Tektronix 2445 Scope Repair? ANY help would be appreciated!!!

Discussion in 'Troubleshooting and Repair' started by Prevost, Jan 6, 2017.

  1. Prevost

    Prevost

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    Hi, my name's Alex and this is my first post to the forum, so please be nice :D
    I was wondering if someone could provide me some insight with what might be wrong with my Tek 2445 Oscilloscope.
    I finished an electronic technology program in CEGEP (Quebec's equivalent of college) and upon graduation, our department let us take some old lab equipment home with us. I ended up with this scope that kinda only half works...
    I would REALLY love some help fixing it (if its at all possible). I'm pretty lost right now....

    I downloaded the service manual and determined that there are at least three problems with it:

    1) The most obvious issue appears to have to do with the crt. I dont know WHAT is wrong, just that it's almost certainly related to the crt. Basically, it's entirely capable of displaying a clear and concise signal (i havent hooked it to any circuits yet, i also don't own a function generator) as i have been able to calibrate it. However, the portion of the readout that should be displaying information like the channel, frequency, amplitude, Vpp, etc... of a signal is garbled and unreadable. (I'll attach a picture).
    I have only been able to (just barely) decipher the text displayed when it boots (or when i force it) into the "Diagnostic Monitor".

    Which brings me to Problem #2:
    It consistently fails Diagnostic Test 04. From what i understand, this is related to the device's readable memory... something called EAROM (Electrically Alterable Read Only Memory)?
    The exact error code is 01 which, according to the service manual indicates: quote "Parity error on read (bit 0 set)". I'm not certain what this means or how i may be able to fix it? I know how to run the Exercisers, #2 of which allows the user to examine the device's memory locations, of which there are 100 (decimal)/63 (hexadecimal) and their parity.

    3rd, it also appears to fail a kernel test about 50-60% of the times i try to boot it up. Everything lights up but then goes out again (including the display), leaving nothing but a blinking Trig'd led and the fan to tell you that its powered on at all.

    This is everything i know and understand about the issues, so if anyone has ANY insight at all, it would be very much appreciated.

    PICS:
    20170106_175331.jpg 20170106_175406.jpg 20170106_175458.jpg 20170106_175610.jpg 20170106_183054.jpg
     
    Prevost, Jan 6, 2017
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  2. Prevost

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    I think your best bet would be to find a forum dedicated to Tektronix maintenance and repair.

    I'm sure there was one, but I can't remember its name.

    If nobody else knows, I'm sure you could ask here.
     
    (*steve*), Jan 8, 2017
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  3. Prevost

    shrtrnd

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    People have recommended some forum out there that I don't remember the exact name of, that deals specifically with Tektronix equipment. Google it and ask them.
    Frankly, from what I see in your pictures, you may have a focus or blooming problem (that can be adjusted), but
    your root scrambling error looks to me like it's displaying in some language other than English.
    Does the scope have a menu for changing the language?
     
    shrtrnd, Jan 9, 2017
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  4. Prevost

    davenn Moderator

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    http://groups.yahoo.com/group/TekScopes/
     
    davenn, Jan 9, 2017
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  5. Prevost

    Velliger

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    Try forum.tek.com
     
    Velliger, Jan 12, 2017
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  6. Prevost

    mister natural

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    Hi, Alex. I recently acquired a Tektronix 2440 scope, similar in design to yours. It didn't have any display, but since there was some light flashing during booting and at shut down, I was convinced that high voltage was there. After a thorough cleaning of all the accumulated dust, which alone made no difference, I carefully pulled out all the ICs that were on sockets, one at a time, and re-seated them, making sure no pins got bent. Since then it has been working perfectly. So give that a try, the scrambled alpha-numeric display could well be attributed to a poorly seated ROM chip, which are used to generate the text and are exchangeable since they can be programmed for different languages. Good luck!
     
    mister natural, Apr 6, 2017
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