04-21-2021, 10:13 PM
Tim,
Seems the remaining transformer has failed as well?
Do try a different ohmmeter...
Some DVM's cannot effectively take a resistance reading of an iron core inductor due to the inductive reactance. The inductance has an effect on the DVM devices. BTW test leads can breakdown noticed at the connector to the meter or at the probe/clips. A somewhat firm pull on the connector/probe will confirm a bad test lead by parting the intermittent copper strands...(Oops)... Leads may be repairable or not...
Use an analog meter:
https://www.homedepot.com/p/Gardner-Bend.../202867892
Resistance should be close to the values given from Leigh Basset's new drawing of the schematic.
It is those resistances that the modern transformer does not have but often freely suggested. Several Antique Radio Forum (ARF) members have used low resistance transformers in battery radios and the radio had had serious unsolvable distortion problems. Their cure was to replace these make-do transformers with ones that have sufficient resistance in the primary. Such transformers are available from ARBE-III web site..
https://www.arbeiii.com/Transformers/
The Hammond Radiola -III transformer also has sufficient resistance not to create distortion.
https://www.tubesandmore.com/products/tr...ment-audio
If you decide to melt out to save the old can be aware that the A-K core is a group of iron wires. It would be best to use a transformer complete with its modern, low loss lamination core, both will fit into the A-K can. Wound bobbins should only be used where the entire OEM frame and laminations are exposed.
GL chas,
Seems the remaining transformer has failed as well?
Do try a different ohmmeter...
Some DVM's cannot effectively take a resistance reading of an iron core inductor due to the inductive reactance. The inductance has an effect on the DVM devices. BTW test leads can breakdown noticed at the connector to the meter or at the probe/clips. A somewhat firm pull on the connector/probe will confirm a bad test lead by parting the intermittent copper strands...(Oops)... Leads may be repairable or not...
Use an analog meter:
https://www.homedepot.com/p/Gardner-Bend.../202867892
Resistance should be close to the values given from Leigh Basset's new drawing of the schematic.
It is those resistances that the modern transformer does not have but often freely suggested. Several Antique Radio Forum (ARF) members have used low resistance transformers in battery radios and the radio had had serious unsolvable distortion problems. Their cure was to replace these make-do transformers with ones that have sufficient resistance in the primary. Such transformers are available from ARBE-III web site..
https://www.arbeiii.com/Transformers/
The Hammond Radiola -III transformer also has sufficient resistance not to create distortion.
https://www.tubesandmore.com/products/tr...ment-audio
If you decide to melt out to save the old can be aware that the A-K core is a group of iron wires. It would be best to use a transformer complete with its modern, low loss lamination core, both will fit into the A-K can. Wound bobbins should only be used where the entire OEM frame and laminations are exposed.
GL chas,
Pliny the younger
“nihil novum nihil varium nihil quod non semel spectasse sufficiat”
