Ilford EM10 Schematic?

[DWThomas]

(Everybody has user instructions.) I noted during a print session yesterday that there was a faint red glow from the right hand red LED with the power switch OFF! A quick test indicates the gadget draws almost half a milliamp from the battery when the switch is off.

Yes, Ilford recommends removing the battery when not using. Unfortunately they made that a PITA by having to remove three little screws to get the battery out.

The compulsive tinkerer in me wonders if maybe there's a capacitor that's gone leaky. The assembly is such that getting it apart without messing something up could be a trifle risky, so I'm a bit reluctant to try. If schematics are hidden from the world, I'll maybe try to put a small switch in the end of the case that will open one battery lead. That will give me an independent OFF as opposed to an odd SORTA OFF!

Thanks in advance for any useful info.

 

[koraks]

https://www.mobile01.com/topicdetail.php?f=255&t=3291569

The battery switch is really a simple electromechanical switch. If the LED comes on even with the switch turned OFF, this means that there's a leakage current through or parallel to the switch. My guess is that this is due to fouling of the switch itself or the PCB. I'd open up the unit and see if cleaning it inside helps any. If not, see if a replacement switch can be found; shouldn't be too difficult to work something out.

 

[DWThomas]

Thanks much. That shows the switch the way I would have expected it to be which made it pretty difficult to believe what I saw.
"Well Dave, guess yer just gonna have to take it apart!"

Thanks again,

 

[koraks]

"Well Dave, guess yer just gonna have to take it apart!"

Hey, that's not too bad, is it? It'll be interesting!
And it sounds like a problem that's relatively easy to fix, so it might be a satisfying little project.

 

[DWThomas]

(Just for future seekers of knowledge ...)

The inside of the EM10 was remarkably clean but the switch had some goopy stuff here and there (those cheap slide switches usually have a bit of lube). So I unsoldered it, and being me, I bent back the four tabs on the switch housing that retain the block with the contacts. I then took all the switch parts and swished them around in denatured alcohol. Somewhere in this process, I found two tiny beads of solder -- less than a millimeter in diameter mixed in the goop. Now that could have just happened but if it was original, it might certainly account for the earlier behavior.

I lubed the pressure spring, roller, and contacts with a teeny dab of silicone grease and gingerly put it back together. After putting it back on the PC board, all appears well; switch closed 2.4+ Ma, open ZERO -- YES!

So it's back together and appears to be working. I shall note there appears to be some component value differences and one "mystery component" compared with the schematic from @koraks. The PC board does have "ISS. 2" so mayhaps there have been some revisions along the way. I couldn't read the printing under this component without unsoldering one end and decided I didn't need to know that badly. Maybe some sort of reference junction -- or CIA encryption code ...

So thanks again for the input.

 

[koraks]

The marked resistor is a zero ohm resistor. It's the electrical equivalent of a piece of wire.

Good to hear you've been able to fix the switch! The advantage of some older equipment is that you can actually get in there and clean things, sometimes.

 

[RalphLambrecht]

(Everybody has user instructions.) I noted during a print session yesterday that there was a faint red glow from the right hand red LED with the power switch OFF! A quick test indicates the gadget draws almost half a milliamp from the battery when the switch is off.

Yes, Ilford recommends removing the battery when not using. Unfortunately they made that a PITA by having to remove three little screws to get the battery out.

The compulsive tinkerer in me wonders if maybe there's a capacitor that's gone leaky. The assembly is such that getting it apart without messing something up could be a trifle risky, so I'm a bit reluctant to try. If schematics are hidden from the world, I'll maybe try to put a small switch in the end of the case that will open one battery lead. That will give me an independent OFF as opposed to an odd SORTA OFF!

Thanks in advance for any useful info.

Iwish they also had that in Gossen meters.great idea!