LEAK st20
- Thread starter Fitnessed
- Start date
Jobs left to do......
Voltage selectors and impedance ,clean and insert solid copper core soldered in.
When i checked the windings there was a difference between the two st20 i have.
I then transferred the modded selectors over and all was good.
X4 input metal film resistors.
91k value to be made up with parallel resistors.
uf4007 diode mod.
fuse holder for drop resistor location.
Need to look at power up methods,variac,dim bulb,dummy load and measurements.
Have known good valves...
Voltage selectors and impedance ,clean and insert solid copper core soldered in.
When i checked the windings there was a difference between the two st20 i have.
I then transferred the modded selectors over and all was good.
X4 input metal film resistors.
91k value to be made up with parallel resistors.
uf4007 diode mod.
fuse holder for drop resistor location.
Need to look at power up methods,variac,dim bulb,dummy load and measurements.
Have known good valves...
Watching your progress with interest as Ive got a st20 I want to fire up again sometime.
If you dont mind me asking , what is the uf4007 mod and the fuse holder for drop resistor location ?
I plan to power mine up slowly via my variac, probably first up to something like 50% with dummy load while
monitoring voltages ?
Good find about the voltage and impedance selectors. I'll have a good look at mine now.
If you dont mind me asking , what is the uf4007 mod and the fuse holder for drop resistor location ?
I plan to power mine up slowly via my variac, probably first up to something like 50% with dummy load while
monitoring voltages ?
Good find about the voltage and impedance selectors. I'll have a good look at mine now.
diode mod and more
https://pinkfishmedia.net/forum/threads/leak-stereo-20.113461/page-28Rs part number for diodes -671-5740
IMG_6037 - Copy by vintage audio vintage audio, on FlickrIt appears that my st20 originally ran a stepped network on r5.
A bit of digging reveals that is was something added to later grey st20s.
It does not show on circuit diagrams.
Snowman al(R.I.P) highlighted this on the uk vintage radio and restoration forum.
Anyone have any thoughts on this? worth reinstating?