Light meter underexposed - Pentax K1000 35mm SLR Camera

Try increasing the ISO rating, see if that gives you a different reading - you may indeed be underexposing if there is insufficient light

For normal exposure, set the ISO dial to 400. Meter normally, adjusting the shutter speed and/or lens aperture until the green LED in the center lights up.

For dark pictures, you want to underexpose about two stops. One way is to meter as above, then stop down the aperture two stops (larger F/numbers) or increase the shutter speed two stops (larger number) or a combination of the two. Alternatively, set the ISO dial to 1600 and meter normally.

For light pictures, you want to overexpose about two stops. Meter normally then open up the lens two stops (smaller F/numbers) or slow the shutter speed two stops (smaller numbers) or a combination. Alternatively, set the ISO dial to 100 and meter normally.

You can also experiment. Over/underexpose one stop, then two, then three, then four, and even five. You might want to take a notebook with you and write down what you're doing. Record both the setting and how many stops over/under it is. When you get the film back, you can refer to your notes and see what happened.

needs repairing at a qualified shop
when was it last cleaned or serviced ?
if you think the camera is worthy, since its old how much is it worth to you vs a new one

Yes, the V3800N has an exposure meter.

If the red - lights up, you're underexposed. If the red + lights up, you're overexposed. If the green circle lights up, you're right on. If both the red and green light up, you're within one-third stop of the right exposure.

If you don't see either the green or red lights, then you need batteries. The camera uses two LR44 alkalines or two SR44 silver-oxides. But the only thing that uses the batteries is the exposure meter: everything else on the camera is stil fully functional.

Set the metering mode to Partial Metering. This uses only 9% of the field of view, centered around the middle square in the viewfinder, as the subject area. If you still find it too bright, try changing the exposure compensation a couple of clicks.

You need to do what is called an exposure lock. Aim at the subject, even if it's out of focus and half press your shutter. Then press the * button on the camera (top right) and it will exposure lock. You can then re-focus, but it will hold the exposure that was metered previously, so you'll get focus on a different object to what the camera has focused on. You can exposure lock anywhere, it doesn't even have to be your subject, it could be a nearby window to underexpose, or a nearby dark area to underexpose. Once you've locked the exposure you can focus somewhere else.

what do you mean dark? if they are underexposed... extend you exposure time.

There is a small round button near the shutter release... hold that down, and rotate that thumb wheel thingy. You can over or underexpose your camera's auto metering by 2 stops in 1/2 stop increments...

After that, you should learn how to take control of the camera and shoot in manual mode. It give you the ultime power

If you set your meter based on the white (or substantially white) wall, as per the attachment, I would expect the image to be underexposed.

Your camera light meter uses the concept of multi-spot exposure metering, which is sensitive to subtle differences in scene composition. To determine the overall shutter speed for a scene, the meter takes readings from three zones within the frame. With Portrait orientations, the zones remain in the same place (vertical) on the CCD imager. With landscape orientations, however, the zones are more spread out (horizontal) and the dominant (2 dark and 1 light or 2 light and 1 dark) zones determine the shutter speed. This may cause some areas of the picture to be overexposed or underexposed.

When you are photographing scenes with mostly light objects (for example, snow, water, and sand), the picture is usually underexposed (darker than it really is). The camera meter registers the brightness of the scene and tries to set the camera lens and aperture for an exposure based on average brightness levels (18% reflectance) causing it to underexpose, as in the following picture. When you are photographing scenes with mostly dark objects (for example, shade, shadow, and overcast skies), and very few light objects, the camera may overexpose the image, causing it to be too light. If you have a flash on your camera, you can compensate by adding "fill flash" for some extra light. If your camera has an exposure compensation adjustment, you can increase or decrease the exposure to correct for these exposure problems. Increase the number to make the image lighter, and decrease the number to make the image darker. You may want to try a series of shots with different exposure compensation adjustments to get a feel for how much difference these adjustments make.