Bosch al 3620 cv . charger

[petehall347]

found r3 open can i use a 1/4 watt 1M resistor for R3 just to see if it starts up the supply ?
and what wattage should it be ? it measure about 11mm long .
i found schematics here .. https://www.circuitsonline.net/forum/view/157709

[petehall347]

Re: Bosch al 3620 cv . charger

ok to answer my own question i took full responsibility for my actions and proceeded not knowing what might happen .
and yes it can be done and got a green light on the charger .
that just leaves finding out the correct wattage for this 1MEG resistor .
and why is it am even doing this for a living ? as new chargers are only £35 ..

[CapLeaker]

Re: Bosch al 3620 cv . charger

11mm long is 1 watt resistor.

[R_J]

Re: Bosch al 3620 cv . charger

I could be wrong but:
roughly R3+R9+R5 in series across 327 volts gives about 0.32ma, 0.1watt
with Q2 turned on, 327v across 1meg is still only about 0.32ma and 0.1watt

[petehall347]

Re: Bosch al 3620 cv . charger

wonder why they went for a big one then ? just ordered some 2 watt ones there is plenty of room .

[stj]

Re: Bosch al 3620 cv . charger

higher wattage = bigger case
that resistor has to handle 350v dc or more.
small resistors cant because if they are too short the voltage can arc across them

[petehall347]

Re: Bosch al 3620 cv . charger

higher wattage = bigger case
that resistor has to handle 350v dc or more.
small resistors cant because if they are too short the voltage can arc across them

thanks for clearing that up .

[petehall347]

Re: Bosch al 3620 cv . charger

new 2w resistor in and charger is now working .

[CapLeaker]

Re: Bosch al 3620 cv . charger

Sweet!

[sam_sam_sam]

Re: Bosch al 3620 cv . charger

Great job repairing it