Author Topic: Tektronix 2465B oscilloscope teardown  (Read 747180 times)

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Offline JSC

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1900 on: September 22, 2024, 06:17:33 am »
Any way to manually read the contents of the NV RAM before unsoldering it?

John
 

Online tggzzz

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1901 on: September 22, 2024, 08:52:52 am »
Any way to manually read the contents of the NV RAM before unsoldering it?

John

One of the tests dumps the 256 bytes to the crt.   RTFSM for details :)
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
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Offline Homer J Simpson

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1902 on: September 23, 2024, 04:48:33 am »
2465B SN's

Greetings,

I am interested in finding out what the latest serial numbers were for Beaverton produced 2465B's

My latest unit is BO64879

I think once a saw a listing for a BO7xxx something.

Does any one now how far these got and what was the actual last year of production ?

-K
 

Offline calibrationfixture

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1903 on: September 23, 2024, 06:08:39 am »

I think once a saw a listing for a BO7xxx something.


Hi,

Maybe you saw a H70xxxx (Heerenveen) listing. My latest production 24xxB Scope is a 2455B (J301046) with parts dated 9434 (year 1994, week 34) etc. Last (?) Product Catalogs in which only the 2465B and 2467B are listed are 1995 and 1996. The 1994 Product Catalog lists the 2445B, 2465B. 2467B and 2467BHD. Nothing about the 2455B, 2456BHD (listed recently on eBay) and 2466BHD.

Calibrationfixture
« Last Edit: September 23, 2024, 06:54:29 am by calibrationfixture »
 

Offline JSC

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1904 on: October 06, 2024, 03:19:14 am »
2465B SN's

Greetings,
I am interested in finding out what the latest serial numbers were for Beaverton produced 2465B's
My latest unit is BO64879
I have SN B067580.

John
 

Offline JSC

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1905 on: October 06, 2024, 03:28:24 am »
Any way to manually read the contents of the NV RAM before unsoldering it?

John

One of the tests dumps the 256 bytes to the crt.   RTFSM for details :)

Found it. Page 6-10. I have copied the 256 bytes onto paper. The next question: Where in the DS1225 address space is the starting address? I don't want to risk clearing the RAM when I unsolder the chip.

John
 

Offline calibrationfixture

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1906 on: October 25, 2024, 03:22:07 pm »
Hi Homer J Simpson again,

Looking for some information on TekScopes I noticed this in a Thread:

" On Wed, Apr 22, 2020 at 03:31 AM, victor.silva wrote:

Yes, after around serial number B066xxx (guesstimate) Tek started conformal
coating their A5 assemblies.
The latest serial number on a 2465B, that I have seen, is B079xxx, from 1996.
The early B051xxx A5s had already started leaking, so the conformal coating
was their solution. "

Calibrationfixture
« Last Edit: October 25, 2024, 03:24:00 pm by calibrationfixture »
 

Offline ninja_zx11

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Re: Tektronix 2445A High voltage A2 board cap part no.
« Reply #1907 on: November 02, 2024, 03:44:58 pm »
Hi all,

Last night , I turned my 2445A (assuming 2465B shares the same board) after long time and within 10 mins, saw smoke coming out from the rear but it was still functioning. So I turned it off and opened it. Found 2 caps (.068) and 1 resistor(68) smoked. Could any one please give me the part no. so that I can order and replace. Around 10 years ago, I swapped the complete power supply board with recapped one. But it looks like they never replaced these caps. I am attaching the pics. Thanks.
« Last Edit: November 02, 2024, 03:55:09 pm by ninja_zx11 »
 

Offline AMR Labs

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1908 on: November 02, 2024, 04:14:22 pm »
Very common scenario, specially if scope is operated in a 240V country, but environment humidity also becomes a big factor once those caps start developing the fine cracks.
It happened to me even tough I am on 120V.

Just replace both RIFA caps with non-RIFA branded same spec film caps 0.068uF but ideally higher voltage, say 350-400VAC (instead of just 250V as where the original caps), and make sure to only use X2 line safety rated caps.

You also have a burned resistor R1016, replace with 68-ohm 1/2w, to the left of the top RIFA cap in your picture. Thanks to it things stopped there with it sacrificing itself. Make sure to also check R1019 (I think it is) which is the other series resistor of the other cap, seems like 30-ohms (your pic of the schematic is a bit difficult to read), as this other resistor may have also gone open circuit.
 

Online tggzzz

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1909 on: November 02, 2024, 04:25:11 pm »
Common indeed :(

Condoraudio has a pdf describing recapping, and sells recapping kits on fleabay.

Also check the A5 board for SMD electrolytics; IIRC they are 24x5B only.

Watch out for the battery backed RAM failing and losing the cal constants.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Offline ninja_zx11

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1910 on: November 02, 2024, 04:30:48 pm »
@AMR Labs:  Many thanks for the reply. I am also on 120V 60Hz supply.  Caps i found https://www.mouser.ca/ProductDetail/594-222233810683
Regarding 68ohm  and 30 ohm 1/2 watt resistors, is there any special kind of resister needed or just generic 1/2 watt would do.

@tggzzz: I believe I bought the refurbished A2 board from him 10~11 years ago.  Yes I did all other recommended caps , battery and also installed heat sink on some rare IC at that time IIRC.


 

Online tggzzz

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1911 on: November 02, 2024, 04:37:48 pm »
Good stuff :)

Any correct wattage or bigger resistor will do; it is principally used to limit inrush current.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Offline ninja_zx11

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1912 on: November 02, 2024, 04:41:15 pm »
Thanks!! I am gonna order.
 

Offline calibrationfixture

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1913 on: November 03, 2024, 02:03:38 pm »
Hi,

I use these 1W Resistor Replacements (Mouser PN's):

660-MO1CT52R150J and

660-MOS1CT528R680J

I should also replace both 15R 1/2 Watt Resistors (R1352 and R1353) around Q1351. On half of the A2A1 Boards I came across these look very stressed (to the limit of their dissipation).

Calibrationfixture




« Last Edit: November 03, 2024, 02:05:52 pm by calibrationfixture »
 

Offline ninja_zx11

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1914 on: November 03, 2024, 03:49:53 pm »
I will order these resistors as well. Thanks.
 

Online factory

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1915 on: November 03, 2024, 03:57:16 pm »
Hi,

I use these 1W Resistor Replacements (Mouser PN's):

660-MO1CT52R150J and

660-MOS1CT528R680J

I should also replace both 15R 1/2 Watt Resistors (R1352 and R1353) around Q1351. On half of the A2A1 Boards I came across these look very stressed (to the limit of their dissipation).

Calibrationfixture

I used 1/2W flameproof resistors, for obvious reasons. Can't understand why you would want to increase the wattage, unless you prefer extra crispy PCB in a fault condition.

David
 

Online tggzzz

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1916 on: November 03, 2024, 05:48:19 pm »
Hi,

I use these 1W Resistor Replacements (Mouser PN's):

660-MO1CT52R150J and

660-MOS1CT528R680J

I should also replace both 15R 1/2 Watt Resistors (R1352 and R1353) around Q1351. On half of the A2A1 Boards I came across these look very stressed (to the limit of their dissipation).

Calibrationfixture

I used 1/2W flameproof resistors, for obvious reasons. Can't understand why you would want to increase the wattage, unless you prefer extra crispy PCB in a fault condition.

David

One of mine also removed a 1cm diameter bit of prepreg.

I can't remember whether there is a fuse between the RIFA and the mains socket, but one school of thought is that the capacitor going short circuit causes the fuse to blow.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Offline i386

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Re: Tektronix 2465B oscilloscope teardown
« Reply #1917 on: November 22, 2024, 12:52:29 am »

First post here.

I bought a Tek 2465 about 10 years ago but never learned how to use it. Recently I dragged it out of storage. After a few minutes of being powered on it let the smoke out.

I decided to have a go at fixing it. With the help of this forum I managed to disassemble it without destroying the fan. It is not obvious that the collet is back there! Mine came out perfectly and runs whisper quiet. I only replaced the Rifa caps. There was no swelling or leakage on the electrolytics. The Rifa cap that blew also took out the carbon comp resistor that was adjacent to it. After replacing the caps and resistor, I carefully reassembled everything and timidly powered it on. All good, no errors. It came with 4 10x probes. One is bad (would not compensate).

While I was researching the fix and waiting for parts I found tons of videos that were not available back when I bought the scope. I have the operator and service manuals too.

I'll be using this for audio (guitar tube amp) work so the 300Mhz bandwidth is way overkill for what I need.


I'm going to poke around in here and read some before I start asking questions. Just wanted to say thanks for helping me get this far.
 


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