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bnull
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Unplug the black cables from the motor, test for continuity, measure resistance and then plug the wires back.
The capacitor seems to give continuity while on the board because the continuity is of the circuit of which is part. A capacitor on its own, plugged
to nothing else, gives a resistance value that increases and goes off the multimeter scale. A value below 1 megaohm means it is shorted inside and
should be replaced.
Quod scripsi, scripsi.
B. N. Ull
P.S.: Did you know that we have a Library?
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Sulaiman
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The capacitor looks OK, maybe poorly fitted.
But, if removed and tested with an Ohm meter, (short/discharge before testing)
it should be a near short circuit initially, rising to 10's or 100's kOhm (leakage current), as it charges up.
If it has a continuously low resistance then it's toast.
Polarity matters!
The motor winding also looks OK but that's not conclusive.
I can't remember, but I'd guess 100 Ohms dc for the winding, but could be an order of magnitude out,
anyway, some dc resistance not in Ohms or megOhms.
You can probably just measure directly between the terminals on the motor as-is.
120 Volts, 35 Ohms: Power = 411W..... maybe,
Do you trust your Ohm meter readings?
Oops! repeat of above, I'm too old and slow 
[Edited on 10-7-2024 by Sulaiman]
CAUTION : Hobby Chemist, not Professional or even Amateur
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bnull
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Quote: Originally posted by Cendre  | Edit 2: looks like that transformer is “obsolete and no longer manufactured”. Is there another component I could use to replace it. I wasn’t
able to find the exact model sold anywhere.
(In Europe) |
I think you can use a 230 V model (030-7342) in place of the 115 V (030-7030) (same specs and pinout) and dispense with the 115 V outlet. Which leaves
us with the heater problem.
The heater is rated to 115 V but, if it is damaged and buying a replacement is still better than buying a new stirrer, a 230 V, 1000 W heating element
is suggested. Unless IKA cheated and used a ~400 W element; who knows.
Edit: The motor is a 120 V shaded pole motor (https://www.ika.com/ika/product_art/spareparts/3581201.pdf). It may have been damaged too. Crap.
If the transformer, the heater and the motor are damaged, you can either look for replacements (notice that IKA sells no transformers, only heater and
motor) or buy a new stirrer/hotplate. My crappy solution would be to buy everything 230 V: transformer, motor, and heater. The only parts of the
circuit that deal with mains voltage are the phototriacs, the transformer, the heater and the motor. The maximum allowed in the phototriacs is 600 V,
so they're fine.
There may be some other components between plug and transformer, such as capacitors and whatnot, that need a checking. I wish I could help more.
Edit2: In case heater and motor are both damaged, together with transformer:
Block has a 230 V transformer with the same specs of the original. Available at Reichelt for € 5.60 (https://www.reichelt.com/fr/fr/transformateur-2-3-va-12-v-19...). I haven't seen an 115 V model yet.
The motor is a shaded pole motor (230 V: SKU 3525900; 115 V: SKU 3525901). Originals from IKA sell for about £ 68 (230 V) and £ 78 (115 V).
Heating foil 230 V (SKU 5004800) about £ 96. No sign of 115 V (SKU 5004801).
If you decide to convert the stirrer to 230 V, it will cost about £ 170 or € 195 (according to the prices practiced by The Laboratory Store Ltd),
not including shipping taxes. You will probably get a lower cost from sellers in mainland Europe. Attached below are the lists of spare parts from IKA
for both 115 V and 230 V models.
Attachment: IKA c-mag HS7 spare parts 115 V.pdf (1.5MB)
This file has been downloaded 124 times
Attachment: IKA c-mag HS7 spare parts 230 V.pdf (1.5MB)
This file has been downloaded 161 times
[Edited on 10-7-2024 by bnull]
Quod scripsi, scripsi.
B. N. Ull
P.S.: Did you know that we have a Library?
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Rainwater
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Lets say the psu, motor and heater are all damaged. Using non-ome parts, your looking at a cheap fix.
You could spend a lifetime trying to find parts that fit or an hour with a tap tool, alumnium sheet and some glue
Mains to 12vdc, give you a peak voltage of about 17, at 200ma, 2.3va = around 13vdc. Most the chips parts have listed on that board max out at 18-25v
so there is room to play around and find out. disconect the questionable psu and install a new one, little bit of wire and solder, no worries.
Universal input voltage: 85-264V AC or 110-370V DC. 2000ma peak 1400ma continuous. Ive used a lot of these.
The motor will be the hardest find, if its a nema style, then your on easy street. If not id look at the manufacturer's documentation for suggested
replacement parts
[Edited on 10-7-2024 by Rainwater]
"You can't do that" - challenge accepted
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Cendre
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I stupidly missed the new answers because I obstinately refreshed the first page and didn’t notice the new one. Anyway, it looks like I’m way out
of my depth with all this, I am not trained in electronics nor have I the knowledge to do all this. So I guess I’ll try to find a replacement unit
as with my poor skills I’ll surely pay as much as an other one with no guarantee of it working.
Maybe some day I’ll resell this unit and get back some of the money from a hypothetical new one.
Thanks to everyone that helped on the journey your posts were truly invaluable.
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bnull
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Yes, it is a little more involved than desoldering and substituting stuff. For the money you'd be about to spend, you could find a good used model
from some college lab.
If you know an electronics technician, ask for a check up. The transformer is dead, of course. But the rest may be OK and, with the transformer being
the cheapest part and the repairman fee not too scandalous, it would be better than buying a new one. I'd fix it for a couple of Belgian beers.
Anyway. Good luck with the new one.
Quod scripsi, scripsi.
B. N. Ull
P.S.: Did you know that we have a Library?
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Sulaiman
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(reassurance) Even if the motor and heating element are ok
getting a new hotplate stirrer is probably your best option.
(opinion) If you have spare storage space you could keep it with the thought that you may one day become interested in repairing it,
better to see if anyone wants to buy an electrocuted hotplate stirrer (eBay etc).
even 99 cents plus packaging plus postage saves space and indecision.
CAUTION : Hobby Chemist, not Professional or even Amateur
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Cendre
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Do you happen to know Steinberg systems or Froilabo? They both seem to have a few hotplate stirrers that seem fine on eBay as the usual Ika, Corning
and Thermolyne don’t have interesting listings. In particular the Froilabo one (sold ~350€ new on the listing) seems to have similar specs to the
ika cmag hs7 I had, but seems too good to be true. Anyone have any experience with them?
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