开云体育

On 3/3/2021 12:51 PM, oneenaht@... wrote:

Hi guys,

my first post here.

I have been given a Tektronix 2230 scope.
The previuos owner could remember het go it from somebody else, and there was something about a fuzzy readout.

I always find it a challenge to repair electronic equipment, but this time I am stuck.
The scope is very clean and probably not used very much, if it ever has been used. Or if it has even worked as it should be.
Inside there is no dust, and no repairs have been done previously.
The GPIB option board is present, as well as the memory option. The backup battery is OK.

(please take a look at the video) /

On startup, the analog function looks OK, all the controls are functional. Tested when rest jumper is set.
(Except for an issue with the attenuator which looks to be open in some positions, bad contact?).
After some time, after 40" in the video, the analog screen disappears completely.
When you push beamfind, there is some small rectangular image somewhere, this can be top or bottom, an left or right.
After some time, after 1:20" in the video, things start to change. While pushing beamfind, it looks like some diagnostic things are displayed, but you cannot recognize any text.
So, the fuzzy readout the previuos owner saw was this behaviour.
Pushing the select on the cursor pot or turning it has no effect.

I have a nice service manual (Artek Media).
I must admit it is not very clear to me.

I have tested and measured all sort of things, but there is nothing that looks not normal at first sight.
Voltages are OK, also the plus and minus 15V on the vector board. I have forgotten to measure the 5V ref.
There are no leaking or thick capacitors in the PSU (Why do they make is so difficult to remove te cover?)
Data- and addresslines do not show unlogical signals, ie. shorts between addressline or outputs behaving strange. Tested real-time, and in testmode.
Clock 40MHz and 7.66MHz are OK.
Changed the processor (recovered from a very old Epson XT PC), no change.
Checked the display controller socket, but nothing unusual. The controller heatsink itself is touchable, so no overheating.
The digital push buttons are electrically OK, also the cursor pot (checked with ather scope). No of them seems to be doing something.

From the video, and monitoring addresslines, it seems the processor is running, but maybe it encounters some sort of error.
I have no experience with (digital) Tek scopes. Perhaps I am overlooking something simple.
Anybody has a clue?

Thanks in advance, Harry from Belgium

A few quick points some of which you may already know.

The intensity pot when rotated fully CCW and back switches the readout on and off.

There are separate adjustments for the readout and trace intensity on the MB.

It pays to be very fussy about all of the connections between the MB and the CRT pins as several of these are "dry" circuits and need to be nearly perfect.


Several years ago I bought a "parts" 2230 scope from ebay and at first it didn't do much of anything.

I replaced two bad ribbon cables and in the course of further trouble shooting I was stunned to find a point where there was a signal on one of the eprom socket pins and no single on the eprom pin!

A simple cleaning of the chip and socket brought the scope back to life and it's been fine ever since.

Note that this was not even one of the POS Ti sockets, it was a Amp style socket.


FWIW Whenever I have a 2230/21/21A/32 scope open for service I replace the focus resisters and the input filter (line socket) just as a mater of course.


IMHO Any/all of the? 2221A/30/32/35s are well worth restoring.


Have fun,

? Bert

Hi Dave,
These are the ones I use with their corresponding DIgiKey and Mouser part numbers:
Mill-Max Part Numbers
917-93-103-41-005000 CONN TRANSIST TO-5 3POS GOLD
0552-2-15-01-11-27-10-0 CONN PIN RCPT .015-.020 SOLDER
0552-2-15-15-11-27-10-0 CONN PIN RCPT .015-.020 SOLDER
All three of these are still available from DigiKey.

Mouser Part Numbers
575-055220 Mill-Max 0.015-.022” pin, 0.170” deep, for small transistors & small in-line pkgs.
575-0293015 Mill-Max 0.022-.034” pin, 0.170” deep, for TO-66 transistors
575-031400 Mill-Max 0.032-.046” pin, 0.236” deep, for TO-3 transistors & large in-line pkgs.
Only two are available now from Mouser.

Dennis Tillman W7pF

Yeah, I didn't get into Q1218. It did have me running in circles a bit too because of its -8v at the collector.

I did a couple of things: removing it and trying running the scope without it. No effect.

I also measured voltages while switching S1150/Time/Div (to X-Y is cam switch 14). Mostly "correct" and following the engagement/disengagement of S1150/14 (X-Y mode). I say "correct" because the Q1224 base node is connected too, and it throws off the voltages around R1202, R1219, Q1218e.

What I thought was very telling was lifting R1221 resulted in Q1224 base going all the way up to +8v. No hope of the circuit working, but told me there was nothing else pulling that node down. Not Q1214/Q1218 nor the horizontal position pots.

That's when I ran out of ideas and hollered for help.

I've ordered a box of 250 assorted BJTs from Amazon with free delivery for tomorrow. So I'll have some fresh 2N2906s to try. I'll probably (impatiently) swap Q1226/Q1236 into Q1038/Q1098 this afternoon to see if that brings Q1224base back up. Or releases the magic smoke.

Dave

At 2021-03-03 01:19 PM, Dennis Tillman W7pF via groups.io wrote:

Has anyone had any experience using this WaveStar software?

I have used WaveStar Lite (the free version) with my TDS220 to do screen dumps, before I designed KISS-488. I recall WaveStar being clumsy to use, and i don't recall for certain whether it ran on Win7 or if I had to run it in the XP box.

Steve Hendrix

I quickly scanned your post, I didn't see anything about Q1218 so if you tried already you can ignore the following comment: The voltages you measured say pretty much all the available current is pulled out of the base node of Q1224. I looked at the timebase circuit briefly, the worst that can happen looks like a short to ground (not pulling below). That leaves Q1218 and the circuit around Q1218 as the suspect. It could be as simple as a dirty switch (S1150 going to the diodes).

What voltage do you measure at the emitter of Q1218?

Ozan

I have a few surplus 119-0262-00 Crystals.
They are adjustable for fine tuning through a screw hole on the top of the
package.
These 5MHz crystals are used in the 7D11, 7D14, and 7D15 plugins and
possibly some of the TM5xx/TM5xxx plugins.
They come from Bliley, CTS Knights, and Tyco.

CONTACT ME OFF LIST at dennis at ridesoft dot com if you can use any of
these.

Dennis Tillman W7pF

Is there a resource for the sockets that are soldered into the PCB boards in scopes with plug-in transistors, ICs, diodes, etc.?

Dave

Sometime ago I bought a sealed copy of this Tek software:
WSTRO & WSTRU WaveStar Software for Oscilloscopes, WSTRM WaveStar Software
for Meters.
The label on the back says v2.4 Tek part number 020-2354-00
I can tell from the shape of the package that there is a CD case in it.
The package also has a spiral bound User Manual (071-0220-05) and these
accessories:
A cable with a DB-9 female on one end and a pair of clear LEDs(?) on the
other end where it says it is an Optical Interface Cable .
A DB-9 male to DB-25 female Adapter
Five DB-9 shaped black plastic bezels

Has anyone had any experience using this WaveStar software?

Dennis Tillman W7pF

Hi guys,

my first post here.

I have been given a Tektronix 2230 scope.
The previuos owner could remember het go it from somebody else, and there was something about a fuzzy readout.

I always find it a challenge to repair electronic equipment, but this time I am stuck.
The scope is very clean and probably not used very much, if it ever has been used. Or if it has even worked as it should be.
Inside there is no dust, and no repairs have been done previously.
The GPIB option board is present, as well as the memory option. The backup battery is OK.

(please take a look at the video) /

On startup, the analog function looks OK, all the controls are functional. Tested when rest jumper is set.
(Except for an issue with the attenuator which looks to be open in some positions, bad contact?).
After some time, after 40" in the video, the analog screen disappears completely.
When you push beamfind, there is some small rectangular image somewhere, this can be top or bottom, an left or right.
After some time, after 1:20" in the video, things start to change. While pushing beamfind, it looks like some diagnostic things are displayed, but you cannot recognize any text.
So, the fuzzy readout the previuos owner saw was this behaviour.
Pushing the select on the cursor pot or turning it has no effect.

I have a nice service manual (Artek Media).
I must admit it is not very clear to me.

I have tested and measured all sort of things, but there is nothing that looks not normal at first sight.
Voltages are OK, also the plus and minus 15V on the vector board. I have forgotten to measure the 5V ref.
There are no leaking or thick capacitors in the PSU (Why do they make is so difficult to remove te cover?)
Data- and addresslines do not show unlogical signals, ie. shorts between addressline or outputs behaving strange. Tested real-time, and in testmode.
Clock 40MHz and 7.66MHz are OK.
Changed the processor (recovered from a very old Epson XT PC), no change.
Checked the display controller socket, but nothing unusual. The controller heatsink itself is touchable, so no overheating.
The digital push buttons are electrically OK, also the cursor pot (checked with ather scope). No of them seems to be doing something.

From the video, and monitoring addresslines, it seems the processor is running, but maybe it encounters some sort of error.
I have no experience with (digital) Tek scopes. Perhaps I am overlooking something simple.
Anybody has a clue?

Thanks in advance, Harry from Belgium

Hi Bernd,

There have been several discussions about Bill's transformers of
late, and there is a picture on the group, that looks very much
like epoxy varnish, or some other non wax compound.

However, it is most definitely not scatter wound. It is a nice
looking, self supporting, universal wind.

Bill didn't use an outer tape covering on this transformer. The
naked winding is right there for you to see.

-Chuck Harris

widgethunter via groups.io wrote:

Hey John,

First port of call would be to check all the power supply voltages &
ripple. You have a service manual I trust? There's a section in the service
manual detailing the measurements. The power supplies are all brought out
to J119, which is on the mainboard of the scope.

While you have the scope open, if your A5 board is the SMD version, you'll
want to check the electrolytics on the board for leakage. Even though the
display trouble you describe wouldn't result from that, you don't want to
wait until they leak.

Siggi

Hi Dave,

That is interesting, as I never sold any transformers to Stan.

So, did I pass muster?

-Chuck Harris

Dave Wise wrote:

Some of them have the series number towards the bottom of the meter scale. If you don't see that, look at simpson260.com to help identify the meter by other means.

DaveD

--
This email has been checked for viruses by Avast antivirus software.

Dave Wise <david_wise@...> added the album 547 HV Transformer rewind by Bill Schell: Installed in 2000

---

The following photos have been uploaded to the 547 HV Transformer rewind by Bill Schell album of the [email protected] group.

• IMG_0784.jpeg
• IMG_0788.jpeg
• IMG_0793.jpeg

By: Dave Wise <david_wise@...>

?Roy,


I uploaded pictures to album "?547 HV transformer rewind by Bill Schell". Tell me what you think.


Dave Wise


Update:


Still improving; the intensified part of the trace is now visible at the original intensity setting.

________________________________
From: [email protected] <[email protected]> on behalf of Roy Thistle via groups.io <roy.thistle@...>
Sent: Wednesday, March 03, 2021 8:47 AM
To: [email protected]
Subject: Re: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

On Wed, Mar 3, 2021 at 08:06 AM, Dave Wise wrote:

I used to think my Bill Schell transformer was wax-impregnated; now I don't. I
think it's epoxy

Hi Dave:
Sorry to hear about your trouble.
Perhaps you don't remember... because the last time you handled the transformer was when you installed it... but, how does one mistake wax for epoxy?... or vice versa.

If Ch3 and Ch4 display the sine wave OK at all vertical positions but Ch1 and Ch2 have similar distortions it could point to a problem with the vertical channel switch hybrid.

There are many others here with wider knowledge than me so you will probably have other suggestions.

It is possible to carefully clean the contacts on the hybrid, replacements tend to be expensive.

Regards,

Roger

I've got a 260 that was my grandfather's, but I don't know how to tell what series it is.
I also haven't looked at it for quite a while. How can I tell the series and manufacture date range?

Or Amazon Prime! LOL.

I guess I have a bias against Amazon for such things. Kind of like Radio Shack. But why? I guess as long as I shop carefully and understand I might not be getting the best quality product. Why not?

I see packages of assorted types for cheap. Might be worth having a variety. Thanks for kicking me in a different direction Bob!

Dave

I read somewhere that you get free shipping from DigiKey if you prepay with a check.
Bob

I have removed Q1226/Q1236 PNPs with no effect. They are not part of the problem. This is also part of why I built the LTspice simulation - to get insight into the current switching going on. I've also tested changing horizontal position, as well as unplugging them entirely at P1200 with no effect.

My finding is that, while yes, the Q1224/Q1234 currents drive the signals through the front end of the amp, it doesn't mean that there aren't corresponding voltage signals. The simulation confirms that an excessive negative bias on the input results in the symptoms observed on the bench. It's not a matter of unobservable currents.

I've been chasing the theory that something is pulling the base of Q1224 down, but sleeping on it allowed me to realize that perhaps the issue isn't a pull down, but a weak pull up. As the PNP Q1098 has a problem, perhaps Q1038 does as well. The node at Q1224 base is a huge common point of a lot of drivers. Q1038/Q1098 are significant contributors. I need to order up some fresh 2N3906's, but it occurred to me that the system is likely designed to have Q1038/Q1098 contributing, even if B-sweep is inactive.

I'm thinking about borrowing Q1226 and Q1236 for Q1038/Q1098. I'm hesitant to take them from my working 465 lest I damage them and kill a second scope. I need to accumulate some components to order so I can mitigate the shipping charges from Mouser. Even 100 2N3906's are less than the $8.00 shipping.

Dave