[Premium-Rx] REGCO RG-5500 Low Band First RF Amplifier Replacement

[Борис Никитин]

Hello All,

REGCO RG-5500 very rare Radio and those who have it I think also. I has spent good time with repair and restoration of that beast and perhaps somebody will find this information usefull:

Low Band (radio has two low and hight band's) from 20 to 510 MHz has first RF Amplifier original type number AM-103 by Adams-Russell.
Receiver has NO PROTECTION from static or very powefull signals (from transmitter nearby). Antenna Input N-type connector connected directly
to the 1st RF Amplifier stage via input RF switch.
That is why I found first stage dead along with many others faults...
AM-103 Integrated Wideband Amplifier very difficult to find. At first I replaced it with my own cascode amplifier with two UHF/Microwave discrete transistors and it doing well about two years. Recently one of my good friend in USA found for me AM-123 Wide Band Amplifier. It has same pin connection, gain, and band coverage, but different design. Tab's from both side of the case-power dissipation triple more then AM-103. (Manufacturer recommend 1 WT heat sink) 
That is why replacement not simple, because very restricted space on PCB. After some hard time and scratch the head, good solution found how to use AM-123 instead AM-103 with good heat transfer to the ground plane of PCB. No changes needed on PCB itself.

Good, hight quality, detailed photos available if anybody find this trick interesting...
Contact me directly for more...

All the best,
Boris