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Re: GPIB Connection to 2340A - Response garbled #photo-notice

unclebanjoman
 

Are you sure you're transmitting the LF terminator at the end of the command string? If you send CR/LF pair as line break, the scope can get confused.
Your scope is set to use EOI/LF termination. I suggest to set it to EOI only.
Doing so, you can transmit the ASCII commands without any CR/ LF pair. The response from the scope will be with no CR/LF also, in this way you have to count the characters received and eventually append the CR/LF before to show the response string on the screen.

For a long time I have been working on programs written by me in C/C++ that use GPIB, in conjunction with HP/Tek instruments and I always use EOI as end of transmission signaling.
This way, I avoid to worry about how CR and LF are translated by the various operating systems.

I am not familiar with the Mac OS but being a Unix derivative, I assume that any string that is sent to the transmitting device will automatically contain the LF character appended as line break/ terminator. This is, if you uses a stream device configured as "text". If you do not want the LF character to be added to the end of each transmitted (or received) string, you must remember to open the stream in "binary" mode (no CR or LF translation in input / output).
In Windows the line break terminator is a pair of CR/LF. In Linux/Unix LF only. First Mac (Apple Macintosh!) used CR only as a line break!

Max


Re: Tek 2230, almost fixed but with a problem out of my competences

Pitpat
 

EDIT
Yes all my measurements were taken in Store mode on EXT sweep setting
Im thinking once again to replace U780 and U781 the last one will be a huge PITA since no easy access to the solder joints is available.


Re: Tek 2230, almost fixed but with a problem out of my competences

Ozan
 

On Wed, Jun 9, 2021 at 07:29 AM, Albert Otten wrote:


-3.5 V is about right for that center tapped voltage. There were some time/div
settings (20 ms, 10 ms/div for instance IIRC) where the readout was correct
and where U781/1 must be open drain and U781/6 about -7.9 V (the HOR REF
voltage). Such a setting might show what's going on when CAL is rotated ccw.
U781/1 might jump from some ares2 value to -8.6 V when HOR REF approaches -3.5V
--
If these measurements are in "Store" mode: According to the schematic Variable Horizontal (CAL) pot is not used in "Store" mode, instead 1K/4K switch selects two extremes of Variable Horizontal control.
Ozan


Re: 453 LVPS Isolated from Chassis?

Wayne
 

That would be my guess--ground loops/noise.


Re: Tunnel diode pulses for calibration fixture

Torch
 


Re: GPIB Connection to 2340A - Response garbled #photo-notice

Joerg
 

Yippie - that was too easy!

'ID TEK/2430A,V81.1,"18-JAN-90 V2.31 /2.5"\r'

Oddly, when I tried again now - the scope actually beeped on the request and said: "Unknown Symbol". I have no idea why that was not the case the first time around. I had expected a sensible error message like that.

Thanks for the quick reply.


Re: Tek 2230, almost fixed but with a problem out of my competences

Albert Otten
 

-3.5 V is about right for that center tapped voltage. There were some time/div settings (20 ms, 10 ms/div for instance IIRC) where the readout was correct and where U781/1 must be open drain and U781/6 about -7.9 V (the HOR REF voltage). Such a setting might show what's going on when CAL is rotated ccw. U781/1 might jump from some ares2 value to -8.6 V when HOR REF approaches -3.5 V .
Albert


Re: Tek 2230, almost fixed but with a problem out of my competences

Ozan
 

On Wed, Jun 9, 2021 at 04:42 AM, Pitpat wrote:


EDIT. tested the wrong pin, I've got 0.6v (counting from the front near R702)
and -3.5v (counting from the backside near R733)
--
Figure 9-14 shows PCB component placement. Square pins are usually pin1, R701 pin1 location is away from R702. Looks like you are measuring 0.6V at pin6, and -3.5V at pin5.

What equipment do you use for the measurement since you mentioned a home made probe? It is important to know the loading of the probe (e.g. 1M-ohm or 10M-ohm).

With -3.5 at pin5 of R701 (=pin6 of U781), pin1 of U781 should be in open drain state but you are seeing -8.5V. As Albert said this points to a problem with U781. While you are turning time/div knob, is pin1 of U781 always stuck at -8.5V or does it change at all?

If you have access to board A13, connector W1304-6 is the same signal. Measuring W1304-6 checks if this is a connector issue. Fig 9-15 shows pin1 of W1304-6 is the leftmost pin.

Ozan


Re: Space needed

Ke-Fong Lin
 

Alan, I'm sure you don't need all 3 of the 7A13.
I would be interested by one, and may be a 7D15.
I'm in France, near Paris.


Re: Tek 2230, almost fixed but with a problem out of my competences

Pitpat
 

EDIT. tested the wrong pin, I've got 0.6v (counting from the front near R702) and -3.5v (counting from the backside near R733)


Re: Tek 2230, almost fixed but with a problem out of my competences

Pitpat
 

Done! It should be around -7.8v (consider some probe resistance since i had use a jerry-rig made probe).
Im not quite sure it was pin 5 though from were should i start counting? (I started from the frontside of the scope)


Re: GPIB Connection to 2340A - Response garbled #photo-notice

 

On Wed, Jun 9, 2021 at 11:38 AM, Joerg wrote:


inst.query("*IDN?")

Any help is greatly appreciated.
The 2430A may not understand *IDN?. Try ID? instead.

/Håkan


Re: Space needed

Dave Voorhis
 

Alan A., if you are interested in selling one or more of the 7623A and a
7A13 and a flexible extender, please email me.

I'm in the UK.

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of David C.
Partridge
Sent: 09 June 2021 10:57
To: TekScopes@groups.io
Subject: Re: [TekScopes] Space needed

All sold to Alan A.

David

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of David C.
Partridge
Sent: 06 June 2021 11:04
To: TekScopes <Tekscopes@groups.io>; Tekscopes2@groups.io
Subject: [TekScopes] Space needed

I have a large number of 7000 series PIs (sorry no 7CT1N) and three
mainframes which are taking space that I could usefully use for other stuff.
All is in GWO and to specification.

The mainframes are:

1) 7104 B084650 with 2 * 7A29, 7B10, 7B15 slight screen burn in readout
area only
2) 7854 B052922 with 7A24, 7A26, 7B80, 7B87
3) 7623A (think of it as a later version of the 7633)

In addition to the above I have the following working PIs:

2 * 067-0587-02 Standardisers
2 * 7S12 sundry heads
3 * 7S11 and heads
1 * 7T11 (modified to be 7T11A)
1 * 7T11A
1 * 7M11
1 * 7A11
3 * 7A13 (late)
1 * 7A16A
3 * 7A29
2 * 7A22
4 * 7A26
1 * 7A19
3 * 7B53A
1 * 7B71
3 * 7B80
2 * 7B85
1 * 7B90P
2 * 7B92A
1 * 7B10
1 * 7B15
1 * 7D11
1 * 7D15

I also have number of spares mule PIs.

I have the paper service manuals for at least the 7104 and 7854 and many
other MFs and PIs - may also have the 7623A manual.

The 7104 and 7854 live on a Model 3 lab cart which is also available.

I also have flexible and rigid extenders.

If you are in UK and can collect, I am open to sensible offers (I'm not
about to accept low offers).

If you are seriously interested (particularly if you want all of them)
please contact my off list at [mailto@david.partridge@perdrix.co.uk]

I'll miss them if they go as they have served me very well.

David


Re: Tek 2230, almost fixed but with a problem out of my competences

Albert Otten
 

Can you access network R701 pin 5 (in stead of U781 pin 6) for measurement during operation? Albert


Re: Space needed

 

All sold to Alan A.

David

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of David C.
Partridge
Sent: 06 June 2021 11:04
To: TekScopes <Tekscopes@groups.io>; Tekscopes2@groups.io
Subject: [TekScopes] Space needed

I have a large number of 7000 series PIs (sorry no 7CT1N) and three
mainframes which are taking space that I could usefully use for other stuff.
All is in GWO and to specification.

The mainframes are:

1) 7104 B084650 with 2 * 7A29, 7B10, 7B15 slight screen burn in readout
area only
2) 7854 B052922 with 7A24, 7A26, 7B80, 7B87
3) 7623A (think of it as a later version of the 7633)

In addition to the above I have the following working PIs:

2 * 067-0587-02 Standardisers
2 * 7S12 sundry heads
3 * 7S11 and heads
1 * 7T11 (modified to be 7T11A)
1 * 7T11A
1 * 7M11
1 * 7A11
3 * 7A13 (late)
1 * 7A16A
3 * 7A29
2 * 7A22
4 * 7A26
1 * 7A19
3 * 7B53A
1 * 7B71
3 * 7B80
2 * 7B85
1 * 7B90P
2 * 7B92A
1 * 7B10
1 * 7B15
1 * 7D11
1 * 7D15

I also have number of spares mule PIs.

I have the paper service manuals for at least the 7104 and 7854 and many
other MFs and PIs - may also have the 7623A manual.

The 7104 and 7854 live on a Model 3 lab cart which is also available.

I also have flexible and rigid extenders.

If you are in UK and can collect, I am open to sensible offers (I'm not
about to accept low offers).

If you are seriously interested (particularly if you want all of them)
please contact my off list at [mailto@david.partridge@perdrix.co.uk]

I'll miss them if they go as they have served me very well.

David


Re: GPIB Connection to 2340A - Response garbled #photo-notice

 

To increase reference value for posterity, you may consider changing modelno. to 2430A.

Raymond


GPIB Connection to 2340A - Response garbled #photo-notice

Joerg
 

Hi all,
I've been trying to use use GPIB interface on my 2340A and had only limited success so far. I've bought a Prologix GPIB-USB adapter for the task. I can connect to the instrument and send commands that show up on the debug screen - see https://groups.io/g/TekScopes/photo/263696/3241684?p=Created,,,20,2,0,0 - here just asking for the instrument to identify. The response, however, is not intelligible. The settings I've used on the scope are here: https://groups.io/g/TekScopes/photo/263696/3241685?p=Created,,,20,2,0,0

And the python code I've used is

import pyvisa
rm = pyvisa.ResourceManager('@py')
inst = rm.open_resource('ASRL/dev/cu.usbserial-PX4QY88I::INSTR')
inst.baud_rate = 9600
inst.read_termination = '\n'
inst.write_termination = '\n'
inst.timeout = 2500
inst.encoding = 'latin-1'
inst.query("*IDN?")

and which returns 'ÿ\r'

setting the instrument encoding in python to 'ascii' (the default) instead of 'latin-1' results in an error as byte 0 cannot be decoded. I'm working a Mac and would like to keep working in python and the http://www.ke5fx.com/gpib/readme.htm toolkit is Windows only.

Any help is greatly appreciated.


Re: Tek 2230, almost fixed but with a problem out of my competences

Pitpat
 

I see, so you keep workshop notes, thats cool! I should start doing that too.
For good measure I deoxied (with the Italian version of that :) ) all the switches and gived them a good wiggle but nothing.
Federico


Re: 576 Curve Tracer FET Adapter Differences

Michael W. Lynch
 

Dan,

You are correct! Upon closer examination, what first looked like small rivets were actually shallow headed hex screws. I was able to get it apart. Upon opening the unit, it was then possible to gently push the PC board down and the little ferrule would make connection while you held slight down pressure. So I knew something was amiss. After carefully pulling the PC board, I found that one of those little pins that you were speaking of had been previously broken off and was already completely missing. So there was no connection at one pin. I was able to rig up a suitable repair and make the thing work. Now it operates as it should. THANK YOU for the good advice.

Sincerely,

--
Michael Lynch
Dardanelle, AR


Re: 576 Curve Tracer FET Adapter Differences

Dan G
 

On Tue, Jun 8, 2021 at 10:00 PM, Michael W. Lynch wrote:

Is there any way to open this adapter? It appears to be sealed and
non-serviceable.
That is odd. Every adapter I've seen (both 013-0098 and 013-0099) has
a set of six 5/64" hex head screws accessible from the bottom of the
adapter. Perhaps Tektronix switched to a snap-in design at some
late stage without changing the part number? If so, I wouldn't hazard
a guess on how to open the enclosure without damage.

If you do manage to open the plastic enclosure, I do have one word
of warning: the PCB inside is probably sitting on a set of six very thin
pins that protrude from the rear ends of the banana plugs. If you need to
remove the PCB, lift it very carefully and evenly upwards, so as to avoid
tilting the PCB and breaking the pins. I find that one end of an IC puller
works well to slowly work around the edges of the PCB as it is
gradually pulled up.

Best of luck,
dan

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