[sdiy] Oberheim 4-voice issues (SEM, keyboard)

[Gordon JC Pearce]

On 07/06/12 20:34, Eric Frampton wrote:

> But how does one accurately measure them without pulling them completely off the board?

Aha, well I have an easy time of it since the vast majority of them 
cause stock faults with the radio equipment I work on.  Failing 0.1μF 
SMT ceramics in old Tait T2000 radios either cause it to go 
progressively deaf, or cause the squelch circuit to stay squelched no 
matter how strong the incoming signal is.  As these radios get to about 
15 years old, they're all starting to come in with various problems 
relating to never showing "In Service" because they don't hear the 
control channel, or only working in certain areas coincidentally quite 
close to the repeater sites ;-)

There are others, like the leaky SMT ceramics in certain Kenwoods that 
cause DC conditions around the mike preamp to go haywire and give you 
terrible audio.

Horrible bloody things.

-- 
Gordonjcp MM0YEQ