Date   

Re: Have some free 151-1001-01 FETs, and added piles of hard to find Tek 148 Relays

Dave Wise
 

151-1001 is also mentioned in the Circuit Concepts book, “Vertical Amplifier Circuits”, although they don’t say where it’s used.

https://www.davmar.org/TE/TekConcepts/TekVertAmpCircuits.pdf

From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Dave Wise via groups.io
Sent: Monday, April 26, 2021 3:47 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Have some free 151-1001-01 FETs, and added piles of hard to find Tek 148 Relays

Talon Electronics has one in stock: “Tektronix 050-0486-00 Modification kit for P6045 FET probes. Modifies probe to accept 151-1001-01 FET.”
So 151-1001 is used in late-production P6045, and upgrading was easy enough that Tek issued a kit.

FWIW,
Dave Wise

From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of walter shawlee via groups.io
Sent: Monday, April 26, 2021 3:39 PM
To: TekScopes@groups.io
Subject: [TekScopes] Have some free 151-1001-01 FETs, and added piles of hard to find Tek 148 Relays

I have NO idea what these tiny gold flat-pack 151-1001-01 (FN1919 from Siliconix) FETs are used iin, the RPR only calls out an 050 kit, just not much help. anyway, I have 3, if anybody needs one, contact me off list, they can be yours for free.


Re: Have some free 151-1001-01 FETs, and added piles of hard to find Tek 148 Relays

Dave Wise
 

Talon Electronics has one in stock: “Tektronix 050-0486-00 Modification kit for P6045 FET probes. Modifies probe to accept 151-1001-01 FET.”
So 151-1001 is used in late-production P6045, and upgrading was easy enough that Tek issued a kit.

FWIW,
Dave Wise

From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of walter shawlee via groups.io
Sent: Monday, April 26, 2021 3:39 PM
To: TekScopes@groups.io
Subject: [TekScopes] Have some free 151-1001-01 FETs, and added piles of hard to find Tek 148 Relays

I have NO idea what these tiny gold flat-pack 151-1001-01 (FN1919 from Siliconix) FETs are used iin, the RPR only calls out an 050 kit, just not much help. anyway, I have 3, if anybody needs one, contact me off list, they can be yours for free.

Many people have been searching for the tiny Tek made relays, and the larger P+B R10 148 series parts, I dug out a
lot of new 148 parts, and posted them to the stuff page in the tek section here:
https://www.sphere.bc.ca/test/stuffday.html#tekfans<https://www.sphere.bc.ca/test/stuffday.html#tekfans>

Also there are FREE 1/4 turn case cover latches I found, and two types of Tek handles, might be something there that will help you, have a look. Lots of cool goodies in the other categories too, have a look.

I have a HUGE pile of Tek mechanical new spares, not any help to me. Too much time and grief to photo and list everything individually, I was going to try and group like things together in piles, and toss them up on the page, any suggestions appreciated. There is a lot of hardware, odd trim and plastic stuff, covers, etc. There's some new FAN impellers for the tiny siemens motors too. If you have a specific request or idea, let me know.

Please contact me off list.
all the best,
walter (walter2 -at- sphere.bc.ca)
sphere research corp.
https://www.sphere.bc.ca/test/index.html<https://www.sphere.bc.ca/test/index.html>


Re: Tek 1503C TDR

 

On Mon, Apr 26, 2021 at 01:36 AM, <warren.stirling@bigpond.com> wrote:


Does anyone, by faint chance, have a replacement lcd assembly for a 1503C TDR?
If it's just failed backlights, like in my 1502B and 1503C: I replaced both electroluminescence foils with foils sold by some car accessory shops, intended to brighten up dashboard speed and RPM scales and the like.

Raymond


Have some free 151-1001-01 FETs, and added piles of hard to find Tek 148 Relays

 

I have NO idea what these tiny gold flat-pack 151-1001-01 (FN1919 from Siliconix) FETs are used iin, the RPR only calls out an 050 kit, just not much help. anyway, I have 3, if anybody needs one, contact me off list, they can be yours for free.

Many people have been searching for the tiny Tek made relays, and the larger P+B R10 148 series parts, I dug out a
lot of new 148 parts, and posted them to the stuff page in the tek section here:
https://www.sphere.bc.ca/test/stuffday.html#tekfans

Also there are FREE 1/4 turn case cover latches I found, and two types of Tek handles, might be something there that will help you, have a look. Lots of cool goodies in the other categories too, have a look.

I have a HUGE pile of Tek mechanical new spares, not any help to me. Too much time and grief to photo and list everything individually, I was going to try and group like things together in piles, and toss them up on the page, any suggestions appreciated. There is a lot of hardware, odd trim and plastic stuff, covers, etc. There's some new FAN impellers for the tiny siemens motors too. If you have a specific request or idea, let me know.

Please contact me off list.
all the best,
walter (walter2 -at- sphere.bc.ca)
sphere research corp.
https://www.sphere.bc.ca/test/index.html


Re: Tek 1503C TDR

Paul Amaranth
 

Someone on eevblog replaced the lcd screen on a 1502B with an LCD panel:

https://www.eevblog.com/forum/repair/tek-1502b-tdr-restoration-project-and-more/msg3555459/#msg3555459

Some useful info there.

Paul

On Mon, Apr 26, 2021 at 01:08:05PM -0400, Harvey White wrote:
In one of the TM5000 series function generators with an LCD display, I was
able to replace the Tek display (with an EL backlight) with a standard 2
line x 16 character off the shelf LCD display.  The two displays looked
physically identical with the exception of the EL backlight, of course.

Harvey


On 4/26/2021 11:44 AM, Jeff Dutky wrote:
Judging by the pictures on TekWiki those LCD displays could use replacing even when they were "working."

It looks like the LCD is getting 8-bit parallel data from the CPU with 3 address lines and read and write strobes. The display modules are only referenced using Tek part numbers (672-1241-00 below SN B023854, 118-9050-01 after), but I wonder how hard it would be to decipher that protocol. At the very least you could read the Z-80 assembly that generates the video output straight out of the ROMs.

That would be a lot easier to read with a modern LCD and backlight, or a nice, old-school gas plasma or vacuum fluorescent display.

-- Jeff Dutky
--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@AuroraGrp.Com | Unix/Linux - We don't do windows


FS: A-B pots; FFP: 515/515A manual

Brad Thompson
 

Hello--

FREE FOR POSTAGE plus a cuppa coffee: one only 515/515A manual in good condition
(plastic spiral binder chipped, front cover missing small piece). There's no serial number
inscribed on the front page).

FOR SALE: I'm offering one batch of 32 pieces each of used/removed from equipment
Allen-Bradley type J potentiometers. These feature screwdriver-adjustment locking-shaft bushings and
are an unsorted mix of 10Kohm and 20 Kohm pots. They were used in rheostat mode
(soldered connections to wiper and one end). The original applications were unknown,
but were likely used as set points in fearsome analog kludge.

(Note: my long-gone RM515 used a 20K A-B pot as the -150V adjustment.)

For a detailed description and a source of NOS type J pots, go here:

https://www.tedss.com/LearnMore/American-Made-Potentiometers

I'm asking $13.50 for this assortment of 32 pots (with some mounting hardware),
which includes $8.45 for USPS Priority-mail shipment.

Questions welcomed, PayPal honored.

Thanks, and 73--

Brad  AA1IP

FAQs:

Q: how long are the pots' shafts?
A: they're designed for screwdriver adjustment and hence have stubby shafts unsuitable for attaching knobs.

Q: what's the resistance taper?
A: random samples appear to be linear versus rotation resistance-tapered.

Q: are these all tested?
A: sorry, no. There's a limit to my patience.

Q:  what's the power rating?
A:  they're spec'ed  for 2.25 watts. Ohm's Law applies to the entire resistive element.

Q: what's with the weird part numbers (e.g., CBZ xxxxx) stamped in some of the pots' cases?
A: it's a military specification.

Q: what's a kludge?
A: an inelegant solution using available parts and poorly-suited tools
     to expeditiously solve  a problem at hand. You'll know one when you see one.
--
Sent from Postbox <https://www.postbox-inc.com>


Re: Cannot delay the B sweep on a 465B

Ozan
 

Hi! Thanks! In the end I found the problem: R7069 which lies between a
55VDC supply
and Q7074/Q7075 was cracked and open circuit....It's supposed to be 6.2
kOhm. After replacing it, my 465B works perfectly!
Great news, congratulations for the fix.
Ozan


Re: Cannot delay the B sweep on a 465B

Torquil Macdonald Sørensen
 

On 26/04/2021 07:17, Ozan wrote:
Hi Torquil,

I have a problem with my 465B where the delay time position 10-turn pot for
the B sweep has no effect. Everything else seems to work. Please see this
youtube video for a demonstration:

https://youtu.be/17ZGEw_jOmo

The intensified portion of the A sweep trace always starts on the leftmost
part of the display no matter how much I turn the delay time position knob.
However, the holdoff knob does make the B sweep duration/length vary, in a
periodic manner as I turn the holdoff knob slowly clockwise.
------
I don't have a 465B but B sweep delay circuit works similarly on several scopes. On sheet <7> Q7067 compares delay potentiometer voltage to "A ramp" voltage. Depending on where ramp crosses the delay pot voltage, B sweep starts with that delay. "A ramp" waveform (node 60) is not shown in the PDF I found but it is the same signal as node 82 which is in the manual. First check is whether the pot changes comparator threshold. Voltage on C7052 should change from 2.8V to 12.9V as you turn the delay pot.

If the delay pot voltage is OK next check is voltage at R7157 & R7152 junction. Looking at the schematic I expect it to be ~ -0.5V when "A ramp" is more that the delay pot voltage and should jump to ~ +1V when it goes below.

If you report back the observations there may be other suggestions.

Ozan
Hi! Thanks! In the end I found the problem: R7069 which lies between a
55VDC supply
and Q7074/Q7075 was cracked and open circuit....It's supposed to be 6.2
kOhm. After replacing it, my 465B works perfectly!

The fault with R7069 turned out to be intermittent. Since it was open
circuit on my first measurement, I just added on 6.2 kOhm in parallel.
However, measuring after that I found 3.1 kOhm across the parallel
combination... So I though perhaps it was a cold solder joint that I had
fixed when tacking on the second 6.2 kOhm. But on closer inspection, I
found the crack, and R7069 was back to being open circuit. So I clipped
it out and replaced it with a correct resistance.

Best regards,
Torquil Sørensen


Re: Tektronix 465B servixe manual containing waveforms 56-70

Torquil Macdonald Sørensen
 

Hi!

Thanks for the link. However, I found that the 468 was essentially the
same as a 465B when it comes to the analog parts. So I could find the
waveforms there, but numbered differently.

In the end I found the problem: R7069 which lies between a 55VDC supply
and Q7074/Q7075 was cracked and open circuit....It's supposed to be 6.2
kOhm. After replacing it, my 465B works perfectly!

The fault with R7069 turned out to be intermittent. Since it was open
circuit on my first measurement, I just added on 6.2 kOhm in parallel.
However, measuring after that I found 3.1 kOhm across the parallel
combination... So I though perhaps it was a cold solder joint that I had
fixed when tacking on the second 6.2 kOhm. But on closer inspection, I
found the crack, and R7069 was back to being open circuit.

Best regards,
Torquil Sørensen

On 26/04/2021 19:26, pdxareaid wrote:
i have a free manual i just checked and it has the same problem. i guess i never really used it.
i use a very good artek pdf manual purchased at http://artekmanuals.com/manuals/tektronix-manuals/
both hi and low serial number manuals available. just enter 465b into search box for options.





Re: Tektronix 465B servixe manual containing waveforms 56-70

pdxareaid
 

i have a free manual i just checked and it has the same problem. i guess i never really used it.
i use a very good artek pdf manual purchased at http://artekmanuals.com/manuals/tektronix-manuals/
both hi and low serial number manuals available. just enter 465b into search box for options.


Re: 485 super weak brightness control

Ozan
 

The node 1312/1318 is 0.0V in A and -0. 6V in B in the 521 mode
0.9V in A and -0. 6V outside of the 521
That looks suspect
I agree this needs to be investigated further. Easy explanation is N4 signal on <11> is wrong but we looked at it before.

--- copied from our earlier exchange --
In sheet <12> N4 is expected to
be -3V in B sweep and 5/2/1n mode. What voltage do you see at N4 when you
are in B sweep vs A sweep 5/2/1n?
I can see -3.6 when 521 is selected, -3. 7 when B is selected and -5.3
when there is A selected and outside of the 521 range
-- end copy ----------------------------------

Confirming again is a good idea.

How do waveforms look in the following points in 521n setting A vs B at:
"A sweep from Q888" left side of R1307
"B sweep from Q1236" left side of R1322

Again we expect no change.

Ozan


Re: Tek 1503C TDR

Harvey White
 

In one of the TM5000 series function generators with an LCD display, I was able to replace the Tek display (with an EL backlight) with a standard 2 line x 16 character off the shelf LCD display.  The two displays looked physically identical with the exception of the EL backlight, of course.

Harvey

On 4/26/2021 11:44 AM, Jeff Dutky wrote:
Judging by the pictures on TekWiki those LCD displays could use replacing even when they were "working."

It looks like the LCD is getting 8-bit parallel data from the CPU with 3 address lines and read and write strobes. The display modules are only referenced using Tek part numbers (672-1241-00 below SN B023854, 118-9050-01 after), but I wonder how hard it would be to decipher that protocol. At the very least you could read the Z-80 assembly that generates the video output straight out of the ROMs.

That would be a lot easier to read with a modern LCD and backlight, or a nice, old-school gas plasma or vacuum fluorescent display.

-- Jeff Dutky





Re: Tek 7844 Alphanumeric Display Issues

 

On Mon, Apr 26, 2021 at 10:56 AM, David C. Partridge wrote:


If you are asking where to find schematics of the EPROM version of the readout
board, I can't help
The RO board wasn't unique to the 7844. I'm pretty sure that some later 7904A's had the same board. I guess (free) SM's are available. I'd look for schematics there.
Just checked: My (ArtekManual's) 070-4593-00 contains two RO versions; one of them is the EPROM-one.

Raymond


Re: 485 super weak brightness control

Ondrej Pavelka
 

Hi,

The horizontal control is -3.6V and -3.7V with A and B. That's very much
ok. It changes to 1.16V when XY is selected

The node 1312/1318 is 0.0V in A and -0. 6V in B in the 521 mode
0.9V in A and -0. 6V outside of the 521
That looks suspect

The node 1358/1356 is 0.545V in A and 0.6V in B and only changes to -0.7V
in XY mode


Unfortunately I didn't have time to pull out the two translators and test
them out

On Sat, 24 Apr 2021, 08:40 Ozan, <ozan_g@erdogan.us> wrote:

Hi Ondrej,
Great news that relays fixed many of the issues, congratulations.

As you know in 521 setting only B sweep is used so if you look at "B sweep
from Q1236" on sheet <11> it should look the same as you press "A" or "B".
Base node of Q1312 and Q1318 select A or B (should be in B in 521
regardless of switch), that node should be the same voltage in "A" or "B"
in 521 mode. Base node of Q1358 and Q1356 select sweep or XY mode, should
also stay the same in "A" and "B".

Once you know which node misbehaves you can find the root case, most
likely in sheet <12> or one of the switches that feed into <12>.

Ozan



Guys,

New Relays arrived and nearly all is healed. When B is selected all works
flawlessly, when A is selected everything works up till the 521 range. In
521 it's not displaying properly. More in the video

I'm so happy it's nearly there now!

https://youtu.be/xCO4kJbXaMw






On Fri, 26 Mar 2021, 01:21 Raymond Domp Frank, <hewpatek@gmail.com>
wrote:

On Fri, Mar 26, 2021 at 12:48 AM, Ozan wrote:


I agree sometimes stepping back and looking with fresh eyes helps.
Let
us know
when you want to bounce off ideas again.
Ozan
I fully concur, Ozan.

Raymond










TM500/5000 plug-in failure modes.

Dave Peterson
 

Hi all,

I'm going through a number of unknown TM500/5000 plug-ins and have encountered a couple that seem to fail in the same mode: a trace to pin 9B of the rear edge connector (33v common) overloads and begins to burn. I had one go completely smoky before I realized what was happening. After that I caught another one in time because I was monitoring the power supplies and saw a drop in the supply (not huge). It still caused noticeable trace damage.

The thing is, some plug-ins load this supply (and pin) and others don't. The one's that don't test just fine. Not that they work necessarily, they just don't go up in smoke. Now whenever I plug-in a unit that does include 33v sources I of course see a load on the power supplies. I don't have sophisticated load monitoring yet, but I do know about the issues with power supplies, pass transistors, and the TM500/5000s tester. For now I just blip the power on and immediately off if I see any load on 33v/17.5vac.

This has also happened on a couple of different power supply units: a TM503 and a TM504. These units test good for supply level, ac phase, and basic pass transistor continuity. I don't have a curve tracer at hand at the moment, but no shorts before and after testing. Also the failure mode does not appear to be on the pass transistor. Though I cannot be certain that the pass transistors aren't involved as I don't have good knowledge of the plug-in internals. But pin 9B isn't a pass transistor pin.

I'm pausing my testing for now until I have this sorted out so I can know the difference between a load on 33v and a plug-in on its way to death.

I'm thinking a current monitor on 33v common, but don't know how I'd implement that. Otherwise I'm left watching the 33v supply - 17.5vac also shows load when this happens. I can't tell the difference (yet), in a quantitative way, between a normal load and impending death. You can imagine, I'm not keen to sit and watch another plug-in load those supplies and wait to see if it's dying or just a normal load. Some of these are valuable.

So my question is, is this "33v common/pin 9B" overload a known thing? And how do I definitively monitor for it? Why the common pin and not the TM504 33v supply (or other) fuse?

I'm new to the TM500/5000 world and I'm trying to catch up. There's a lot out there to review, but I haven't seen anything yet on this failure mode.

Thanks,
Dave


Re: Tek 1503C TDR

 

Judging by the pictures on TekWiki those LCD displays could use replacing even when they were "working."

It looks like the LCD is getting 8-bit parallel data from the CPU with 3 address lines and read and write strobes. The display modules are only referenced using Tek part numbers (672-1241-00 below SN B023854, 118-9050-01 after), but I wonder how hard it would be to decipher that protocol. At the very least you could read the Z-80 assembly that generates the video output straight out of the ROMs.

That would be a lot easier to read with a modern LCD and backlight, or a nice, old-school gas plasma or vacuum fluorescent display.

-- Jeff Dutky


Re: Tek 1503C TDR

Dale H. Cook
 

Good luck - failure of the LCD is a frequent problem in the 1502/1503 A/B/C TDRs. That is why I own a 1503 (as Scotty said in the NextGen episode "Relics", "No bloody A, B, C, or D").

Dale H. Cook, GR/HP/Tek Collector, Roanoke/Lynchburg, VA
https://plymouthcolony.net/starcity/radios/


Re: Tek 7844 Alphanumeric Display Issues

 

We already replied to you that the fault is most likely to be in the auxiliary input of the 2nd Vertical amplifier, and that the readout vertical position pot is R2700 on the vertical amplifier board.

If you are asking where to find schematics of the EPROM version of the readout board, I can't help, but none of the original boards had a vertical position pot on the RO board, and none of the later 80C31 versions did either, so its my bet that the EPROM version also didn't.

David

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of Liam Perkins
Sent: 22 April 2021 05:34
To: TekScopes@groups.io
Subject: [TekScopes] Tek 7844 Alphanumeric Display Issues

I have a 7844, ser. no. B173417, that works fine but for the character
display which is shifted upward 5 divisions, making of course the top
portion of the display invisible.


Re: Cannot delay the B sweep on a 465B

Ozan
 

Hi Torquil,


I have a problem with my 465B where the delay time position 10-turn pot for
the B sweep has no effect. Everything else seems to work. Please see this
youtube video for a demonstration:

https://youtu.be/17ZGEw_jOmo

The intensified portion of the A sweep trace always starts on the leftmost
part of the display no matter how much I turn the delay time position knob.
However, the holdoff knob does make the B sweep duration/length vary, in a
periodic manner as I turn the holdoff knob slowly clockwise.
------
I don't have a 465B but B sweep delay circuit works similarly on several scopes. On sheet <7> Q7067 compares delay potentiometer voltage to "A ramp" voltage. Depending on where ramp crosses the delay pot voltage, B sweep starts with that delay. "A ramp" waveform (node 60) is not shown in the PDF I found but it is the same signal as node 82 which is in the manual. First check is whether the pot changes comparator threshold. Voltage on C7052 should change from 2.8V to 12.9V as you turn the delay pot.

If the delay pot voltage is OK next check is voltage at R7157 & R7152 junction. Looking at the schematic I expect it to be ~ -0.5V when "A ramp" is more that the delay pot voltage and should jump to ~ +1V when it goes below.

If you report back the observations there may be other suggestions.

Ozan


Re: Unable to see some images in 75th anniversary consolidated pdf

 

Dave

Thanks so much.
A real trip down memory lane!

Menahem Yachad

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