Test Equipment Anonymous

mnementh wrote: ↑Thu Sep 05, 2024 5:08 pm I sortof assumed you'd just steal a battery out of one of your Winblows laptops from work to bust up for decent quality cells...

That makes me think of an old slogan, and mutate it to "WWBOFH do?"

mnem
*shameless*

Ok minor update. Mostly thinking. I looked at power options because quite frankly replacing the NiCd cells is a no. Options considered were:

1. Replace with NiMh. Discarded due to cost.

2. Replace with power bank and USB-C. Discarded due to cost, complexity and safety.

3. Run on external DC power only. Urgh just no.

4. 8V SLA. Discarded as requires mechanical and electrical work.

5. Convert existing charger into 7.5V series regulator. Bingo.

So I did some scribbling and I can remove about 8 components from the HV board and reuse the charge transistor for this. Add three new resistors and a TL431 as a reference and job done. I will order the bits tomorrow which total about £2. This is still only a little more than 10% of what I paid for the scope so border line acceptable

This is similar to the battery eliminator circuit mods I did on Fluke DMMs.