----- Original Message -----

From: pdxareaid

To: TekScopes@...

Sent: Saturday, September 29, 2012 12:00 PM

Subject: [TekScopes] 465B schematics and tantalum curiosity

?

Greetings,
I am waiting on replacement tantalums to show up to complete my 465B scope.

While I was waiting, I thought I would dive in and do a tant survey and look for dry tants in circuits that are dangerously close to their rated voltage (and therefore subject to early failure). I have already found a couple without really looking so i thought a more in depth look might be worthwhile. I found the schematics in the service manual are not clear enough to read the component numbers (Cxxxx etc.) I could probably muddle thru it, making good guesses and cross checking, but I was wondering if someone had a better set of schematics for the 465B. I have both the standard pdf and djvu versions of the service manual (found at ) and they are both problematic. I asked this question once for the 465M and got lucky with "try this". hoping to get lucky for the 465B.

Another question: I know very little about dry tants but I do know that even a brief reverse polarity connection will damage the tant. Does one need to worry about such when looking for shorted tants, realizing the volt meter is providing its own polarity for resistance readings? ie. Are tants sensitive to such a miniscule current? If not a practical worry...academically: is there some small degradation? I see there are people in here with lots of tant knowledge that might be able to comment.
Phil
ps. If i do the survey, I will post the results for 465B owners to fret over :-)

Greetings,
I am waiting on replacement tantalums to show up to complete my 465B scope.

While I was waiting, I thought I would dive in and do a tant survey and look for dry tants in circuits that are dangerously close to their rated voltage (and therefore subject to early failure). I have already found a couple without really looking so i thought a more in depth look might be worthwhile. I found the schematics in the service manual are not clear enough to read the component numbers (Cxxxx etc.) I could probably muddle thru it, making good guesses and cross checking, but I was wondering if someone had a better set of schematics for the 465B. I have both the standard pdf and djvu versions of the service manual (found at ) and they are both problematic. I asked this question once for the 465M and got lucky with "try this". hoping to get lucky for the 465B.

Another question: I know very little about dry tants but I do know that even a brief reverse polarity connection will damage the tant. Does one need to worry about such when looking for shorted tants, realizing the volt meter is providing its own polarity for resistance readings? ie. Are tants sensitive to such a miniscule current? If not a practical worry...academically: is there some small degradation? I see there are people in here with lots of tant knowledge that might be able to comment.
Phil
ps. If i do the survey, I will post the results for 465B owners to fret over :-)

I built a homemade normalizer using a 22pf 1206 cap and a 1Meg 1206 resistor. I expected it work be a 22pf normalizer. It produces a square wave with my 7A16P 20pf amplifier but shows a bit of low freq rolloff on the leading edge with a 7A26 or 7A18. The 22pf caps I am using seem to be a bit over 22pf. I am puzzled that it looks better with the 7A16p than the 7A26. How are normalizers calibrated?



Jerry Massengale

----- Original Message -----

From: jerry massengale

To: hp_agilent_equipment@... ; lecroy_owners_group@... ; tekscopes@...

Sent: Saturday, September 29, 2012 8:32 AM

Subject: [TekScopes] Normalizer calibration

?

Hi,

I built a homemade normalizer using a 22pf 1206 cap and a 1Meg 1206 resistor. I expected it work be a 22pf normalizer. It produces a square wave with my 7A16P 20pf amplifier but shows a bit of low freq rolloff on the leading edge with a 7A26 or 7A18. The 22pf caps I am using seem to be a bit over 22pf. I am puzzled that it looks better with the 7A16p than the 7A26. How are normalizers calibrated?

Jerry Massengale

Hi Jim, Rich and Rolynn

I am so sorry I have not been back to reply for almost a week but my Dog got really sick on Sunday and looked like he was not going to make it, so I pretty much dropped everything and took 3 days off from work so I could get him to the Vet so they could figure out what had happened (seems like he contracted some kind of massive cardio infection).

After that he was home on Meds but very sick so I stayed with him during the days and my wife took care of him in the evenings while I slept and then I took over the night shift when she went to bed. He is doing much better now but is still not out of the woods yet.

I wanted you guys to know that I took the advice from Rolynn and purchased an ebay auction supposedly for all the cables for a 27xx. The only problem is that the guy could not guarantee me that the TG cables are in the lot but looking at the pictures I think they are there.

Can you guys take a look and tell me if I got lucky or picked door Number 2 (LOL).

Scroll down to the bottom he has multiple pictures.



I pulled the trigger on this just after the Dog got sick, so I had very little time to really check it out properly but I figured Rolynn knew that the cables where in the pictures.

I will be back soon, but things are still a bit rough because now I have a serious back log at work but I will try to log in again tommorow.

Thanks again for all the help guys.
Robert
KD8MJR





--- In TekScopes@..., "dreadlk" <dreadlk@> wrote:

Rolynn Thank you so very much for that :)
I will be in touch soon.

--- In TekScopes@..., "ROLYNN PRECHTL K7DFW" <k7dfw@> wrote:

I think my biggest hurdle is going to be getting the proper Semi Rigid cables that are needed I
have no clue where to buy these........

There are two Chinese sellers on eBay who say they have the CA3102.
Another thought... the 2213A, 2215A, 2235, etc. all have three of those CA3102 chips on the mainboard.
Is there any chance of someone in your part of the world having a broken 22xx with some CA3102?
The part is not worth much, but the shipping to Thailand costs a lot.
tom jobe...



----- Original Message -----
From: tjeenz
To: TekScopes@...
Sent: Saturday, September 29, 2012 2:34 AM
Subject: [TekScopes] Re: 2213 no trigger



Hi David,

After waiting for one week for the ca3102, I found out it is not available here (thailand, bangkok area). I checked the internet but come out at companies who want to have minimum order of 150usd.
amazon lists them for 8 usd and shipping around 20 usd. maybe you know of a cheaper seller/location?

tjeenz.

--- In TekScopes@..., David <davidwhess@> wrote:
>
> On Mon, 24 Sep 2012 10:43:12 -0000, "tjeenz" <tjeenz@> wrote:
>
> >I removed u460. (ca3102 from rca). it is broken (20ohm between 1 and 14 in both directions)
> >also i found a diode connected on the top to pin 12. i couldn't detect pin 12 in the schematics... now start looking for a ca3102
>
> On Mon, 24 Sep 2012 08:50:17 -0000, "tjeenz" <tjeenz@> wrote:
>
> >> Voltage U460 pin3 and 9 is -8.6V, R456 is ok.
> >> pin 1 and 8 are 3.5V not 2.2
>
> That fits with pin 1 being 3.5 volts instead of 2.2 volts. The low
> resistance between the collector and base is pulling that node up via
> the high output of U480C.
>
> Pin 2 and pin 10 at about 0.0 volts while pin 3 is -8.6 volts suggests
> that the emitters of U460E and U460B is open as well.
>
> Pin 12 and pin 5 are connected internally to the substrate. The
> CA3102 is built on a junction isolated process so the substrate
> connects to each transistor via a diode which is reverse biased to
> provide isolation.
>
> >> u460 is unfortunately not on a socket.
>
> When replacing U460, I would cut the collet pins out of an IC socket
> and individually install them into the PC board to make a low profile
> socket for the new IC.
>
>
>
> >> To access u460 and area, i see i have to remove some components. I will start on that a.s.a.p. but a question: some loose contact in the timebase switch. sometimes it generates only half screen image when i move with that knob. is that the pot-meter in the middle?
>
> From what I remember of the 2213, the timebase switch uses a different
> and unreliable design from the other 22xx series oscilloscopes.
> Someone else may have suggestions for repairing it.
>

Azzy,

The basic method of making a tracking generator is to mix a frequency equal to the first IF with the first Local Oscillator to produce a signal equal in frequency to the analyzer input frequency. This is somewhat complicated in the 494P by the fact that the first IF frequency is somewhat variable (since the second local oscillator is sometimes swept). For the 0-1.8GHz band, the first IF is about 2.072 GHz. For most of the higher bands the first IF is 829MHz.

For a simple 2 to 3 GHz tracking generator you could use an external 829MHz source (approximate frequency), buffer amplifiers for the first LO output and a mixer. You would need to operate at sweep widths that did not sweep the second local oscillator.

Fancier tracking generators would include signal leveling and would include the second LO oscillator to allow proper operation with narrow sweeps: Take a look at what John Miles did for the 0-1.8GHz band:
<<>>

--John Gord



--- In TekScopes@..., "Asadullah" <mirasad31415@> wrote:

I have purchased a Tek 494P off Ebay yesterday. ( It is still in transit). What I must have is a tracking gen to go with her. I looked through the 494P manual but could not determine what it is. ( I am bit slow at understanding) Besides I might not be able to buy one even if I can find one.
So the big question. What will work as a substitute? Where could I find information on how to build one if possible? My current interest is in the 2 to 3 GHz range only, but might go to around 10 GHz.
Even a block diagram will help. I could jury rig something to work.
Any help is welcome. Thanks

Azzy.

----- Original Message -----

From: tjeenz

To: TekScopes@...

Sent: Saturday, September 29, 2012 2:34 AM

Subject: [TekScopes] Re: 2213 no trigger

?

Hi David,

After waiting for one week for the ca3102, I found out it is not available here (thailand, bangkok area). I checked the internet but come out at companies who want to have minimum order of 150usd.
amazon lists them for 8 usd and shipping around 20 usd. maybe you know of a cheaper seller/location?

tjeenz.

--- In TekScopes@..., David wrote:
>
> On Mon, 24 Sep 2012 10:43:12 -0000, "tjeenz" wrote:
>
> >I removed u460. (ca3102 from rca). it is broken (20ohm between 1 and 14 in both directions)
> >also i found a diode connected on the top to pin 12. i couldn't detect pin 12 in the schematics... now start looking for a ca3102
>
> On Mon, 24 Sep 2012 08:50:17 -0000, "tjeenz" wrote:
>
> >> Voltage U460 pin3 and 9 is -8.6V, R456 is ok.
> >> pin 1 and 8 are 3.5V not 2.2
>
> That fits with pin 1 being 3.5 volts instead of 2.2 volts. The low
> resistance between the collector and base is pulling that node up via
> the high output of U480C.
>
> Pin 2 and pin 10 at about 0.0 volts while pin 3 is -8.6 volts suggests
> that the emitters of U460E and U460B is open as well.
>
> Pin 12 and pin 5 are connected internally to the substrate. The
> CA3102 is built on a junction isolated process so the substrate
> connects to each transistor via a diode which is reverse biased to
> provide isolation.
>
> >> u460 is unfortunately not on a socket.
>
> When replacing U460, I would cut the collet pins out of an IC socket
> and individually install them into the PC board to make a low profile
> socket for the new IC.
>
>
>
> >> To access u460 and area, i see i have to remove some components. I will start on that a.s.a.p. but a question: some loose contact in the timebase switch. sometimes it generates only half screen image when i move with that knob. is that the pot-meter in the middle?
>
> From what I remember of the 2213, the timebase switch uses a different
> and unreliable design from the other 22xx series oscilloscopes.
> Someone else may have suggestions for repairing it.
>

---
Think I solder inside the 132 a 51 ohm parallel to the bnc and 47 ohm in series instead of the short wire. Then it is always terminated in 98 ohm. Close enough. Then two short 50 ohm cables and if nessacary for BW two 50 ohm inline terminators on the scope. Voltage over the 50 ohm internal will be 0,5V so thats correct to be able to use the scopes standard V/div setting, and using 50 ohm in line terminators or 50 ohm 7A24 plugins ( or the 50 ohm input of my hameg) the voltage will be 0.25V so only thing I have to do is choose a lower V/div position and i do not have to use the variable in between gain on the scopes.
---
Fred pa4tim

On Mon, 24 Sep 2012 10:43:12 -0000, "tjeenz" <tjeenz@...> wrote:

I removed u460. (ca3102 from rca). it is broken (20ohm between 1 and 14 in both directions)
also i found a diode connected on the top to pin 12. i couldn't detect pin 12 in the schematics... now start looking for a ca3102

On Mon, 24 Sep 2012 08:50:17 -0000, "tjeenz" <tjeenz@...> wrote:

Voltage U460 pin3 and 9 is -8.6V, R456 is ok.
pin 1 and 8 are 3.5V not 2.2

That fits with pin 1 being 3.5 volts instead of 2.2 volts. The low
resistance between the collector and base is pulling that node up via
the high output of U480C.

Pin 2 and pin 10 at about 0.0 volts while pin 3 is -8.6 volts suggests
that the emitters of U460E and U460B is open as well.

Pin 12 and pin 5 are connected internally to the substrate. The
CA3102 is built on a junction isolated process so the substrate
connects to each transistor via a diode which is reverse biased to
provide isolation.

u460 is unfortunately not on a socket.

When replacing U460, I would cut the collet pins out of an IC socket
and individually install them into the PC board to make a low profile
socket for the new IC.

To access u460 and area, i see i have to remove some components. I will start on that a.s.a.p. but a question: some loose contact in the timebase switch. sometimes it generates only half screen image when i move with that knob. is that the pot-meter in the middle?

From what I remember of the 2213, the timebase switch uses a different
and unreliable design from the other 22xx series oscilloscopes.
Someone else may have suggestions for repairing it.

Hi Fred,

Did you read messages around #41521 ?

IIRC (but not sure) the Type 132 should not be used without a plugin because of those too high voltages. The -150 V needs some minimum load because of the 1.5k bypass resistor in the regulator.
Also without plugin the grids of the signal input tubes would be NC.

Albert

But if it is so simple I gues the Tek Engineers would had
figured that out instead of using 93 ohm and seperate
teminstors. So what am I ovelooking ?
----
1A7a without tubes and a CA gave no smoke. Voltage with plugin inserted are OK and regulate well if I use the variac. But without a plugin they are way off. -150 is -198V, and the rest is also very much higher.
---
Fred pa4tim

I'm in trouble with my 564, I'm not sure if the CRT is exhausted or not.
The tube is the 154-0410-00 (T5640-200).
I don't find neither electrical specs nor some test method to measure cathode emission to determine if my CRT needs replacement.
Any suggestion is appreciated, thanks!

Max

I have purchased a Tek 494P off Ebay yesterday. ( It is still in transit). What I must have is a tracking gen to go with her. I looked through the 494P manual but could not determine what it is. ( I am bit slow at understanding) Besides I might not be able to buy one even if I can find one.
So the big question. What will work as a substitute? Where could I find information on how to build one if possible? My current interest is in the 2 to 3 GHz range only, but might go to around 10 GHz.
Even a block diagram will help. I could jury rig something to work.
Any help is welcome. Thanks

Azzy.

I don't recall seeing Iwatsu or any other company producing a scope
with plugins similar to the Tek 7000 series. Here is an Iwatsu
TS-8123 Storagescope, in non-working condition, which failed to get a
bid on eBay for USD$150:



- Robin

Fairchild made a series of very nice scopes way back when with plug-ins. A friend of mine has several of them. Beautiful construction inside.
Here's one on ebay

Rick
=================================================================

--- In TekScopes@..., Robin Whittle <rw@> wrote:

I don't recall seeing Iwatsu or any other company producing a scope with
plugins similar to the Tek 7000 series. Here is an Iwatsu TS-8123
Storagescope, in non-working condition, which failed to get a bid on
eBay for USD$150:



- Robin