Re: Tek 2215

Jay

Ok thanks..
Are there alot of caps that should be replaced and any other mods that should be done ???

CL: Lot of 5 Tek 453's

John Clark

Re: 7603 weirdo inverted Z axis

On 24 Jan 2016 13:45:16 -0800, you wrote:

Typo in "I think you took 130 V across R1120 while it is about 128.4 V". Should read 130 V - 11.6 V = 118.4 V, not 128.4 V.

Albert
I have been going through your post and figured that was a typo. I
used 11.6 volts at the top of VR1148.

On 24 Jan 2016 13:40:48 -0800, you wrote:

Hi David,

It seems that you forgot about R1155?
Yep, I missed it. I might have designed it with an AC coupling
capacitor in series with R1155 but technically that is not needed. I
thought R1155 controlled the gain of Q1156 but the effect would be
very small. Who designed this thing?

Hmm, the later design used in the 7623A and 7633 lacks R1155 among
other minor changes and I had all of the schematics open when I did my
first analysis although I only scribbled on the correct schematic.

4.8 V across R1155 gives 0.48 mA. That 0.48 mA reduces the zener current and reduces the current via R1159 by the same amount.
I think you took 130 V across R1120 while it is about 128.4 V, this gives 0.21 mA less via R1120 and 0.21 mA more via R1159.
Together this yields 0.27 mA less via R1159 or 4.7 V lower output voltage. Then our results are the same.

Albert
4.8V / 10k [R1155] = +0.48mA
-15.6V / 9.1k [R1141] = -1.7mA
(130V - 11.6V) / 56k [R1120] = +2.1mA
-11.6V / 10.1k [R1121 and R1122] = -1.15mA
2.48mA - 2.85mA = -0.27mA
0.27mA * 17.4k [R1159] = 4.7V
4.7V + 11V = 15.7V

With Q1107 (a slow 2N3904???) removed on my 7603, the output at point
B is 14.8 volts which closely agrees with our current calculation so I
wonder if Marian's <public@...> measurement of 20 volts at the
output of the z-axis amplifier is significant and indicates a problem.
I get the same 14.8 volt output with Q1107 installed, the readout off,
and the intensity control turned to minimum.

I also measured the output at point B and as the intensity control is
turned fully clockwise, the output increases to about 28 volts
monotonically.

Re: Tek 2215

On Sun, 24 Jan 2016 16:02:14 -0600 (CST), you wrote:

While the power switch is the same, keep in mind that the main board in
the 2213A/2215A is completely different from the board used in the
2213/2215.
I consider them separate designs with the 2213/2215 (1982 to 1985)
being the beta test for the series which starts with the 2235/2236
(1984) and includes the 2213A/2215A (1986) as replacements for the
2213/2215. Besides differences in the overall design, the 2213/2215
has a 30pF input capacitance and 10kV acceleration while all of the
later models have a 20pF input capacitance and 14kV acceleration.

Re: CL: Lot of 5 Tek 453's

Chris Pierce

Yes I would like them, but I can't put the money together until Feb, 10 will try to get some money together Monday but I don't think I can put that much together. I live in Goose Creek call me Monday if you want to 8436702873

On Sunday, January 24, 2016 5:21 PM, "johnclark05@... [TekScopes]" <TekScopes@...> wrote:

Anyone in Charleston, SC area need some 453's? \$150 for 5 of 'em.

http://charleston.craigslist.org/ele/5417533394.html http://charleston.craigslist.org/ele/5417533394.html

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

Re: CL: Lot of 5 Tek 453's

John Clark

Oh, no, they're not mine. I just saw them pop up on Craigslist today.

John

To: TekScopes@...
From: TekScopes@...
Date: Sun, 24 Jan 2016 23:46:40 +0000
Subject: Re: [TekScopes] CL: Lot of 5 Tek 453's

Yes I would like them, but I can't put the money together until Feb, 10 will try to get some money together Monday but I don't think I can put that much together. I live in Goose Creek call me Monday if you want to 8436702873

On Sunday, January 24, 2016 5:21 PM, "johnclark05@... [TekScopes]" <TekScopes@...> wrote:

Anyone in Charleston, SC area need some 453's? \$150 for 5 of 'em.

http://charleston.craigslist.org/ele/5417533394.html http://charleston.craigslist.org/ele/5417533394.html

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

Recommendations / 2247A

John Dickens

I have my eye on a 2247A on Craigslist that looks very clean and appears to be fully functional.

Does anyone have any thoughts about this scope - reliable, repairable, etc.? It would be my first scope with a microprocessor. I also have a 7603 and a 2236 as well, not to mention a 503 in poor shape.

Thanks, John

Re: Tek 2215

Tothwolf

On Sun, 24 Jan 2016, jasontucker70@... [TekScopes] wrote:

Ok thanks..
Are there alot of caps that should be replaced and any other mods that should be done ???
As far as preventive maintenance parts goes, I replaced all of the electrolytic capacitors, the 5 Rifa brand safety capacitors, the 1M ohm carbon comp resistors in the high voltage divider, and some other misc resistors.

The 6 silver colored Mallory capacitors on the main board are an absolute must replace item, and if your 2215 still has the original parts installed, you'll probably find that they are beginning to leak from their bottom seals.

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 difficulties I ran into with the 2213 scopes were that the component leads are bent down to hold the parts in before they were soldered, and the two small electrolytics on the front panel board were difficult to get to (I used some long tweezers to fit them).

While some people claim that the small 5mm and 6.3mm capacitors never fail, some of the small electrolytics in my scopes were visibly leaking or had corrosion on their leads which was only visible after removing them, so I think replacing them is a good idea.

I posted this link previously, but some photos of my scopes can be found here: http://strudel.ignorelist.com/~tothwolf/photos/Tektronix_2213/

Overall, the 2213/2215 isn't a scope I would recommend for a beginner, but if you have the patience and a vacuum soldering tool, they aren't that hard to service.

Re: Tek 2215

On Sun, 24 Jan 2016 18:56:02 -0600 (CST), you wrote:

On Sun, 24 Jan 2016, jasontucker70@... [TekScopes] wrote:

Ok thanks..
Are there alot of caps that should be replaced and any other mods that
should be done ???
....

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.

Re: Recommendations / 2247A

I do not have any complaints about mine. The 2247A duplicates the
universal timer/counter functions found in your 2236. Calibration is
*not* done digitally so there are no worries about dead batteries or
floating gate storage memory like with the 24xx oscilloscopes.

On Sun, 24 Jan 2016 18:45:59 -0600, you wrote:

I have my eye on a 2247A on Craigslist that looks very clean and appears to be fully functional.

Does anyone have any thoughts about this scope - reliable, repairable, etc.? It would be my first scope with a microprocessor. I also have a 7603 and a 2236 as well, not to mention a 503 in poor shape.

Thanks, John

Re: Recommendations / 2247A

Tom Jobe <tomjobe@...>

Hi John,
I have some 224x scopes and use a nice 2247A regularly. It's a wonderful
scope and I know it's very complicated, but I'm hoping all of you will
help me fix it if or when it does fail!
I'd say, go for it and worry about future in the future.
Ordinary things like re-capping the 224x power supply is a very simple
thing to do, and the details of it are well documented. Also the 2247A
probably came late in the 224x series so it probably has some
improvements they learned of earlier in the series.
tom jobe...

On 1/24/2016 4:45 PM, John Dickens jake_117_dickens@...
[TekScopes] wrote:

I have my eye on a 2247A on Craigslist that looks very clean and
appears to be fully functional.

etc.? It would be my first scope with a microprocessor. I also have a
7603 and a 2236 as well, not to mention a 503 in poor shape.

Thanks, John

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

Re: Tek 2215

Jay

Why are you replacing the resistor that your listed ???

Re: Tek 2215

Jay

I have a hakko fx-888d iron and nice desoldering iron that works really good.I know I'm a noob to scopes but right now I have no scope cause I had a nice Rigol DS1054z but had to be sold in order to pay rent and a place for my family.. The scope is show in the pics working but will need further testing and why replace the resistors ... When I get the scopes is there anyway I could could post pics and you guys could show me what is needed to be replace or part# or something ???
About how much should the parts cost me for the rebuild here in the usa ???

Re: Tek 2215

Tothwolf

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:

Ok thanks..
Are there alot of caps that should be replaced and any other mods that should be done ???
....

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.

Re: Tek 2215

The focus resistor chain is just a common point of failure in the
early 22xx oscilloscopes and if you have to order parts like the
aluminum electrolytic capacitors, it might be worth ordering the
resistors and changing them also.

I think Tothwolf <tothwolf@...> has a better idea about
parts and pricing but we need to know which version of the power
supply you have. My guess is that the total cost should be less than
\$20.

On Mon, 25 Jan 2016 03:51:37 +0000 (UTC), you wrote:

I have a hakko fx-888d iron and nice desoldering iron that works really good.I know I'm a noob to scopes but right now I have no scope cause I had a nice Rigol DS1054z but had to be sold in order to pay rent and a place for my family.. The scope is show in the pics working but will need further testing and why replace the resistors ... When I get the scopes is there anyway I could could post pics and you guys could show me what is needed to be replace or part# or something ???
About how much should the parts cost me for the rebuild here in the usa ???

Re: Tek 2215

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?

Re: Tek 2215

Tothwolf

On Sun, 24 Jan 2016, David @DWH [TekScopes] wrote:

The focus resistor chain is just a common point of failure in the early 22xx oscilloscopes and if you have to order parts like the aluminum electrolytic capacitors, it might be worth ordering the resistors and changing them also.
The 18k ohm 1/4W resistor used for the focus control located just in front of the HV multiplier is also problematic. I also replaced a handful of other carbon comp resistors on the preregulator board which had drifted and plan to replace a couple more on the main board with carbon film and metal oxide parts.

I think Tothwolf <tothwolf@...> has a better idea about parts and pricing but we need to know which version of the power supply you have. My guess is that the total cost should be less than \$20.
With the price breaks for buying in bulk, the preventative maintenance parts for my 2213 scopes were just under \$20.00 per scope. Buying in smaller quantity, based on my old spreadsheets, I suspect the total will be closer to \$25.00.

I suppose since these scopes seem to be turning up more often, I should work up a parts list with both Mouser and Digi-Key part numbers.

Re: 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.

Re: Tek 2215

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.

Re: Tek 2215

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