Audio is easy fix. C91 or another cap just off the Audio IC i did one only a couple of days back (sold on ebay and will probably end up at yours) there's about four caps which fail on these, two for TX Audio and two for channel display VCO. As for the TX meter if you don't have a dummy load or an antenna that's near to 50ohms the meter will never read right, but CBers won't accept it works unless it's hitting hard right over.
I reckon it's for this reason that new sets nearly all have fake RF meters that are pre-programmed to sweep across...whether the radio is doing 1W, 4W...ir not actually tranmitting any RF power at all. Richard
Hi just watched the uniden 300 repair and set up ,only a couple of days ago i tried my one that hasnt been used in at least 10 years or more ,sad to say the only thing that works is the light in the signal meter ?no transmit no channel display nothing , any ideas ,advice , many thaks bob
Yes, the two 220uF capacitors & the two 470uF capacitors fail. All four need changing...if you don't do all four, one of the others will fail at any time. Richard, G0OJF, UK
I have watched a few ham radio videos recently where ceramic filters have been mentioned as being a weak point in sets that are left on for extended periods, as you mention factory ceramic filtering in this and other older sets I am wondering if you can confirm if it is in fact an issue or not. I am thinking of setting up an always on rig on my solar system so wondering if there are sets to be avoided or not.
Crystal filters are more likely to fail with age than ceramic ones. On CB's I've never had to replace any 10.695Mhz ceramic filters, but have had to replace crystal filters at 10.695Mhz. On the other hand I've replaced plenty of 455Khz ceramic filters. I can't talk for amazteur radio gear as I don't service it. With licenced business radios that we do service I've probably only ever replaced a couple of 21.4Mhz crystal filters & half a dozen ceramic filters at 455khz ever. That's interesting as business radios use the same 455Khz filters (more or less). This tells me that CB radio get dropped...or thrown in skips. Richard, G0OJF, UK
Yikes. 5 W x 24 h x 365 days = ~44 kWh/year. Here, at ~$0.20/kWh it would cost me $9/year just to have it plugged in but turned off. Power strips are a thing ...
My electricity here in the UK is 32p/KWH = £14.08....just for leaving it plugged in. So many electronic appliances run the PSU whilst ever plugged in. Richard, G0OJF, UK
Here's the scinario....you have a small factory unit making widgets. There is an office on a mezzanine level. You have a CB base station & can talk to your fork lift drivers on the shop floor & loading. The phone rings; It's a relative of one of the workers who's in the factory unit making widgets. "Can you tell Fred I gave him the wrong packed lunch please". The office worker switches the CB to PA & announces "Fred, your Wife has phoned to say she's given you Marmite sandwiches instead of Bovril." Richard, G0OJF, UK
I have a old uniden 300 base been in storage for years when I come to fire it up it receives and will key up but no audio on transmitting tried different microphones ?
