for the collector loads at the output of the vertical amplifier. These resistors run hot making them unreliable and were the first 2213/2215 repair that I made and I know of two other instances where they had to be replaced. The later models used 3 resistors in series for each collector load to distribute the heat better.

The collector load resistors are not difficult to replace so I would change them also.
Are those the 4 resistors mounted to the board plus the two inline with V+ and V- on the left side of the board in this photo? One of my scopes has one carbon comp and one carbon film for the two inline resistors. I'm planning to replace the two inline resistors with Vishay CCF6015R0FKE36 and the 18K R877 with a Vishay CCF0718K0GKE36. I hadn't planned to replace the 4 resistors on the board, but they look like they might be 1W parts. I've seen photos of these boards where the board is discolored badly from heat around those 4 resistors.

http://strudel.ignorelist.com/~tothwolf/photos/Tektronix_2213/Tektronix_2213_3/1600/IMG_9288.1600.jpg
Sorry for taking so long to respond. Those are the ones.

The parts list says they are 1/2 watt 1% film 340 ohm resistors (and metal film based on the part number) and since there was only one modern choice matching that available, I was not picky. I bought 10 from Mouser, replaced the 4, and left the remaining 6 inside a bag taped to the inside of the chassis with a note.

The originals in my case were visibly discolored and cracked and once removed, their coating flaked off. I was able to replace them without removing the CRT using needle nose pliers. The original parts were spaced above the printed circuit board so I used the shaft from a Q-tip as a temporary spacer during installation.
I didn't notice any cracks in the coating of those resistors in my 2213 scopes. All 3 of my 2213 scopes have those 4 resistors mounted close to the board so I'm wondering now if I should replace them and space them away from the board. B0233xx in the photo above got a lot more use than either B0228xx or B0229xx and the board under those 4 resistors is just starting to discolor.

I initially only had the CRT out of B0233xx so I could replace the damaged front bezel.

I've been using Richco CER-6 ceramic spacers (~$0.073/ea) to space these type of components off the board (pointed end goes towards the board). I also used them on the preregulator boards when I replaced R911, 150K 1W carbon comp. The replacement metal oxide resistor in the photo below is actually a 2W part even though it is physically smaller than the original.

http://strudel.ignorelist.com/~tothwolf/photos/Tektronix_2213/Tektronix_2213_2/1600/IMG_9112.1600.jpg

The replacements were physically smaller than the original parts. I thought Tektronix might have selected the originals for good RF performance but other than size, they are the same series of film resistors used throughout the rest of the oscilloscope and a transient response test showed that the new physically smaller replacements worked fine.

I did not check it before since I did not have more than one resistor to select from but the Dale MFF series datasheet says "very good high frequency characteristics" for whatever that is worth:

http://www.33audio.com/enter/data/DaleFilmpart2.pdf
These are the resistors you used in your scope? I'll add these to my notes to consider later when I finally get back to working on the 2213s.

Tothwolf
 

On Mon, 25 Jan 2016, David @DWH [TekScopes] wrote:

The replacements were physically smaller than the original parts. I
thought Tektronix might have selected the originals for good RF
performance but other than size, they are the same series of film
resistors used throughout the rest of the oscilloscope and a transient
response test showed that the new physically smaller replacements
worked fine.

I did not check it before since I did not have more than one resistor
to select from but the Dale MFF series datasheet says "very good high
frequency characteristics" for whatever that is worth:

http://www.33audio.com/enter/data/DaleFilmpart2.pdf
I believe I found them. They are actually the same Vishay/Dale CCF series I was going to use for R398 and R399, although it appears I inadvertently ordered 15 ohm instead of 51 ohm for those two (good thing I only purchased 10), so I guess those are going on the next parts order.

R378,R379,R388,R389 340 ohm 1% 1/2W metal film Dale MFF1226G340R0F

Replace with Vishay/Dale CCF60340RFKE36

R398,R399 51 ohm 5% 1/2W carbon comp Allen-Bradley EB5105

Replace with Vishay/Dale CCF6051R1FKE36 (51.1ohm, but close enough ;)

 

On Tue, 26 Jan 2016 00:42:40 -0600 (CST), you wrote:

On Mon, 25 Jan 2016, David @DWH [TekScopes] wrote:

The replacements were physically smaller than the original parts. I
thought Tektronix might have selected the originals for good RF
performance but other than size, they are the same series of film
resistors used throughout the rest of the oscilloscope and a transient
response test showed that the new physically smaller replacements
worked fine.

I did not check it before since I did not have more than one resistor
to select from but the Dale MFF series datasheet says "very good high
frequency characteristics" for whatever that is worth:

http://www.33audio.com/enter/data/DaleFilmpart2.pdf
I believe I found them. They are actually the same Vishay/Dale CCF series
I was going to use for R398 and R399, although it appears I inadvertently
ordered 15 ohm instead of 51 ohm for those two (good thing I only
purchased 10), so I guess those are going on the next parts order.

R378,R379,R388,R389 340 ohm 1% 1/2W metal film Dale MFF1226G340R0F

Replace with Vishay/Dale CCF60340RFKE36

R398,R399 51 ohm 5% 1/2W carbon comp Allen-Bradley EB5105

Replace with Vishay/Dale CCF6051R1FKE36 (51.1ohm, but close enough ;)
There is probably no reason to preemptively replace them if close
inspection shows no damage. On the one I repaired, the resistors were
visibly discolored but the cracks could not be seen with the CRT in
place until they were removed.

The symptom of attenuated and nonlinear vertical deflection pointed
directly at the collector load resistors and ohms measurement from the
bottom of the printed circuit board conclusively showed they were bad.
They were the first thing I checked because it was easy to do and
visual inspection showed that the printed circuit board itself was
discolored from high temperature in the area under and around them.

The value for the 51 ohm series resistors is not critical but I wonder
how hot they run and about higher parasitic inductance of spiral cut
film resistors. Why did Tektronix use carbon composition resistors
there?

Craig Sawyers
 

The symptom of attenuated and nonlinear vertical deflection pointed directly at the collector load
resistors and ohms measurement from the bottom of the printed circuit board conclusively showed
they were bad.
They were the first thing I checked because it was easy to do and visual inspection showed that
the
printed circuit board itself was discolored from high temperature in the area under and around
them.

The value for the 51 ohm series resistors is not critical but I wonder how hot they run and about
higher
parasitic inductance of spiral cut film resistors. Why did Tektronix use carbon composition
resistors
there?


------------------------------------
Posted by: David <@DWH>
------------------------------------
Tek had a bit of a blind spot when it came to power dissipation in resistors on circuit boards.
They invariably mounted them tight to the board. So even if the part was operating inside its
dissipation limit, that power specification is always quoted by the resistor manufacturer "in free
air". Resistors which are dissipating a decent percentage of their power limit should be mounted on
spacers (which can be just a few mm) to ensure good air flow. If you put them tight to the board,
the contact is a hot spot which (a) discolours, or in some instances burns the board and (b)
compromises the lifetime of the resistor. Seen the same thing is some classic era Fluke gear too.

Tothwolf
 

On Tue, 26 Jan 2016, David @DWH [TekScopes] wrote:
On Tue, 26 Jan 2016 00:42:40 -0600 (CST), you wrote:

I believe I found them. They are actually the same Vishay/Dale CCF series I was going to use for R398 and R399, although it appears I inadvertently ordered 15 ohm instead of 51 ohm for those two (good thing I only purchased 10), so I guess those are going on the next parts order.

R378,R379,R388,R389 340 ohm 1% 1/2W metal film Dale MFF1226G340R0F

Replace with Vishay/Dale CCF60340RFKE36

R398,R399 51 ohm 5% 1/2W carbon comp Allen-Bradley EB5105

Replace with Vishay/Dale CCF6051R1FKE36 (51.1ohm, but close enough ;)
There is probably no reason to preemptively replace them if close inspection shows no damage. On the one I repaired, the resistors were visibly discolored but the cracks could not be seen with the CRT in place until they were removed.
I was mainly thinking if I space them away from the boards, there will be less heat to discolor the boards in B0228xx and B0229xx, and will also help prevent any further heat damage to B0233xx.

The symptom of attenuated and nonlinear vertical deflection pointed directly at the collector load resistors and ohms measurement from the bottom of the printed circuit board conclusively showed they were bad. They were the first thing I checked because it was easy to do and visual inspection showed that the printed circuit board itself was discolored from high temperature in the area under and around them.
I could certainly measure them with a thermocouple, however since the board in B0233xx is showing signs discoloration/heat damage just around R378,R379,R388,R389, that alone probably means those resistors are running hot enough where they shouldn't be in direct contact with the board.

The value for the 51 ohm series resistors is not critical but I wonder how hot they run and about higher parasitic inductance of spiral cut film resistors. Why did Tektronix use carbon composition resistors there?
Given that one of the scopes had one carbon film and one carbon comp fitted for R398 and R399 from the factory, it may be that the carbon comp resistors were just readily available 1/2W resistors. I came across this with other 1/4W and 1/2W resistors in these scopes where carbon film and carbon comp seemed to be used almost interchangeably. The downside to the carbon comp parts of course, is that many of them have drifted out of spec, which is why I've replaced quite a few with metal oxide or carbon film parts.

Tothwolf
 

On Tue, 26 Jan 2016, 'Craig Sawyers' c.sawyers@... [TekScopes] wrote:
On Tue, 26 Jan 2016, David @DWH [TekScopes] wrote:

The symptom of attenuated and nonlinear vertical deflection pointed directly at the collector load resistors and ohms measurement from the bottom of the printed circuit board conclusively showed they were bad. They were the first thing I checked because it was easy to do and visual inspection showed that the printed circuit board itself was discolored from high temperature in the area under and around them.

The value for the 51 ohm series resistors is not critical but I wonder how hot they run and about higher parasitic inductance of spiral cut film resistors. Why did Tektronix use carbon composition resistors there?
Tek had a bit of a blind spot when it came to power dissipation in resistors on circuit boards. They invariably mounted them tight to the board. So even if the part was operating inside its dissipation limit, that power specification is always quoted by the resistor manufacturer "in free air". Resistors which are dissipating a decent percentage of their power limit should be mounted on spacers (which can be just a few mm) to ensure good air flow. If you put them tight to the board, the contact is a hot spot which (a) discolours, or in some instances burns the board and (b) compromises the lifetime of the resistor. Seen the same thing is some classic era Fluke gear too.
Maybe mounting such resistors directly to the board was part of the new low-cost process Tektronix was using for the 2213/2215 scopes? All of the boards apart from the preregulator add-on board were made from a single panel which was snapped apart after soldering and all of the components had their leads clenched to hold them into the boards during the wave soldering process.

The only real exception I noted was R911 near the center of the preregulator boards. It is hard to see in the photos, but the original R911 had formed leads to keep it spaced away from the board.

http://strudel.ignorelist.com/~tothwolf/photos/Tektronix_2213/Tektronix_2213_2/1600/IMG_8886.1600.jpg
http://strudel.ignorelist.com/~tothwolf/photos/Tektronix_2213/Tektronix_2213_3/1600/IMG_9379.1600.jpg

Do you think the Richco CER-6 spacers will be sufficient for R378,R379,R388,R389? With a single spacer under each lead, a Vishay/Dale CCF60340RFKE36 resistor would probably only be 2-3mm away from the board, although the spacers are designed so they can be stacked.

One other issue I noticed which I forgot to mention in my posts to the list last year was the metal bracket that the focus control is mounted to was showing signs of tin whisker growth in all 3 of my 2213 scopes. While I had it and the potentiometer removed so I could replace the 6 1M ohm resistors, I lightly abraded the surface of the bracket to knock the tin whiskers down, but I know if I leave the plating as-is, they will without a doubt eventually return. I am considering using electrolysis to strip the tin plating and then replate the steel bracket with nickel. You can just barely see eruptions in the tin plating on the right side of the bracket in this photo, but up close, 3-5mm long tin whiskers were pretty easy to see.

http://strudel.ignorelist.com/~tothwolf/photos/Tektronix_2213/Tektronix_2213_3/1600/IMG_9288.1600.jpg

stefan_trethan
 

You might be able to tin the sheetmetal using 60/40 solder and a big
soldering iron or a hotplate or something.
That would solve the problem for good.

(Although light brushing and painting with some acrylic laquer would
probably suffice to eliminate any issues during your lifetime).

ST


On Tue, Jan 26, 2016 at 12:12 PM, Tothwolf tothwolf@...
[TekScopes] <TekScopes@...> wrote:

One other issue I noticed which I forgot to mention in my posts to the
list last year was the metal bracket that the focus control is mounted to
was showing signs of tin whisker growth in all 3 of my 2213 scopes. While
I had it and the potentiometer removed so I could replace the 6 1M ohm
resistors, I lightly abraded the surface of the bracket to knock the tin
whiskers down, but I know if I leave the plating as-is, they will without
a doubt eventually return. I am considering using electrolysis to strip
the tin plating and then replate the steel bracket with nickel. You can
just barely see eruptions in the tin plating on the right side of the
bracket in this photo, but up close, 3-5mm long tin whiskers were pretty
easy to see.

http://strudel.ignorelist.com/~tothwolf/photos/Tektronix_2213/Tektronix_2213_3/1600/IMG_9288.1600.jpg


------------------------------------
Posted by: Tothwolf <tothwolf@...>
------------------------------------

Craig Sawyers
 

Maybe mounting such resistors directly to the board was part of the new low-cost process Tektronix
was using for the 2213/2215 scopes? All of the boards apart from the preregulator add-on board
were
made from a single panel which was snapped apart after soldering and all of the components had
their
leads clenched to hold them into the boards during the wave soldering process.
Nope - the 7000 series is exactly the same. Main culprits are the x amplifier in most, and HT
resistor stack on the 7704A (Tek changed the design of that many times - earlier versions carbonised
the PCB).

Craig

 

Not forgetting the Vertical amp in the 7904 which has two *very* marginally
specified 1W resistors snugged right up the to the PCB, and which are almost
always out of specification.

Dave

-----Original Message-----
From: TekScopes@... [mailto:TekScopes@...]
Sent: 26 January 2016 12:41
To: TekScopes@...
Subject: RE: [TekScopes] Tek 2215

Maybe mounting such resistors directly to the board was part of the
new low-cost process Tektronix was using for the 2213/2215 scopes? All
of the boards apart from the preregulator add-on board
were
made from a single panel which was snapped apart after soldering and
all of the components had
their
leads clenched to hold them into the boards during the wave soldering
process.

Nope - the 7000 series is exactly the same. Main culprits are the x
amplifier in most, and HT resistor stack on the 7704A (Tek changed the
design of that many times - earlier versions carbonised the PCB).

Craig

Jay
 

 

I would go over it with a soldering iron after lightly sanding the
surfaces. Assuming that you can remove it easily from the printed
circuit board, dilute HCl can be used if wetting is a problem.

On Tue, 26 Jan 2016 13:04:28 +0100, you wrote:

You might be able to tin the sheetmetal using 60/40 solder and a big
soldering iron or a hotplate or something.
That would solve the problem for good.

(Although light brushing and painting with some acrylic laquer would
probably suffice to eliminate any issues during your lifetime).

ST

On Tue, Jan 26, 2016 at 12:12 PM, Tothwolf tothwolf@...
[TekScopes] <TekScopes@...> wrote:

One other issue I noticed which I forgot to mention in my posts to the
list last year was the metal bracket that the focus control is mounted to
was showing signs of tin whisker growth in all 3 of my 2213 scopes. While
I had it and the potentiometer removed so I could replace the 6 1M ohm
resistors, I lightly abraded the surface of the bracket to knock the tin
whiskers down, but I know if I leave the plating as-is, they will without
a doubt eventually return. I am considering using electrolysis to strip
the tin plating and then replate the steel bracket with nickel. You can
just barely see eruptions in the tin plating on the right side of the
bracket in this photo, but up close, 3-5mm long tin whiskers were pretty
easy to see.

http://strudel.ignorelist.com/~tothwolf/photos/Tektronix_2213/Tektronix_2213_3/1600/IMG_9288.1600.jpg

Craig Sawyers
 

Have you guys seen this ??

Mod Kits, Parts Replacement Kits and other documents http://hakanh.com/dl/kits.htm
Hakan is one of the good guys on this list - but I actually did not know (or have forgotten) that he
had an archive of Tek data.

Craig

 

I have but last time I looked the actual PDF files were not linked; it
was just a list.

"This modification kit contains the parts and instructions for
installing a fan system [into] a standard 7603 Oscilloscope. The fan
provides cooling for improved reliability, especially when high power
consumption plug-ins are used in the mainframe."

That's the fan I have! 7603 fan mystery solved!

Tothwolf
 

On Tue, 26 Jan 2016, David @DWH [TekScopes] wrote:
On 26 Jan 2016 09:12:17 -0800, you wrote:

Have you guys seen this ??

Mod Kits, Parts Replacement Kits and other documents http://hakanh.com/dl/kits.htm

http://hakanh.com/dl/docs/kitinstructions/050-2242-03.pdf
http://www.hakanh.com/dl/docs/troubleshooting_tips_on_2200_ps.pdf
http://hakanh.com/dl/docs/kitinstructions/040-1099-00.pdf
http://hakanh.com/dl/docs/kitinstructions/045-0034-00.pdf
I have but last time I looked the actual PDF files were not linked; it was just a list.

"This modification kit contains the parts and instructions for installing a fan system [into] a standard 7603 Oscilloscope. The fan provides cooling for improved reliability, especially when high power consumption plug-ins are used in the mainframe."

That's the fan I have! 7603 fan mystery solved!
The links are definitely new. I was looking for some of these documents last year and found the page but it was just a list of document ids and descriptions then.

Unfortunately I'm unable to open any of the files I've downloaded from there. Both of my PDF readers are saying they are encrypted and require a password.

Tothwolf
 

On Tue, 26 Jan 2016, David @DWH [TekScopes] wrote:
On Tue, 26 Jan 2016, Stefan Trethan stefan_trethan@... [TekScopes] wrote:
On Tue, Jan 26, 2016 at 12:12 PM, Tothwolf tothwolf@... [TekScopes] wrote:

One other issue I noticed which I forgot to mention in my posts to the list last year was the metal bracket that the focus control is mounted to was showing signs of tin whisker growth in all 3 of my 2213 scopes. While I had it and the potentiometer removed so I could replace the 6 1M ohm resistors, I lightly abraded the surface of the bracket to knock the tin whiskers down, but I know if I leave the plating as-is, they will without a doubt eventually return. I am considering using electrolysis to strip the tin plating and then replate the steel bracket with nickel. You can just barely see eruptions in the tin plating on the right side of the bracket in this photo, but up close, 3-5mm long tin whiskers were pretty easy to see.

http://strudel.ignorelist.com/~tothwolf/photos/Tektronix_2213/Tektronix_2213_3/1600/IMG_9288.1600.jpg
You might be able to tin the sheetmetal using 60/40 solder and a big soldering iron or a hotplate or something. That would solve the problem for good.

(Although light brushing and painting with some acrylic laquer would probably suffice to eliminate any issues during your lifetime).
I would go over it with a soldering iron after lightly sanding the surfaces. Assuming that you can remove it easily from the printed circuit board, dilute HCl can be used if wetting is a problem.
I've thought about tinning the brackets with Sn-Pb, but I'm not really sure I want to put a thick coating of solder on them. I own several solder pots, so it would be pretty trivial to clean the surface, coat with liquid flux and then dip each bracket in one of the pots.

Another easy option of course would be conformal coating or some sort of spray lacquer, but that also doesn't really seem to be the /right/ way to fix it.

I could also heat the bracket with a propane torch (after removing from the board obviously) or even just replace the bracket entirely with a new one made of brass, aluminum, or zinc plated steel.

Given the high voltage components directly next to the bracket and that tin whisker growth seems to be more common around high voltage and high frequency components, that bracket probably should have never been plated with pure tin anyway. I think the bracket really should have been nickel plated from the factory, and was probably only tin plated for cost savings, so I think the most correct thing to do though, would be to replate it with nickel.

That said, I noticed the same problem in my Simpson 464 meters with brackets nowhere near any high voltage. The two brackets in each of my 464 meters which join the LED display board to the main board at a right angle are absolutely covered with long tiny tin whiskers. Whatever I end up doing with the focus control brackets in my 2213 scopes I will likely also do to the display mounting brackets in the 464s.

Torch Fireman
 

Interesting. PDFProtection Manager can't access them either.

However, they will open just fine in FireFox's PDF viewer. From there I was able to print to PDF (using cutepdfwriter) and the resulting file opened quite cheerfully in Acrobat.


Unfortunately I'm unable to open any of the files I've downloaded from
there. Both of my PDF readers are saying they are encrypted and require a
password.