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Pillar drill help
carlknight1982 - 14/4/15 at 02:31 PM

Ok so the speed controller board in my pillar drill has burnt out some transistors and resistors now I can Id the transistor easy enough as its one of several and they are all the same however the resistors are burnt beyond reading.
I've removed them from the board and measured them with a (fluke) multi meter my question is how accurate will these readings be and how can I figure out what type of resistor I need to replace then with

I can't just buy another board as they are no longer in production and spares are out of stock

theprisioner - 14/4/15 at 03:37 PM

You cannot rely on these measurements. Your best hope is either a circuit diagram or another owner who is willing to take images of the board. If you draw the circuit out I can make educated guesses of the values.

carlknight1982 - 14/4/15 at 03:55 PM

Can't get a diagram been trying for a month
Will the readings not be sufficient for an educated guess?

gremlin1234 - 14/4/15 at 04:11 PM

get some photos of the board,, plus the approximate working voltage/ current/ power/ speed
will give us something to work with...

MikeRJ - 14/4/15 at 04:39 PM

quote:
Originally posted by carlknight1982
Can't get a diagram been trying for a month
Will the readings not be sufficient for an educated guess?


If the resistors have burnt out, you have no idea how close their value will be to the original resistance. If they haven't gone completely open circuit then they might be within the same order of magnitude, but you have no way of knowing.

If you can trace the relevant parts of the circuit out, including voltages then we should be able to make an educated guess at a suitable value.

Mentioning the brand and model would also be handy, someone may have the same machine.

[Edited on 14/4/15 by MikeRJ]

carlknight1982 - 14/4/15 at 04:51 PM

warco k1605fvc

240v in 180v dc out



theprisioner - 14/4/15 at 04:53 PM

Another way of doing this is to replace the motor with a mechanically identical 3 phase motor. My pillar drill has a 3 phase motor. Rather than being a curse it is in fact an asset. It came like that from the s/h dealer. It now has a single phase - 3 phase electronic inverter that also controls the speed - absolutely fantastic would not have anything else.

see: eBay item number:

381206535585

carlknight1982 - 14/4/15 at 04:59 PM

Tbh I'm hoping for a cheap fix I rarely use the drill so it's not worth a lot of money on repairing it to me

gremlin1234 - 14/4/15 at 05:15 PM

certainly the resistor from 'next to c6' is now the wrong value, 13Mohm; would not fail so catastrophically with <400V, the others look more realistic.

however, with so many failed components, and a 'scorched' board, I would say its beyond a safe/long-lasting repair.
edit: cant use &#937;, so ohm

[Edited on 14/4/15 by gremlin1234]

RedAvon - 14/4/15 at 06:13 PM

You could replace it with one of these if I have read the spec. correctly?

Regards
Ian

http://www.amazon.co.uk/Input-Output-Motor-Speed-Controller/dp/B00843ILD8

[Edited on 14/4/15 by RedAvon]

rf900rush - 14/4/15 at 08:36 PM

Can you post the Motor Spec
and Make / Model of the drill.

More info will help.

carlknight1982 - 14/4/15 at 08:47 PM

Off the motor


Drill make and model are on the other post with the photos

alfiebeard - 14/4/15 at 09:16 PM

quote:
Originally posted by carlknight1982
warco k1605fvc

240v in 180v dc out





The two "Transistors" are actually Thyristors/Triacs these are commonly available and used in most variable speed control systems, they are also used in Lighting Dimmer switches.

what we do at work with burnt up resistors to get a measurement if they don't have any colours left on them..is to read from either end to the centre of the resistor and double the value. you would have to scratch the probe into the resistor to read the value, if you cant get any continuity half way down the resistor then try a third of the way down and times the reading by three..

The physical size of each resistor denotes the Wattage of it.

Hope this helps.

Alfie