Date   
Re: Calibration after repair

Jelcke de Boer
 

It is in relation to parametric measurement and auto setup not work correctly on my 2465B...

Re: Calibration after repair

Colin Herbert
 

What is this in relation to?
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Jelcke de Boer
Sent: 04 October 2019 16:22
To: TekScopes@groups.io
Subject: Re: [TekScopes] Calibration after repair

Hello,
Same issues here with "Noisy or Aperiodic signal".
Did you resolve this issue?
thanks,
Jelcke

Re: 453a-1 no trace

quadzillatech@...
 

well i found a couple of transistors dead on the z axis board,ive now a trace but its thick and wont focus properly,any ideas where to look?

Re: 7904 with vertical problem

Göran Krusell
 

Hi, quite possible that you have an oscillation here. If so something is broken. What you can do is to measure all DC voltages in this amplifier and compare with the schematic. If you find unexpected voltage levels it would be an indication of instability and oscillation. You can also poke around with a wet fingertip and check if the noise would disappear at some point.
Göran

Re: 7904 with vertical problem

Dennis Turner
 

I know this is a very old thread. My venerable 7904, low serial number, has developed an issue with the vertical output amp. The signal to the plates has a band of high frequency noise about 1 division wide. I think this is an oscillation in the video output stage as it does not appear in the input to the output chip U745. Does this sound correct? Is there a procedure to trim this oscillation out? I see many of the components in the video compensation area are selected so replacing the chip (ebay $50 plus shipping) may not be the answer. I'm afraid getting the vertical working is beyond my capability. I'm a retired electronics engineer but with little analog experience in the digital age.
This scope also has power supply problems with the inverter startup circuit, it delays startup sometimes for minutes after long power off but is not in pulse mode. I have ordered the caps in that area so this should be an easy fix. In addition the readout is inoperative. No pulses out of the timer chip so no readout video at all. I can live no readout as long as it is not effecting the vertical. Any thoughts?

Re: 453a-1 no trace

johncharlesgord
 

The manual for the 453A is available at ko4bb.com. I believe that the 453A-1 is similar.
--John Gord

On Fri, Oct 4, 2019 at 10:54 AM, <quadzillatech@...> wrote:


hi folks,ive got a tec 453a-1 to fix,it has no trace,ive looked at the
voltages on the psu low votlages board and they seem fine as far as i can
tell,all the manuals i seem to get are for a 453 but not the same model,ie
mine has no beam finder button or scale illumination pot,can anyone help on
this.? anyone know where i can get the manual for this,one of the boads has a
1970 date on it so i assume its a late model. manual,cheers m3vuv?

TM500 stuff

ron roetzer
 

I found this ad on CL. the parts are located near Albany NY.

https://nwct.craigslist.org/ele/d/troy-vintage-tektronix-test-equipment/6973803052.html

453a-1 poor astig and focus.

quadzillatech@...
 

Hi folks,ive poor focus on my 453a-1,the hv bias supply is low,any idea where to get new caps for the hv compartment?,cheers Paul m3vuv.

453a-1 no trace

quadzillatech@...
 

hi folks,ive got a tec 453a-1 to fix,it has no trace,ive looked at the voltages on the psu low votlages board and they seem fine as far as i can tell,all the manuals i seem to get are for a 453 but not the same model,ie mine has no beam finder button or scale illumination pot,can anyone help on this.? anyone know where i can get the manual for this,one of the boads has a 1970 date on it so i assume its a late model. manual,cheers m3vuv?

Re: Calibration after repair

Jelcke de Boer
 

Hello,
Same issues here with "Noisy or Aperiodic signal".
Did you resolve this issue?
thanks,
Jelcke

Re: National Instruments GPIB-400

Roy Thistle
 

On Wed, Oct 2, 2019 at 08:45 PM, Arie de Muijnck wrote:


BTW, did anyone ever buy this

The open source is here
I didn't buy one of those units yet; but, reading the description (and looking at the schematic) posted at
https://www.aliexpress.com/item/4000034884174.html
(http taken from Arie's post)
… it appears the "designer" has not included the GPIB driver chips ( these are octal general purpose interface bus transceivers, meeting 488-1978 )…. those driver chips are in Fenrir's design. Instead the Aliexpress unit is relying on the GPIO pins on the C8051F383 (an 8051 based microcontroller with USB). IMHO because of the signal voltage and current sink/drive on some user's GPIB buses, the C8051F380 alone, won't work robustly, to drive a 488-1978 compliant GPIB bus.
A trend I think I've noticed is manufactures (sometimes), users (sometimes), and designers of low cost microcontroller based GPIB controllers (a lot of times) are not paying much attention to the IEEE 499-1978 standard. So GPIB means a lot of things, to a lot of people, in a lot of different and sometimes conflicting ways.
In the case of the Aliexpress unit, the designer already had about 10.00 USD per unit cost... adding the driver chips (which can be something like 2.00 to 4.00) is going to increase the bottom line in cost and complexity significantly, relative to the 10.00 cost. But I'd claim that most of the designer's motivation was that the designer thought that he could "get away" with not adding them... they'd have something that worked most of the time, for most of the sales, at least until they got most of the money... but, maybe that's too cynical.
It seems, from the Aliexpress vendor's description you will have to jam Fenrir's firmware into the unit yourself.
Best regards and wishes.
Roy

[OT] Looking for a CHEAP Metcal WS1 workstand

Alexandre Souza
 

The subject says all =)

---8<---Corte aqui---8<---
http://www.tabajara-labs.blogspot.com
http://www.tabalabs.com.br
---8<---Corte aqui---8<---

Re: Sanity check- is the TM500 interface spacing .150" or .156"?

EJP
 

Agreed. They are if anything underpriced. I have both this and a Tek original cable and I never use the original.

EJP

Re: 7904 excessive shadow/flare

Robert Simpson
 

Strange, my 7904 does not show that kind of flare at normal settings. Initially I did have to fix the HV supply. I also changed out some DC restorer diodes that were leaky. Its been working fine ever since. I have a 7A26 and a 7A19 for now.
Bob

Re: Sanity check- is the TM500 interface spacing .150" or .156"?

Harvey White
 

I have two, and wouldn't part with them.  They're a very good piece of work and well worth the price.

Every once in a while, he might be convinced to make some more.

Considering the two wide plugins there are, two would be rather nice.  Three could be better.

Harvey

On 10/3/2019 5:40 PM, Dennis Tillman W7PF wrote:
The JAMMA extenders have been around for a long time. I made one of them myself even though I already had a Tek TM500 extender. The big advantage of the JAMMA extender is its rock bottom price. It will do just fine assuming extenders are something that you use infrequently.

More recently Dan Meeks <dan-meeks@...> created a much more functional (and gorgeous) implementation of the TM500 flexible extender with several useful debugging features that make it more than just an extender. The price for the kit was also rock bottom: $22 + $7 shipping, and they were available through Amazon. Unfortunately they sold out. I bought one and I was very impressed. It quickly became my favorite extender.

You can still see the original Amazon listing to see what it looks like and read about what it can do at this link:
https://www.amazon.com/dp/B078SY3X1H

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Alexandre Souza
Sent: Thursday, October 03, 2019 2:26 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Sanity check- is the TM500 interface spacing .150" or .156"?

BTW
I did my extender with a JAMMA edge board female connector and a JAMMA edge board used to retrofit older boards (which before JAMMA standard, every single different game had a different pinout/connector) to JAMMA standard

Works well, I have it for decades =)



Re: 7904 excessive shadow/flare

 

I enjoyed this discussion, being not so CRT educated as most people here.

I have a Non-Tek scope, the first one I have where the trace ghost is
actually noticeable enough to bother me.

I started looking for explanations and landed here where the most CRT
knowledgeable people are.

My CRO has 1.9 and 18kV acceleration voltages.

To add a little to the discussion on my oscilloscope in X-Y mode and spot
off centre, out of focus, with a little (optical) magnification the mesh
can be seen as a chess pattern on the wanted spot, the unwanted ghost spot
doesn't show it.

https://www.eevblog.com/forum/index.php?action=dlattach;topic=211046.0;attach=847330;image

https://www.eevblog.com/forum/index.php?action=dlattach;topic=211046.0;attach=847334;image

What is the mesh electrically connected to?



Le dimanche 7 juillet 2019, Ed Breya via Groups.Io <edbreya=
yahoo.com@groups.io> a écrit :

Haha - this tidbit of terminology just popped in from my unconscious
long-term storage. It was called "MSE" for "meshless scan expansion."
Googling the the full phrase quickly got a lot of hits, including this one:

https://patents.google.com/patent/US4137479A/en

Ed



Re: ebay 7104 arrived :-)

@0culus
 

Awesome! Incidentally, I'm also looking for actual manuals for my stuff, so if you find someone who has more than one copy would you drop me a note off list?

Sean

Re: National Instruments GPIB-400

toby@...
 

On 2019-10-03 11:13 a.m., Reginald Beardsley via Groups.Io wrote:
FYI I've decided to commission the design of an OSHW board to plug onto a $3 Arduino Nano with footprints for a BNC, USB B and either a 2x12 0.1" header or a PCB mount Centronics connector. The 2x12 header will allow easily making up custom GPIB cables using ribbon cable and IDC connectors. I made a 2 device adapter using an Uno. Soldering the ribbon cable to the Uno was quite a pain because of the way the cable mapped to the pins. Hence the 2x12 header.

The BNC is for a strobe signal for the 34401A and similar and the USB B to provide a more robust connector than the mini USB on the Nano.

A later version will use the Mega 256 with relays, T&H, RTC, etc.

My intent is to make OSSW/OSHW GPIB-USB-HS adapters available for <$10 without the need to find old GPIB cables.

The chap I'm having do the board is pretty busy with a couple of other projects, so it may be a while before the board design gets posted online.

The Nano will handle 10-12 GPIB devices as the 328P operates at 5V and can source or sink 40 mA per pin. At $3 + connectors for a GPIB-USB-HS adapter, the ATMEGA 328P deserves more respect than I had been giving it. They make great glue for old TTL interfaces. Most other MCUs won't drive TTL loads. Interestingly, the Nano is cheaper than a single IDC Centronics connector.
I also did a Nano-based GPIB project, but using driver ICs:
https://github.com/qu1j0t3/gpib-adapter


AR488 is an extension of the Prologix command set. ...
Reg



Re: Sanity check- is the TM500 interface spacing .150" or .156"?

Vince Vielhaber
 

Something to be careful about with the JAMMA extenders; they sometimes tie A & B sides together at the high number end, where the interconnect pins are. I had ICs popping their tops in an FC-501 because of it. Fortunately it was going to be parted out anyway, but I also remedied those pins that were tied together before anything else was plugged into it.

Vince.

On 10/03/2019 05:40 PM, Dennis Tillman W7PF wrote:
The JAMMA extenders have been around for a long time. I made one of them myself even though I already had a Tek TM500 extender. The big advantage of the JAMMA extender is its rock bottom price. It will do just fine assuming extenders are something that you use infrequently.

More recently Dan Meeks <dan-meeks@...> created a much more functional (and gorgeous) implementation of the TM500 flexible extender with several useful debugging features that make it more than just an extender. The price for the kit was also rock bottom: $22 + $7 shipping, and they were available through Amazon. Unfortunately they sold out. I bought one and I was very impressed. It quickly became my favorite extender.

You can still see the original Amazon listing to see what it looks like and read about what it can do at this link:
https://www.amazon.com/dp/B078SY3X1H

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Alexandre Souza
Sent: Thursday, October 03, 2019 2:26 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Sanity check- is the TM500 interface spacing .150" or .156"?

BTW
I did my extender with a JAMMA edge board female connector and a JAMMA edge board used to retrofit older boards (which before JAMMA standard, every single different game had a different pinout/connector) to JAMMA standard

Works well, I have it for decades =)



Re: ebay 7104 arrived :-)

Reginald Beardsley
 

Mel,

I've downloaded some of the PDFs, but not yet all. I have manuals for all my other gear. Many as PDF though I will probably get or print paper copies as that is much more convenient when working on the stuff.

What I *really* want is schematics and other component level repair data for the 11801. My understanding is that the museum has them, but the lawyers have not cleared them for release.

I'm collecting parts to allow me to measure bit skew for DSP pipelines on the Zynq and cyclone V FPGAs to create open source firmware for DSOs based on those chips. I've got four SD-26 heads so I just need to convert the differential 100 ohm high speed PMOD outputs on the Zybo Z7-20 to single ended 50 ohm. And find 8 cables which are close enough to the same lengths. I figure that my best shot is to buy 2 dozen SMA-M RG402 cables and pick the most closely matching pairs. Then use the delay adjustment for each head.

My goal is stackable math and filter pipelines a la LeCroy but with considerably more flexibility. Once I've written the FPGA code I'll start back to work on hijacking COTS DSOs from Siglent and GW Instek using the Zynq. I was making good progress on that until I accidentally fried the SPI flash chip while trying to sort out the factory programming header. I've not yet worked up the nerve to try to replace the chip. Hopefully I just fried that one cheap part and not the Zynq.

The motivation of this is the same as buying a 485 and a 7104. I do *not* like ringing on steps. As neither Keysight nor Rohde & Schwarz offer scopes which will do what I want even for $20K I decided to do it myself. Marketing wants to claim BW all the way to Nyquist and the unavoidable consequence is ringing on a step. For a decent edge you have to accept 50-70% of Nyquist as the -3dB corner.

I've never programmed an FPGA, but I spent my career in the oil industry doing DSP on general purpose computers. I did have a run in with an FPS-120B attached to an 11/780 once. So I'm familiar with the ugly side of DSP. And 20 years ago I wrote a parallel DSP code to run on an MPI cluster which required close to 2000 hours of work. I wrote *all* of it. So I do understand what I'm taking on.

Have Fun!
Reg