[time-nuts] T-Bolt lightning damage

John or Susan Lundberg Lund5 at infionline.net
Sat Jul 2 09:01:02 EDT 2016

Two weeks ago we had a lightning strike a tree in the backyard, and it coupled energy onto the coax to my 20M dipole. The coax was disconnected from the house, but the energy jumped to another coax running to my FMT setup in the garage. Carnage! The last (I hope) piece of equipment that I am attempting to repair is my T-Bolt.

There is no visible sign of damage to the board and the external power supply is functioning, but Lady Heather reports no communications with the board. 

Voltages on the 232IBE ic suggest that it is damaged, in that there are only 4 volts on pin 2 (should be +10) and +0.8 volts on pin 6 (should be –10 volts). It appears that the 232’s on-board dc to dc converter is not working. 

While I was making the measurements, I felt something radiating a lot of heat. Poking around with my finger identified the large ic next to the 232 chip as the source of the heat. This chip is labeled “Trimble” and has a FW=3.00 label on it and another label that reads 48051-30. This ic gets hot enough to burn my finger within about 5 minutes! Before I salvage the oven and consign the pwb to the scrap box, I thought I would ask if this is normal? If it is, I will go ahead and replace the 232 chip.


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