The audio circuit with the dual secondary driver transformer and transformerless output was quite commonly used in high fidelity amplifiers as well during the germanium transistor era.
Great job, Frank! With the old transistor radios that have zero sound, first thing I always check is the earphone jack. 90% of the time, someone shoved the wrong plug in them and bent the cutout switch. Or the switch terminals are corroded. Did you check the voice coil wires behind the terminal board on the old speaker. Some times those are broken and, if you are careful enough, can be repaired.
14:04...actually, no: if you're tuning in 1600kc signal, and expect to get an IF signal of 455kc, the local oscillator will have to produce a 2055kc output signal...
They havent changed much...i have a eye for the Chinese kits. Assemble them and show them off :::check old computers for a passable speaker. Ps if you heare a" putt" then the final amp is getting some power😊
I just purchased another one last week, (the green one of the series) and it works. Arvin smartened up and made a bigger battery compartment for this one as it takes a standard 9 volt battery.
![Faulty Roberts R900 Radio [Repair Cafe] | Can I Fix It?](/img/n.gif)
The audio circuit with the dual secondary driver transformer and transformerless output was quite commonly used in high fidelity amplifiers as well during the germanium transistor era.
Great job, Frank!
With the old transistor radios that have zero sound, first thing I always check is the earphone jack. 90% of the time, someone shoved the wrong plug in them and bent the cutout switch. Or the switch terminals are corroded. Did you check the voice coil wires behind the terminal board on the old speaker. Some times those are broken and, if you are careful enough, can be repaired.
@@videolabguy There is no continuity in the speaker. I've hung onto it and might attempt a repair sometime.
...that's the TRUTH...
I had that radio in turquoise with a real leather case. It took Sears batteries.
@@stanleycostello9610 I believe the one you had takes a regular 9 volt battery.
14:04...actually, no: if you're tuning in 1600kc signal, and expect to get an IF signal of 455kc, the local oscillator will have to produce a 2055kc output signal...
If you look at it again, you'll notice that I put a correction in the visuals and said that it was around 2 MHz .
Beautiful🌹 and🌹👍
They havent changed much...i have a eye for the Chinese kits. Assemble them and show them off :::check old computers for a passable speaker. Ps if you heare a" putt" then the final amp is getting some power😊
@@Steven-re7xt old laptops have really interesting speakers also.
Germainum vs silicon 😊
@@Steven-re7xt Sometimes they have to work together LOL
This radio was made by Arvin.
I just purchased another one last week, (the green one of the series) and it works. Arvin smartened up and made a bigger battery compartment for this one as it takes a standard 9 volt battery.
0:19...well, "if it doesn't WORK- then it doesn't EAT!!!"
@@daleburrell6273 No battery juice.