开云体育

I am still waiting for some advice.
In the mean time I checked for poor connection solder joints.
Clean the A4 timing board.

On Sun, Mar 30, 2025, 8:42 AM Saroj Pradhan via groups.io <sarojman.Pradhan=
[email protected]> wrote:

I was working on 2230 which has power supply failure.
Changing the main bridge rectifiers CR901... CR904, Q9070 and Cr907
restored the power supply. The scope power ons with an issue CDT issue CDT
value changes from 73 to 77 during different sessions of power on.

After pushing the one of the menu scrolling key CDT goes off.
I have following display issue:
1. No trace
2. Readout tex for volt/div and sec/div display.
3. Intensity and focus works
4. Sec/div switch in A mod doesn't work.
I can see only 50m 5ns and. 2s changing the position of switch.
5. Horizontal position switch works but only for half portion of the
screen.
What I did so far.
1 since there is no trace just a dot I started to
Look for horizontal section.
2 looked for ramp signal at waveform 24 and 29 but I could not see any
just a dc offset.
3 decided to clean the sec/div switch so according to the instruction I
pulled out A4 board which contains sec/div switch. In the A4 boaed I found
strange connection. Collectors of q742 and q732 are tied together and
connected to A sweep input of U760 while B sweep input is left floating.
I will be thankful if some one in this forum suggest on this issue and
guide me to resolve the issue of my scope.
Thanks
Saroj

Hi Thomas. Long time. How are you? Thanks for the link.

New eBay link:



-Thomas

On Wed, Apr 9, 2025 at 11:53 AM, Giuseppe Marullo[iw2jww] wrote:

RECAPPING
Of course, if I have someone to recalibrate it, I may well think of
recalibrating it AFTER recapping.

I'm very interested in the topic of 'recapping.'
I know there was a problem with some brands of electrolytic capacitors, coming from China, circa 1999... and that has an effect on those things manufactured that used them... mostly from China.
Yet...IME... what I have seen is more damage to the PCB, then good.

What's the motivation for ordering a capacitor 'kit'... and doing 'shotgun' replacement of capacitors?

IMO... if one does not take the time to test... for a bad component... and then to identify, and specify the appropriate component....
Well how do you know, you are not replacing something, with something that is worse?
Also... but importantly, using inappropriate de-soldering, and soldering tools, and supplies, risks damage to the pcb... which might not be trivial.

--
Roy Thistle

If you have an A or B series, you can get the calibration values back in the NVRAM with this utility (or with GPIB, if you have the equipment):

/g/TekScopes/files/24xxAB-writecal-1.1.zip

The only way to get them back into a 2445/2465 (plain) that I know of at the moment is via the optional GPIB interface (OPT 10). A similar utility to the above for A/B versions could be developed for 2445/2465 scopes, but ER1400 failures are far and few between (unlike dead batteries), and virtually no one has backed up their 2445/2465 cal data so it can be used with such a utility. If you have a backup of your cal data and are trying to get it back in the ER1400, please speak up!

The above zip archive has demonstration code in ./related/earom.c on how the Tek "spiral add" checksum algorithm works on the 2445/2465, plus how parity is calculated for the range of locations that include parity. So, you might be able to determine the offending entry by putting your EXER 02 data in the code.

If you want to post your 2465 EXER 02 data, we could also look at it together in this thread.

Theoretically, you could force the scope to recalculate the checksum by performing a calibration step, such as CAL 04, where you don't actually modify anything and then exit the cal procedure. I haven't tried this, but keep in mind if you do you're ignoring bad cal data that could affect the scope's operation.

From a reliable source, I am told there is an undocumented screen utility similar to EXER 02 for *entering* the data, but the person I spoke to can't recall how it was done. More work with a better logic analyzer (which I have now), and/or analysis with Siggi's 2465 Ghidra image and 2465 MAME simulator may find the answer. It's on my to-do list.

-mark

Hello Paul
thanks for the info I have just ceck the 100 Mhz oscillator but thats up and running ?
any other problems to check ?
best regards
Hubert

Jon,
many thanks but:
1) I have hopefully a good capture video of all the CAL 02 values.
2) I found a lab that claims they have all the required equipment to fully calibrate it

I was wondering:

a) if there is a method to be certain that the values I captured in video can be checked against the checksum(no GPIB card). I have found a source code for the spiral checksum but not sure how to apply to the data. Not much of a cryptologist, but still can code something.

b) assuming I will make recalibrate it in the lab (still deciding about it) I would like to recap the scope prior to recalibrate it. So I am looking for a BOM for Digikey or Mouser. a reasonably priced kit (price+customs and so on, shipped to Italy) can be a viable option.

Hope it is more clear.

--
Giuseppe Marullo
IW2JWW - JN45RQ

Dear tektronix fans


To introduce myself Hubert ON6JZ living in Belgium and an electronics
repairer for 45 years
I now have a tektronix 2712 on the table that does not work.
It has been idle for over a year.
At startup it gave all kinds of error messages , after replacing both
batteries on the digital board and on the digital option board it seems to
start up normally ,
But I get no response from any button and the encoder does nothing either
All supply voltages are correct and viewed cleanly with a scope
I replaced all the smd electrolytics on the sweep board and on the digital
storage board
No result
On the screen I get an image of out of memory.
Does anyone have any tips on where I can look for this error?
Thanks in advance



Hubert

What do you do with the values read from CAL/EXEC function. is there a way to enter/change them?

I am asking as I have a 2465 as well that just had 04 10 which is describes by Tektronix as just out of cal (guessing old data or checksum fails. ER1400 can hold data for 10+ years) but TBH the cost of calibration if you dont have the very specialised TMG is not worth it for a scope this age (my opinion as you can by newer versions for 3-500GBP) or go crazy old skool and aim for 4xx series IF BW is the issue.

I am for fun experimenting with reading the data out of the ER1400 (potentially replacing is if it is bad - I got like 10 spare ones). I am not too fuzzed about accuracy as I have digital never scope as well if needed).

Just curious to understand the logic behind what is stored in ER1400, checksums, etc and if it can be trigged into thinking it is calibrated and don't fail on selfcheck.

Cheers.

Giuseppe

For the parts, contact me
yachadm AT gmail DOT com

Menahem

Giuseppe,

I did post a photo of the parts list for my higher s/n B model. The part prices and some parts will be different. Maybe some parts will have to have a different series due to Nichicon stopping production of some series.

Mark

Check to see if the 100MHz oscillator has output. It is just to the right of the CRT looking from the front.
If there's no output then that is likely the source of the issues, but may be other problems also.

Best,
Paul

Old A 5 bd, battery backup, easy to change

Use EXER function to read RAM cal.values, or gpib bus f has the option

CAL requires correct test equipment, see service manual

Usually a complete Cal is required

On forums many threads on 2465/7/AB cal.

Jon

CHECKSUM
I would kindly like to know, assuming I dumped correctly the CAL 02 values, if there is a sound method to verify the checksum for my scope before fiddling with the battery.
Any pointer before I get mad with X-Way forensics editor?

I found a guy that could re calibrate it for 300EUR (maybe 250, we have two scopes) so I could just avoid the hassle to change the battery myself and/or switch to FRAM. It seems it could even be a reasonable price, I don't know.

RECAPPING
Of course, if I have someone to recalibrate it, I may well think of recalibrating it AFTER recapping.

Is there any current BOM for Digikey/Mouser available?

TIA.

--
Giuseppe Marullo
IW2JWW - JN45RQ

Dear tektronix fans

To introduce myself Hubert ON6JZ living in Belgium and an electronics repairer for 45 years
I now have a tektronix 2712 on the table that does not work.
It has been idle for over a year.
At startup it gave all kinds of error messages , after replacing both batteries on the digital board and on the digital option board it seems to start up normally ,
but I get no response from any button and the encoder does nothing either
All supply voltages are correct and viewed cleanly with a scope
I replaced all the smd electrolytics on the sweep board and on the digital storage board
No result
On the screen I get an image of out of memory.
Does anyone have any tips on where I can look for this error?

Thanks in advance

Hubert

If anyone is interested in old GPIB adapter hardware and has a USA mailing address, I can offer for free:

- HP 27209-60001 GPIB 8-bit ISA card, or

- IOTech Micro488/EX Bus Controller (this is a bi-directional RS232<-->GPIB gateway), w/power adapter and manual

Either (or both, if you can use both), would be for the cost of postage on a USPS flat-rate box. You would email me a label.

Either can be used to do the cal backup, and communicate with other GPIB/HPIB/IEEE-488 equipment. They're not doing anything here except collecting dust for years. Please contact me off-list if interested.

-mark

I run Linux with the linux-gpib driver, which from personal experience works fine with the NI GPIB PCI card and the Keysight 82357B.

For windows, I'm certain other users can jump in with some recommendations. Steve Hendrix, a user on this group, has a product called the KISS-488, but I have not used it: . There are a number of open source GPIB (aka IEEE-488) adapters, such as the AR-488, if you are looking for something more home-brew.

If you are asking specifically about the cable, I would recommend getting a used HP 10833A/B/C/D cable. They come in various lengths depending on the suffix letter.

Note that GPIB functionality is very limited on the 2445/2465 (plain)/A/B and 2467 scopes and only provides basic control and can also return measurement values. It does NOT allow you to download a copy of the displayed waveform, if you are expecting that. So, if you have a GPIB interface laying around, it's handy to use for calibration backup, but I probably wouldn't go out of my way to get one just for backup.

For the software on the PC, you just need to be able to send a command and capture the output to do a cal backup. All adapters have this capability in their host software. No one has written any special application for backing up these scopes, as far as I know.

-mark

On 2025-04-09 9:40 AM, Alex wrote:

I know there are those rather pricey HP GPIB to USB adapters floating around ebay for $100 and plus.

Well, my KISS-488 is one of those "pricey" adapters, at $129 single piece via my www.hxengineering.com, but it does way more than just USB. USB/serial at 115.2 KBPS, Telnet, HTTP (any standard browser), SNTP (sets a local clock, to timestamp data it records and graphs), ICMP (so you can ping to confirm connection), and TFTP (for firmware updates). And I've recently added some "quantity purchase" options as well. Best of all, it's as close to obsolescence-proof as I could make it - no PC side drivers to load, indeed not even tied to PC, as one of my beta testers uses it with an Apple. Just a lot of standard protocols that are well establish and not likely to go away soon. Others have suggested the roll-your-own approach, but I'm here to tell you it takes a lot more than it first appears, and I'll never make enough on it to justify the amount of time in it. But I mode it for my own use and decided to share it to help keep these old boat anchor precision instruments alive.

Pardon the sales pitch, but I only mention it when directly applicable to solve a list member's need. I'll shut up now, and any queries should be taken offline directly to me at SteveHx@....

Steve Hendrix

Yes, it also works with the 2465 (meaning not A or B versions).

With the 2445 or 2465, you will get 200 calibration values returned instead of 256. If you don't have any options installed, I believe it will only return 100 values because the second EEPROM (EAROM) resides on the options card cage which is only installed if you have options.

-mark

Just for completeness of the information, what kind of cable is needed to do the GPIB backup into a windows PC?
I know there are those rather pricey HP GPIB to USB adapters floating around ebay for $100 and plus.
Would that be the correct cable type?

And what software is needed in the PC?