A Conn 6029 tube organ amplifier.There are 3 in the amp. 1 is bad and needs to be replaced.
I think it is a BY127 but check the voltage drop across the good ones to make sure they are silicon and not selenium.
A 1N4007 will replace it as long as there is less than 500 volts on the DC supply from a full wave bridge. (NTE lists it as a 600 volt diode.) To be safe replace all of them.
(Selenium in that package would be very low voltage.)
(Selenium in that package would be very low voltage.)
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A BY127 is a 1250Volt version of a 1N4007 but in a miniature case. A BY127 will look better and be more in keeping with the age of the machine.
According to the schematic, I'm speculating that these are Tunnel diodes and they are being used in reverse bias operation as Back diodes. The + sign is at the cathode, but 100% I'm not sure.
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Not tunnel diodes. These are standard rectifiers as everyone has pointed out.
The striped end of the replacements should be where the + symbol is on the diagram.
(That puzzled me no end as a youngster. If the cathode of the diode has the stripe, why do diagrams put a + marking there)
Tunnel diodes? I think not! TDs are low voltage (and delicate) diodes with a "snap-back" reverse characteristic, much used in trigger and oscillator circuits.
The schematic shows 50/60Hz HV rectifiers, as already suggested.
The schematic shows 50/60Hz HV rectifiers, as already suggested.
Gotcha. It was a guess.
I haven't come across diodes like this. I have a bunch of DO-41's and smaller on hand, and a few bigger. Would one of these bigger ones be better?
Thanks in a advance and for the replies!
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The white ceramic ones are probably glass passivated types. The crucial requirement is that the P.I.V. or peak inverse voltage is 1000v or higher, and that the current rating is suitable. Any of the type mentioned by the others above are suitable. 1N5408's are another, a chunky 3 amp diode of 1000 volt rating.
No, No, No...
Although the BY127 and 1N4007 would work, the BY127 is harder to get in the US and the 1N4007 way too common. As the original power supply looks like it used an obsolete metal can gold plated rectifier you will need special diodes available only through me for $85.00 ea. plus shipping.
Pay no attention to the 300 volt rating on the power supply capacitors and the stacking arrangement (Voltage doubler) that was used to get by with the lower voltage diodes back when the amplifier was built. Buy the special diodes quickly before I have to raise the price..
Although the BY127 and 1N4007 would work, the BY127 is harder to get in the US and the 1N4007 way too common. As the original power supply looks like it used an obsolete metal can gold plated rectifier you will need special diodes available only through me for $85.00 ea. plus shipping.
Pay no attention to the 300 volt rating on the power supply capacitors and the stacking arrangement (Voltage doubler) that was used to get by with the lower voltage diodes back when the amplifier was built. Buy the special diodes quickly before I have to raise the price..
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