TEKTRONIX 2430A

[Stevescope]

I have this scope. I bought it some years ago and it was perfect with the self-test OK (full PASS). I put it in a cupboard one year ago and there left. Now I turn it on and I find a lot of FAIL.

3000 SYS-RAM FAIL: 3200 A11U440 e 3300 A12U350
4000 FPP FAIL: 4700 BATT STATUS - 4720 LOW - 4722 U664BT
6000 CKSUM-NVRAM FAIL: 6200 - 6300 - 6400
7000 CCD FAIL: 7100 CENTER - 7140 ENV-FISO-SLOW 7142 CH2
8000 PS FAIL: 8210 POS GAIN CH1 and 8400 GAIN (all 50 mV to 2mV)
9000 TRIGS FAIL: 9100 OFFSET, 9110 A-TRIGGER, 9120 B-TRIGGER, 9113 SLOPE e 9125 EXT1x5*
9200 GAIN FAIL: 9210 , 9211 CH1 and 9214 EXT1x5*/ 9220 , 9221 CH1

What is happened ?

 

[shrtrnd]

When the scope powers-up it compares it's most recent self-test, with it's last stored self-test, ....which was apparently a long time ago. And that can be complicated by the ambient temperature, from last self-test, to the new one at turn-on. If the temperature is considerably different (winter/summer for example, ...if your work area is
out in a garage or something), the tests may not be able to come to an in-tolerance condition, and you get error codes.
Your failure codes are just too extensive for me to believe you have an instrument failure. (Unless you've got some bugs in your cupboard that got into your instrument).
Any moisture in the insturment?
...I'll look for the manual for your instrument, and post what I can find after I check it, ... later, ....

 

[Stevescope]

Thank you for the answer. The wood cupboard is in the garage, but there's no moisture and no bugs inside the instrument. Of course in winter the temperature is cold 4-5° C (39-42° F) and in summer hot about 30-32° C (91° F) but I never turn on the scope with the temperature under 20° C (68° F).
The power supply is OK, all voltage in tollerance.
CH1 is out of tollerance (about 20 %).

I do not know what is happened, the scope was OK when I put it in the cupboard.

 

[shrtrnd]

First I'd try the diagnostic function.
You can exit the EXTENDED DIAGNOSTICS
Press 'SPECIAL' push-button, you'll get "DISABLED-SEE MANUAL"
Remove connector J156 from the A13 board.
Don't try this, unless you can recalibrate the instrument.
Press 'SPECIAL' button again, you'll see 'EXTENDED FUNCTIONS"
"WARNING: SERVICE ONLY-SEE MANUAL", with the choices:
COLD START, CALL PATH ON:OFF, and FORCE DAC.
COLD START eliminates all the previous calib constants and restores them to known nominal values. it's usually used for removing scrambled data from the NVRAM (and you NEED to use it when replacing the memory battery (Which may be your problem).
BUT after a COLD START, a partial recalib is needed to return the instrument to it's previous state. If you can't do that, I wouldn't try this.

 

[shrtrnd]

Wait on that last post, .... msg sent before I was done, ....
continuing, ....

 

[shrtrnd]

From the beginning:
You can exit EXTENDED DIAGNOSTICS mode by pressing
MENU OFF/EXTEDND FUNCTION BUTTON
LED's flash, and are held on for a short period to indicate a failure has been found: then the sequence of turning on the LED's begins a code number of the failed test.
1st number, 'READY' LED turns on for binary number of test failure level,
2nd number is test number
(ALL LED's flash to indicate to you, space between test numbers)
3rd number of failed test turns on both 'TRIG'D & READY' LED's, and are summed to obtain the 3rd number (1+2=3)
And all LED's are lighted to separte the numbers.
IT takes practice to learn to read the code.
If you miss the code the first time, you need to turn off the 2430, and turn it back on to read the code again from the LED's
(The 4th number is always a '0')
Again, I wouldn't try the 'COLD START" if you can't recal instrument.
But this is what I'd do, to clear-out all the old data, that might be mucking-up your initial start up.
You might replace that memory battery, ...it may be what's screwing-up your initial
start-up test in the first place.
The service manual for this istrument is 'Maintenance-2430 Service',
you might be able to get it online someplace, Diagnostics start on page 6-25.
I hope you get this going easily. I'd be looking at software problem, probably the
memory battery, more than a hardware instrument failure.
Good Luck.

 

[Stevescope]

Thank you so much, very kind. Yes I think I can recalibrate the scope I have a Oscilloscope Calibrator Bradley 192 and other instruments.
Now I print your messages and in this weekend I try to do something.

This 2430A last version have NO the memory battery.

 

[shrtrnd]

My manual is from the 1990's.
If you've got no memory battery, there must be a way to reset the scope for default (factory settings), that might clear the problem in your memory IC's.
Good luck with it.
No one failed IC, should cause all your error codes to go haywire.

 

[Stevescope]

Hi, I tried a COLD START, no LED flashing and in EXTENDED-DIAGNOSTICS I can see all items PASS except 7000 CCD, 8000 PA, 9000 TRIGS which are no indicated. Also on the screen I saw all MVRAM parameters erased. After that, I tried to push CAL/DIAG and then SELF CAL and SELF DIAG, now all EXTENDED-DIAGNOSTICS are PASS. EXT CAL is UNCALD. Probably now must I do a complete recalibration ?
Could you indicate where is the calibration procedure in the manual ?

 

[shrtrnd]

Recalibration starts Section 5 of the Tek manual (page 5-1).
Internal Adjustments starts on page 5-3. It describes which internal jumpers must be pulled-off to enable the menu choices for extended calibration.
Some cals will use your Bradley 192, some cals use internal patterns generated by the scope itself.
Self calibration is on page 5-10
External Calibration starts page 5-11
It looks like you cleared whatever was giving you the erroneous error codes, now you just have to recal instrument.
Good luck.

 

[Stevescope]

Thank you so much, have you any suggestion for the calibration ?