Hello guys,
I recently bought an A77 and a B77 Revox recorders and I´ll be thinkering with them, replacing the caps, doing an overhaul and I´ll probably be asking a lot of questions in the forum, but since I´m starting slowly, refreshing my 25+ years of unused electronics knowledge I~ll have to do it step by step.
So, right now, I´m studying the monitor amplifier PCB (1.117.260-12) and I found a couple diodes AN 116 broken, so I need a current replacement for them.
On the web i found it´s parameters :
Material/Aufbau: Germanium Punktkontakt;
Form/Case: Allglas, ähnlich DO-29;
Daten/electr.data: I F: 10 mA; U F: 1 V; I sp: 20 µA; U sp: 10 V; Imax: 30 mA; Umax: 20 V; tmax: 75 °C.
AA 116, Tube AA116; Röhre AA 116 ID34222, Solid-State-Diode
But I could not find a direct replacement equivalent that can be readily available today.
I thank you all in advance for any help on this matter.
Regards,
Mauricio
I recently bought an A77 and a B77 Revox recorders and I´ll be thinkering with them, replacing the caps, doing an overhaul and I´ll probably be asking a lot of questions in the forum, but since I´m starting slowly, refreshing my 25+ years of unused electronics knowledge I~ll have to do it step by step.
So, right now, I´m studying the monitor amplifier PCB (1.117.260-12) and I found a couple diodes AN 116 broken, so I need a current replacement for them.
On the web i found it´s parameters :
Material/Aufbau: Germanium Punktkontakt;
Form/Case: Allglas, ähnlich DO-29;
Daten/electr.data: I F: 10 mA; U F: 1 V; I sp: 20 µA; U sp: 10 V; Imax: 30 mA; Umax: 20 V; tmax: 75 °C.
AA 116, Tube AA116; Röhre AA 116 ID34222, Solid-State-Diode
But I could not find a direct replacement equivalent that can be readily available today.
I thank you all in advance for any help on this matter.
Regards,
Mauricio
One of the current 1N4148 or 1N914 silicon signal diode families would work except for one spec: the Vf is more like 0.6 or 0.7V.
So it depends on the application whether that is important.
Do you have a schematic?
BTW Are you sure they are 'broken'? If they are, you might have a more serious problem, they dont just 'break' from nothing.
Jan
So it depends on the application whether that is important.
Do you have a schematic?
BTW Are you sure they are 'broken'? If they are, you might have a more serious problem, they dont just 'break' from nothing.
Jan
In a B77 they would have used an ordinary Si diode if it was possible, which probably rules out that sort of replacement.
A modern alternative like a Si schottky might be suitable, but it is far from certain: after all, point contact diodes are essentially Ge schottky's which means they beat all "modern" diodes on threshold, except a few exotic types, zero threshold or shifted threshold, but these don't exist in "normal" cases anyway, even if you are ready to pay the price.
This leaves you basically with two options: a cheap, modern schottky like the BAT81 fe., or any point contact diode: they may not be exact equivalent, but in most applications they will be interchangeable.
You can easily find on Ebay OA95, OA81, 1N34, 1N62, 1N95, 1N273, or their AEI CG equivalent, AA119, AA134, AAZ15, plus japanese and soviet types. That is probably the safest option once you have fixed the problem that broke them in the first place, of course.
A modern alternative like a Si schottky might be suitable, but it is far from certain: after all, point contact diodes are essentially Ge schottky's which means they beat all "modern" diodes on threshold, except a few exotic types, zero threshold or shifted threshold, but these don't exist in "normal" cases anyway, even if you are ready to pay the price.
This leaves you basically with two options: a cheap, modern schottky like the BAT81 fe., or any point contact diode: they may not be exact equivalent, but in most applications they will be interchangeable.
You can easily find on Ebay OA95, OA81, 1N34, 1N62, 1N95, 1N273, or their AEI CG equivalent, AA119, AA134, AAZ15, plus japanese and soviet types. That is probably the safest option once you have fixed the problem that broke them in the first place, of course.
Hey guys, thanks for the prompt answers.
Yeah, the terminal disconnected from the glass body.
This B77 was from Rio, so sitting seaside for 30+ years was not so good for it.
I got some light corrosion over metal parts, I got some IC´s that will have to be replaced, all (but one) metalic transistors that kinda fell apart from the board, lots of connectors that need cleaning.
But I think it will be fun to get it running again.
Thank you all again. I´ll check every option you guys gave me.
Yeah, the terminal disconnected from the glass body.
This B77 was from Rio, so sitting seaside for 30+ years was not so good for it.
I got some light corrosion over metal parts, I got some IC´s that will have to be replaced, all (but one) metalic transistors that kinda fell apart from the board, lots of connectors that need cleaning.
But I think it will be fun to get it running again.
Thank you all again. I´ll check every option you guys gave me.
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