yeah, i never had one that was this restricted. usually can pull it back to about 2W and it screams
-
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 PC122, low AM modulation
- Thread starter kp3ft
- Start date
In something like this, I'd start checking the Voltage at the Jumper board.
The best way to tune this is to pre-set the AM power to 5.6 Volts - SOLID.
Don't peak anything at this time, just observe.
Look at wattage and the Bias. Keep Bias mA to 50mA on Driver and Final.
Look on foil side for rework - correct and clean, reheat cold joints as needed Reflow the leads with a touch of rosin core solder to let the flux in it reflow around the leads.
Using No Mod, check jumper voltage across it to ground - then modulate. Does the voltage drop as well as the RF swing in any simple RF meter?
Don't kill it by removing the limiter - at least not yet.
Then don't use too much mod, just low - level types of sound to see if a Positive swing can be made. IF you see forward swing - then the issue is from limiter area - if' you can't get any forward swing at 5.6V - then how far do you turn down the voltage before the swing is not backwards - NOR forwards - but steady?
Once at that voltage - then I'd look at peaking - retune the strip, can you see an increase in power - then recheck - if the thing re-creates the original condition - then something is going on in the limiter section.
This may be an over peaked radio - so be careful with too much power trying to get swing - these are unobtainium right now.
This thread has got three different variants of the same radio - might want to do voltage checks around the Pre-driver - as this thing ages, even the DISC caps can fail - turn into plain old dirt sandwich.
The best way to tune this is to pre-set the AM power to 5.6 Volts - SOLID.
Don't peak anything at this time, just observe.
Look at wattage and the Bias. Keep Bias mA to 50mA on Driver and Final.
Look on foil side for rework - correct and clean, reheat cold joints as needed Reflow the leads with a touch of rosin core solder to let the flux in it reflow around the leads.
Using No Mod, check jumper voltage across it to ground - then modulate. Does the voltage drop as well as the RF swing in any simple RF meter?
Don't kill it by removing the limiter - at least not yet.
Then don't use too much mod, just low - level types of sound to see if a Positive swing can be made. IF you see forward swing - then the issue is from limiter area - if' you can't get any forward swing at 5.6V - then how far do you turn down the voltage before the swing is not backwards - NOR forwards - but steady?
Once at that voltage - then I'd look at peaking - retune the strip, can you see an increase in power - then recheck - if the thing re-creates the original condition - then something is going on in the limiter section.
This may be an over peaked radio - so be careful with too much power trying to get swing - these are unobtainium right now.
This thread has got three different variants of the same radio - might want to do voltage checks around the Pre-driver - as this thing ages, even the DISC caps can fail - turn into plain old dirt sandwich.
Just some random going thru old electronics-i repair pretty much any newer electronics and i found one of these (or similar at least) from 1988. I know its either junk-or someone would prolly kill for it and its parts. Best i can tell it works fine, looks undamaged,
Just wondering, something from 1988 like this that i can barely find info on could be invaluable to someone in need... Just doing my part to help others out here. Shoot me an email at skylarr12227@gmail.com if its not junk-if it is dw about it and ill toss it in a week or so.