Hi!
I am also working on a Bosch AL3640 CV I had to replace the 180k resistor, the uc3842 ic and the P6NK90 N-FET components. Now the machine turns on and the output dc 39v is present on the relay. However, the 2 2k-ohm resistors connected to the relay will be hot in 30-40 seconds. The battery is not connected to the device. Can you help me, what could be the problem the device?
Thank you in advance for your help!
Zoltan

Zoltan, July 2023

Having seen the sudden and severe damage a lithium battery fire can cause, please consider the wisdom of blindly replacing components without understanding the charger's workings. A new one is cheap enough. Here's one with a warranty.

https://www.ebay.co.uk/itm/266335878535?

Ddfh, July 2023