Need help with a crosley 516

I am just getting started on repairing old radio's and could use some help on a crosley 516 I am working on....I am def learning as I go, so be patient. I picked this radio up a while ago and have been repairing obvious problems. It has been recapped, some tubes replaced, a bad socket and so on. When i power the radio up I get nothing at all out of it and cannot seem to figure out why ? I have good B+voltage, audio transformer is good. Can anyone point a beginner in a good direction ?

Thanks,
Mark

Does that radio use locktal tubes? If so, suspect sockets with poor connections, and, rusty tube pins. Very common problem.
Another, have you tested the tubes?
Still another, disconnect one end of ouput transformer from spkr., and, check resistance. Is speaker good? Might be around three ohms on an ohm meter.
Is voice coil on spkr. moving freely?
If frozen, that can also kill your sound.
Bill Cahill
Oh, and, welcome to the forums.

Hi Bill and thank you for the welcome ! I have checked all the tubes and replaced as needed. Have cleaned sockets and even replaced one. I have checked the voice coil and the output transformer and they appear to be fine. I even hooked up a spare speaker to double check but still nothing....I am really stumped....any other suggestions ?

Thanks Mark

Check the value of your resistor to make sure they are within tolorance. Check for burned resistors or shorted caps, sometimes they can be buried so deep underneath other components that they get overlooked. Check IF coils. Make sure that the primary and secondary voltages are correct coming out of your "power" transformer. Is there any sound at all? Buzz or hum? Are all of the tubes glowing?
Dave

Hi Dave. I have replaced all the caps and gone over the power stage and it is all working well...good voltages etc. I have checked the resistors and except for one questionable candohm all are fine. All the tubes light and have been tested good. No noise at all from the speaker ???

I repeat above questions on spkr.
BC

Hi Bill,

I disconnected the output transformer and it read 3 ohms. Also the voice coil moves freely.

Did you check both the primary and secondary ?

The candelohm resistor is a serious resistor that must be checked, sometimes they open or go bad. they are usually a dropping resistor for the filaments. May have more than one tap.

Yes I checked the secondary too...it was 2 ohms. I am waiting for two replacement resistors to come in to replace the candohm...but I dont think that is the cause of the trouble Im having. Thanks for all the advice !!

How about trying to measure for sound at the detector output using a small amplifier (signal tracer) - be careful of high voltages and couple the output using a capacitor.

rascal wrote:How about trying to measure for sound at the detector output using a small amplifier (signal tracer) - be careful of high voltages and couple the output using a capacitor.

I second using a signal tracer. I would be lost without mine. I have a sencore am/fm analizer I use to inject the signal. I follow that signal all the way to the speaker using the signal tracer. I made my own using plans from the late 70s/early 80s in a electronic magazine. It used a simple am radio and tapped into the volume control. It had a switch with a cap that switched from rf to audio. I made one around 84 and it still works like a champ. I need to scan it or at least post the schematic. Anyway I highly suggest a signal tracer to anyone working on one.

Put your finger or the tip of your plugged-in solder iron on the center terminal of the volume control. You should hear a loud buzz if all is well. If no buzz, your problem is from the volume control to speaker. If buzz, your problem lies ahead of the volume control.

The volume control on this radio is at the front end, so you may have to probe a bit differently. See:
http://www.nostalgiaair.org/PagesByModel/374/M0003374.pdf