Chosen Solution
Hi, A complement to my previous question: I’m trying to indentify this electronic component in and old Pentax Spotmeter V light meter. It measures 178 ohm, but I’m not quite sure what it is, because it doesn’t really looks like a resistor. It is brownish of color, very tiny (a tenth of an inch or approx.2.5 mm) and has a white painted stripe on it, perhaps a color code. I was thinking maybe a thermistor, but I’m not sure.
Any ideas are welcome, Thanks! Update (10/12/2021) The yellow wire comes straight from the contact button and is going to the lamp, it is a sub-circuit. The lamp is there as an extra ‘illuminator’ to be able to read low light readings (in low light situations) on the scale. Nothing special really. But on the other hand, there is a similar component in red with a black marking, between the red wire going straight from the battery and the yellow wire followed by this brown component going to the lamp. Someone suggested a voltage divider, perhaps this is true: 2 resistors after each other. The red one reads 1.9 kOhm, the brown one 178 Ohm. the voltage of the device is 4.5 V (3x alkaline batteries). The voltage of the light bulb is unknown to me, but it withstands 4.5, I tested it. I don’t know of this makes any sense? But the light of the lamp is now so faint, and isn’t working most of the time, that I’m wondering if this is the purpose? This little PCB is the first one you encounter, btw, it is placed after the battery, so to speak.
Here’s the repair manual for your meter Pentax Spotmeter V service manual
Before we had SMT devices we had small wired devices which someone would hand solder to a board. This is a micro resistor used in cameras and photography meters. Pentax never offered a full schematic for the meter. But they did offer the analog side which you’ll find in the manual I posted in your other question. Be careful! The wire legs are easy to snap off. The resistor is part of a voltage divider used to adjust the voltage of the sensor.
