Maverick 250 keying problem

[ace512007]

Hi. I turned on my rci-2980 and maverick 250 today for the first time in a couple years & was talking skip on sideband. a few guys said i had a hum in my mic so i changed to a stock mic after adjusting the mic gain didnt fix the hum. they said i sounded 100% better. my relays chattered a bit but i expected that using a stock mic on sideband I always look at my power meter when talking and the relays stopped chattering and my power dropped completely out while i was still talking i unkeyed and tried it again and they chatter and my needle fell again.

So I switched everything back to a.m and keyed the mic and the relays didn't engage. so i hooked my sadelta back up to it and same thing the amp wouldn't key up.

I put it back on ssb & keyed the mic, i heard a relay engage but i had no transmit. needle stayed burried to the left even while trying to talk. i took the case off the maverick and pushed on the relays to make sure neither was stuck and they weren't. they were moving fine. Radio still works fine running it barefoot.

Any help would be much appreciated
Thanks

2112
East Tn.

 

[tvrc18]

I think there is a capacitor that senses the rf to key the relay. Look on the cb tricks web site he may have a schematic to help.

 

[ace512007]

Thanks tvrc18. I looked at the schematic but it was for the maverick with the 2 meters on the front and i couldn't find the one for the model i got that has just the one meter. I went ahead and checked all the caps inline with the relays and they all showed a charge on the meter then started slowly discharging except for one that was on like a bus bar with two pretty good sized black resitors next to it.

the cap was about the same size dim. as the resistors next to it and it was silver it never did show a charge.

another thing i noticed was when i took the case off i looked at the top of the tubes and noticed that on one of the 6lq6 tubes where the coiled wires run to the choke that it looks like they are all wraped around some ferite. and one of the peices of ferite are busted completely into. was wondering if this would cause an issue besides power loss...

Sorry if i am not much help but i haven't messed with electronics in quite a few years and it was just a hobby i done back then and didnt have a whole of time to mess with it.

Appreciate the reply Tvrc18

 

[fnkycoldmedina]

does your maverick have the keying tube?be a small skinny tube (the only one ).if so it may need replacement .

try cleaning the relay contacts as well. if it sat for years mostly likely they are dirty anyway .

if you no longer hear the relay engage when you key the mic the keying circut could have went bad ,or the tube if you have keying tube .

you could try taking a wooden dowel and engage the relay yourself while radio is keyed and see if the amp is making any power out .
just be very careful.dont touch any tube caps or any high voltage areas .

if the amp no longer makes any power ,then you got bigger issues .if you have or know anyone with a tube tester ,have the tubes tested .

good luck.

 

[ace512007]

Thanks for the reply's yeah it has a keying tube. it is good. i finally found where the tech i use to use along time ago is at yesterday. so i'm gonna take the maverick to him. I appreciate everyones insight on my issue. I can tell this is gonna be a good site.

Thanks

2112
East Tn.