Jet AFS-1000B Air Cleaner

[sam_sam_sam]

Re: Jet AFS-1000B Air Cleaner

What parts are under the big heat sink

[diif]

Re: Jet AFS-1000B Air Cleaner

Whilst not a legal requirement, ensuring all devices are PAT tested have been a requirement for insurance in several places I've worked. Both the device and flex are tested.
That air cleaner is a portable device. It's got a carrying handle on the top.

[stj]

Re: Jet AFS-1000B Air Cleaner

you shouldnt pat-test electronics, the input stage often isnt rated for more than 400v

you dont need to anyway, firstly there is no legal requirement to pat-test anything - it's a scam-industry.
second, it's only for portable devices - hence the name "portable appliance test" and is targetted at the flex and it's entry into the device more than anything.

i look forward to someone trying to rebutt this so i can post a link to the government website!!

[Gromit20]

Re: Jet AFS-1000B Air Cleaner

My JET AFS-500B (looks like the same board as the 1000B) was making grumbling noises on startup and not really getting up to speed so initially I assumed that the bearings in the fan had dried up (it's about 16 years old), but on giving the rotor a spin by hand it ran for ages with no mechanical noise, so I had a search and arrived here.

I've been familiar with ESR problems for many years - when I first fixed power supplies with high ESR capacitors it was just like magic! I had a Bob Parker ESR meter and more recently have been using a Peak Atlas ESR70 ESR meter.

So, took the board out and firstly visually checked the Cs (C1 and C3) for cracks bulges etc. All looked OK so tested their ESR: C1 0.94uF/0.60 ohms, and C3 590.4uF/0.16 ohms. Not what I was expecting, ie they measured OK!

Powered up the board and found 2.6V across C3, where I'd be expecting something like 5V or so, with a 5V6 zener close by. Despite the low volts across C3 the board seemed to work fine; the control buttons did what they were expected to do and so did the LEDs. However this was without the motor connected, as it was still in the cabinet mounted high in the workshop.

So, long story short, the actual problem was the two-pin connector for the AC-in, marked AC1 and AC2. While gently flexing the components and looking at the solder side I noticed that the connector had been soldered in without the pins being square to the board, so the tips of the pins were only attached to the board with a thin film of solder, and when wiggled a bit the solder broke away.

I desoldered the connector, cleaned the pads etc and resoldered it correctly. This now gave me 5.2VDC across C3 so I confidently got up the ladders again to refit it to the cabinet. PAT tested it (don't forget the earth wire from the earth stud to the motor). Powered it up and...

All sorted!

[kc8adu]

Re: Jet AFS-1000B Air Cleaner

c2 being marginal could do this too.
motor drops the line voltage slightly and micro resets.
measuring across c3 while starting the fan may reveal this.
or just replace c2 and c3.

[wdreisbach]

Re: Jet AFS-1000B Air Cleaner

Thanks for all this information on this forum! My neighbor also has the JET and he recently (Nov 2017) tried to fix it by replacing the board (for $80) that he bought around 2015. Unfortunately, he didn't screw down the board (just wanted to see quickly if it worked) and the fan sucked it towards metal and the sparks did fly! The board is really messed up; blew some PC runs, fried some resistors, and blew apart (like into 2 pieces) one of the Triacs.
Anyhow, I have this 'fried' board Rev 1.1 and the original defective board Rev 1.0 and I think given this info that I can get one of them to work; I'm focusing on the original board since it is intact. I replaced all 3 Triacs on the Rev 1.0 board (they really aren't very expensive, like under $1 each, and upgrade from 400v to 600v) and suspect the 2200uf 10v 'slightly bulging' capacitor so it will get replaced as well. (I did unsolder the capacitor and it seemed to be ok, but I'll replace just to be sure.) I'll check the board out carefully at the bench to be sure the power supply and IC is working before putting it back into service. The photo of the old board is exactly like Elmo's post above.
I noticed that his new board is REV:1.1 and they made some changes. The Triacs were changed to 600v, not sure if this was because you can't get 400v anymore or for some other reason. Also instead of 2x BTA08 they went to one BT137-600E (for M pin) and one BTA08-600C (for L pin). BT139X-600F still used for the S pin. Also there are circuit changes that I have not traced out. They also changed the IC to an 18 pin device "SN8P2612PB 145CATD11", and they added some resistors and capacitors too.
As I'm focusing on the old board, I probably won't work on this one Rev 1.1 unless I can't get the old one working again, for example if the IC is dead.
Again, thanks for the input from this board - very helpful!

[elmo]

Re: Jet AFS-1000B Air Cleaner

I didn't record the voltage. I think it was a little over 5 volts. However, the ripple was substantially more - about 60 mV. Both times the voltage was measured with the control board out of the air cleaner, i.e. no load on the triac.

[budm]

Re: Jet AFS-1000B Air Cleaner

Thanks for the follow-up on the repair.
BTW, what DCV did you get before you changed the C3?

[elmo]

Re: Jet AFS-1000B Air Cleaner

Success! I replaced C3 and am now getting 5.1 VDC with about 5 mV of ripple. I seems our forum is well named. Bad capacitors have been the cause of two of my electronics problems and probably more. I have now run the air cleaner for over an hour without shutting down. Thanks to everyone for all their thoughts, effort, and advice.

[kc8adu]

Re: Jet AFS-1000B Air Cleaner

half a triac equals a diode.

Since triacs are used in AC circuits, I can't see how a bad one would impose a DC component to the load. If the triac becomes shorted, your motor runs all the time. If the triac has turned into a resistor, then the motor gets lower AC voltage than it is used to. The motor might not start or may get hot, but the triac will get even hotter. So far, no evidence of thermal problems. The controller would be the next best choice.

[Longbow]

Re: Jet AFS-1000B Air Cleaner

Other possibilities, taking into consideration all of your observations: the 32 KHz clock crystal used in this circuit is a type widely used in lots of gear. If possible, check the waveform on the osc pins, or if test equipment is unavailable replace it next time you place a parts order (they are very easy to find and inexpensive). Also check the resistor on pin 2 of the controller. This resistor sends zero crossing information to the controller, and it may have changed value. That would upset the firing on the triacs.

As mentioned before, the soldering on your board is terrible. Heat and vibration will create miniature cracks that can hardly be seen. I would run small tinned bus wire along any of the AC traces starting with the board AC connector pins. The points where the connector pins solder to their traces are of special interest. Same goes for the legs of the triacs.

[elmo]

Re: Jet AFS-1000B Air Cleaner

Thank you all for your suggestions. I can't see the motor, but I presume that is the correct one since it is the replacement part for the AFS-1000B. I think the motor is all right since I ran it for over an hour with the board jumpered out. I just measured the -5V power supply voltage. It does indeed measure 5 volts with about 60 mV of ripple. Of course this is with no load on the board. This may not be surprising since the blower always ran when started. It just does not run for long when powered by the board. I, too, am suspicious of C3 since the top of it is bulged out somewhat. I guess the only thing to do is to replace it and see if that helps. It seems that most of you think Panasonic makes good capacitors but are not Nichicon, Rubycon, Kemet,ans Vishay good brands too?

[kaboom]

Re: Jet AFS-1000B Air Cleaner

That's a multispeed PSC motor- exactly the same as a common furnace blower motor. Four wires=three speed taps, plus neutral/common.

If more than one tap is energized at the same time, you get smoke and a dead motor.

[budm]

Re: Jet AFS-1000B Air Cleaner

Is this the blower motor?
http://www.ereplacementparts.com/motor-p-446851.html
It has AC caps for the motor.

[budm]

Re: Jet AFS-1000B Air Cleaner

Do you have the pictures of the blower motor?

[Longbow]

Re: Jet AFS-1000B Air Cleaner

Half shorted or leaky triacs will impose a DC component to the voltage fed to the motor. An induction motor such as the one you're dealing with will not tolerate this. The stator will saturate- motor draws excessive current and pops the breaker/overload.

Since triacs are used in AC circuits, I can't see how a bad one would impose a DC component to the load. If the triac becomes shorted, your motor runs all the time. If the triac has turned into a resistor, then the motor gets lower AC voltage than it is used to. The motor might not start or may get hot, but the triac will get even hotter. So far, no evidence of thermal problems. The controller would be the next best choice.

[stj]

Re: Jet AFS-1000B Air Cleaner

the original soldering is a joke, most of it is only touching the pins and not binding to them.
it almost looks like they used the wrong type of flux on the production line.
specially the large connector.

[kaboom]

Re: Jet AFS-1000B Air Cleaner

If C3 is bad/fake/questionable, the micro gets bad power and resets- unit appears to then be "off," since powerup state for micro is to default to fan off.

This is a capacitive divider power supply- C2, 2.2u (10%) if decreased in value will cause strange symptoms- things like micro dropping out upon driving triac gates (for instance).

I'm suspecting C3- replace with good 105 degree low esr unit, such as for an SMPS. Extreme ripple into that micro will wipe its programming, seen this with cheep "tower" fans and crock pots. Use PW, HE, FR, FC, or equivalent.

[elmo]

Re: Jet AFS-1000B Air Cleaner

Sorry about the photos. I thought I had uploaded then earlier.

[budm]

Re: Jet AFS-1000B Air Cleaner

Still no pictures of the boards?