Howardlong I sent you a PM.
SoundTech-LG
Thanks for the compliment. Fortunately, I only had one trace/pad that was damaged so it made it easy to replace the suspect parts. If you look closely at the first picture, the third component above the tantalum capacitors I installed, you will see the resistor is installed just a little to the right of where it should be. That was the component that has the trace that came off during desoldering. Fortunately, there was enough of the thin trace to make a solder connection to. I put a drop of superglue at the base of the capacitor after I was done soldering to ensure it was mechanically anchored to the board. Not much trace there to hold it on the right side.
Mitch
All,
Last night while I was looking for a service manual for my Tektronix 221 battery powered scope (works great, bad battery) I stumbled upon a Tektronix Scope WIKI page that lists lots of information about Tek scopes. You can select by series, then individual model numbers within the series. Once you select a particular model, it takes you to a page where they usually have a link to manuals for the model selected. Its not 100%, but I was able to find the service manual for the 221. This is the only place where I have found the manual free online. I had not seen this page referenced in any of the posts I have read on this group. Anyway, take a look and see if its of use to you. Here's the link.
http://w140.com/tekwiki/wiki/Main_Page#2000_Series_ScopesMitch
Howardlong I sent you a PM.
I cant make the PM work.
It works, but by default it doesn't save the messages you send, for that you have to go to the message settings:
https://www.eevblog.com/forum/pm/?sa=settingsand check the "Save a copy of each personal message in my sent items by default." check box
I did that but didnt log out.After logging back in I have sent messages now. Thanks for the tip.
All,
I was given some guidance over on the Tek Scope Yahoo group on a test to run to see if the channel 1 trace is getting a position signal from the A5 board. Basically it was to check the signal at pin 17 on the channel 1 and 2 preamps. This pin receives position control from the A5 board and varies with the position control on the front. The voltages varies the same when I adjusted the vertical position controls for both channels. So with that said, it looks like the channel 1 preamp has an issue.
So, ignoring the fact I needed to go to bed, I removed the little shield over the solder connection on the channel 1 preamp, unsoldered the connection, then removed the nuts holding the preamp to the circuit board, installed the replacement preamp, and put it all back together. Plugged it in, and turned on the power. Low and behold, I now have a channel 1 trace! It moves with the position control and everything. I hooked it up to the internal cal post, which is supposed to measure .4volts, and the display said it was .43volts. Close enough for me tonight. Anyway, It appears that I now have all four channels working.
I still have to change out the power supply caps, but that can wait until a later date. Now I just need to learn all of the capabilities of this scope, and of course, I have the two 1465's to see if I can get back into service. The fun never ends.
Mitch
Hi All,
This is my first post, so I thought I'd send best wishes to everyone here.
@BravoV: Awesome post! Thanks for the info here, and to everyone who contributed. I just purchased a used 2465B, and am looking forward to using it for my projects.
At some point, I will try the U800 modification.
Best,
:MJ
Michaela Joy Boy are you going to have a lot of rewarding fun! This scope is one of the most pleasing . It has full schematics and other manuals. It is easy to work on. There are many fans to ask questions. and it is powerful- just ask w2aew.
Dont worry about what the Rigol fundamentalists say, they dont know quality when they see it.
Dont worry about what the Rigol fundamentalists say, they dont know quality when they see it.
@malch: The truth is, the 2465B was a better deal than the new digital scopes are. I don't need storage or FFT / math functions, I just need to look at signals.
As long as it functions ok, I'll be happy. I have some inexpensive probes that I'll be using until I buy the "correct" probes. The "good" probes are expensive, but worth the price. Then, I'll do the U800 mod, just to be safe.
:MJ
Question Re: Dallas Chip Replacement
I recently picked up a 2465B locally, serial BO57xxx. The scope will only be used for hobby purposes, and I know nothing about programming an IC (and would prefer not to make this scope my first experiment in programming an IC). As a preventative measure, does it make sense to buy a pre-programmed IC (e.g., from the seller in Greece) and replace the existing chip with the pre-programmed chip or would it be better to have someone copy the info from my chip info to a new chip? What functionality/calibration information of potential significance to a hobbyist, if any, is lost by replacing the Dallas chip with a new chip pre-programmed with "basic" settings? Thanks.
Question Re: Dallas Chip Replacement
I recently picked up a 2465B locally, serial BO57xxx. The scope will only be used for hobby purposes, and I know nothing about programming an IC (and would prefer not to make this scope my first experiment in programming an IC). As a preventative measure, does it make sense to buy a pre-programmed IC (e.g., from the seller in Greece) and replace the existing chip with the pre-programmed chip or would it be better to have someone copy the info from my chip info to a new chip? What functionality/calibration information of potential significance to a hobbyist, if any, is lost by replacing the Dallas chip with a new chip pre-programmed with "basic" settings? Thanks.
Your chip contains calibration information specific to your scope. You want to have a copy of that, so get someone to do it for you if that's an option.
I don't know how bad the calibration would be with a generically programmed chip, if that's what you're asking.
DC912,
You can copy down the calibration constants for your scope found by running the EXER 02 routine. Then download a copy of a bin file for your model scope. Using a bin editor, replace the portions of the downloaded file with your calibration data, then your ready when you replace the DS1225Y. That should but you a bit of confidence you won't loose your calibration data. It's actually pretty easy to do. I'm sure you can find someone near you that can assist with programming.g the replacement chip.
Mitch
That means it doesn't like the cal data. Bad checksum? Contact them, tell them you got a shit chip.
SoundTech-LG
Did you ever get the Greek Dallas chip working in your scope? Did you do a full calibration, or did you just program the chip with another scopes calibration data?
I'm loving my 2445B now that I have it up and running. Looks like I may need to do a vertical section calibration, but the horizontal is dead on. I fed a 175Mhz signal into the scope, and it auto measured it perfectly. It also is accurate at lower frequencies too. Still need to get some good Tek probes to go with it. I recently purchased a couple of P6138 probes off of _bay. They should be here any day. Then the real testing can begin.
Mitch
I just received my 2465B yesterday. I noticed that one of the front panel buttons was stuck. I managed to unstick it with a little bit of contact cleaner spray.
The scope seems to work well, although I think it needs to be opened and the front panel switches need to be cleaned. Cosmetically, it's in great shape. All 4 traces come up and I can see waveforms on the screen. I don't have 400 MHz probes to test it fully. I do have some inexpensive scope probes that will work fine for anything upwards of 10 MHZ.
I have a friend who has worked on His own Tektronix scopes before. He also does a lot of radio / RF work, so, I'll see what signal generators He has that will go up to 400 MHZ.
Then, we'll open it together, clean it, and see how far off the calibration is.
All in all, I'm super happy. I feel like I bought a "diamond in the rough".
:MJ
It would be a good idea to follow along with post #1 and see some possible problems.
the Greek Dallas is screwy for sure because if I load on any of the .BIN files previously uploaded from this 2465 Teardown topic, it works fine with the scope (although would still need a CAL of course). Yeah, I should at least get a refund for the programming part of that Dallas.
the Greek Dallas is screwy for sure because if I load on any of the .BIN files previously uploaded from this 2465 Teardown topic, it works fine with the scope (although would still need a CAL of course). Yeah, I should at least get a refund for the programming part of that Dallas.
So, as you stated, it sounds like the chip is good, just bad programming. That's too bad that the Greek programming is faulty. I was looking at contacting them for a standard cal for my 2445B while I was performing other repairs and afraid that my original Dallas chip would go flat and become unreadable. Fortunately for me, that didn't become necessary. At least you have a good chip to copy your calibration into. Do you still have the original chip, and is it still readable?
Mitch