-
You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
uniden pc 66 XL no power
- Thread starter kaos513
- Start date
Don't care if it was made out of bamboo, it would explode because the polarity was reversed. That's just simple physics.
....uh oh...
kaos513 some times we can be our own worse enemy. put a part in wrong and no one will be able to help until you do the work yourself to verify if you did it wrong or not. I do not know how many radios over the years a guy would bring it in with a problem then they would say no one has opened the radio up.get inside and find a part backwards or splashed solder on 2 traces and after you find it they would say, I did replace a part or did a mod for more swing etc. even have seen the cans and VR's turned until they kill the radio trying to peak the radio their selves.
have a good day
Sonoma
have a good day
Sonoma
That's why I wanted to know.
C155 is a ripple filter for the isolation circuit - the actual circuit that filters out and keeps RF and eddy currents from entering into and affecting the receive. It's the tiny traces and caps that are all along the edges by the fasteners and rear speaker jacks - used as a method to keep RF off the audio lines so it doesn't find a way back in.
Anyone whom has had alternator whine - has heard this filter in action.
And anyone whom used the, or replaced parts in the, wrong two holes in the back by the PA and EXT SP. jacks - is also aware of poor silkscreened and extra holes that really need to be left as holes, unfilled...
Anyone who's been close to a lightning strike, has also been saved by it. For the circuit provides static as well as ground rise / ground fault - protection to keep spikes out of the radio and not travel into the operator. Or, ruin the equipment. Keeps it, or attempts to - at the antenna and any protection you can provide it via case shielding.
But - it can only do so much.
Any cross or reverse polarity on these parts won't show up readily - but can provide an RF oscillation path. A natural resonance can form and if the cap can't dissipate the RF eddy current so the radio will go into self-oscillation if the chassis is not routed to a known ground - so it doesn't "Drain into" and potentially (sic) damage a reverse - as in positive grounded ignition - biased condition - where Earth potential is greater than vehicle or location's own ground potential. These caps can show up as resistors and form a ground path that makes the natural resonance more like a free running relaxation oscillator.
It's happened - The more ancient radios when Dynascan and Uniden were more hand-in-hand - used this as a method to keep radios safer. But they're not bulletproof. The caps - reversed - would gas and explode if the operator wired it up wrong and tried to ground thru the chassis not the power plug. Datsun's and the like were notorious for bad ground returns in their positive grounded ignitions.
Why do people call themselves "big strappers"? It's not because of bowl scrapings they leave behind in the toilet (or wherever) - it's because a grounded system - properly done, would have radios' negative and chassis' and earth ground tied together to earth potentials - but that never stopped them from achieving the ultimate goal of harnessing the power of a thunderstorm and St- Elmos Fire - and would up on the menu as "Todays Special - Don't Ask" at a local Restaurants with "questionable deliveries" occurring at odd hours of the days - usualy following a rather unfortunate catastrophic local event like mass shootings or drug related sudden "die offs" caused by stuff that - turned ...bad..
I just wanted to know if KAOS was working on a legit problem or not - for if I made the wrong suggestion - and they wind up hurt from poor workmanship, damaged equipment or mis-guided work - I'm the one that looks bad not them.
PC-122's have this same setup...
:+> Andy <+:
TYPOS!
Don't you just Luv auto-correct/suggest/recommend?
C155 is a ripple filter for the isolation circuit - the actual circuit that filters out and keeps RF and eddy currents from entering into and affecting the receive. It's the tiny traces and caps that are all along the edges by the fasteners and rear speaker jacks - used as a method to keep RF off the audio lines so it doesn't find a way back in.
Anyone whom has had alternator whine - has heard this filter in action.
And anyone whom used the, or replaced parts in the, wrong two holes in the back by the PA and EXT SP. jacks - is also aware of poor silkscreened and extra holes that really need to be left as holes, unfilled...
Anyone who's been close to a lightning strike, has also been saved by it. For the circuit provides static as well as ground rise / ground fault - protection to keep spikes out of the radio and not travel into the operator. Or, ruin the equipment. Keeps it, or attempts to - at the antenna and any protection you can provide it via case shielding.
But - it can only do so much.
Any cross or reverse polarity on these parts won't show up readily - but can provide an RF oscillation path. A natural resonance can form and if the cap can't dissipate the RF eddy current so the radio will go into self-oscillation if the chassis is not routed to a known ground - so it doesn't "Drain into" and potentially (sic) damage a reverse - as in positive grounded ignition - biased condition - where Earth potential is greater than vehicle or location's own ground potential. These caps can show up as resistors and form a ground path that makes the natural resonance more like a free running relaxation oscillator.
It's happened - The more ancient radios when Dynascan and Uniden were more hand-in-hand - used this as a method to keep radios safer. But they're not bulletproof. The caps - reversed - would gas and explode if the operator wired it up wrong and tried to ground thru the chassis not the power plug. Datsun's and the like were notorious for bad ground returns in their positive grounded ignitions.
Why do people call themselves "big strappers"? It's not because of bowl scrapings they leave behind in the toilet (or wherever) - it's because a grounded system - properly done, would have radios' negative and chassis' and earth ground tied together to earth potentials - but that never stopped them from achieving the ultimate goal of harnessing the power of a thunderstorm and St- Elmos Fire - and would up on the menu as "Todays Special - Don't Ask" at a local Restaurants with "questionable deliveries" occurring at odd hours of the days - usualy following a rather unfortunate catastrophic local event like mass shootings or drug related sudden "die offs" caused by stuff that - turned ...bad..
I just wanted to know if KAOS was working on a legit problem or not - for if I made the wrong suggestion - and they wind up hurt from poor workmanship, damaged equipment or mis-guided work - I'm the one that looks bad not them.
PC-122's have this same setup...
:+> Andy <+:
TYPOS!
Don't you just Luv auto-correct/suggest/recommend?
Last edited:
Did I think I new things? I remember knowing stuff once upon a time.... As far as C155 is concerned in this radio I will now have nightmares about it and most likely wake up in cold sweat and I will have to rush to eBay and buy one of these so I hook it up backwards on a 50 amp supply and record what happens! Stay tuned it will get at least a 2 hits on the tube? LOLOL
We'll keep a night-light on for you...
That glow, from what was once an innocent meter light...
:+> Andy <+:
So far i have wired 3 mics to work with the radio, anyone needs pin out and make of mics i wil be posting soon.
One of the first radios I'd ever recapped had one cap explode and shoot across the room, it littered the inside of the radio with the guts of that cap. Cleanup on isle five - please! Went off with a unmistakable >snap!<. Well; this is how you learn.
Can't seem to find C155 on the schemo I looked at; but that was the Cobra 25 LTD schemo.
Can't seem to find C155 on the schemo I looked at; but that was the Cobra 25 LTD schemo.