10-04-2015, 08:57 AM
(This post was last modified: 10-04-2015, 09:02 AM by Old Sparky.)
Ah! The dreaded 'Tin Whisker' problem with AF117s and their ilk. BTW I always replace AF11x transistors, rather than fiddle about trying to cure them. Recently I have found, courtesy of a fellow meber of UKVRRR, that theree is a russian transistor, type no GT322, which can replace AF12x & AF11x types. It is a TO-72, presumably alloy-diffused, device like the AF126/127, etc, however it's base & emitter connections are reversed compared to those of the AF12x series -i.e. the same as tose of an AF139, 239 etc. Specification, however, is similar to that of an AF127. The GT322 is available from several eBay sellers at around £1 each in quantities of 15, so is a more economical buy that AF127s.
As to the problem with the overheating, I can only second the suggestions that smoothing capacitors may be the culprit(s), or possibly faulty output transistors, though it's just possible that the fault may have been caused by soldering connections to the earphone jack with the radio switched on. Incidentally, if i may mention it here, the service info. for the TR114 is available from 'Vintage radio Service Data' ( part of UKVRRR), but you have to register as a member before you can purchase this.
As to the problem with the overheating, I can only second the suggestions that smoothing capacitors may be the culprit(s), or possibly faulty output transistors, though it's just possible that the fault may have been caused by soldering connections to the earphone jack with the radio switched on. Incidentally, if i may mention it here, the service info. for the TR114 is available from 'Vintage radio Service Data' ( part of UKVRRR), but you have to register as a member before you can purchase this.
