On 5/17/2020 10:04 PM, Cursitor Doom wrote:
On Sun, 17 May 2020 21:06:23 +0530, Pimpom wrote:

I used to have some OC71s and OC72s a long time ago. They made neat
phototransistors with the paint scraped off from their glass
enclosures.

OK, I got the AC188s. With a DMM they measure 25-50 ohms forward and a
few Ks in the reverse direction.

I think you've misunderstood the problem here, Pimpom. The leakage in
question is between the case ("screen") and the die and significantly pre-
date the black-painted phototransistors we all fondly recall from 50
years ago. :-)


Ah, sorry. Then those low-ohm figures can't be normal.

My dad bought a Sony transistor radio in the early 60s. I
remember that it used Japanese Ge transistors like 2SA12, 2SA15
for RF and 2SB75 and 2SB77 for audio. One of my regrets in life
is that I never got around to restoring it when he was still
alive. This is the model -
https://priceguide.thecollector.com....or-56-2019.jpg