Tektronix P6245 Probe Repair - Page 1
Forum section: electronics / repair

author: k1mgy
author_rank: Regular Contributor
timestamp: November 05, 2016, 06:13:12 pm
content: They say it can't be done. But, I never say never.E-bay sent me a P6245 probe whose business end (the probe tip) had been crushed.. looks like it was impinged between a chair caster and a floor. The cable where it enters the probe body (base) is trashed.The probe occasionally complains that it can't be read when attaching to my TDS 744A. Had to adjust the locking collar and this seems to have corrected the issue.Attached, I have no signal from the probe.1. removed the deteriorating rubber around the probe tip, revealing a metal housing.2. Clipped off the cable, which looks to be crap (at the end it has a slight greenish tinge at the braid.. so moisture has been at it for a while).3. The cable attaches to a teflon pc board with the rather sensitive preamp components. The circuit side of this board is soldered to the metal housing through a 3mm hole. Solder wick helped here and I was able to remove the board.4. There are 3 wires and a coax cable in the cable bundle. The coax is intact and attaches to the board nicely. The three other wires, GND, +5 and -5, have detached from the board, and only one of these has left a telltale behind.So, looking for a photo or other guidance as to where these wires connect.Note in photo that the red wire looks to have received enough heat to cause it to move from the bottom-left-most pad. At least, I think this is where it originated. I also note that there are three pads with solder blobs. So this is probably where they go. The question is where...

author: smaultre
author_rank: Regular Contributor
timestamp: July 09, 2020, 05:42:58 am
content: Hello, i also has received the Tek P6245 probe with fault (failed to read config), but the offseted but good siglal is present.When i disaccemble the compensation box, i see that three transistors cr1,cr2,cr3 got "magic smoke" problem..And it seems that flash ic (24C02) has fault too.Now i need help with service manual, marking CR(X) components, and 24C02 dump.

author: picburner
author_rank: Frequent Contributor
timestamp: July 09, 2020, 07:27:30 am
content: Attached the dump of 24C02:

author: smaultre
author_rank: Regular Contributor
timestamp: July 09, 2020, 08:09:18 am
content: Thanksi removed burned elements, it seems it is been the diodes assembles to prevent static.Find, and reflash 24c02 and its recognized and starts to work!Standart calibration signal frome scope, seems to be good, try to connect DC 10V calibrator, and readins looks like normal, but calibration procedure says "FAIL" why?There is some offset on 10mV/div, like a ~ -19mVPS i'll change the serial number to my-one probe in the .bin

author: smaultre
author_rank: Regular Contributor
timestamp: July 30, 2020, 02:57:57 pm
content: Removed burned Op Amp, install the newone, set the offset (as on service manual) and it works, it says "Pass"!

author: RecursiveLogic
author_rank: Newbie
timestamp: September 23, 2020, 08:02:02 pm
content: Thanks for the information and pictures. Can you share details on the components replaced, how you removed the microcircuit (3mm hole didn't seem to free the board in attached images), and flashing the IC? I've included images of the P6249 probe (destructive teardown) for anyone interested.

author: smaultre
author_rank: Regular Contributor
timestamp: September 24, 2020, 05:40:36 am
content: i repair it from the scope connector side.