My Bosch PMF 180 has packed up. Fuse OK, power going in according to a NCVD. Can't get the bugger apart due to recessed Torx screws.
I'll buy a set of longer Torx bits tomorrow, but any ideas on the most likely cause? No smell of burning or smoke, it just stopped dead - like the fuse had blown.
If you turn it on with its switch, and measure the resistance between live and neutral on the plug, what do you measure?
Brushes?
My Bosch delta sander (very similar to the multitool design) failed a few moths ago and the mains lead had fractured where it joins the circuit board inside - almost certainly caused by the vibration. Easy repair. Bob
power cable deteriorated at tool end, simple job
I have a DMM with ranges 200, 2k, 20k, 200k, 2m & 20m. On all settings the display reads 1. If I touch the probes together it reads 0.00 on all settings.
The Medway Handyman wrote: Can't get the bugger apart due to recessed Torx screws.
Got the Torx bits & removed cover. Got 230v to terminal on circuit board. No signs of overheating, burning etc.
Even sprayed the board with WD40 and that didn't work - must be serious :-)
Brushes? Check field continuity
OK, since you have it open. Check continuity from live pin on plug to termination inside. Repeat for neutral. If you can verify that there is continuity between the pins on the plug and the ends of the cable inside then you have eliminated the cable and plug - to be sure move the flex about a bit near the plug and the machine to see that you retain continuity.
Now check the switch - using a resistance range over the contacts it should be able to see that it switches correctly.
Check the final continuity to the motor. If all the above is ok then the motor is suspect. Next check the brushes. Depending on what you can get to, you may be able to check for a connection to the wires attached to the commutator - hence proving the brush connection as well (you may need to manually rotate the motor a little).
If you can prove as far as the commutator, then you should be able to measure the coil resistance between the input terminals on the motor - again rotate by hand. If that is open circuit, then the armature is shagged.
Stcik one meter probe on the live plug pin, unplugged of course, and with the other probe just follow the circuit all the way round back to the neutral pin, you'll soon find where it goes dead.
NT
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