25-10-2017, 11:09 AM
Well, since you mention it, running the same thread on 3 different forums can become a bit awkward. Whenever this has happened in the past, it's always led to confusion - especially if the person asking the questions is a beginner.
First of all, it is correct that there are no voltages on the collectors. Or rather, there is 0V at the collectors.
To help us understand you better, to what extent are you able to follow the diagram?
For the benefit of others who commented on this earlier, please look at the schematic. It is available via the Yahoo Hacker Radio group.
The other voltages mostly look OK at a glance, but T1 is a bit suspicious.
Why are you changing the detector diode? I strongly advise that you don't do that until you have firm and conclusive evidence that it is faulty. They are very reliable - I've repaired hundreds of these sets and can't recall the last time I had to replace them. In addition, it is buried inside the IFT, and so requires a fair bit of skill to replace without causing more faults.
You also mention "various replacement parts". Why?
With the greatest of respect, you are treating this radio like a modern garage treats obscure faults on cars. This "scattergun" approach of randomly replacing parts is not the correct way to repair a radio. AF117s aside, there might only be one or two faulty components, and you need to find them using logic. Every time you change a part you risk creating a new fault. Stop it!
It's likely that the oscillator is the problem and the IF amp might well be OK. Or perhaps not. Either way, we need to do some diagnosis to decide where to look. So, to save me having to re-read all the threads, have you managed to inject a 455kHz tone yet? Apply it to C8 in the first instance, and come back to us with the results.
If you don't have the means to generate 455kHz, then either obtain a suitable generator, or leave the poor set alone!
I repeat: do not change that diode. Yes, it might well be faulty, but we don't know that yet. If you damage the IFT, they are very hard to find.
Sorry if some of that seems to be bit blunt, but for the sake of the poor set, we need to focus.
In some ways, it's unfortunate that Hacker sets have a reputation of being easy to work on. It's true that mechanically, they are superb. But electrically, they are complex sets, and need just as much skill as any other set when they do go wrong.
First of all, it is correct that there are no voltages on the collectors. Or rather, there is 0V at the collectors.
To help us understand you better, to what extent are you able to follow the diagram?
For the benefit of others who commented on this earlier, please look at the schematic. It is available via the Yahoo Hacker Radio group.
The other voltages mostly look OK at a glance, but T1 is a bit suspicious.
Why are you changing the detector diode? I strongly advise that you don't do that until you have firm and conclusive evidence that it is faulty. They are very reliable - I've repaired hundreds of these sets and can't recall the last time I had to replace them. In addition, it is buried inside the IFT, and so requires a fair bit of skill to replace without causing more faults.
You also mention "various replacement parts". Why?
With the greatest of respect, you are treating this radio like a modern garage treats obscure faults on cars. This "scattergun" approach of randomly replacing parts is not the correct way to repair a radio. AF117s aside, there might only be one or two faulty components, and you need to find them using logic. Every time you change a part you risk creating a new fault. Stop it!
It's likely that the oscillator is the problem and the IF amp might well be OK. Or perhaps not. Either way, we need to do some diagnosis to decide where to look. So, to save me having to re-read all the threads, have you managed to inject a 455kHz tone yet? Apply it to C8 in the first instance, and come back to us with the results.
If you don't have the means to generate 455kHz, then either obtain a suitable generator, or leave the poor set alone!
I repeat: do not change that diode. Yes, it might well be faulty, but we don't know that yet. If you damage the IFT, they are very hard to find.
Sorry if some of that seems to be bit blunt, but for the sake of the poor set, we need to focus.
In some ways, it's unfortunate that Hacker sets have a reputation of being easy to work on. It's true that mechanically, they are superb. But electrically, they are complex sets, and need just as much skill as any other set when they do go wrong.
