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One way to achieve a voltage drop without using a high wattage series resistor if replacing a Selenium unit for higher b+ : use a …
Well-Known Member. Dec 12, 2016. #9. Use a 6A (or more) rectifier bridge bolted to the chassis near the power transformer. (or use the original selenium mounting hole and screw) Connect the two yellow transformer wires to the (AC) inputs of the bridge. Connect the (+) bridge output to the filter capacitor (brown wire).
ment. Two small selenium "stacks" could easily replace a type 80 or 5Y3 vacuum tube rectifier in many circuits. Since each plate of the selenium stack could support about 30 volts, you will typ-ically find 5 or 6 plates in a 120 Vrms rectifier. Tube rectifiers need filament power to ther-mally stimulate electron flow. The 5Y3, for exam-
The negative end of the selenium rectifier goes to the 47 ohm resistor, then to chassis ground. It doesn't matter which end of the power transformer red leads go, or whether the rectifier ... You can therefore replace the selenium with a 1N4007 silicon rectifier and the the 47 ohm resistor with a 100 Ohm 3 watt metal film resistor at either or ...
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CEHCO is a leader in supplying selenium rectifier stacks. We are selenium rectifier replacement specialist. In fact, the company can assemble and deliver any selenium rectifier in 48 hours or less. And …
selenium rectifiers also have a greater voltage drop vs silicon. Typical silicon diode for up to 1000v is 0.6 volts. Each slice of selenium is good for about 20 volts reverse and loses about 1 volt forward. To get high voltages they simply stack up the slices, which of course stacks up the forward voltage loss.
Here's a step-by step guide on how to replace the selenium rectifier in your Trans-Oceanic. 1. Unsolder the wire from the bottom lug of the selenium rectifier. 2. Unsolder the 130 ohm sand resistor from the top lug of the selenium rectifier. 3. Solder the wire to the top lug of the selenium rectifier. 4.
A 600 Volt 8 amp dual diode (probably in a TO220 case) would be practically bullet proof for a replacement of a selenium rated at around 1 Amp. You WILL need either 1 or 2 resistors to 'bulk out' the inherent 'loss' exhibited by the selenium type and this (these) can get pretty warm so a wirewound part possibly bolted to the chassis could be ...
I wanted to replace the selenium rectifier. I took some voltage readings off the Selenium Rectifier ( 1/2 wave, not full wave) while it was still in the circuit. The positive connection from the selenium rectifier is connected to one side of the 125 V power transformer output and the negative side of the rectifier is connected to a voltage ...
A single silicon diode in the 1N4004 - 1N4007 series will replace you selenium rectifier. i would add a 47 ohm 1 watt resistor in series to reduce voltage to the radio. The silicon diode will have a banded end. This side goes to the same place as + …
Selenium Rectifier Replacement. I have another project radio, a Zenith Model Y723 that needs a new rectifier or preferably, a diode replacement. I looked on ebay for a NOS selenium rectifier to no avail. Zenith has several listed in their parts list such as a Federal 1101A or a Tarzian 100A but I couldn't' find these. The current rating is …
Post by jukeboxmarty onJun 19, 2023 at 8:50am. I rarely replace selenium rectifiers unless they show signs of failure. Replacing with a silicone rectifier is an acceptable option, and yes, adding an inline fuse to the AC side is a good idea. When a silicon rectifier fails it tends to short, so you want to protect your transformers.
Selenium Rectifier Replacement Resistor. Thread starter multichamp12; Start date Dec 3, 2015; multichamp12 Well-Known Member. Dec 3, 2015 #1 Hello, I am in the process of rebuilding a pair of Pilot PA-913 Preamps and want to replace the selenium rectifiers. I will use two 1N4007 Diodes, but want to determine whether I should add a …
When you replace the selenium, add the trimmer and get the heater voltages on the 12AX7s to about -23v (sounds like 2 in series) which will give you …
JohnLillig. Usually a selenium rectifier drops a volt or 1.5 or so per plate, or 5 to 10 volts usually in a stacked rectifier. On tubes, sometimes the extra bias voltage is not a bad thing, but yeah you would need to use Ohm's Law and figure out the specs of the resistor to use for correct or spec voltage.
You can replace a selenium bridge rectifier with a modern silicon bridge rectifier that consists of four diodes in a bridge configuration. Voltage Rating: Ensure …
Many improvised technicians conclude that selenium rectifiers are unreliable, their life being quite limited, then they must be always replaced. According to some sites, the direct voltage drop increase with age, …
This poor, manual select, "H" was abused and neglected for more years and then left abandoned in a basement. I purchased a Rockola 1446 30 years ago from a vending company and the addiction began. A friend, 'Donnie' a jukebox technician from the 1940s, encouraged me to learn about these magnificent machines. So, here I am retired …
After the wiring is corrected you can try measuring the output DC voltages. The filaments of the tubes on each board are in series, so if the tubes are removed, you will have to measure between the ends of each twisted pair where they are. soldered to the board. The DC voltage between the ends should be around 24VDC.
The two diodes in the schematic are the selenium rectifier! Just connect your replacements the same way as in the schematic. Yes, but if you're not familiar with selenium rectifiers, the connections can be a mystery. I can certainly read the schematic but I would have needed the same help figuring out the selenium connections.
There are some good threads on how to replace a selenium rectifier to silicon bridge rectifier, with four snubbing capacitors, and a dropping resistor (possibly with a capacitor instead). The color television of the 1960's owes its presence to the use of the 1N4007 diode. By then the majority of electronics manufacturers abandoned selenium ...
Replace Rectifier LOW READING= SHORTED DIODE Replace Rectifier The diode allows Voltage to flow through it, so the meter is indicating a "short circuit". We expect a good diode to be shorted in this test, so this is all good. +-AC AC Selenium Full-Wave Bridge Rectifier Testing Drawn by Jon Pardue 2007 Updated 2013 +-
Subscriber. Nov 17, 2022. #9. Put in the rectifier 1st. Then check your voltages with a WALL VOLTAGE of 117vac via variac. Meter the resistor before you consider replacing it. 24V is ok if you consider doing IBAM / IBBA and use Russian EH7591 or Tung-Sol 7591 re-Issues. I don't normally change the resistor unless it's actually bad.
Selenium rectifier replacement in Pilot PT-1030 B Update - the schematic you will see in this thread shows the selenium rectifier arrows pointing in the wrong direction if you are planning to replace it with two silicon diodes and a resistor. The diode cathodes should be tied together and the anodes connected to the two 16V transformer …
Armed with a 1n4004 and a suitable high voltage electrolytic capacitor, I proceeded to replace both the selenium rectifier and the filter cap that followed it (on principle — the existing cap was cosmetically in OK condition, but old electrolytics often don't work well, and sometimes fail catastrophically) to bring the 88 V B+ line and -40 V bias voltage back into …
I got the parts together, drilled out the selenium rectifier rivets, and replaced the caps. I decided to check voltages before closing things up. Across the rectifiers, I got about 320 volts, almost exactly as in post #11 above.
I also don't get too hell bent on selenium rectifier replacement unless it shows signs of issues. As long as the output voltage is good, the rectifier is workable. In a low current situation, they don't really go bad that often. The ones that cook are in filament supplies and sometimes B+ circuits. Grid bias rectifiers are under extremely ...
However, currently there are 2 wires coming from the DC terminal of the selenium rectifier. In addition to the wire to the resister/capacitor, a second wire goes from the same DC lug on the selenium rectifier directly to the same capacitor but a different lug of the capacitor.
Here are two solutions for replacement of the selenium rectifier. Whatever you do, place a high wattage dropping resistor of about 100-150 ohms on the B+. The first photo is actually from my …
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