Nexus 5 LG with a dodgy power switch.
I had to use a microscope in order to see and solder the new switch in.
Photo shows a pin next to the switch for scale…
Here’s a macro view of the old switch. Soldering to the two pads at the back was entertaining!
After putting the scope back together, I thought, perhaps it would be a good idea to copy the EPROM data off in case they loose their programming/get corrupted.
Date code is week 8 of 1989 which makes them nearly 27 years old. Bit of a struggle getting to them without taking the whole lot to pieces again. But images are now safely copied off…
Dating from around 1989 a piece of test gear that I imported from the US at great expense about 12 years ago. I recently dug it out to try and it was failing it’s self test. The calibration values are stored in non-volatile RAM, which is a memory chip with built in battery.
The repair was successful, although the specifications and size of this machine are pretty dated when compared with my modern Rigol scopes.
Taking the scope apart and removing the main board:
This is the original Dallas NVRAM. I desoldered the chip and put a 28 IC pin socket on the board. Fitted a replacement chip, which was a cheapo Chinese eBay special, so not sure of its age. However the chip socket will make future replacement simple.
On power up. The scope started rebooting at random intervals. So I took the power supply out and checked some of it’s output capacitors. Two were found with very high ESR values and a further one with slightly high value. All were 220uF 50V. The other capacitors tested ok. There was some electrolyte leakage from the worst caps. And slight board damage. So this was cleaned up:
New capacitors fitted:
After a reset and restore to default calibration, all the self tests passed:
Finally the calibration routines were done: