[Premium-Rx] RA1772 vs RA1792

[David Bobbett]

"How would you compare the RA-1772 against the RA-1792?"

I have had repair experience of the 1772, 1778 and 1792 receivers, I have owned 1772's in the past and currently I have 3 1778's and a 1792.

Personally, despite the advanced AGC design of the 1792 and its 100 channel memory, I prefer the 1778 as a 'users' radio. I find the ergonomics of the 72/78s superior and the smoothness of the tuning control is streets ahead of the 1792. This is because it uses a pair of shielded ball-race bearings and a large brass weight to give momentum to the tuning action. The design also allows you to rebuild the tuning assembly if the bearings are shot. The 1792 on the other hand uses a 'shaft in a nylon tube' approach which gives a rather dead tuning action and is prone to failure where each end of the tube is bolted down onto the PCBs. Presumably it would be possible to have a new nylon tube fabricated, but changing a couple of stock bearings (type FRW4ZZ) is far easier.


In terms of the sort of ongoing repair/refurbishment work needed on these radios:

RA1792 suffers from: failure of its tantalum capacitors; leaky back-up battery damaging the CPU board; LCD displays failing - although there is now a source of replacement LCDs, at least for a while.

RA1772/1778 suffers from: poor PSU cooling; PSU smoothing caps failing; brittle wiring due to overheating above the PSU PCB; dried out electrolytics.


Of the two radios the 1792 is easier to work on if you are able to swap boards, although the hinge-out PCBs on the 1772/78 are not very difficult to work on in my view. As John mentioned in his post, a small fan blowing onto the 1772 heatsink helps a lot - and Enrigue's link to GM1SXX's site, where it is suggested that the hottest rectifier pack D2 is moved elsewhere is a good idea.

I suppose if I really had to choose only one radio, I would probably keep a 1778, add a cooling fan and a wider AM filter such as is found on the 1772.