Salossi
Well-known member
Hi folks,
I currently have a problem with my V276 preamps, made in ´69...
I own 5 of these preamps, and I use 4 of them all the time... the 5th unit had a technical issue and was sitting on the shelf for years - I also used it to take out some spare parts to repair the other units...
A few days ago, I recognized that one channel of my 4Ch-V276 Box is not working… No signal at all…
At home I spotted, that those thin wires coming out of the input transformer are pretty much corroded… I tested the coils with the component tester of my oscilloscope, and by comparing to the other (not working) unit I could immediately spot that there is an open connection at one coil (where I could detect a coil at the other unit).. on the other hand, this already broken preamp also had another bad coil - probably this was the reason, THIS second unit didn´t work in the past…
Anyway I swopped the transformers, being extremely careful with the wires…
After I installed the other tranny, the coil, that was still working beforehand, was also dead :-(
FFS!!
It seems as if those thin wires are EXTREMELY brittle, as they probably are completely corroded…
I would like to repair those trannys now, I hope that maybe the corrosion is only an issue at the outside of the shielding, and maybe I can clip of the wires inside the magnetic shield, resolder and then reassemble? What do you think?
My questions are:
- Is this a common issue on those trannys?? Or is this problem maybe caused by humidity at the previous owners place or whatsoever???
- Did anybody restore / rewind one of those trannys already? Does anybody have a schematic (winding diagram) of those input trannys, used in the V276??
- Is there any other accepteable option for a replacement?
- Any ideas, how I could protect the leads in my other 3 still working preamps from the same issue?
Cheeers, Salossi
I currently have a problem with my V276 preamps, made in ´69...
I own 5 of these preamps, and I use 4 of them all the time... the 5th unit had a technical issue and was sitting on the shelf for years - I also used it to take out some spare parts to repair the other units...
A few days ago, I recognized that one channel of my 4Ch-V276 Box is not working… No signal at all…
At home I spotted, that those thin wires coming out of the input transformer are pretty much corroded… I tested the coils with the component tester of my oscilloscope, and by comparing to the other (not working) unit I could immediately spot that there is an open connection at one coil (where I could detect a coil at the other unit).. on the other hand, this already broken preamp also had another bad coil - probably this was the reason, THIS second unit didn´t work in the past…
Anyway I swopped the transformers, being extremely careful with the wires…
After I installed the other tranny, the coil, that was still working beforehand, was also dead :-(
FFS!!
It seems as if those thin wires are EXTREMELY brittle, as they probably are completely corroded…
I would like to repair those trannys now, I hope that maybe the corrosion is only an issue at the outside of the shielding, and maybe I can clip of the wires inside the magnetic shield, resolder and then reassemble? What do you think?
My questions are:
- Is this a common issue on those trannys?? Or is this problem maybe caused by humidity at the previous owners place or whatsoever???
- Did anybody restore / rewind one of those trannys already? Does anybody have a schematic (winding diagram) of those input trannys, used in the V276??
- Is there any other accepteable option for a replacement?
- Any ideas, how I could protect the leads in my other 3 still working preamps from the same issue?
Cheeers, Salossi
