Author Topic: Tektronix 2465B oscilloscope teardown  (Read 425654 times)

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Offline linux-works

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Re: Tektronix 2465B oscilloscope teardown
« Reply #100 on: March 15, 2014, 06:37:44 pm »
I would email that seller and have him explain himself.  his business seems to be fixing up old scopes and reselling them as refurbished units.

I don't want to make you feel bad, but I'm so glad I decided NOT to buy from this guy!  I had emailed him a few times and thought about buying one of his scopes, but I would have had some real issues with his repairs had I seen that in a scope I paid EXTRA for, for so-called expert repairs.

did you leave him feedback already?

I would try for a discount or even to return the unit.  its a disgrace.  sorry, but it is quite disgraceful given those pictures and the burn mark on the wima cap, too.

and to charge that much for the refurb scope and to NOT do the dallas module.  shameful.
 

Online BravoV

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Re: Tektronix 2465B oscilloscope teardown
« Reply #101 on: March 15, 2014, 06:40:30 pm »
Another comparison photos yours vs mine, just in case you need it when "talking" with that seller. Hope it will ended well towards you, really, your A5 board looks scary to me.  ???



Offline linux-works

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Re: Tektronix 2465B oscilloscope teardown
« Reply #102 on: March 15, 2014, 06:44:25 pm »
hey victor, what camera are you using?  that's a REALLY sharp photo there!

I wonder what the burn marks are on the IDC (or is it IDT, I get those confused) connector.  just dirt or temperature issues?  victor's is quite clean and mine is also quite clean with no discoloration.
 

Offline linux-works

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Re: Tektronix 2465B oscilloscope teardown
« Reply #103 on: March 15, 2014, 06:49:07 pm »
now, I'm wondering if the seller used hot-air rework tools to try to remove the smd caps.  that might explain the burn marks (if they are actually that) on the plastic vertical pin idc/idt connector.

maybe he lifted traces when he did the repair, so maybe he had to run green wires and pot that.

you might also post this to the yahoo tekscopes group and get some opinions on this.

sharper shots would help, though.  if you can avoid using flash, put your cam on a tripod of some kind and set the self-timer to auto fire, you might be able to get some sharper, more telling shots.  I'd be happy to come by and take some decent SLR shots if you want.  this should really be documented so that people know what to expect from such a seller.
 

Offline GreyWoolfe

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Re: Tektronix 2465B oscilloscope teardown
« Reply #104 on: March 15, 2014, 08:47:22 pm »
FWIW, it looks like he's trying to hide a bodged repair job |O.  If this is an smd board, there shouldn't be wires added.  If I couldn't get any satisfaction, as in returning it or getting a deep discount for the crappy repair job, I would see about getting a replacement board and keep that as an emergency spare if you have to fix the primary board.  Negative review and epic fail!
"Heaven has been described as the place that once you get there all the dogs you ever loved run up to greet you."
 

Offline linux-works

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Re: Tektronix 2465B oscilloscope teardown
« Reply #105 on: March 15, 2014, 08:53:56 pm »
just a thought: since the seller 'repairs' scopes regularly on ebay, I'd ask to swap this 'fixed' board with a totally stock unfuc^H^Hixed board.

then just do the usual things needed for a5 boards yourself.
 

Offline chksum3

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Re: Tektronix 2465B oscilloscope teardown
« Reply #106 on: March 15, 2014, 09:16:28 pm »
Hmmm. I've thought about this all day, and I agree that the seller really should be expected to replace this board with a functioning and professionally refurbished substitute.  After struggling with this for awhile, and reading your identical suggestion - I did write to him again and ask that he fulfill this compromise. I asked for a professionally refurbished substitute board, as that is what I paid for in the first place (as I have no experience replacing surface mount components), and as I believe he should be given the chance to make good on the work.
 

Offline casinada

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Re: Tektronix 2465B oscilloscope teardown
« Reply #107 on: March 15, 2014, 09:28:14 pm »
 ;)Not to defend anybody, that looks like a sloppy job. My A5 board was very corroded and it really crumbled to pieces as I was desoldering components. I was afraid I was going to lose traces but in the end everything worked out. I had to use some wire wrap wire to recreate traces. I removed the cotton traces after I took the picture :(
« Last Edit: March 15, 2014, 09:31:42 pm by casinada »
 

Offline GreyWoolfe

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Re: Tektronix 2465B oscilloscope teardown
« Reply #108 on: March 16, 2014, 02:18:51 am »
Your work is much better than the so called "professional" refurb job.
"Heaven has been described as the place that once you get there all the dogs you ever loved run up to greet you."
 

Offline linux-works

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Re: Tektronix 2465B oscilloscope teardown
« Reply #109 on: March 16, 2014, 02:48:20 am »
Hmmm. I've thought about this all day, and I agree that the seller really should be expected to replace this board with a functioning and professionally refurbished substitute.  After struggling with this for awhile, and reading your identical suggestion - I did write to him again and ask that he fulfill this compromise. I asked for a professionally refurbished substitute board, as that is what I paid for in the first place (as I have no experience replacing surface mount components), and as I believe he should be given the chance to make good on the work.

or, to make it easier on him (and you, too!) get an UNTOUCHED board from him, that way you don't trade one problem of his for another of his.  if its stock tek, then you can do the smd cap work and you already have done the unsoldering, so you are good at it, now ;)

you also have a copy of your eeprom data.  that data belongs more to 'the scope' than the a5 board (folks, correct me if I'm wrong about that) and so I'd restore that data to the new a5 board and you'd be whole again.

in fact, you already have the data in your NEW chip, so just keep the new chip. send the old chip back on the old a5 board (with the socket; leave that in, of course) and when you get the new untouched a5 board, do the socket thing again and you're back to where you should have been.

hope he goes for it.  by asking him for a non-modified board, it actually should be appealing to him.  he gets his 'work done to it' board, which he seems to think is worth something and you get to start fresh and do your own work on that a5.
 

Offline linux-works

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Re: Tektronix 2465B oscilloscope teardown
« Reply #110 on: March 16, 2014, 02:50:07 am »
oh, and if he does offer you an untouched a5 board, I'll help you out with the smd cap removal.  not a problem.
 

Offline chksum3

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Re: Tektronix 2465B oscilloscope teardown
« Reply #111 on: March 16, 2014, 03:08:36 am »
I emailed the seller and got his reply: an offer to receive the scope back for my money back.  I suspect folks out here will disagree with my decision, but I declined that offer and will keep the scope, aesthetic warts and all.   I am definitely bothered by the Ferrari with a Chevy bumper metaphor, but will fix all of that by finding another A5 board to work on myself. That will enable me to play with removal and replacement of SMDs in addition to replacing the NVSRAM again, which I found much easier than I thought would be the case.  All in all, it's all a learning experience, and it's all good.
 

Offline linux-works

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Re: Tektronix 2465B oscilloscope teardown
« Reply #112 on: March 16, 2014, 03:15:39 am »
you paid a lot for that scope and I would worry about 'what else could he have done wrong, to it'.  so far, you see the a5 'patches'.  you should probably look deeper to see if anything else was done.

yes, shipping is not going to be cheap, but a fresh start on another scope could be liberating ;)  and very likely, you'll be able to find one that is a good $150 or more cheaper and that could help offset the cost in shipping.  it would be fair if you two split the shipping cost; so he pays shipping out and you pay shipping back to him.

just a suggestion.  once there is doubt about a repair guy, I would want no part of anything he touched.
 

Online BravoV

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Re: Tektronix 2465B oscilloscope teardown
« Reply #113 on: March 16, 2014, 06:38:16 pm »
Gary, what ever the decision, its yours. Hopefully it will last long and really interested to hear how it performs once its properly calibrated.

At least look at the bright sides, thanks to your sharing, which are don't buy Dallas DS1225 chip from Jameco  ::), and approach with extra cautions should anyone "desperately" needs to deal with that seller in the future.

Offline chksum3

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Re: Tektronix 2465B oscilloscope teardown
« Reply #114 on: March 29, 2014, 03:15:18 am »
Dear BravoV and Linux-works (I don't know your names)... thought I'd let you know that I changed my mind about the 2465b with the "potted" A5 board and returned it to the seller for a refund. I found that it also had non-linearity issues and was clearly not a properly calibrated instrument.  I've now purchased another 2465b that has not (I hope) been "refurbished," so I can go ahead and make that a project for myself.  Thank you again for your good advice and your patience.

-- Gary
 

Offline linux-works

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Re: Tektronix 2465B oscilloscope teardown
« Reply #115 on: March 29, 2014, 03:54:55 am »
that's good to hear, gary.

at least it was a learning experience for all involved ;)

/bryan
 

Offline chksum3

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Re: Tektronix 2465B oscilloscope teardown
« Reply #116 on: April 03, 2014, 06:56:42 pm »
The saga continues... I've now returned and received a refund for the previously purchased 2465b with the "potted" A5 components, and I've now received another scope (at a much lower cost) that functions well, but does show damage to the A5 board from the well described leaking SMT capacitors.  I've included 2 close-up photos of the leakage/damage, which seems localized.  What do you folks think: is this easily repairable, or not?  I've not (yet) played with SMD devices, but I'm eager to learn and experiment. 

Also, I note that the NVSRAM chip was manufactured 3/1992. If I go ahead with repairs, I'll order another DS1225 from Digikey along with the other needed components for a refurbishment of the A5 and the low-voltage power supply, as also appears to be recommended.   Thanks in advance for any advice.

-- Gary
 

Offline casinada

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Re: Tektronix 2465B oscilloscope teardown
« Reply #117 on: April 03, 2014, 09:45:06 pm »
It is good that the scope works but that corrosion looks nasty. Try to neutralize the corrosion as soon as possible. Worst case scenario you'll have to rebuild traces with wire. As soon as you try to remove some of the components, things will disintegrate, look at my pictures a few posts back. :(  Good luck with the scope :)
 

Offline linux-works

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Re: Tektronix 2465B oscilloscope teardown
« Reply #118 on: April 03, 2014, 10:27:47 pm »
if it was my board, I'd use hot air and remove as many of the smd parts near the corrosion as I could.  then clean with alcohol and ohm out the traces to see if the solder pads are connected (to the right traces).

 

Offline chksum3

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Re: Tektronix 2465B oscilloscope teardown
« Reply #119 on: April 03, 2014, 11:59:02 pm »
Thank you both.  I'll be ordering parts tomorrow, and will be practicing SMT techniques over the coming few days before diving in.  I'll photo document my progress also. 

Another question: Could changing out old power supply capacitors change scope characteristics such that a scope calibrated within the past few years could then fail to function because of retained NVSRAM calibration factors that were recorded at last calibration, when the older components were in place?
 

Online BravoV

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Re: Tektronix 2465B oscilloscope teardown
« Reply #120 on: April 04, 2014, 02:36:41 am »
Another question: Could changing out old power supply capacitors change scope characteristics such that a scope calibrated within the past few years could then fail to function because of retained NVSRAM calibration factors that were recorded at last calibration, when the older components were in place?

Don't think just by replacing the old "decaying" cap in the psu will affect the scope's cal, especially if the new replacement improves the psu output quality as the specification compared to previous state.

Remember, the psu output (as long within specification), is not the reference point for the measurements mechanism in the scope.
« Last Edit: April 04, 2014, 02:40:10 am by BravoV »
 

Online BravoV

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Re: Tektronix 2465B oscilloscope teardown
« Reply #121 on: April 04, 2014, 02:49:03 am »
Had an offline discussion with Kibi when he was repairing his Tek 2445 (Here) that he had to lift the huge A1 board, the mounts & connections which is identical to 2465/B, and he shared few photos that I think will be useful if anyone plan to detach the A1 board, and I think this photo tips is valueable and never seen elsewhere even at the Yahoo Tek maillist.

Thanks and credit to Kibi for allowing me to share this photos here.  :-+

Quoting his tips & photos on detaching the A1 board :

1. Must unsolder the wires that go to the X and Y plates.




2. Now, I did not remove this PCB (HV) because it looked quite difficult to remove. The A1 PCB is easy to remove without taking this board out, but it's a bit more difficult to put the A1 back in because the pins don't line up nicely because of the A1 being at an angle when you put it back.




3. Don't forget where these coax cables go and their orientation, (take some pictures).




4. After removing the plastic front bezel, you must remove the strip of aluminium here to allow the front end BNC's to come out clear.

« Last Edit: April 04, 2014, 03:01:27 am by BravoV »
 

Offline MarkL

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Re: Tektronix 2465B oscilloscope teardown
« Reply #122 on: April 04, 2014, 11:48:43 am »


Thanks and credit to Kibi for allowing me to share this photos here.  :-+

Quoting his tips & photos on detaching the A1 board :

1. Must unsolder the wires that go to the X and Y plates.
[...]

Just a minor note - You don't have to unsolder these wires.  They lead to single pin connectors on the CRT neck.  You can pull them off the CRT through the slot in the shield (carefully!).
 

Online BravoV

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Re: Tektronix 2465B oscilloscope teardown
« Reply #123 on: April 04, 2014, 01:35:23 pm »
Just a minor note - You don't have to unsolder these wires.  They lead to single pin connectors on the CRT neck.  You can pull them off the CRT through the slot in the shield (carefully!).

Thanks for the tiny detail update, didn't know that.

So are you saying that 4 wires some how get joined together into single wire, and it is connected to this white board pointed by the red arrow at photo below ?
« Last Edit: April 04, 2014, 06:18:06 pm by BravoV »
 

Offline MarkL

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Re: Tektronix 2465B oscilloscope teardown
« Reply #124 on: April 04, 2014, 03:55:40 pm »
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.
 


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