20-11-2012, 10:22 AM
I agree David regarding the AVO 8, the industry standard and still available at reasonable cost.
Once Robs set is sorted it would pay him to do several resistance checks on the different types of receivers he may have that are working ie:
AC/DC type with thermistor fitted: resistance across mains input (typical value to be expected)
Ditto but no thermistor fitted.
AC only sets, ie mains transformer primary (typical value to be expected)
Same then for typical resistance readings from HT to Chassis:
Sets with screen grid bleeder network(s)
Ditto without.
Write typical values down for reference, after you've serviced a few you will know what to expect automatically.
Rob is clearly on the early stages of the learning curve so any practical hints will help him and others in a similar situation.
To me efficient fault diagnosis/finding is an art, but an art that is easily achhieved by first understanding the basic building blocks of the receiver, what each blocks function is and what you can expect to see test wise from each block.
It is sometimes easy to be tempted to just jump in and hope for the best, if you are lucky you might just crack the fault and be ok, a methodical approach is always best though, once you know what to expect out of each stage of the receiver then it's relatively plain sailing so far as fault finding goes, I am generalising here so no offence to the seasoned repairer/engineer.
I personally still like to diagnose and fault find down to component level as the faults arise, it's the only real way of learning, then once all up and running you can use the scatter gun method if required to increase the reliability factor of the receiver.
Lawrence.
Once Robs set is sorted it would pay him to do several resistance checks on the different types of receivers he may have that are working ie:
AC/DC type with thermistor fitted: resistance across mains input (typical value to be expected)
Ditto but no thermistor fitted.
AC only sets, ie mains transformer primary (typical value to be expected)
Same then for typical resistance readings from HT to Chassis:
Sets with screen grid bleeder network(s)
Ditto without.
Write typical values down for reference, after you've serviced a few you will know what to expect automatically.
Rob is clearly on the early stages of the learning curve so any practical hints will help him and others in a similar situation.
To me efficient fault diagnosis/finding is an art, but an art that is easily achhieved by first understanding the basic building blocks of the receiver, what each blocks function is and what you can expect to see test wise from each block.
It is sometimes easy to be tempted to just jump in and hope for the best, if you are lucky you might just crack the fault and be ok, a methodical approach is always best though, once you know what to expect out of each stage of the receiver then it's relatively plain sailing so far as fault finding goes, I am generalising here so no offence to the seasoned repairer/engineer.
I personally still like to diagnose and fault find down to component level as the faults arise, it's the only real way of learning, then once all up and running you can use the scatter gun method if required to increase the reliability factor of the receiver.
Lawrence.
