Author Topic: Tektronix 2465B oscilloscope teardown (Read 738762 times)

BravoV · « **Reply #50 on:** March 06, 2014, 07:47:23 am »

Confirmed, its blowing out.

At the 1st post of this thread, there is a picture of mine which is the original came from Tek factory untouched when it was shot, although its not very clear, you can see faintly the two arrows showing the rotation and air direction on the top of the fan.

linux-works · « **Reply #51 on:** March 06, 2014, 08:04:54 am »

thanks!

I should have noticed the label on your photo; that's enough to know which way the wind should blow

all the parts from mouser and digikey came, but I'm still waiting on the chip programmer. I'll probably replace some of the caps, replace the fan and put it back together to make sure I didn't 'go backwards' (do damage in my refurb effort). I like doing incremental changes, anyway, so that if things don't work, you have some idea which thing you did between working and not-working.

linux-works · « **Reply #52 on:** March 08, 2014, 01:56:15 am »

bought a new friend for my 2465b:

(the scope cart, not the scope. already had that scope from a purchase last year).

this cart was made for 2400 series and that's what will eventually go there.

went to my local shop, found this cart in decent shape (dirty as hell but not banged up) and just had to take it home with me

BravoV · « **Reply #53 on:** March 08, 2014, 02:07:58 am »

Nice score, now I'm so jealous.

How much did you pay for that ?

linux-works · « **Reply #54 on:** March 08, 2014, 02:32:21 am »

the cart was marked at $75, but I got it for 10% off when I talked nice to the salesman

scope was $90 plus $25 shipping, about 2 years ago.

linux-works · « **Reply #55 on:** March 09, 2014, 04:06:31 am »

well, I replaced the 4 smd caps and the fan, then put it back together to do a quick check.

I don't think I like this fan ;( its not at all quiet! the original fan had more blades and maybe that helped keep it somewhat lower noise. this one from mouser is not what anyone would call 'quiet'. it works, I guess, and I think I'll have to live with it for now, but I don't suggest this model, really. oh well.

next step for me, replacing the dallas module (not really looking forward to unsoldering it, to be honest.)

BravoV · « **Reply #56 on:** March 09, 2014, 04:24:31 am »

Quote from: linux-works on March 09, 2014, 04:06:31 am

replacing the dallas module (not really looking forward to unsoldering it, to be honest.)

I'm afraid you just can not escape from that.

Please, post your original Dallas's content here once you backed it up.

Btw ...

... c'mon, more photos please.

linux-works · « **Reply #57 on:** March 09, 2014, 08:11:36 am »

here we go...

dallas is removed with the help of hakko 808. a few pins gave some trouble so I skipped them, did the rest and went back to the trouble ones with a soldering iron, some fresh solder and then re-attack with hakko 808. no traces seemed to have gotton harmed.

the new dallas chip is there and a surplus gold pin socket, as well. next step is to copy data over using that '$50 programmer' from china.

linux-works · « **Reply #58 on:** March 09, 2014, 09:17:02 am »

success!

the minipro copied the dallas chip just fine to the new digikey-supplied fresh chip.

I just bought another 10-20 years of cal data

and the next guy does not have to unsolder that crazy chip.

firmware upload:

http://www.netstuff.org/tektronix_2465b/ds1225_firmware_linuxworks/

the .BIN file is the rom image and the .md5.txt file is the unix 'md5sum command checksum output (not needed for the chip programmer, but only used if you want to verify the file came thru ok on your download).

BravoV · « **Reply #59 on:** March 09, 2014, 06:21:58 pm »

Bryan, good to hear it went smoothly, the cheap minipro just works for the 1st time without any problem here too.

Quote from: linux-works on March 09, 2014, 09:17:02 am

I just bought another 10-20 years of cal data and the next guy does not have to unsolder that crazy chip.

With a refresh on the power supply caps + good luck, I pretty confident that the whole scope it self will last for another >10 years, especially yours was made in 1992, imo its still in very young age compared to others that were made in 80s and still working fine today.

Have you check it's power on hours and cycle counts ? Really curious to see yours.

Btw, thanks for RAM image file.

echen1024 · « **Reply #60 on:** March 09, 2014, 06:30:53 pm »

@Linux-works

That's really quite a clean scope. Not like some of the Israeli "boat anchors" or "totally harmonically distorted" equipment.

linux-works · « **Reply #61 on:** March 09, 2014, 06:57:40 pm »

I see that ebay site in israel that sells stuff in truly throw-away-and-don't-look-back condition

what a funny thing to see how abused gear can be and they still want to sell it. too weird!

this scope has some dings on the plastic front bezel (which I'm on the lookout for, to replace) but other than that its fairly clean and inside was no rust on any of the screws or nuts, like victor's had. I bought this from a san diego seller and I suspect it spent its life in calif, so there would be little to no rust.

I'll check the power-on hours, but its not trustable since you can zero that out easily enough.

wish I could find a good clean front cover and also the top vinyl pouch; those didn't come with my scope and I'm on the lookout for a bargain on any of those.

echen1024 · « **Reply #62 on:** March 09, 2014, 07:15:01 pm »

eBay auction: #231098193016

The description is just beautiful:

This unit powers up but not working,after powering the item up you see nothing on the display the display completely DAMAGED but when you press all the buttons you hear beep. it is mainly for part or repair,What you see in the pictures is exactly what you going to receive, if you have any questions please contact us.11819

"You see nothing on the display" Well really now? It's been damn smashed out!

linux-works · « **Reply #63 on:** March 09, 2014, 07:17:33 pm »

"that meter kept lying to me, so I just punched his friggin face out!"

lol

maybe the main board was still good and worth that price.

but *I* wouldnt' trust it!

jonpaul · « **Reply #64 on:** March 09, 2014, 07:21:04 pm »

Hello all, my first post, great teardown and good work on the NVRAM.
I have 2465B, 2467B, both need NVRAM, but I am NOT good with digital stuff, and getting on in years, loosing the ability to do the very fine work you folks can do!

I would be interested to buy or swap for a few of these parts if someone can make them, prefer the one with the external lithium battery.

Happy to furnish the serial numbers and exact NVRAM part numbers in my units.

I have a lot of TEK and HP units, manuals and some parts for swap.

Kind Regards,

Jon

BravoV · « **Reply #65 on:** March 10, 2014, 02:02:33 am »

Jon, welcome to the forum.

About fresh NVRAM chip + content sourcing, I guess linux-works can easily help you out since he is US too, its pretty straight forward and pretty quick to copy/write into a fresh DS1225 chip.

Its just I'm curious why you need that ? Cause every NVRAM image is unique since it has that particular scope's calibration values, and imo can not be used to other as it will cause your scope out of calibration.

If you've lost the NVRAM, you need to buy new Dallas DS1225AD and replace the old one, and send the scope to the calibration service to have a proper cal values in it.

casinada · « **Reply #66 on:** March 10, 2014, 03:11:19 am »

Jon,
Probably if you say where you live, some Tek Fan /Blog Member might be in your neighborhood and willing to help you.
I was able to calibrate my 2465BDM starting from a downloaded NVRAM from the KO4BB web site, programming a new NVRAM and calibrate most of the settings with the equipment I have. I'm not a calibration site by any means but willing to help if you're in my neck of the woods (Tucson, AZ)

linux-works · « **Reply #67 on:** March 10, 2014, 03:17:01 am »

I don't have any new pics (nothing really exciting to photo) but I finally did replace the caps in the lvps.

I hate getting that board set out! on my scope, its very hard to wiggle that board pair out of the metal; its wedged in there very tightly. I don't like how tek designed this part; they could have used slides or rails to vertically align the boards and things could have slid in a LOT easier than they do.

if you remove the power IEC socket and pull off its wires/clips you can get more room for your fingers to pull off the 120/240v switch wires. that was identified as one of the harder things to do when removing these boards.

I didn't replace every cap there; but I did replace the big silver ones and a few others. I don't notice any change in the scope but at least I know I have fresh caps in the critical places.

I read on one lvps upgrade that if you find 2 100uf caps, you want to keep them exactly 100uf (for some reason). I replaced those with exact values but using new caps, just for good measure.

it took a good 2 hours to do the power supply boards. kept scratching my head on how to remove that board pair and not break anything. putting it back in was just as hard. something must have been bent since I had to flex the rear metal chassis (near the fan) to create clearance for the metal and plastic standoffs.

anyway, it seems done now. I'd like to get it professionally calibrated but at least its rejuvinated.

linux-works · « **Reply #68 on:** March 10, 2014, 03:18:14 am »

jon is in my general area, so I'll contact him offline and see what we can do.

BravoV · « **Reply #69 on:** March 10, 2014, 03:22:23 am »

Quote from: casinada on March 10, 2014, 03:11:19 am

I was able to calibrate my 2465BDM starting from a downloaded NVRAM from the KO4BB web site, programming a new NVRAM and calibrate most of the settings with the equipment I have. I'm not a calibration site by any means but willing to help if you're in my neck of the woods (Tucson, AZ)

Any chance you could share how you do that in details ? What sort of equipments do you have there ?

As cheap cal service is basically none at where I live, I will be content even for a poor man cal process that yields only with a "good enough" result.

Quote from: linux-works on March 10, 2014, 03:17:01 am

anyway, it seems done now. I'd like to get it professionally calibrated but at least its rejuvinated.

Really curious on the upcoming result, is there any chance you can pre-arrange with the calibrator, that you can get the detail on how much that thing has drifted from the current cal ? This question also for Casinada for your DIY cal as well.

If yours doesn't drifted too much, with the recent components refresh, I guess it will be in cal for many years ahead as the references in side are cooked well enough and wont drift anymore.

casinada · « **Reply #70 on:** March 10, 2014, 05:08:28 am »

I posted some pictures on the Yahoo TekScopes group last september:
https://groups.yahoo.com/neo/groups/TekScopes/photos/albums/1871970004
I used an arbitrary waveform generator that only goes so far in frequencies and I used a signal generator for the high frequencies. When you go trough the calibration procedures, if something is out of range it won't let you finish the calibration so you go back and forth until you get it right.
You need a good DMM to adjust some of the voltages.
I connected with a member of the Tektronix group that lives at a reasonable distance and had good equipment that we used to verify that my calibration was within specs. He has a leveled signal generator and frequency counters that are referenced to GPS. The Scope is not a precision instrument so is not that critical to have it calibrated by a Lab. If you can verify the amplitudes and frequencies are correct and it triggers properly
Then you should have a very usable instrument. You can spend as much time as you want trying to get it as perfect as you want. It can be lots of fun but then it can get tedious as some of the procedures are long.

chksum3 · « **Reply #71 on:** March 12, 2014, 02:31:18 pm »

Congratulations to linux-works on your successful replacement of the 2465B's NV-SRAM. I'm brand new to this Forum after having found a partially renovated 2465B on EBay. The offending caps had been replaced within the power supply and A5 board and a heat sink was fitted. The DS1225Y was however not replaced... leaving that to me. I've followed the task of removing the chip, copying the calibration data from it, then writing the data to a new DS1225Y and re-seating it (via socket) to the A5 board. Before opening the 2465B and removing the 1225Y, I went ahead and bought a new one (DS1225Y 200ns) from a local - SF Bay Area - supplier, Jameco Electronics, and a universal programmer (GQ-4X) off of EBay, which was supposed to read and write to the DS1225Y. I thought it best to prove to myself that I could read and write to a new chip before getting involved in 2465B surgery. Sad to say, I've been unable to read and write to the new chip (tried on 2 of them) with the GQ-4X programmer. Reading that you were able to navigate these waters and successfully program and install a new chip has raised my spirits considerably. Could you detail the exact programmer model number and the exact chip you used (the Y version, or AD, etc.). I'd like to follow the path you've cut through the forest. Thank you! -- Gary

linux-works · « **Reply #72 on:** March 12, 2014, 02:33:46 pm »

if you can return the jameco part, you may want to do so.

I was advised by a 2465b repair guy that the jameco chips are old and not to be used or trusted. what is the date code on your new chip?

I got mine at digikey (they seem to be out of stock right now) and my date code was 2012, so I know it was pretty fresh.

if you are in the bay area and need help programming the chip, let me know and we could meet to do the copy. but you may want to buy the chip from mouser or digikey if your date code is not recent enough.

chksum3 · « **Reply #73 on:** March 12, 2014, 02:50:41 pm »

Thank you for the information! I'll see about returning the chips to Jameco and will order a DS1225Y from digikey today. I really appreciate your offer of reading the old and programming the new chip -- saves me having to find and buy a programmer that works. Now, did you go with ordering a Y version or some other version of the DS1225? And, just for curiosity - what programmer model number did you use? Once the new chip arrives from digikey I'll open the 2465b and desolder the old chip then get in touch with you for the read/write. Thank you extremely! Re: date code on the jameco chips --> none present.

linux-works · « **Reply #74 on:** March 12, 2014, 03:22:32 pm »

I bought this programmer:

http://www.ebay.com/itm/321085130796

it arrived safely and quickly.

for the chip, this is the one I ordered but it seems to be out of stock right now:

DS1225AD-200IND+-ND

AD is a wider temperate range (I think) but nothing critical to the scope. the 200 is the speed of the device and I used the same speed as the original chip. not sure if going faster or slower would matter but I just matched the same chip speed.

mouser has one that is not AD but very close and that's probably also ok:

DS1225AB-200+

and those are in stock.


EEVblog Main Site	EEVblog on Youtube	EEVblog on Twitter	EEVblog on Facebook	EEVblog on Odysee

Author Topic: Tektronix 2465B oscilloscope teardown (Read 738762 times)

Share me