Simpson Model 260 Series 5 Repair

RE: Simpson Model 260 Series 5 Repair

fmilburn — Tue, 17 Oct 2023 05:07:53 GMT

I've had some more time to take it further apart and look at things.

There is more corrosion on the back of the PCB and the main selection switch isn't making good contact in places. At least the meter movement appears to be good. I may just stabilize the corrosion and put it back together for now. I can use it as a volt meter.

For others who may need to work on these old meters here are some resources, especially at simpson.com:

Manual: simpson_260-5_and_5m_user_manual-1969.pdf (simpson260.com)

Schematic: simpson_260-5_and_5m_schematic.pdf (simpson260.com)

Calibration: TB 9-6625-2147-35 (simpson260.com)

Uses: http://simpson260.com/downloads/1001_uses_1965.pdf

Repair: simpson_260-3_to_6_repair_instructions.pdf (simpson260.com)

W2AEW also has some good videos on use and also replacement of the meter movement, e.g. #115: How to replace the meter movement in a Simpson 260 multimeter VOM - YouTube

RE: Simpson Model 260 Series 5 Repair

fmilburn — Sun, 08 Oct 2023 03:04:06 GMT

I still haven't removed the PCB but I did a few more tests. The meter is reading voltages to within one or two percent. It should be capable of a bit better than this after calibration. I have the 1.5V battery working and hooked up my power supply at 6V to simulate the 4AA batteries. The X1 Resistance setting is not working at all. The X100 setting is working. The X10,000 setting is working but I can't zero the needle. I'm hoping the X10,000 setting can be calibrated with the pot on the PCB. There are a number of things to check for the X1 setting - e.g. the selection switch/contacts and broken traces. I'll probably just live with the needle that occasionally sticks.

RE: Simpson Model 260 Series 5 Repair

dougw — Sun, 08 Oct 2023 00:39:28 GMT

It has been many moons since I've seen a Simpson meter - definitely a classic.

RE: Simpson Model 260 Series 5 Repair

DAB — Sat, 07 Oct 2023 19:35:17 GMT

Nice, I remember using the Simpson meter in tech school.

They have that nice well built feel that can take a lot of abuse and keep on working.

RE: Simpson Model 260 Series 5 Repair

genebren — Sat, 07 Oct 2023 16:33:23 GMT

These are some really nice finds. I have a lot of memories of using Simpson meters (High School, College and early career). I too have thought about attempting to find one of these meters just for the nostalgia and connection to the past. Good luck on your attempts to restore this meter.

I have a few plastic slide rules laying around, but try as I might, I can't seem to find my nice bamboo one from college. I might have to head out to the garage and forage through the boxes again.

RE: Simpson Model 260 Series 5 Repair

fmilburn — Sat, 07 Oct 2023 05:29:49 GMT

It occurred to me that I don't need batteries to test voltage so I tried low voltage DC and the meter is working full scale although the needle sometimes sticks if the meter is lying flat. It doesn't seem to stick if at an angle or upright. One of the battery terminals was so corroded that it broke so I will need to fabricate a new terminal. I haven't taken the PCB off yet but will need to do that in order to give a thorough cleaning.

RE: Simpson Model 260 Series 5 Repair

fmilburn — Sat, 07 Oct 2023 03:35:42 GMT

Here is another picture taken after the rough cleaning.

The silver-colored smear center left appears to be flux or other residue from manufacture. The lighting and camera have accentuated it more than it appears to the eye.