Offered to buy cheaply a Voigtlander Bessa R3A but has a rangefinder patch issue?

Take a look at the instruction manual http://www.cameramanuals.org/voigtlander_pdf/voigtlander_bessa_r2a_r3a.pdf .
Remove the lens. Inspect the contacts on both the lens and the body, they should be bright and shinny and not recessed. If there are any levers that engage with the lens check them for full movement.
Are the batteries fresh? Camera battery check function do not put the batteries under load, they may show good in a non load condition but be substandard under load.

The manual shows 3 focal length settings for the rangefinder frames, is it malfunctioning in all positions? Yes = electronics at fault. Its not uncommon for a single function of a multifunction chip to fail.

Rangefinder is not using batteries. Those are for metering and shutter in this camera.

I really don’t understand how focusing can have anything to do with electronics in this camera. If meter and shutter works and lens is included you have to decide if you can live with zone focusing. If so, price seems ok. If not, pass it by.

Walk away from it. Sounds like there are two separate issues. 1, the rangefinder cam is broken/stuck, or the connector arm is broken; likely came from dropping the camera lens down. 2, having to turn camera off and on indicates an electrical/shutter issue, but this it could just need fresh batteries. I wouldn't buy it for $10.

Sounds like there's 2 potential issues here:

1. These cameras don't have on/off switches. The meter is activated if the film is wound and the shutter button is partially depressed. After 10 sec, the meter LED will turn off. If the shutter fires and the photos appear well-exposed, there are probably no electronic issues.

2. The rangefinder is mechanically linked to the lens and will function even without batteries. I don't believe the Topcor came in M-mount, only screw-mount, which means he must be using an LTM-to-M adapter for the lens to mount to the camera. It's possible he's using an incorrect or damaged adapter, which may prevent the rangefinder linkage from functioning correctly. To verify the rangefinder functionality, I'd want to try it with an M-mount lens to be sure.

If you can't inspect the camera personally, see if he will agree to have a camera shop check it out before you agree to purchase it. Otherwise, you are taking a chance that there might be problems. Bessas are good cameras, though. The R2/R3/R4 series are very capable and I've had good luck with the few that I've owned. If it's in good condition, then $240 is a good price for this camera.

Good Luck!