Wiring in a new Paterson 2000D timer to LPL enlarger
Hello,
It's my first post on here, apologies if this has already been written about. I'm using an LPL C7700 enlarger, it came with the transformer and a Durst TIM60 timer. Has been working fine the last couple of weeks but I wanted to get a new timer with a bit more precision. I've now got a Paterson 2000D and rewired the transformer into the 3 point plug that came with it, I've plugged it in and the run button works great - counts down no problem, etc so I figure I've wired it properly. However the 'focus' button isn't turning the light on. Does anyone have any ideas? I figure either it'll be the way I've wired it, or it's the transformer, but if anyone has had any similar experiences that'd be great to know. Thanks so much! |
I don't know this timer but I don't see a wiring fault or a transformer fault, it just looks like a simple timer cct between the mains and the transformer.
If it works on a timed exposure it should work on the focus, if it doesn't then its an issue with the timer I think. |
Looking at an image of the circuit board (Mr Google comes up trumps again! http://www.lclelectronics.co.uk/perf...phy-equipment/) shows this timer is controlled by a single-chip microcontroller. I would expect the Focus switch, like the other switches, to connect directly to the pins of the chip.
Hence, either the switch is duff (quite likely as small momentary switches are not robust) or something has happened to the circuit board twixt switch and chip (also quite likely if there has been any liquid ingress). I would take the cover off and see what you can see. Look for any crud around the switch and/or chip (or anywhere else really). I see a mains fuse on the board and what looks very much like the footprint of a mains transformer mounted on the other side of the board so be aware that there are mains voltages present on the board when plugged in. If you are happy with this fact (and *only* if you are happy with the obvious dangers) try shorting the Focus switch contacts on the board with a bit of wire and see if that actuates the lamp. If it does, the switch is unwell and a squirt of switch cleaner (with the unit disconnected from the mains) may - with a lot of luck - work. The switches will be working at a low voltage (probably 5 volts) but as I said - there is 240V on other areas of the same board so if unsure, do not mess with it. But a visual inspection may suggest what is wrong without risk of instant electrocution... Edit: I just realised that you didn't actually state if it switches the lamp at all - only that it counts. If it counts and switches the lamp then what I wrote above applies. If it counts but does not switch the lamp then: can you hear the relay (I can see what looks like the circuit to switch a relay and what looks like the footprint of one...) clicking on/off? If it clicks then it is probably wired incorrectly, or the internal wiring has failed in some way. While making a visual check, also check for any other fuses that may have blown. Cheers, Bob. |
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Terry S |
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The circuit comprising Q2, the diode to its right and the resistor nearby looks like a classic relay driver circuit (the diode being connected across the relay's coil). The five pins above the diode look like the footprint you would expect from a relay (two pins for the coil, three for the SPDT switching contacts. The IN terminals will likely be going from the mains input cable/socket to the relay (and powering the board via a low-voltage dc regulator circuit visible above the IC2 chip). I expect the OUT terminals carry the switched mains from the relay to the enlarger power socket. You can just make out that N IN and N OUT are connected together, hence the relay is used to switch the L OUT via the relay. I suspect all the electronics and power supply circuitry is on that board and only input and output sockets are mounted on the case. Little of which helps the OP, except that interpreting pictures is sort of what we sometimes do here :D Sort of... ;) Cheers, Bob. |
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