Gallery, Projects and General > Project Logs
Oh Blimey I bought a CNC Lathe !!!!
Fred Bloggs:
Awemawson
I have been following this thread with interest and as an electrical/electronics engineer with 30 years tinkering professionally, I take my hat of to you sir :bow: as you've got more balls than I have to buy 4 plus tons of gear which keeps kicking back at you :bang:(If my SWMBO copped wind of a toy like that papers would be served within 24hours).
On a more serious note might I suggest that you rip all the 'ebay'able electronics out - flog them and then use the cash generated to buy some huge stepper motors and associated control gear, at least that way you understand how it would work. although there would be a lot of work fitting the motors :dremel:
Good luck :bugeye:
Fred
awemawson:
Thanks Fred. :beer:
Started in earnest trying to find WHY that track burnt out. It runs from one pin of the transformer so I decided that I needed to pull the transformer so I could hopefully work out its windings and thus the circuitry around the blown track
A/ Transformer in way - remove it!
B/ Clear Board where it was
C/ Transformer underside
D/ That blown track
E/ Equipment used to remove the transformer
F/Transformer Diagram
awemawson:
Removing the transformer was a bit of a pig, as there was masses of solder on the component side that I couldn't get at. Ended up using the "SMD removal" low melting point solder to dissolve it and sucked out ok then! Turns out a single ended winding on the transformer (which presumably is driven as an oscillator at a few kHz) is being used as a very simple voltage supply as per diagram below. I cannot for the life of me see how this circuit can produce sufficient current to blow the track, as all other components in the cct are ok.
awemawson:
To prove the circuit I lashed in a lab supply in place of the transformer, which allowed me to measure that the (unmarked) zener diode is a 5v one (probably 4.7 actually)
SO HOW DID THE TRACK BLOW?????
A/ Lash up to power it
B/ Lab supply
Fred Bloggs:
Sir
Just noticed your comments about what caused the track to blow & how!!
My pennys worth "Is the transformer primary connected to a high voltage or is the transformer only to isolate grounds" either way have you tested the transformer at high voltage (Flash or 'Megger' insulation resistance test) .
Also can you test the transformer primary drive electronics with a load resistance in place of the primary and use a scope with Differential probes to observe whats going on??
Best regards
Fred
PS you've probably done all this but sometimes a different pair of eyes can sometimes spot the obvious (more to the point I'm not worrying about divorce papers :D)
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