do you know why it's overheating? i have an leica( or letiz wizlar) focomat 1c and it's having the old wires. It gets really hot when working like 30 minutes. Do you know should i just give it a break like every twenty minutes?
It wasn't a single time it must have taken place over a good number of years but was eventually traced to the ceramic block into which the bulb is plugged and the two tiny tubes where the wire pins go. These holes were corroded internally.
This was discovered for me by an electronics engineer who suspected the circuitry and tested it for me and found the Ohm resistance was very high.
This was increasing the resistance to the power and apparently the heat. Now, these ceramic blocks are unobtainable so what I did was use an old bulb and covered the pins with very fine abrasive paste and pushed the base of the bulb in and out number of time to try to clean up the corrosion, then cleaned them out to remove any residue.
This of course will open out the holes so that the pins would now not necessarily give a good contact, but by cleaning the pins themselves and 'tinning' the pins with a coating of soft solder and adding a small blob of solder on the tips of the pins. Then by using a bit of pressure forced the pins into the holes. This has the effect rubbing away the 'blobs' of solder onto the insides of the holes, and as solder does not corrode this will both make the pins of the new bulb fit with a good close contact and stop or reduce the risk of corrosion returning.
As a post script the same bulb is used in other enlargers which will use a similar ceramic block so there may be spare block available and it may be possible to splice one of the other manufacturers ceramic blocks onto the wires so they will work.
To answer your question about overheating with your Leitz 1c. Why do you need to leave the enlarger switched on for 30 mins? Surely an exposure for prints must be measured in seconds not minutes! When the exposure is complete you shut the light off which will be enough to cool the lamp house. I believe the 1c uses a normal full voltage bulb (in UK 230V) with good ventilation, so the same problem with the LPL will not happen because they work with 24V but in an enclosed space which to be honest has very little in the way of through ventilation only by conduction
If you are worried about the condition of your wires in the 1c you can easily replace them using a good quality 3 core cable which has an outside covering of a woven material just like that used on electric irons.
www.photrio.com
