Author Topic: 2445B Repair  (Read 2179 times)

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Offline mskobier

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2445B Repair
« on: March 13, 2015, 01:24:50 am »
All,
    A few weekends ago, I stumbled upon a 2445B laying in a scrap pile waiting to be crushed. I have a thing for test equipment in general, and particularly high end equipment. I just could not leave the scope there to be destroyed. So for just a fe dollars, it followed me home. I have been posting about this scope over in the Test Equipment in the 2465B Rebuild thread. I figured I should start a separate thread so as not to hijack that one. Anyway, here is where I am at on it.

I brought the scope home and cleaned it up, looked it over, and plugged it in, not expecting much. To my surprise, the scope came to life and at first look appeared to be fully functional. After checking things over, I discovered that channel 1 did not have a trace. I could push the beam find button and channel 1 trace would show up, but I could not change the position with the vertical adjustment knob. That is as far as I went with it at that point, as it has a couple of broken and missing knobs. I did remove the dented case, and did not see any obvious issues with the scope.

After reading many post in this group and on Tekscope, I discovered that as well as repairing the no functioning channel 1, I needed to replace some capacitors on the A5 board, and get a replacement for the DS1225Y NVRAM module. So parts were ordered.

Prior to reading the comments about china -bay sellers IC being junk, I ordered a couple of DS1225AD-200 chips as well as Ramtron  FM1608 chips. After I read the experiences of others in the group, I ordered a DS1225AD-200 from Mouser, and a couple of FM1608's to be sure I had functional chips. Well, the DS1225 chips arrived from china and the chips from Mouser arrived, and were promptly tested in two different programmers. The chips from china are junk and will not program. The chip from Mouser worked the first time, and a number of times testing it since. So to parrot another poster, DO NOT buy your chips on -bay. The chips I ordered from two different sellers are junk!

The mechanical parts arrived yesterday (knobs shafts etc) I ended up ordering an entire control panel to scavenge for parts from a seller on -bay in Israel. Everything I needed to repair the 2445B was there, and has been changed out and re-installed in my 2445B. Everything test exactly the same as the original tests. One note of interest, on the back side of the control panel is a sticker listing the part number as well as the assemblers ID number. Both panels were assembled by the same person!

As soon as the capacitor for the A5 board arrives, I'll do the swap out and hopefully I can remove and read the DS1225Y and not loose my calibration. I'll have access to the same programmer as sparkybg used on is rebuild. Hopefully, I'll be as successful as he was. I have made a video of my EXER2 settings, so if I loose the calibration, I can use them to modify one of the good BIN files that I have downloaded from the net.

Last weekend I went to the Puyallup, WA hamfest/electronics swap meet. While there, I came upon two 2465's that are non functioning. I figured I could at least use them for parts. Anyway, the price was right ($80.00) for the pair, so they followed me home. I have performed some testing on them. One is completely dead, the other actually has a trace when I press the beam find button. Looks like I have some more fun waiting for me when I get the 2445B finished.

Sorry for the long post, but I wanted to get everything up to date.

Mitch
 

Online tautech

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Re: 2445B Repair
« Reply #1 on: March 13, 2015, 01:52:23 am »
@ mskobier
Mitch, thanks for sharing this, I'm sure it will be of help to others.  :-+
Pics etc would be great too.

As you might have some leftovers  ;) , put a flag in your profile so if anybody close needing bits might know which country you are in for a PM.
« Last Edit: March 13, 2015, 04:46:14 am by tautech »
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Offline Zucca

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Re: 2445B Repair
« Reply #2 on: March 13, 2015, 08:11:57 am »
DO NOT buy your chips on -bay

AMEN TO THAT!
Can't know what you don't love. St. Augustine
Can't love what you don't know. Zucca
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Offline mskobier

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Re: 2445B Repair
« Reply #3 on: March 14, 2015, 11:53:08 pm »
All,
     BravoV asked if I would continue to post in the thread he started "Tektronix 2465B Oscilloscope Teardown" in the Test Equipment section to keep the info on this series of scopes in one place. Made sense to me to do so. I have updated my latest activities in that thread and will continue to do so. This should end this thread. Here is the link to that thread

https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/

Thanks
Mitch
« Last Edit: March 14, 2015, 11:55:09 pm by mskobier »
 


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