useful stuff here
- posted
13 years ago
useful stuff here
That was quite painless. I suppose as audio, between mains frequency and SMPS f., T&I iron lamination but air gap, all E in one varnished lump and all I in one lump. Between interlaced I&E iron of mains and ferrite airgapped of smps. 34.48gm of bobbin,terminals, thick wire and the broken
0.13mm wire . On outside winding , should count off easily via paint stripper softening or hot air and weight if not. No obvious overheating on the outside or telltale melting of the bobbin at the now revealed centre. I suspect just marginal overheating combined with too much wire , it is seriously squashed up on the bobbin to have got it slid over the E plates, and pehaps just a mechanical break somewhere, but it did occur in the same session as the loss of bias meltdown.Counted off with no breaks, paint stripper on outer layer and then blast of hot air if the wire was "grabbing" . No hot spot or shorted turns. Break 5mm from the end due to mechanical strain presumably. No wonder only 0.2R over the inner coil , it is .78mm diameter wire. 3 amps of audio ac expected ? , I can see 0.6mm wire going back there ,or whatever, for 1 layer of same number of turns 1 and a part layers , the part layer had ruckled under the tape allowing the thin wire turns to drop off at the ends , hence grabbing on counting off, and pushing radially over the wire lead-out, especially as a few part turns to take up the recess from the thick wire part turn. Surprisingly no obvious punch through between primary and secondary (which is which in this circumstance?) as ruckling had allowed fine wires to touch thick wires it would seem, bypassing the intended interlayer tape
anyone aware what the innards of valve/tube output matching transformers look like? do they have air gapped soft iron aggregated E& aggregated I laminations ?
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