Hakko 470 solenoid

[sampler1]

Hi all,
I have a Hakko 470 with an 802 gun. I have no suction and when I remove the solenoid valve all works fine. I guess the solenoid is toast? Does anyone know the voltage ? Can anyone explain its purpose and function. Also does it even matter if its removed?
Regards,

[ijchan223]

i really don't see a reason it is there. My guess is that it is there to hold a small vac in the system so you will get suction faster.

[helius]

The solenoid B1033 opens the spring-loaded valve B1032 to control the timing of suction for the desoldering gun. Specifications indicate that the controller delays 0.2 sec after the button is depressed before suction is applied, and again delays 0.5 sec after the button is released before terminating suction. One reason you would want to use a solenoid to control suction, instead of relying on starting/stopping the pump, is to prevent a pressure pulse from pushing air outward. It also helps to prevent the tip from clogging.

The solenoid most likely operates from the main DC voltage which is 24V I think? I have a similar unit I can check.

[floobydust]

I have a Hakko 470-2 and did a schematic for it here https://www.eevblog.com/forum/repair/hakko-470-471-de-soldering-station-schematic/msg1298018/#msg1298018
There are two timers- one for the solenoid (on delay), and another for both the pump and solenoid (off delay). They have trimpots to set the delay time.
When the gun trigger is pulled, the pump starts and after a short delay the vacuum solenoid valve opens, to give a crisper, fast vacuum pulse at the tip.
Without it, the tip vacuum would slowly come up and not as clean a desolder joint results.

I would check if the solenoid is getting pulsed and that it's not plugged with junk.