[Completed] 2465B Tektronix repair, missing A5 SMD version board....

[Satbeginner]

Hi all,

yesterday I received my (second..) 2465B I wanted to repair through eBay.
I bought it broken, not working, for parts, and although I specifically asked if there were any boards/parts removed from the scope, I received it with the A5 board removed....   
It does have an Option 06 or 09 board in it, I have to look better to see what option it is.

I will file a complaint with eBay, but based on previous exercises with eBay I do not expect anything from that.

Anyway, I still wanted to see how much does function on this machine, so I powered it up and checked the Power Supply voltages.
The 10V was a fraction low, like 9,89V, so was the rest, but when I adjusted the 10V all the rest was within spec as well.

So today I will (temporarily) move the A5 board from my first 2465B to this one, to see what will happen.

Meanwhile, if there is anyone out there with a SMD A5 board they gave up on, please let me know.   

I will update later.

Un saludo,

Satbeginner  (Leo)
 

[Satbeginner]

First test successful!!

With the A5 board from my other scope it does seem to respond.
There is an error "CT TEST 81 FAIL 03" but at least the basic deflection etc. seem to work.

Un saludo,

Satbeginner (Leo)

[grumpydoc]

With the A5 board from my other scope it does seem to respond.

That was brave - hope that you checked the PSU rails etc before plugging in a precious working A5 board. 

[Satbeginner]

With the A5 board from my other scope it does seem to respond.

That was brave - hope that you checked the PSU rails etc before plugging in a precious working A5 board. 

Oh yeah!! For Sure I did!!

But I did hold my breath a while when I switched it on...., but it all turned out well.

At least I now know I have to start looking for a replacement A5 board.
I would not mind finding a broken one, I have time on my hands to fix it....

Maybe someone would like to swap a broken 2465B A5 board for my option board?? 

Un saludo,

Satbeginner (Leo)

[Teknow]

Congratulations! The U800 seems to be OK!

[Satbeginner]

Congratulations! The U800 seems to be OK!

Some luck at least!
In this scope it is a Maxim chip, in my other it is the Tek.

[Satbeginner]

Hi all,

I gave this scope a good cleaning -inside and out- and it is a shame to see this one go unused.
(SN H708xxx, should reasonable young?)

So I either have a lot of spares for my other scope, or I am able to find an unused/broken A5 board I can fix to revive this scope.

Can anybody help me identifying these A5 boards please?

Is the 24xxB version the one with the 3rd, extra bandcable connector in the lower right corner?
Is the 24xx (without the B) the A5 board without this connector?
Is there an 24xxA version of the A5 boards as well?
Is a 24xxB version always the SMD version?
Is the partnumber always 671-0965-0x, where the 0x are just minor changes?

If so, then the 24xxB and other versions of the A5 board are not interchangeable?

I know, a lot of questions, but many thanks for all the help I can get,
Any tips to find an A5 I can use are welcome!

Leo

[Satbeginner]

Hi all,

it's been quite some time, but there is progress again!
Through the "Want to buy, For Sale, Want to Trade" part of this forum I met with a great member who donated me an A5 controller!
Before doing that, he also replaced the 4 suspicious caps, and placed the Dallas in a socket, so if I could get the scope working and calibrated gain, I could replace the Dallas as well.

Anyway, long story short, the scope is up-and-running again, but not yet calibrated.
I was able to perform a (partial, quick-and-dirty) horizontal and vertical calibration, so at that point in time the scope was working again.

Because the Dallas had a 1991 timestamp I decided to replace the Dallas first, before trying a full calibration.

I did not have a programmer to do this, so after reading a lot about programmers able to do Dallas chips, I ordered a MiniPRO TL866CS on AliExpress that arrived today.
This one:  https://www.aliexpress.com/item/MiniPro-TL866-Universal-Programmer-TL866cs-Willem-Bios-Programmer-support-about-13000-chips-IC-High-quality/1946666826.html (I have no links with this seller!)

I installed the software on my Win10 64bit machine, it came with USB-drivers as well, and it works.
The first time I started the program, it gave a message about new firmware and program version being available, so I clicked to install that too.

Now it was time to see if it could read and write the Dallas chips.....
I encountered one minor glitch: you must select a chip-type first, so I selected the "DS1225 (test)" I found in the long list of possible chip-types (>13000), thinking it was the right one.....
Wrong!! This "DS1225-test" erases the chip and confirmed it was working..... So my previous calibration was gone!

After this I looked a bit further and found a second "DS1225 R/W" entry in the MiniPRo program , which was NOT a test, but the real thing.
To be able to do something useful today, I decided to remove the Dallas from my other, still calibrated 2465B to read that data so I could preserve it for future use, this worked.
After that I wrote this file into my new Dallas DS1225 I ordered at Mouser Europe, all OK, nothing weird happening.
Although this new chip has a 2016 timestamp, it should be OK, because it is the newer style Dallas, that will enable the battery only after the first use.

So now I have my second 2465B up-and-running, using the calibration data from my other scope.
This obviously means I have to calibrate it again, but at least I have a new Dallas so it should be good for many years to come, and I have a backup from my other scope.

Things I ran into while calibrating before: I did not have any pulse generator able of generating 1ns and 2ns period pulses so I just skipped these steps by confirming them, so I could go on with the rest of the process.

Attached some pictures of today, and the 2465B Dallas image from my still calibrated scope, if somebody needs it.
(it has a .txt extension, because of the upload limits of the forum)

So far, un saludo,

Satbeginner (Leo)

[Satbeginner]

First test successful!!

With the A5 board from my other scope it does seem to respond.
There is an error "CT TEST 81 FAIL 03" but at least the basic deflection etc. seem to work.

Un saludo,

Satbeginner (Leo)

The "CT TEST 81 FAIL 03" message was caused by the fact there is a Option-06 counter board installed in this scope.
There is a simple "CAL 81" calibration routine that clears this message.

Un saludo,

Satbeginner (Leo)

[woodchips]

Ah, interesting, the option 06 counter board. Just looking through the 24x5 parts mules before scrapping and found what is an opt 06 board, 'counter/timer/trigger'.

Because my scopes are very incomplete, is it just this board, 670-7997-07, that is opt 06 or does it need other or modified boards. Is the option actually of any use?

Thanks.

[Satbeginner]

Ah, interesting, the option 06 counter board. Just looking through the 24x5 parts mules before scrapping and found what is an opt 06 board, 'counter/timer/trigger'.

Because my scopes are very incomplete, is it just this board, 670-7997-07, that is opt 06 or does it need other or modified boards. Is the option actually of any use?

Thanks.

Hi Woodchips,

In my case, the 2465B has the SMD version of the A5 board.
This SMD board is three things in one:
- it is the actual Controller,
- but it also is the display board;
- and it is the buffer board.

So, in my case the 06-option board is place between the side of the scope and the Power Supply, and there are some cables running to it.
There is the wide flatcable, in the middle of the A5 board, that interfaces the buffer-part of the A5 board with the 06-option board.
And there is a flatcable that splits in two smaller flat cables, they connect to the A1 Main board on two places.
Furthermore there is a (8-pin?) dual round shielded cable, also running to the A1 Main board, but at the back of the scope.

As far I can see now, the 06-option can be used for frequency and period measuring, and also as a pulse counter.
When the 06-option is installed in the scope, these functions can be reached by pressing the brown/orange "Measure" button, followed by button nr 4 ("CH4"), it there says "Counter" on the display.

I have read that in other versions of the 2465, with the through hole controllers, there must be a separate bufferboard installed to connect to the option board.
These "older" controllers also have a small, separate display board installed, so I have read.

I will open the scope this afternoon to take some pictures to show the places of the board and the cable routing, etc.
I will post them here later.

Update: Pictures added, they show the location of the 06 Option Board, the split flat cable running from the option to the A1 board, the dual coax cable running from the option board to the back of the A1 board, the Data cable running from the SMD A5 board (with the integrated buffer board on it) and the Display cable from the SMD A5 board (with the integrated Display board) to the A1 board

It looks like there are some jumpers in the two split flat cable receptacles on the A1 board, when there is no option 06 installed. (I'll have to check my other 2465B)

Un saludo,

Satbeginner (Leo)

[Satbeginner]

Hi all,

I decided to install cooling on the U800 as well, especially since in this scope the chip was made by Maxim..... 

Earlier I used a Dual TO-220 heatsink I got from Mouser, so I decided to do the same with this one.
I removed the nut on the side of U800 where the metal tab is.
I made a small, copper, thermal conductive spacer block the size of the metal tab, with the exact same height as the distance from the tab to the outer surface of the chip.
Using thermal conductive paste on the tab, the block and the surface of U800 when placing the block and the heatsink, and putting back the original nut with (roughly) the same torque as before. (I played with Meccano a lot when I was a kid, so it was just using fingertip feeling)

In this case I had to bend three "fingers" a bit in a wing shape, to make room for the flat cable coming from the 06-Option board, but everything is still completely flush with all other parts, so the distance between the outside cover is fully maintained.

Un saludo,

Satbeginner (Leo)

[Satbeginner]

Hi all,

today I consider the repair finished.

I performed a calibration (twice... ), because, after I was finished the first time, I moved the CAL/NO-CAL jumper before switching the scope off, so it came with a TEST 04 FAIL 02...

Anyway, after the (second) calibration I ran some other tests with different signals, and everything is spot on: I am a happy bunny right now.
I was missing one of the little knob covers, but that one is coming as well, so I temporarily put one of my other scopes on this one.

Attached the final result and the contents of my calibrated Dallas.

Un saludo,

Satbeginner (Leo)

[james_s]

Nice job, looks good!

[lanza2005]

Buenos dias Satbeginner. Me llamo Valerio y resido tambien en España. Tengo un Tektronix 2467B, con problemas en la placa A5. Lo mismo de siempre. Las tapas abiertas y el liquido, por la placa. Despues de cambiar las, el TRACE se ve solamente cuando muevo el potencimetro de INTENSITY y luego desaparese. Me puede aconsejar, por donde meter la mano? Muchas gracias y saludos

[Satbeginner]

Hola Valerio,

Si te entiendo bien, ya has cambiado las condensadores en el A5?

Has verificado que todos las conexiones en el A5  están bien también?
Muchas veces cuando hay problemas con las condensadores, hay conexiones en la placa rotos también, eso pr el ácido.

El primer de verificar son las voltages del fuente y especialmente del referencia de 10V.

Y después las dos voltages en el A5 como se describe en el manual de servicio, son las voltages del DAC, -1,25V y un diferencial de 2,5V



Es en el primer parte donde se describe la calibración.

Saludos,

Leo

[lanza2005]

Thanks for the reply. I measured all the currents and especially the + 10v ref. They are just right. I put photos and connections, it refers to tracks from the board. How to adjust the potentiometer? Thank you

[lanza2005]

IMG

[lanza2005]

Forgive me, I don't know how to attach multiple photos

[lanza2005]

IMG

[lanza2005]

Y sobre todo FELIZ NAVIDAD

[Satbeginner]

IMG

Is is described in the service manual, this potmeter is used to adjust the positive and negative voltages used in the "fly by wire" control system of the scope.

In short this is used to adjust the control voltages at a 2.5V difference, going from -1,25V to +1,25V , but more important is the 2,500V difference.

All settings are controlled by an 8bit register counting the 2,5V in 1024 steps. These register values are stored in memory, and used in the power on of the scope. These values are sequentially read and saved in a DA converter, followed by a Sample and Hold circuit.

Some if the SH circuits use the same voltages, and some use a level shifter and amplifier, other use just and amplifier to obtain a bigger voltage range.

In the manual, in the calibration section you will find the description of how to adjust the control voltages using that por meter.

Leo

[lanza2005]

Thank you for answering me so explanatory. If you can tell me more precisely the Calibration pages, which ones are (from which manual), which are several, that I have, I would appreciate it. I am going to measure and deeply examine the steps. And if you have any questions, can I write to you, by PM? Or, if you have an email address? Thank you.

[lanza2005]

IMG

[Satbeginner]

Hi, I have and use an original manual 070-6863-00.
The adjustments you are looking for are in section 5, item 2, Adjust DAC Ref (R2010), in my manual on page 5-3.

Saludos,

Leo