Gallery, Projects and General > Oooops!
CNC Crash Compilation
AdeV:
--- Quote from: awemawson on March 17, 2013, 10:51:27 AM ---It's a long time since I was in an Interact cabinet, but I seem to remember that one of the two 24v supplies is just a little regulator board. Top left hand side if I remember correctly.
--- End quote ---
Aye, I've found the board, I haven't had chance to probe it yet, due to limited access. If I'm lucky, it'll be the regulator board at fault, it doesn't look too difficult to repair, although getting the right regulator might be an interesting task, I can't see any writing on mine.
awemawson:
7824 is the generic number for the 24v 1 amp three terminal regulators - widely available on ebay:
http://www.ebay.co.uk/itm/L78xx-Series-Positive-Voltage-Regulator-5V-6V-9V-10V-12V-15V-18V-24V-/130836774030?pt=UK_BOI_Electrical_Components_Supplies_ET&var=&hash=item1e767abc8e
Cost all of £1.90 for a pack of five ! IIRC it is a very simple circuit. AC feed from the transformer to a rectifier, followed by a reservoir capacitor across the + and - of the regulator, going to the input leg of the three legged regulator.
DMIOM:
Ade,
Probably not relevant, but DC won't latch in on my TNC155 if the E-stop is active (either manual or a hard limit is tripped).
Dave
PekkaNF:
Probably not relevant at all, but we used to shed a crapload of those 78-series regulators when we were students (like stone age....), but they had a grave drawback (least back then)...they were pretty sensitive for about 400 V voltage spikes emitted from relays or any contact within meters or even on same vehicle. LM317 used to be somewhat more robust....but we generally put a freewheeling diode over every contact and RC-pair as well + some ferrites or small toroids on every incoming supply line and "dirty" outputlines as well. Oh, and 78xx really needs those small "unnecessary" capacitors on both sides that are shown on every application sheet. Funny thing what you learn after you redo the same PC-board third time....It was a relay on auxiliary line and worked like a charm long time, but the 78xx would fail once every blue moon.
Pekka
awemawson:
Those 'unnecessary' capacitors stop parasitic oscillations.
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