Hello again,
This little green Roberts R303 s/n 14544 I bought from Paul Stenning when it was offered on the forum. It didn't work and the bottom kept falling out but apart from a scratch on one of the chrome knob trims it was absolutely unmarked.
The R303 has a Mullard LP1159/1 IF module in it which I reckonned probably had AF117 transistors in it and sure enough after a couple of firm taps on the module box away it went. I gave the case a quick clean and stopped the bottom door from falling out by reinstating two small strips of rubber pinched off a scrap R600 on one of the chrome door retainers.
Ron Bryan very kindly fixed this set, the LP1159/1 module was removed, the 3 x AF117s inside replaced with AF126s and the module replaced. The set now worked fine but while checking the quiescent current Ron noticed that the output transistors were getting hot and the current was unstable. It was then noticed that the BA114 stabilising diode MR1 was cracked, indeed when shoved it broke in half so a suitable replacement was fitted. The quiescent current and output transistor biasing was then successfully adjusted.
The R303 is not one of Roberts most interesting offerings but it works well and is a sensitive little set and will play remarkably loud. This one is unmarked but like most R303s (and RIC1s) one can see darkening of the edges of the rexine cover where the glue was applied under it when it was assembled. Many thanks to Ron for fixing it.
Howard
