Jet AFS-1000B Air Cleaner

[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.

[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

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.

[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!

[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.

[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!

[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!!

[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.

[sam_sam_sam]

Re: Jet AFS-1000B Air Cleaner

What parts are under the big heat sink