"Bob Engelhardt" wrote in message
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On 1/5/2017 12:07 PM, Bob Engelhardt wrote:
The transistor is a DLG600. ...

Oops - D _T_ G, as you said

TBH: I'd strip out the original current limiter circuit and rebuild with one
from a more modern linear PSU.

Its usual practice to use a separate small signal transistor who's B/E
threshold detects the volt drop across the current sense resistor. Its
collector shunts away base current from the pass transistor. If you go that
far - a Darlington pass transistor has a number of advantages.

The B/E threshold is different between silicon and germanium, so you need to
re calculate the current sense resistors. There's various online archives of
test gear schematics - you can probably find a circuit that you can pretty
much copy.