Tektronix 2465B oscilloscope teardown

[MeloMel]

Awesome thread and comments! I have the 2445B and I suppose it's much the same internals and should be helpful since I'm planning on opening my case and cleaning it out a bit. It's not been used in years, and is displaying an error code "Test 05 fail 44" - Main Board Positive level too positive. I've posted a thread for it already

Mel

[BravoV]

The individual wires are not joined together.  Those "pins" sticking out of the shield are actually connectors.  You can pull on them, gently, to detach them.

I've attached a picture of what it looks like without the shield.  (It's a different type of wire, but I'm just trying to illustrate what I mean).  This is a 2465 CRT (#154-0850-01) and you can see the three pins from your picture.  There are 4 pins on the other side where it attaches to the A1 board.

The CRT pins are thin and delicate.  Avoid bending them as much as possible since you don't want to stress where it goes into the the metal-to-glass seal.

I've also attached a picture of the whole gun assembly.  I think it's an impressive piece of glass work.  Those little dots taped to the outside are magnets to tweak the beam position.

Thanks, but after seeing the tube and those metal pins and also the fragile glass that is holding them, why suddenly I had the chill and goose bumps. 

Anyway, this will come into mind if I'm going to lift the A1 board as plan B.

To be honest, I prefer to de-solder those Horz & Vert wires, only 4 and not too difficult and much less risk than cracking those glass while pulling the wires, imo.

[casinada]

Actually, if you need to take it apart is a good idea to disconnect and reconnect those pins as they tend to rust a little. So many problems can be fixed that way

[MarkL]

Actually, if you need to take it apart is a good idea to disconnect and reconnect those pins as they tend to rust a little. So many problems can be fixed that way

I'll second that.  When I got my 2465 the traces were intermittently jumping vertically.  I traced it to one of the deflection plate connectors.

It took a while to figure out.  The vertical plate pins on the A1 side pass *through* the CRT to the termination board on the other side.  I wasn't expecting that and I kept focusing on the vertical amp because I could see the output jumping.

I hate connectors.  It's always the connector.

[linux-works]

slightly OT: this is one reason (connectors suck) that I like wire-free builds as much as possible. 

on some pc's (mini-itx) you can have a full system with no cards (pci) and no wires at all.  the atx psu can be onboard, m-sata drives fit on m-sata connectors (the only connector you can't avoid other than RAM) and don't need power cables and everything else is soldered onboard.  for industrial use stuff, I try to remove as many wires and connectors as I can.

when I get old gear that has ic sockets, I also mistrust those, too.  cpu sockets seem ok but DIP sockets are often a failure point.  the old heathkit 'molex pins' sockets were the worst thing I've seen, for 'sockets'.

[chksum3]

re. 2565b A5 Board repair -->

I've now double checked the components on the A5 board here against the serial number of the scope (59877) and the service manual parts list to verify the board I have was not a swapped-out replaced board (different serial numbered boards used slightly different component values).  Everything checks out, i.e. this A5 is appropriate to the scope's serial number. 

I've also looked over the entire board under high magnification and have convinced myself that damage only extends from a leaking C2113 (10uF-35V electrolytic) to C2520 and C2222 (0.1uF-50V non-electrolytics). All other traces and components seem to have escaped damage. 

Before I can go ahead and order replacement components, I've got a very basic question for you all, as I am entirely new to SMDs and don't have a micrometer to do my own measurements.  From an earlier posting (here, or elsewhere - I don't remember) by H.Holden Oct. 2013, I plan to replace the four leak-prone cylindrical electrolytic units (C2011, C2331, C2113, C2965 - Panasonic FK SMD series devices) with tantalum SMDs instead.  I have no idea if there are preferable replacement types for C2520 and C2222 (the 0.1uF-50V) non-electrolytic capacitors.  Does anyone have the specifics re: sizes, manufacturers, etc. for these 6 components?  Thanks again...

[BravoV]

Gary, since you're going to clean it up 1st anyway, and you still don't know the extend of the damages at the traces and the cap's pads there.

Cause once all cleaned and damages are fully inventoried, there are chances they you may need to do some patch works to restore the cap's pads if they're heavily corroded, and "probably" it may need larger foot prints than the original ones, just a thought.

[chksum3]

Good point - I hadn't considered that! Thanks.

[chksum3]

Progress report re: preparing to renovate my 2465B A5 board's SMT components: I just received a cheap, used Aoyue soldering tweezers station via eBay and tried it out on an old, discarded board populated with various SMDs.  It was surprisingly easy to desolder various components (all of which are significantly smaller than those populating the A5 board).  Resoldering, using a fine tip temperature controlled iron (also an inexpensive Aoyue unit), went just about as easily.  I've become a believer that SMD board repair is not a particularly difficult undertaking, provided the correct tools are at hand.  Many thanks to linux-works for his insight and suggestion to go with the tweezers.

[linux-works]

I predict the tweezers are going to go up in price once people start to catch on to how useful those things can be.

I was watching a pace video that showed them removing large square smd chips with right-angle tweezer 'tips' and it was amazing to see how easy and fast it was!

one thing I am going to try, next time around, is this nozzle for hot air.  looks like just the thing for removing 2 lead devices:



one nozzle is fixed and the other can move in or out, then you tighten the philips screw and do the hot air unsoldering.  I can't wait to try this attachment out

[m1kta]

Seem to have lost the post to thread... ho hum apologies if this appears twice.

I have created photos and break down notes from my 2465CTS... slightly different model to what I have seen here and lot more packed inside.

http://m1kta-qrp.blogspot.co.uk/2014/04/oscilloscope-tektronix-2465cts.html

72

Dom
M1KTA

[m1kta]

Images

[KJDS]

I picked up a 2465B today, which as it is in full working order isn't something I'm going to take apart, but have enjoyed seeing what's in there.

[BravoV]

I picked up a 2465B today, which as it is in full working order isn't something I'm going to take apart, but have enjoyed seeing what's in there.

If its still untouched from Tek factory, as least you need to do the A5 digital board to refresh the pesky Dallas bbsram that is holding the scope cal. , and definitely its already passed it's specified battery life.

Btw, just curious, you're well known here that have access or probably own many high end T&M gears and also selling them, which some beyond the reach of common hobbyists level, why still buy this "old clunker" ?  Sentimental value ? Anyway, welcome to the club. 

[KJDS]

I picked up a 2465B today, which as it is in full working order isn't something I'm going to take apart, but have enjoyed seeing what's in there.

If its still untouched from Tek factory, as least you need to do the A5 digital board to refresh the pesky Dallas bbsram that is holding the scope cal. , and definitely its already passed it's specified battery life.

Btw, just curious, you're well known here that have access or probably own many high end T&M gears and also selling them, which some beyond the reach of common hobbyists level, why still buy this "old clunker" ?  Sentimental value ? Anyway, welcome to the club. 

I bought it because it was the right price. I may need a fast scope soon, just bidding on some design work that may need a genuinely fast scope and the next fastest analogue scope I have is a 150MHz 2445. I do prefer analog scopes for looking at analog signals.

Thanks for the warning on the Dallas RAM.

[grumpydoc]

The SMD caps on the A5 board in the 2465B are also notorious - probably should be replaced even if they look OK (see earlier in this thread).

[m1kta]

If its still untouched from Tek factory, as least you need to do the A5 digital board to refresh the pesky Dallas bbsram that is holding the scope cal. , and definitely its already passed it's specified battery life.

Does this effect ALL 2465 models?

Is this process documented/detailed anywhere?

Dom

[linux-works]

not the base model or the A version, just the B version.

lots here on the 2465 series; you'll spend a bit of time searching thru it all, but its all explained here and on the yahoo tek-scopes group.

[BravoV]

The SMD caps on the A5 in the 2465B board are also notorious - probably should be replaced even if they look OK (see earlier in this thread).

+1, the well known problems for this Tektronix series which are the SRAM battery that is running out of juice, and the SMD electrolytic caps at the A5 board that leak like hell, this thread has a good example -> HERE, or HERE (The damaged vs the good one)

Does this effect ALL 2465 models?

Is this process documented/detailed anywhere?

Dom

Dom, not sure about your 2465CTS, maybe you can share the photo of your A5 digital board about the caps and maybe its using the same Dallas DS1225Y too, not very sure my self.

On the Dallas, its a "Battery" Backed Static Ram (BBSRAM), and just read the datasheet yourself, it's specification on the battery life is maxed out only for 10 years. And if your 2465CTS also using it, its very likely already aged more than 10 years.

[casinada]

On the B series probably above serial number 50000

[guido]

Does this effect ALL 2465 models?

A plain 2465 (no A or B) does not have SMD caps and no Dallas chip. Instead regular elco's and a very early kind of EEPROM (called EAROM).

I'm working on one. I've done a nearly full recap (elco's and X and Y caps), replaced two broken zeners and swapped the switches pannel. I'm now looking at a focus problem (found a broken pot, but there is more damage) and i need to get a new preamp module for one of the channels.

[m1kta]

The SMD caps on the A5 in the 2465B board are also notorious - probably should be replaced even if they look OK (see earlier in this thread).

+1, the well known problems for this Tektronix series which are the SRAM battery that is running out of juice, and the SMD electrolytic caps at the A5 board that leak like hell, this thread has a good example -> HERE, or HERE (The damaged vs the good one)

Does this effect ALL 2465 models?

Is this process documented/detailed anywhere?

Dom

Dom, not sure about your 2465CTS, maybe you can share the photo of your A5 digital board about the caps and maybe its using the same Dallas DS1225Y too, not very sure my self.

On the Dallas, its a "Battery" Backed Static Ram (BBSRAM), and just read the datasheet yourself, it's specification on the battery life is maxed out only for 10 years. And if your 2465CTS also using it, its very likely already aged more than 10 years.

I'll drop a photo of the board here after lunch (about 3 hours from now).

The A5 logic and control board is the one the outside right of the scope looking from the front right?

Dom

[BravoV]

I'll drop a photo of the board here after lunch (about 3 hours from now).

The A5 logic and control board is the one the outside right of the scope looking from the front right?

Dom

Yep, the long rectangle shaped board at the right side of the scope (front view), and if you see it closely, the board has almost all logic chips populated in it.

[casinada]

It has SMD components => s/n > 50000

[BravoV]

I bought it because it was the right price. I may need a fast scope soon, just bidding on some design work that may need a genuinely fast scope and the next fastest analogue scope I have is a 150MHz 2445. I do prefer analog scopes for looking at analog signals.

Hey KJDS, I just visited your ebay shop and I can see you're also selling a 500 Mhz DSO.   

Understand its an old DSO, its just I'm very curious why your prefer using a 400 Mhz old analog scope than the one you already have in hand ?

Please, if its not too troublesome for you, share on the real world examples or any reasons even its subjective that at your design work, this old clunker is better than that DSO, maybe create another new thread for that ?