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skot
12th July 2017, 05:58 PM
Looking for the easiest way to Test if a Capacitor is faulty.

4 Years ago the PC Board on my Jet Air Filter got corrupted by a Gecko crawling inside and crapping on the board. I bought a new PC board and gecko proofed the board so all was well for 4 years until recently I tried to turn the Air Filter on and the motor turned very slowly and made a humming noise. Youtube shows plenty of vids of the same problem and they mostly stem from a bad capacitor.

Each vid I watch seems to replace a different Cap. There is no visible signs of damage to the Caps and I took a punt and replaced the Cap circled in Red on the image below with a new one. This didn't solve the problem...motor still hums and moves slowly. No big loss, the cap only cost 95c so it was worth a try.

I have no

416176

There is also a Cap on the motor. The motor spins freely by hand so it is not seized or sticking.

I have a number of options:

1) Purchase a new PC Board at $165.00

2) Replace every Capacitor on the Board (circled in Blue in image above above) which wouldn't be a big cost but I don't like changing things over just for the sake of it.

3) Find a way to test the Caps with my multimeter to find the faulty one.

Number 3 above is my preferred option but I am not sure which setting on the multimeter or what I should be looking for in the readout...essentially I am looking for a crash course in finding a faulty Capacitor.

My multimeter is the type shown in image below

416177

Cheers Scott

BobL
12th July 2017, 06:45 PM
Not all multimeters will have a capacitance (C) measurement setting but that is what you will need.

To measure them correctly you will need to disconnect the power and wait for couple of minutes so they self discharge.
To be sure the are discharged you can connect a light globe across the end of the cap.

Then disconnect one leg of the Cap from the circuit board and apply the meter leads to each leg - it takes a few seconds to do the measurement so wait a while before removing the lads.

The next problem you might come across is that the Cap might have a capacitance that is too large for the meter to measure.
Then you need to combine other know caps caps in series and this will reduce the overall capacitance to a measurable level.

The total capacitance Ct is related to the individual caps (1, 2, 3 etc) by 1/Ct = 1/C1 + 1/C2 + 1/C3 etc
If 1 is your unknown and you measure Ct, C2 and C3 you can do some maths and find C1.

Repost both you picture so I can read the scales on the meter and the values of the components on your board.

Pete57
12th July 2017, 09:09 PM
I am not familiar with the Jet Air Filter so don't know what the circuit board does. But a humming motor could be the motor start capacitor. If the start capacitor is the issue, giving the motor a spin then applying power while still spinning should make it run. Warning - only do this if safe to do so.

Peter

skot
12th July 2017, 10:02 PM
I'll give it a try...I know what you mean ...I'll start it spinning with something other than my fingers....stick of celery perhaps.

If it is the Starter Capacitor, it is the one attached to the top of the motor. At least that may eliminate one of the Capacitors in the equation.

skot
13th July 2017, 01:36 PM
Well it doesn't appear to be the Starter Capacitor.......I was able to give the motor a big spin and then turned the unit on and the motor immediately slowed down to it's slow turning & humming again as if a brake was applied to it.

Cliff Rogers
13th July 2017, 01:43 PM
Disconnect the one on the motor & try the same push start trick.

It could be shorted & that will give you the same symptoms.

skot
13th July 2017, 05:34 PM
So instead having the current pass through the Capacitor......join the 2 wires that the capacitor is connected to at the moment and take the capacitor out of the line.

BobL
13th July 2017, 10:05 PM
NO definitely not.

1) Start with the Motor off.
2) spin motor by hand
3) remove hand and apply power.

Cliff Rogers
13th July 2017, 10:07 PM
So instead having the current pass through the Capacitor......join the 2 wires that the capacitor is connected to at the moment and take the capacitor out of the line.
No, disconnect the cap & tape up the ends, then try the push start.

If the cap is shorted, that is the same as connecting the 2 wires.

The Start winding is out of phase with the Run winding, the Cap causes the AC to be moved out of phase.

It is there to start the motor rotating in the same direction each time.

If it was shorted, both windings would be getting the same phase AC & with one winding out of phase with the other, you would get the symptoms you are describing.



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skot
14th July 2017, 11:15 AM
Cliff,

That doesn't appear to be the problem. I tried as per above but it still has the same problem.

There is another capacitor on the board ...2.2uF 250VAC....the big rectangular black one on the PC board image I posted

I saw a Youtube vid that showed a Jet Air Filter with the same problem as mine. The owner replaced that Capacitor and that fixed the problem but when I enquired at Jaycar Electronics, they didn't stock those types.

Any help in where I can source one of those 2.2uF 250VAC capacitors would be appreciated. This will probably be my last attempt in repairing the PC Board components as it should be just a couple of dollars for the Cap. If that doesn't work, I might just have to go to Gregory's and cough up the $165 for a new board. (I think the last one I bought for this unit in 2013 was only $75)

Cheers

Scott

Big Shed
14th July 2017, 11:34 AM
Try Mouser Electronics

Mouser Electronics Australia - Electronic Components Distributor (http://au.mouser.com/?gclid=CjwKEAjwtJzLBRC7z43vr63nr3wSJABjJDgJOwR_BXAKxRdPGbvr4UnzykxlXxMq3wTxigaSfJjjJxoC8z3w_wcB)

..

Cliff Rogers
14th July 2017, 03:26 PM
Ignore the value on the pic, it is just a sample to show you what it looks like.
https://www.wagneronline.com.au/motor-start-horizontal-mount/capacitors/electronic-components/2smf250-433/39/pd/
https://www.wagneronline.com.au/motor-start-vertical-mount/capacitors/electronic-components/2sml250-369/34/pd/

skot
14th July 2017, 05:13 PM
Thanks Cliff...that would explain why the one I removed from the board says 105K 400VAC....going to Jaycar tomorrow with Capacitor in hand to see if they have one...if I can not get one locally tomorrow I will give Mouser Electronics a try as recommended by Big Shed.

This is the one I removed .....


416376


I am hoping that Jaycar has staff that knows their gear but I have also looked on the net for a conversion table...can you knowledgeable folk tell me the equivalent...is 105K = 1uF ?

Lappa
14th July 2017, 05:56 PM
Yes. 105k is 1uf. The code equals. 10 *10^5 if I remember correctly.

We buy most of electronic parts from Jaycar or, if they don't carry it, element14 (used to be Farnell)

B32524Q6105K - EPCOS - CAPACITOR POLY FILM 1UF 400V RADIAL | element14 Australia (http://au.element14.com/epcos/b32524q6105k/capacitor-poly-film-1uf-400v-radial/dp/2127336?mckv=s_dt%7Cpcrid%7C59148083448%7Cpkw%7C%7Cpmt%7C%7Cslid%7C%7Cproduct%7C2127336%7C&gross_price=true&CATCI=pla-299831399493&CAAGID=12550800888&CMP=KNC-GOO-SHOPPING-2127336&CAGPSPN=pla&gclid=CJOftYyaiNUCFc4IKgodcN4DAw&CAWELAID=120185580000190992)

BobL
14th July 2017, 06:09 PM
Yes. 105k is 1uf. The code equals. 10 *10^5 if I remember correctly.

Gnats hairs, but 10x10^5 would be 10^6 or 1 Mega . . . . .
10x10^-5 would be 10^-4
To be 1 uF it would need to be 0.1x10^-5

For some codes see. Capacitor code table | Kaizer Power Electronics (http://kaizerpowerelectronics.dk/theory/capacitor-code-table/)

Lappa
14th July 2017, 08:56 PM
??? BobL

10^2=100
10^5=100000
10*10^5 = 1000000 (tel:1000000)
105k = 1000000pf = 1.0uf

Cliff Rogers
14th July 2017, 10:18 PM
http://www.marvac.com/fun/images/pmylar.jpg

http://www.electroschematics.com/wp-content/uploads/2013/02/capacitors-eia-code.jpg

Cliff Rogers
14th July 2017, 10:22 PM
You can get components from http://www.altronics.com.au/ as well.

Uncle Al
15th July 2017, 09:09 AM
Apologies up front if this has already been done, I am not familiar with this type of machine.

Is it reasonably easy to bypass the circuit board altogether and just wire up the motor to a 3 pin plug and turn it on to see if the motor by itself runs?

If this can be done, you will be able to identify the faulty section, and then repair or replace as necessary.

Alan...

NCArcher
15th July 2017, 10:51 AM
Gnats hairs, but 10x10^5 would be 10^6 or 1 Mega . . . . .
10x10^-5 would be 10^-4
To be 1 uF it would need to be 0.1x10^-5

For some codes see. Capacitor code table | Kaizer Power Electronics (http://kaizerpowerelectronics.dk/theory/capacitor-code-table/)

The marked value is in pF. 10x10^5 pF = 0.001nF = 1.0 uF

skot
15th July 2017, 10:53 AM
Uncle Al...I have heard of that option but my Air Filter is hung from the shed ceiling so I need the Remote control to operate it from floor level which dictates that I need the PC Board to be working properly.

I will order a new capacitor on line as Jaycar don't stock them....Not a big problem, I'll just have to wait until I attempt to fix it again.

Thanks to all for the feedback, I am hoping that it is the Cap I am about to order will fix the problem.


I am having fun trying to find 400VAC......plenty of 400DCV

I also have to find a Cap that will fit into the space....the components on the PC board have to fit in the 15mm space between the board and the front control panel.

NCArcher
15th July 2017, 11:06 AM
I don't think plugging the motor in directly would be possible.
I don't know anything about these machines but from the manual it looks like the control card is for fan speed selection and running time. I think the motor has multiple windings to get your 3 speeds. You could connect one winding at a time but it would take a bit of messing about.

Uncle Al
15th July 2017, 10:08 PM
Uncle Al...I have heard of that option but my Air Filter is hung from the shed ceiling so I need the Remote control to operate it from floor level which dictates that I need the PC Board to be working properly.


Skot, what does the remote control thingy do? Is it just on / off, or does it have a speed selection function?.

We have four Carbatec square box filter units at the wood club, 2 of these units fried their circuit boards, so we ordered 2 from Carbatec at about $150.00 each. One arrived after several weeks and was fitted, the other never arrived, never heard from Carbatec regarding the board on back order, but then it was only 3 years ago.

We bypassed the circuit board which only controlled the remote control function (ours aren't variable speed) and purchased an Arlec brand remote power point controller from Bunnings for about $30.00, never had a problem since doing this. We have had 3 of these circuit boards fail over the years, the Arlec system is still working just fine.

Hope you resolve the problem without too much pain to the wallet.

Alan...

skot
15th July 2017, 10:25 PM
Alan,

It is ON/OFF, Time Setting & Fan Speed.

If I can not get the Unit to work with this next Capacitor, I will bite the bullet and buy a new PC Board for $165 but I only live 10 mins from Gregorys Machinery ...they have over 20 boards in stock, so I will drive over and pick one up.

No lost postage

Uncle Al
16th July 2017, 08:32 AM
Ah, not quite the easy fix after all.

You should be back in business soon.

Alan...

skot
5th August 2017, 04:12 PM
Capacitor Update.

First of all, Thank you to all who have kindly offered advice on my Jet Air Filter problem.

I was finally able to source a new 1uF 450VAC Capacitor from an Ebay electronics mob in Sydney and it was delivered to my door for $8.15.

Finally had time today to wire it into the PC Board and I am very happy to say that the new capacitor fixed the problem. The Air Filter kicked up beautifully and was able to be switched between the 3 speed settings and the 3 time settings just like a new one. That's $165 new PC Board vs $8.15 capacitor. It took a little time but it feels good to solve the problem with a minimum of cost.

Only slight downside is that the new cap is slightly larger in physical size to the old one so I may have to do some fiddling around to fit it. ATM it is hooked up but the PC board is not fixed back onto the front panel of the filter. Fortunately the new cap came fitted with approx 80mm long connector wires so I may even be able to place it away from where it is meant to be placed, which is sandwiched between the PC Board & the front panel.

skot
5th August 2017, 06:30 PM
All I need to do now is hang it back on the ceiling.

Here is a link to a YouTube vid which lead me in the right direction. My Air Filter had exactly the same problem.....https://www.youtube.com/watch?v=O8Jb4y7iLis


Pics of new capacitor wired into PC board and I was able to fit it in the space that the old one occupied...with very little wriggle room

417726 417727


Links to my machine now running ...sorry about the noisy wind sounds but that proves it is now working to the max.

Repaired 1 (https://youtu.be/70L3UmD9oIQ)


Together again (https://youtu.be/vzfqy3BbQVk)