Questions tagged [vintage]

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6
votes
2answers
907 views

Fixing old CRT oscilloscopes… what to look for first?

I've been amassing a pretty large collection of these old scopes, and it's about time I got to trying to fix them. About half of the ones I run across and buy don't have traces. I don't need to get ...
0
votes
0answers
113 views

Russian germanium transistors

The germanium transistor era was long over in the west when the Berlin wall came down. Nowadays, new old stock Russian germanium transistors are appearing on world markets. Some musicians prefer ...
3
votes
1answer
74 views

Why do they not make center tapped loadspeakers?

An early Australian solid state portable receiver manufactured by AWA used a 30 ohm centre tapper speaker that was directly driven by a push pull PNP germanium output stage. The orthodox arrangement ...
2
votes
3answers
58 views

Can I replace a dual section capacitor in a tube amplifier design with two single capacitors?

I was planning on building this schematic, but found it hard to source their 20/20 dual section cap (C3/C4). Could I replace this with two single 20uF caps, or is it a dual-section for a reason?
2
votes
2answers
69 views

Ferrite rod antenna improvements

Most early solid state portable MW AM radios used a ferrite rod antenna. Some valve receivers like Phillips in the late 1950s used ferrite rods also. The early Germanium RF transistors were not too ...
1
vote
1answer
56 views

Envelope Detector Improvements?

The classic Envelope Detector is very old and very cheap and very simple .Sure there are now better schemes like synchronous detection ,PLL etc.The circuit is responding to the peak of the Amplitude ...
33
votes
1answer
4k views

Why were germanium diodes so fast and germanium transistors so slow?

Germanium diodes were used for Radar during WW2. Germanium transistors appeared about a decade later. Most early transistors were only specified for audio use, like the OC71. The specified RF types ...
0
votes
1answer
104 views

Identify component in 1970s vintage video game from photo

Can anyone identify these two components, marked "SKY 4433" and "2.000000 K.D.S", respecitvely? Are they capacitors, crystals, or something else? They are from a vintage 1970s ball-and-paddle-style ...
1
vote
2answers
110 views

Why do older (green) PCBs have primarily a darker color, whereas new ones are lighter

Note the difference in color between this old commodore board and this newer board. It might seem like lighting, but after looking at my own collection of scrap boards, the older ones tend to have a ...
1
vote
1answer
65 views

What is an impedance bridge?

Today, I saw a very old historical piece of lab equipment at the university. It had a large number of dials, although not as large as you would see in an oscilloscope. The size was similar to an ...
3
votes
1answer
181 views

What are these hybrids from National Semiconductor?

I found some parts in my junk drawer that I can't identify. I'm pretty sure they're National Semiconductor hybrid circuits from 1969-1970, but I have no access to a National Hybrid Products databook. ...
0
votes
0answers
34 views

Volume control reliability

Log potentiometers were the mainstay for volume controls in radios .I have seen values of 5 to 10K in early solid state radios .Valve radios would use 250K to 1 meg .Crystal cartridge record players ...
1
vote
1answer
342 views

RIFA PME271M547 replacement

I just broke my sewing machine (it's an old Viktoria machine about 30-40 years old) and now I am looking for a replacement safety capacitor. The one installed is a RIFA PME 271 M 547 paper capacitor. ...
1
vote
2answers
169 views

EM Vs PM Speaker

Modern Speakers have permanent magnets and are called PM speakers.Permanent magnet materials technology has improved a lot over the last 80 years .Around WW2 EM speakers were common because permanent ...
0
votes
1answer
85 views

Design questions regarding LM2735 (boost-converter) for DC-DC

I'm doodling with a future circuit. The application (Commodore 64) expects 5VDC (which I will provide with a pass-through) and 9VAC 50Hz. I do not have any working circuit or a schematic, because the ...
1
vote
2answers
171 views

What connector did this IBM Model M keyboard have?

I got got hold of an old IBM Model M (Model 1391403, to be precise). Unfortunately, the fixed cable was cut off by an unknown idiot. Does anyone know what kind of connector (I assume PS/2?) was ...
2
votes
1answer
101 views

old 80C31 circuit not working. EPROM data retention issue?

I have an old piece of pro-audio gear in for repair. It dates from 1990. It was a fairly high-end piece of gear at the time and still has some value so it is worth repairing. But the symptoms I see ...
2
votes
1answer
155 views

Can old vintage quartz crystals handle more power?

Old crystals are very large compared to present day devices. Vintage transmitter circuits did not have many valves in their line up. I have seen a 2 valve 50 watt CW transmitter for 80 meters in a ...
7
votes
1answer
513 views

Identify Vintage Power Cord for 1980s Organ [closed]

I Recently acquired a Technics SX-C600 organ but it needs a power cord. Does anyone know what type of power cord I should get for this? My understanding is that this is a rare organ.
0
votes
1answer
97 views

How does a rocking arm voltage regulator work?

I am trying to determine the suitability of replacing a (ancient) rocking arm voltage regulator with a modern digital device. I assume a rocking arm regulator has an electromechanical or magnetic ...
0
votes
1answer
46 views

Increase rotational velocity of synchronous motor

I recently got my hands on a Philips PM8110 (a single pen recorder which is basically an analog printer for voltages) which sadly provides paper with a velocity of 8 cm/hour. Although this would ...
14
votes
1answer
611 views

Old equipment to identify

I volunteer at the Dauphin Railway Museum in Manitoba, where we recently received a donation of equipment collected by CNCP Telecommunications in the 1970s and earlier. Most has been identified, ...
2
votes
0answers
122 views

Please help identify this vintage component [closed]

I got this item in a bidding lot and have been trying to figure out what it is ever since. The nearest I can tell it is either an electro shock therapy device or perhaps a remote detonator. It has ...
14
votes
1answer
1k views

What is a “universal bridge”?

I recently came across this intriguing instrument from the 1970s(?): It's a "Universal Bridge" made by Wayne Kerr. It's not a type of device I've come across before and I'm curious what these are (...
2
votes
2answers
214 views

Old-school pseudorandom pulse generator (requesting assistance with hardware design)

I would like to design an old-school pseudorandom pulse generator to trigger various types of events (hardware suggestions only please - no programmable ICs). The events that I want to control need to ...
9
votes
2answers
597 views

Identifying an old RF circuit

I got an old RF circuit (I guess), probably used for pedagogical purposes. Here's the schematic: I chose the positive and ground rails as it seems right to me, looking at transistors and resistor ...
12
votes
7answers
1k views

What kind of capacitor blew up in my old IBM monitor?

I pulled this out of an old IBM 5154 EGA monitor from the 80's. Clearly both are bad (though the monitor itself works anyway...). I know they're capacitors, but what kind? What would a replacement for ...
1
vote
1answer
84 views

Stereo Enhanced Mono

Medium Wave AM in most countries is monophonic. AM stereo was never universally adopted. Given a monophonic signal, how can one create a stereo output? I know there are some 'tricks' you can play on ...
7
votes
2answers
244 views

1977 GE 6RS20SP9B9 - what the heck is this component?

Ok so, ordinarily I'd not ask a "what is this" question, but this component really has me scratching my head - both at its function in the circuit and how it is constructed. Anyone know what a GE ...
0
votes
0answers
23 views

Restore or replace an old NiCad battery

I was finally able to buy a used Toshiba T4700CT to play my DOS games. I cleaned it, disassembled it and replaced both the backup battery and CMOS battery, but I have a question regarding the main ...
0
votes
1answer
33 views

Pearmability Tuning Vs Cap tuning for MW AM

I constructed a wide band Hi Fi TRF tuner for MW AM that sounds great. It used an old 365 pF air spaced 3 gang variable capacitor that had equal sections. Selectivity was marginal at the top of the ...
3
votes
1answer
229 views

Amplify Raspberry Pi Zero W Audio with 60s Tube amplifier circuit

First of all, thank you for taking a look at my question. Electronics is not my field of expertise, and I have found myself a bit stuck. I have been restoring some old 50s and 60s tube amplified ...
0
votes
1answer
183 views

Tape Deck solenoids

I found an old Tape Deck recorder that I tore apart to scavenge for interesting parts. Two different kinds of solenoids left me wondering: From an old service manual (not related to the tape deck ...
0
votes
1answer
154 views

Help looking for an 220V AC transformer replacement [closed]

My old Philips MC-M250 stereo transformer has died after a power surge. I can't find spares so I'm looking for some compatible replacement. I found a power board circuit in the service manual. AC is ...
0
votes
1answer
323 views

Germanium Diode 455KHz AM Detector

Ge Diodes have been used for AM detection many decades before Si Diodes became cheap.They were attractive when compared to the large power hungry valve .Nowdays Si diodes are much cheaper and easier ...
5
votes
2answers
1k views

What do “cycles” in a capacitor mean?

I'm trying to replace some old leaky capacitors for this radio I'm working on and in the data sheet they have this rating of cycles for the large capacitors near the bottom of the sheet here: What ...
1
vote
1answer
171 views

how to drive 1930s bakelite headphones

I’ve received a very old pair of mono bakelite headphones that I would like to re-use for demonstration purposes. Just for voice audio and morse code tones. The writings on the side of each headphone:...
51
votes
10answers
9k views

Amplification before tubes and transistors were invented

Telephones are older than vacuum tubes and of course transistors. How was signal amplification done? I mean the technology, not the details. EDIT Some additional informations that I should ...
5
votes
3answers
1k views

How to identifiy this “2222 063 90025” vintage capacitor?

I am restoring an old stereo valve amp and would like to test (and replace if needed) some components. I don't know the history of the amp, but it's made in New Zealand and looks to be from the 1960'...
1
vote
1answer
307 views

How to “fake” a megawattmeter

I have a vintage megawattmeter. It is able to indicate values from -1 to 7 MW. I wish to be able to provoke it to display any value I want, preferably without actually generating megawatts of power. ...
1
vote
3answers
102 views

Figuring out a substitute for an old amp capacitor #2

What type are the yellow caps in the picture and what do I substitute them with?
0
votes
2answers
373 views

Capacitor value for rectified magneto PSU

## Need capacitor value for below circuit ## Hi guys, Kindly help me with the situation below. I want to run my LED headlamp (with upper & dipper functions) via flywheel magneto. Current setup:...
0
votes
1answer
453 views

AM Detector Peak Vs Average

The Envelope detector is over 100 years old .In its classic form it is a simple half wave diode that peak detects the carrier with the load resister and load capacitor time constant chosen to allow ...
4
votes
2answers
2k views

Should I replace these resistors on my vintage radio?

The one in the image isn't the 250k one exactly, but it's one I had a picture of. The 250k just has a different colour but is the same kind of resistor. EDIT, the big red one is a capacitor, the ...
0
votes
0answers
173 views

Ascertaining Valve Part Numbers

Old valves (vacuum tubes) sometimes do not come in their original boxes. Sometimes the part numbers seem impossible to read. Is there an easy way to read an apparently illegible part number? Would UV ...
-2
votes
2answers
215 views

Old AMD portable charger [closed]

I found this device in my garage a few hours ago. It seems to be a very old portable charger, but I can't find what it's called or the model: The cables plug into a small jack like so: It uses a ...
3
votes
3answers
616 views

Do I need to terminate my oscope in a specific way for viewing video signals?

I'm a novice and have used my Rigol scope to look at small circuits from kits and attempt to diagnose issues on my vintage computers. I'm at a point where I want to check out composite video (for ...
0
votes
2answers
812 views

455 KHz Double tuned IFTS for Wideband MW AM reception

Vintage AM MW radios often had double tuned IFTs .The shape of the frequency response curve is well documented elsewhere .The coupling coefficient of these double tuned transformers is low and the Q ...
1
vote
0answers
75 views

Ge Vs Si for AM envelope detector

Early solid state radios used Ge diodes as a detector .Si was not available then so this makes sense .Impedances were much lower than the Valve stuff.A 5k Log volume control pot was common for early ...
13
votes
4answers
2k views

Are there special protocols one should take when handling vintage/old electronics?

UPDATE: I am mainly interested in learning about vintage chips, ics, cpus etc, mainly non-soldered chips. It would also be interesting to know about any other component (i.e., capacitor) that could ...