Products > Test Equipment
Tektronix TDS220 repair
sbeube02:
Hello from France!
I am new to this forum. Found lot of great stuff and useful informations.
I would like to share with you my TDS220 fail search and repair procedure.
Someone given me a TDS 220 for free as it was not calibrated and not working.
Here is a picture of this tiny little scope:
I plugged it on the mains, it powered up but the screen stay white:
Decided to open it and look what I find!!
The power connector to the main board is no longer connected :o
I plugged the connector and now the scope power up but display a strange message:
Acquisition CH1 and CH2 self test failled :(
Anyway, if I press any button the scope display traces and works correctly.
If I go to the service menu, I can show lot of errors in the log:
At each later power up, the line trigger self test failled (error #6 DI).
The error appeared once at powerup #349 and at #508 and folowing.
I have no history of this scope but I can tell these things:
* The power supply board is from 96' and there is a ground modification
* One diode on the power supply seems to have already replaced (brillant solder joint with flux)
* All boards are dated from circa 96' except the main CPU board wich is the newer one from 2000 with firmware v2.03
* Serial number is early type B014XXX
* CH1 connector is broken at PCB side
Here are some random pictures:
So the next steps are to repair this broken CH1 BNC connector and repair the trigger line.
Any help will be appreciated ;)
andy2000:
There should be a 50/60 cycle signal coming out of the power supply for line trigger. I would start by verifying that.
dr.diesel:
--- Quote from: sbeube02 on July 22, 2015, 12:54:06 pm ---Someone given me a TDS 220 for free
--- End quote ---
I'm gonna get flamed for saying this, but you scored big my friend! I still use my 220 to this day, completely silent and simple, a pleasure to use.
sbeube02:
I will check the 50 Hz signal from the power supply board.
Anybody have a high res. picture of the PSU board? I suspect some components to have been changed previously.
For information here are some pictures of the main board with firmware v2.03.
The cpu is smaller than the previous version and the ROM is now stored in a tiny BGA flash chip.
The main chips on this board are:
* 2 x NAIS V214S -> input high voltage photo MOS relay
* NATIONAL SEMI ASIC ADG321D -> front end amplifier acquisition ASIC (amplifier, ADC and trigger logic)
* NATIONAL SEMI ASIC ADG422 -> display ASIC and front panel driver
* MOTOROLA MC68SEC000PB10 -> ยต-processor
* XTAL 60.606 MHz
* OKI M54V16255A-45 -> 4 Mb DRAM ?
* IDT 74FST6800PG -> 10 bit bus switch
* AMD AM29DL800BB90 -> 8Mb CMOS Flash memory
* ELANTEC EL4581C -> Video Sync Separator
* 3 x unknown voltage regulator
* Various 74HCT chip and LM358
Now, the problem with the CH1 BNC input connector:
The center conductor is not broken but can move in the PCB. I don't know how to explain that, it's like the solder have shrinked.
The gold plate one the connector is oxydized :
You could see the BNC connector have four ground legs compared to the older one who have only 2 ground legs.
I have desoldered the bottom shield for better access. The BNC connector was cleaned and correctly resoldered:
That should work better now!
Next step is the line trigger signal investigation ???
vishaldotgupta:
hi
i also have this model with error messages of ADG and line trigger fail. surprising after repeated on off the system some times work okay.
when it is working okay the probe output is 1khz and when failing about 3 khz.
i suspect that some how the calibration constants are not loading into the system. These are in flash memory. I removed the flash
and powered up, the system works with same error message. the calibration command doesnt function
a way could be to read the flash from working unit and reprogram another one with same constants or to do a fresh programming altogether
Navigation
[0] Message Index
[#] Next page
Go to full version