Update to the Uniden Uniace 100 repair

The project to repair the Uniden Uniace 100 I picked up for £20 from a radio rally is coming along nicely, with the radio receiving to some extent I turned my attention to the transmitter, and it now transmits fine.

One of the tuning stages within the transmitter had a broken core so I turned this over and adjusted it with an improvised trimmer tool from a piece of plastic I had lying about, this has brought the transmitter up to a suitable output and the 10dB switch does attenuate the signal as it is meant to do, though the default position on the Uniden Uniace 100 is in fact the low power mode, for high power it requires you push the switch in.

With the transmitter now operational my next job is to replace all of the usual suspect capacitors with new ones and any other capacitors that need to be replaced, these are normally electrolytic capacitors, and with the radio at least 41 years old it would be prudent to change them.

All repairs carried out so far have involved traditional 60/40 tin/lead solder for any soldering work as this is what would have been used by Uniden in 1981 as the powers that be hadn't outlawed lead solder in consumer electronics at that point.

Once the capacitors are done the radio will be subjected to a full retune of both transmitter and receiver as changing them may effect the tuning

I hope this set can give another 41 years of service, who knows, it may outlast me!

73 de M0WNU/26CT730

Uniden Uniace 100 repair project

After attending the 2022 Durham & District Amateur radio society rally I came away with 2 CBs, keeping up my long-standing tradition of buying radios at rallies, these were the Midland 77-095 and the Uniden Uniace 100, both type approved under the original CB 27/81 regime started in November 1981.

The Midland was all fine though if it did not work I'd have swiped the volume control from it for the Midland 38 as I suspect the part is identical, the Uniden was modified to 10-meters and this post is about me beginning to restore it to CB use.

So the first thing I found opening the radio was a board added by another ham long ago, this had a few components including 2 crystals and were tapped into the TX and RX stages of the radio, removing this and reinstating two resistors got it back on frequency but very little TX power, RX was fine bar channel 2, I next removed an errant resistor from the bottom of the board and replaced another resistor that was of an incorrect value, TX still very low output and still this fault on channel 2, I next spotted a link across one of the receive tuning cans and a capacitor across the unoccupied 10.695MHz filter position, removal of the link deafened the receive greatly, I then spotted a cut track leading from one of the tuning cans and the filter to another part of the circuit, this was reinstated and improved the receive by a tiny margin, so the radio is in need of a proper tune up once I get trimmer tools.

I suspect that the radio has been retuned to be optimum on 28MHz, so every stage of both the transmitter and the receiver will need to be gone over several times and the discriminator checked, deviation appears to be untouched as received on my handhelds, the meter has a working lamp but due to damage to the front panel it is held in by sticky pads, and fouled the latching mechanism on the PA switch.

This radio is the second Uniden I own so far as they made the President Grant II, and hopefully the third Uniden I'll have used as the first CB I used was an Audioline 341 that the owner mucked up with a screwdriver in front of me, the 341 using the same board as the Uniden Uniace 200, interestingly the Audioline equivalent of the Uniden Uniace 100 does not have a PA facility.

I'll update as progress on this 1980s classic is made

73 de M0WNU/26CT730