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just bought a used uniden 78- have a question

T

trailrider

Member
Jul 22, 2012
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on my way to the truckstop to buy a new road king 56 mic i heard a trucker advertizeing a uniden pc78ltw for sale. i asked if it worked and he said he was talking on it. it sounded good. he told me how much he wanted for it' so i went to take a look. it was hooked up and on when i got there so just to make sure this was the same radio i had heard i parked my pick-up about 50 feet away and talked on this uniden. sure enough it sounded like the same radio i had heard blowing smoke earlier. so i bought it. now for my question. according to the owner this radio has had some mods done to it. what has me puzzled is this. when you key the mic this radio pins the needle to the other side of the scale. even dead key there is no key the mic at 5 watts and swing to max when talked into. this radio swings to max with a dead key. any ideas on what mod this might be??? regardless this radio blows smoke.
 

mechanic said:
AM power is most likely maxed out... Not good and should be adjusted correctly by a reputable shop. Biggest problem is that the life of the radio will be short and next may be splatter! :eek:

73 mechanic
Click to expand...

thank you very much for the reply. I didn't pay much for this radio and he didn't elaborate on what mods had been done to it' but it sure sounds good. I put it in the closet with some others as it will be awhile before i can take it to a shop and have someone look at it. it's just the first one i had ever seen that would pin the needle with a dead key. now i'm curious to find out what someone did to it.
 
My Uniden Grant XL was like that. I bought it, used, on ebay. I hooked it up to make sure it worked and saw that it slammed the needle against the stopper. The description did advertise 30W or 40W. I immediately unhooked the radio and put it back into the box. Then off it went to DTB Radio and had him tune it up right (I guess in this case, tune it down). Now it sounds great, gets out, and will probably last for a while.
 
I was under the impression the meter was completely adjustable and separate from the power output?

I know there was a rumor around these parts of a tech that did nothing more than make the needle peg to make people believe he was tuning their radio and making more power.
 
trust me guys this radio is deffinetly making power. it's one of those things that you know it when you hear it. i'm being kept in town this week so maybe one night i'll open it up and see if it has a 1969 or a mosfit final in it.
 
trailrider said:
thank you very much for the reply. I didn't pay much for this radio and he didn't elaborate on what mods had been done to it' but it sure sounds good. I put it in the closet with some others as it will be awhile before i can take it to a shop and have someone look at it. it's just the first one i had ever seen that would pin the needle with a dead key. now i'm curious to find out what someone did to it.
Click to expand...

If the meter is pegged when you key the mic; are you sure that it isn't in the 'SWR Cal' mode?
That will do it.

Put the switch in 'S/RF' mode and plug the radio into an antenna and see if it doesn't key up on the edge of the red/green on the meter . . .
 
Last edited:
robb. nope this radio is in the s/rf position. I don't know what has been done to this radio or who did it or when' but to hear it... it's loud and proud. I have just never seen a radio swing to max on the meter at a dead key. it's deffinetly not set to run an amp.
 
maybe i'll put it in my pick-up this weekend. maybe it's so powerfull it'll make my headlights go dim when i key the mic. lmao
 

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