Date   

Re: PCB sockets for plug-in xtors/etc.

Larry McDavid
 

Dennis, do you know the appropriate finish hole size in the PWB for each of these replacement sockets?

Larry

On 3/3/2021 11:02 AM, Dennis Tillman W7pF wrote:
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
-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Dave Peterson via groups.io
Sent: Wednesday, March 03, 2021 10:34 AM
To: TekScopes@groups.io
Subject: [TekScopes] PCB sockets for plug-in xtors/etc.
Is there a resource for the sockets that are soldered into the PCB boards in scopes with plug-in transistors, ICs, diodes, etc.?
Dave
--
Best wishes,

Larry McDavid W6FUB
Anaheim, California (SE of Los Angeles, near Disneyland)


Re: Tektronix 606A that resists being repaired

jrseattle
 

Q714 is currently a Tektronix transistor marked 151-0606-00 referenced as Motorola SJE375 but I can't find any info on this device. The transistor that used to be there (broken) has no identification at all. I tried several MJE800 Darlingtons as listed in the manual but they fail because of rush-in current at startup. Can I add a small power resistor at the collector of Q714 to prevent this? Under normal operation, the current through Q714 seems to be about 1Amp (see below) so the MJE800 should work (4Amp rating)

If I set the cathode voltage at about -5000V (or a more positive value, max -4700), the device works find and oscillation doesn't stop anymore. The voltage drop across R714 in this mode is 1V or less (so 1 Amp current) and stays there. At -5000V, the image is clear but intensity control is limited. At -5500V, the specified value, the oscillation circuit eventually stops, after almost 30 minutes.

Still using 1R for R715 because my experiments show that a higher value here increases the oscillator run-time (limits current flow through Q714 is my guess, thus postponing the thermal runaway). Once I install the faster diodes (UF4004), I'll try to original 0.5 Ohm R715 again.

You say "The output will be shifted up if there is 1-ohm". I assume you are referring to U740 pin 6. Even at a limited cathode voltage of -5000V, the voltage here starts at 2V (with 1 Ohm R715).

Note that the screen image is crystal clear with -5000V cathode voltage but I would like to completely fix this device.

Should have more results in about a week.

JdR


Re: [HP-Agilent-Keysight-equipment] FS: Two Simpson VOMs!

Larry McDavid
 

Better look for internal batteries for Ohms.

I have a similar Precision Instruments VOM and removed the D cell and 15 volt battery for safety against leakage.

Larry

On 3/3/2021 9:23 AM, DaveH52 wrote:
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?
--
Best wishes,

Larry McDavid W6FUB
Anaheim, California (SE of Los Angeles, near Disneyland)


Re: Very Inexpensive 7623A, but Problems

 

Jean-Paul,

I will post photos shortly to the "Sick 2365A" album (https://groups.io/g/TekScopes/photos?p=created,,,20,2,20,0&jump=1)

I have the service manuals from TekWiki, which purport to be from 1974, have not effective or discontinued serial number ranges in the part lists, but do have two MCI pages (also from 1974).

Yes, I have come to the same conclusion as you about scopes, especially the large, non-portable sort, on eBay. Out of three such scopes I have bought, one was a complete loss, with the CRT shattered in shipping (thankfully I got a refund and return shipping label on that), and the other two are yet to be determined. The prices for all three, however, were right (each less than $100, shipping included), so it's hard (not impossible) to go too far wrong.

The reason I bought this scope was to expand my technical skills by fixing it (and just to have a 7000 mainframe scope, and a storage scope), so it's money and time well spent. If I were just trying to get a working scope to use for other things, then this would be a real waste. Aside from being a storage scope, the 7623A is inferior every portable scope that I already own. All of those scopes are working (and various kinds of rough handling, either in shipping, or by the original owners), and are my preferred bench scopes. This is really just a toy, at least until or unless I get a nice plug-in (e.g. a 7CT1N or one of the spectrum analyzer plug-ins).

Roger,

It's always good to be reminded of what I allegedly know (but may not, in the moment, recall). I had read about the color coding, but I'm not sure it helps much in this instance. My real concern was both getting the cables connected in the right places and orientations, and getting all the cables connected again.

I did notice that the case of the C811 seemed to bridge two "ground planes," and I added a jumper wire to do the same. I'm not sure it's of adequate current rating: it's single strand copper AWG 22 or 24, the spool is unmarked, but it's heavier than the AWG 26 that I normally use for breadboarding. I could easily add a second or third jumper if necessary.

It has occurred to me, after looking at the picture of the original CRT malfunction, and thinking about what would cause the current malfunction, that one of the horizontal deflection plates might be loose or disconnected, and that now both may be loose, or otherwise malfunctioning. After I get the power rails sorted this may be my second avenue of investigation.

-- Jeff Dutky


Re: 547 HV Transformer: Bill Schell rewind failed

snapdiode
 

Whoah, that's odd. My 547 has a Bill Schell transformer, also installed many years ago, and my 547 was working fine yesterday, but it didn't run for more than 30 minutes.


Re: PCB sockets for plug-in xtors/etc.

 

Hi Jeff,

I always wondered what the Tek PCB sockets were filled with and was that stuff really necessary?

The Tek PCB sockets are really great. I wish there was someone selling something like them now. I didn't find any other manufacturers of PCB pin sockets other than Milli-Max. Maybe someone else can locate a company that makes the kind that have a filler in them and explain how the filler helps the socket make better contact.

I always wondered how a wire was able to make contact with the inside of the Tek PCB sockets since the filler material (whatever it is) may get in the way of making contact to the socket.
I haven't tried to see if the filler material is conductive but I always assumed it isn't conductive at all.

If I remember correctly the Milli-Max pins I used have three spring fingers that press inward inside the socket where they grip the wires of the part. I like that idea because it tells me these sockets have the greatest area in contact with the wire.

40 years ago I worked for a company that used pins similar to the ones Tek used. They were filled with a similar material. They came on a flexible 1/4" mylar ribbon for automatic insertion into a PCB. These were square unlike the Tek ones which are round. These also required a 40% bigger hole in the PCB partially (a drawback) because they were square.

Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Jeff Dutky
Sent: Wednesday, March 03, 2021 12:10 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] PCB sockets for plug-in xtors/etc.

Dennis,

So it doesn't look like any of the available sockets (at Mouser, at least) have the silicone gaskets that the Tek sockets seem to have. Do you know if that was something Tek did themselves?

-- Jeff Dutky







--
Dennis Tillman W7pF
TekScopes Moderator


Re: 2467B with display anomalies

johnasolecki@...
 

I had checked Channels 3 & 4 previously and forgot to add that they work properly. Looking more like U400.


Re: 2467B with display anomalies

Jean-Paul
 

Hello I had the exact oppsite symptom: CH1, 2 30% nonlineariyt as traces enter lower 1/3 of CRT, but fine in center or top.

CH3, 4 OK.

I used a triangle wave to see the nonlinearity clearly.

Chuck mentioned that this symptom is indicating a failed Hybrid, Channel switch U400.

You can find the signals in and out of the TEK Hybrid on the A1 main bd schematic.

IF it is indeed U400, BEWARE: Used parts on epay or from China may also be defective, TEK 155-0236-00

Q service in Greece has them ~$100, or perhaps Sphere in BC.

Be careful in replacing, static sensitive and follow Chuck's procedures to remove and reattached.

Bon Chance,

Jon


Re: PCB sockets for plug-in xtors/etc.

 

Dennis,

So it doesn't look like any of the available sockets (at Mouser, at least) have the silicone gaskets that the Tek sockets seem to have. Do you know if that was something Tek did themselves?

-- Jeff Dutky


KUDOS to Chuck Harris for fixing/calibrating my 2465b

Mark Hatch
 

With the voluntary help of many of you on this list, I successfully re-caped the LV PS on my 2465B and in the process, fixed the intermittent power-on failure (it was one of: LV PS, on/off switch, or the resistor that was part of the power on circuit). Thank you all!

But I was faced with replacing the NVRAM and getting the scope calibrated better (frequency was close, voltage was off 10-15%). Neither of which I had the tools or experience to do so.

Chuck Harris (one of the frequent contributor on this list) was willing to take care of both issues at what I considered more than a fair price. Just got the scope back yesterday and it is so much better!

Although I am sure that there are others on this list that provide similar services for fee or free, I can definitely recommend Chuck as a fair and competent technician if you are looking for similar services on your Tek scope.

Regards,
Mark
AJ6CU


Re: 547 HV Transformer: Bill Schell rewind failed

Chuck Harris <cfharris@...>
 

Hi Dave,

I have long believed that the reason there were so few
failures with beeswax HV transformers is "wet" beeswax will
get hot and melt, letting the water out. Because the
windings are so close together, they act like a sponge,
and as long as the beeswax isn't made to boil, its surface
tension should keep it in the coil... It shouldn't drip
everywhere.

-Chuck Harris

Dave Wise wrote:

Chuck, your transformer worked great in 2010. A note reads that 6AU5 screen voltage was about 45V, and stable. That's way better than new.


Update.


With the intensity control at its original position, the trace is approaching original brightness.

My long-term-idle Bill Schell transformer is responding to baking.


Dave Wise

________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Chuck Harris via groups.io <cfharris=erols.com@groups.io>
Sent: Wednesday, March 03, 2021 9:47 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

Hi Dave,

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

So, did I pass muster?

-Chuck Harris

Dave Wise wrote:
?Update.


I retract my doom and gloom. Further warming seems to be restoring it after all. I simply left the scope running, with the intensity control at a safe position. I don't have a visible trace yet but as time passes I have to advance the control less and less to get one.


This data point corroborates the theory of moisture-ingress or other reversible reaction.


I will report back later.


Dave Wise


Note: This 547 has the 6AU5 screen grid voltage limit mod.

________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Dave Wise via groups.io <david_wise=phoenix.com@groups.io>
Sent: Wednesday, March 03, 2021 8:06 AM
To: TekScopes@groups.io
Subject: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

In 2017, my 547 with Bill Schell HV transformer (installed around 2000) was working. It has sat unused in a dry basement since then.

Today, in March 2021, that transformer exhibits the same thermal runaway symptom as the original Tek part. (Fades out in ten minutes.)

Hours of warming have not restored it. I don't think it will. I used to think my Bill Schell transformer was wax-impregnated; now I don't. I think it's epoxy, and like Tek's, it has gone bad.

I hope other Bill Schell customers can check in with their status.

I have an ace in the hole. In my drawer is... a 2010 Chuck Harris rewind. To ice the cake, it's the one Stan Griffiths was evaluating - he gave it to me after he was done with it. I'll install it soon.

Dave Wise


















Re: 547 HV Transformer: Bill Schell rewind failed

Dave Wise
 

?Roy, your signature is not included in the groups.io footer. Thanks for including your name in the message body.


Dave Wise

________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Roy Thistle via groups.io <roy.thistle=mail.utoronto.ca@groups.io>
Sent: Wednesday, March 03, 2021 11:33 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

Hi Dave:
Thanks for the reply... I'll check it the pic.
Hi it's Roy ( I'm a bit confused as.... usually.... if one doesn't address the O.P. directly by name... one is talking to the group... maybe that's not the convention? ) Also, I thought my "signature" in the footer was appearing?


Re: 547 HV Transformer: Bill Schell rewind failed

Dave Wise
 

?Chuck, I think *I* bought that transformer from you - just to have a spare on hand - and loaned it to Stan for evaluation. Since my Bill Schell was happy, I wouldn't have swapped it out.


Dave Wise

________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Dave Wise via groups.io <david_wise=phoenix.com@groups.io>
Sent: Wednesday, March 03, 2021 11:24 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

Chuck, your transformer worked great in 2010. A note reads that 6AU5 screen voltage was about 45V, and stable. That's way better than new.


Update.


With the intensity control at its original position, the trace is approaching original brightness.

My long-term-idle Bill Schell transformer is responding to baking.


Dave Wise

________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Chuck Harris via groups.io <cfharris=erols.com@groups.io>
Sent: Wednesday, March 03, 2021 9:47 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

Hi Dave,

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

So, did I pass muster?

-Chuck Harris

Dave Wise wrote:
?Update.


I retract my doom and gloom. Further warming seems to be restoring it after all. I simply left the scope running, with the intensity control at a safe position. I don't have a visible trace yet but as time passes I have to advance the control less and less to get one.


This data point corroborates the theory of moisture-ingress or other reversible reaction.


I will report back later.


Dave Wise


Note: This 547 has the 6AU5 screen grid voltage limit mod.

________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Dave Wise via groups.io <david_wise=phoenix.com@groups.io>
Sent: Wednesday, March 03, 2021 8:06 AM
To: TekScopes@groups.io
Subject: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

In 2017, my 547 with Bill Schell HV transformer (installed around 2000) was working. It has sat unused in a dry basement since then.

Today, in March 2021, that transformer exhibits the same thermal runaway symptom as the original Tek part. (Fades out in ten minutes.)

Hours of warming have not restored it. I don't think it will. I used to think my Bill Schell transformer was wax-impregnated; now I don't. I think it's epoxy, and like Tek's, it has gone bad.

I hope other Bill Schell customers can check in with their status.

I have an ace in the hole. In my drawer is... a 2010 Chuck Harris rewind. To ice the cake, it's the one Stan Griffiths was evaluating - he gave it to me after he was done with it. I'll install it soon.

Dave Wise










Re: 547 HV Transformer: Bill Schell rewind failed

Roy Thistle
 

Hi Dave:
Thanks for the reply... I'll check it the pic.
Hi it's Roy ( I'm a bit confused as.... usually.... if one doesn't address the O.P. directly by name... one is talking to the group... maybe that's not the convention? ) Also, I thought my "signature" in the footer was appearing?


Re: 547 HV Transformer: Bill Schell rewind failed

Dave Wise
 

Chuck, your transformer worked great in 2010. A note reads that 6AU5 screen voltage was about 45V, and stable. That's way better than new.


Update.


With the intensity control at its original position, the trace is approaching original brightness.

My long-term-idle Bill Schell transformer is responding to baking.


Dave Wise

________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Chuck Harris via groups.io <cfharris=erols.com@groups.io>
Sent: Wednesday, March 03, 2021 9:47 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

Hi Dave,

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

So, did I pass muster?

-Chuck Harris

Dave Wise wrote:
?Update.


I retract my doom and gloom. Further warming seems to be restoring it after all. I simply left the scope running, with the intensity control at a safe position. I don't have a visible trace yet but as time passes I have to advance the control less and less to get one.


This data point corroborates the theory of moisture-ingress or other reversible reaction.


I will report back later.


Dave Wise


Note: This 547 has the 6AU5 screen grid voltage limit mod.

________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Dave Wise via groups.io <david_wise=phoenix.com@groups.io>
Sent: Wednesday, March 03, 2021 8:06 AM
To: TekScopes@groups.io
Subject: [TekScopes] 547 HV Transformer: Bill Schell rewind failed

In 2017, my 547 with Bill Schell HV transformer (installed around 2000) was working. It has sat unused in a dry basement since then.

Today, in March 2021, that transformer exhibits the same thermal runaway symptom as the original Tek part. (Fades out in ten minutes.)

Hours of warming have not restored it. I don't think it will. I used to think my Bill Schell transformer was wax-impregnated; now I don't. I think it's epoxy, and like Tek's, it has gone bad.

I hope other Bill Schell customers can check in with their status.

I have an ace in the hole. In my drawer is... a 2010 Chuck Harris rewind. To ice the cake, it's the one Stan Griffiths was evaluating - he gave it to me after he was done with it. I'll install it soon.

Dave Wise










Re: Tektronix 2230 - no readout

Bert Haskins
 

On 3/3/2021 12:51 PM, oneenaht@gmail.com 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) / https://www.youtube.com/watch?v=8YkXAwB-x4Y&feature=youtu.be

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





Re: PCB sockets for plug-in xtors/etc.

 

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

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Dave Peterson via groups.io
Sent: Wednesday, March 03, 2021 10:34 AM
To: TekScopes@groups.io
Subject: [TekScopes] PCB sockets for plug-in xtors/etc.

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

Dave







--
Dennis Tillman W7pF
TekScopes Moderator


Re: TEK465 Horizontal trace

Dave Peterson
 

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


Re: WSTRO, WSTROU, WSTRM WaveStar Software for Scopes & Meters

Steve Hendrix
 

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


Re: TEK465 Horizontal trace

Ozan
 

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

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