I just brought a sperry dm-350A to test the switches on my dryer I thought they would come with instructions on how to use it but it didn't. Is there a place where I can go and learn what the symbols stand for?

1. Disconnect the test leads from any energized circuit and then from the instrument.
2. Turn the range switch to the "OFF" position
3. Slide off the back case battery cover.
4. Remove the battery from the compartment and unsnap the battery connector.
5. Replace the battery with a 9V transistor type battery (NEDA # 1604), For maximum battery life, alkaline cells are recommended.
6. Reverse the above procedure to complete replacement.

Hello Anthony, I sent you a link so you can find out the manual of the tester Sperry DM-210a and another where you get an explanation of the operation
I hope you can solve your concern
Greetings Franco Dosil

Hola Anthony, te envio un link para que puedas descrgar el manual del tester Sperry DM-210a y otro donde te dan una explicacion del funcionamiento
Espero que puedas resolver tu inquietud
Saludos Franco Dosil

https://www.hunker.com/13414165/how-to-use-a-sperry-dm-210a-meter

https://greenlee-cdn.ebizcdn.com/media/52058078REV01.pdf

https://www.hunker.com/13407450/instructions-for-a-sperry-dm-210a

Refer to instructions that came with meter, it is there. If you threw away instructions here is a big hint.
https://www.manualslib.com/manual/1346232/Sperry-Instruments-Dm6450.html?page=6#manual

Set the knob to the ~600V position. With the power on/connected, place one test lead on one side of the fuse and the other test lead on the other side of the fuse. Be careful not to touch anything with your hand or you will get shocked. If you read voltage the fuse is bad. If you don't read voltage the fuse is bad.
Alternately you could DIS-connect power remove the fuse and test the fuse for OHMs, which on your meter is the last icon with the ((((.
It will beep and/or read very low ohms <5.

Here's the manual -

Sperry Instruments DSA 500 Operating Instructions

Try it again, with a new, tested battery.

You likely installed a "dud" (or put it in backwards?)

Good luck!

If you've never used a volmeter,Google it.There is a lot of info for free.

yes. But you have to change the LEADS down below. One must connect into the Omega connection at the bottom (looks like an upside down horseshoe). And the meter setting is where the arrow (?) symbol is. Touch the two leads together and it should "zero out". Now you're ready to check continuity.

I assume a "DM-350a" is some kind of a digital multimeter. I Googled and found it might be a "A.W. Sperry DM350A 5 Function 17 Range Digital Multimeter" and looking at the ranges available on that meter, you can't really thest the battery "under load" the only reasonable way to test small batteries. the DC current only goes up to 200 milli amperes. A "C" or "D" size flashlight battery puts out 1 to 4 amps depending on conditions. That's 5 to 20 times the current readable by that meter. The volts on one of those batteries is probably 1.6 volts to 1.3 volts etc. If you live in the United States, I'd say go to Radio Shack and spend $5 to $15 and buy a battery tester like "Enercell Analog 9-Range Battery Checker, $14.99, Model 22-156, catalog # 22-156"
Then you and anyone in your family can read the instructions and test 8 or 9 different type batteries. Battery types: 1.5V button-cells, "AAA"/"N"/"AA"/"C"/"D", 6V, 9V, 12V, 15V and 22.5V..
This is not supposed to be an advertizement, and I have no interest in RadioShack,... but it's supposed to be instructional.

Small price, Good instruction to anyone who can read, and if anyone forgets, they can re-read. Testing a lot of batteries in a sitting goes very fast with these.

Differently, with the sperry, or any voltmeter, you'd have to select a resistor small enough to draw the current, and large enough not to overheat or burn, connect it and measure the loaded voltage drop, compare the voltage and current of the loaded battery, and compare it to that of a new battery, and a battery you might consider too weak for your application.. Voltage equals amps times resistance, and power equals amps squared times resistance... Really, buy a battery tester.
Regards --- GooseBay_Camper

dc .... no lower then the voltage range of the highest voltage of the battery.

The most obvious solution to your problem is that you may have the meter simply connected backwards. To make life easy, Groovetubes sells a thing called a bias probe that makes biasing tube amps a breeze.