Questions tagged [vintage]
For questions about early/old electrical technologies and devices that are no longer available today, or almost extinct.
171
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Proper disposal of PCB oils from old electronics
I sometimes take apart old junk electronics for spare parts. Recently, I was opening up an old (1960s-80s sometime) small power supply to get at its very handsome power switch and dial. Its ...
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3
votes
1
answer
295
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How Does This Antique Television Circuit Work?
I'm trying to learn tube electronics, specifically for antique television applications. The vertical deflection circuit in the 1949 Motorola VT73 Chassis TS-4J confuses me. I can't understand how this ...
0
votes
1
answer
39
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Replacement for vintage 3 terminal motor run capacitor [closed]
I am looking for a replacement motor run capacitor. In the schematic and parts list, it is a 4.5uF ac capacitor rated to 230v. But, it has three terminals. It is a vintage can package and the ...
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2
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2
answers
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What does a grid-cathode bypass capacitor on CRT do, and why is this one not doing it?
I have modified a (US) 1970s solid state B&W TV set for direct (NTSC) composite input for vintage computer use, in accordance with some equally vintage instructions specific to this set. The set ...
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55
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Identification of 3 pin connector for the power supply of the TI silent Model 703/707 Data Terminal [closed]
I want to restore a TI Silent 700 model 703/707 that lacks the power supply.
The power supply provides 20 VAC 35 VA with 3 pins
...
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2
votes
2
answers
60
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Receiver tracking problems
The medium wave band, in which AM is still dominant, has a very high ratio of Fmax to Fmin, unlike most other radio bands. The exact edges vary from country but compare 510-1650 kHz to say 144 to 148 ...
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20
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1
answer
2k
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What is this "/|\" symbol on the enclosures of various appliances?
I keep seeing this symbol on old electronics appliances of varying types.
Two examples that I own...
Early 1960's portable "Megger" insulation tester
July 1969 Marconi attenuator
I have ...
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24
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4
answers
4k
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Why does this vintage DRAM chip enable circuit require such a beefy resistor?
This is a small part of a mid-1970s chip enable circuit for a set of DRAMs. The DRAMs are TI's TMS4060 part (aka the Intel 2107 aka several others), and are 4096x1. So a typical bank requires 8 of ...
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0
votes
3
answers
87
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Polarized capacitor type identification
I need to know what is the type of this capacitor. Never seen these before. It is polarized (red side is +) and rated 4MFD (4uF I would guess) 25v. I also would like to know what would be an ...
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4
votes
2
answers
102
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What is this chip enable circuit doing? (old TTL, with diode, with pull-up?)
I'm trying to understand a small portion of a (vintage, TTL) circuit design and I'm a little unsure of what's going on in this section*, which determines whether the Chip Enable signal on a particular ...
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0
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2
answers
81
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Why is this Zener across the collector and emitter of this transistor driving a solenoid coil?
I am trying to understand a vintage (1970s) impact printer circuit. Each of the pins in the printer are driven by a small individual coil driver circuit, that was originally specified to look like ...
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2
votes
1
answer
90
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Info/substitution for National Semi's obsolete S-1122 transistor?
I am debugging a mid-1970s piece of printer equipment and have traced a failure to what looks like a bad transistor. But I can't find a data sheet for it (or a useful substitution). It's a metal can ...
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3
votes
2
answers
717
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Why is this zener in series at the base of transistor, and has something failed?
I am debugging an ancient little impact printer and in my probing have found an unexpected voltage level. I'd like to understand this part of the circuit, why it's constructed as it is, and whether ...
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18
votes
3
answers
3k
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What's this vintage diode(?) from the 1970s?
This is the PCB from an Elmo Sound Monitor 912, marketed sometime back in the 1970/1980's.
The circled component seems to be a diode of some sort. Or, at least the diode mode on a multimeter measures ...
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0
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2
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165
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What is the purpose of these mercury switches?
I'm looking at a vintage wire recorder that won't even turn on. Examining it, the power leads (both of them) go through separate mercury switches and on to the main transformer, etc.
The switch vials ...
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2
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100
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Replace One Centre-Tapped Resistor with Two Resistors
I have just started research and design on a small tube guitar amp and have hit the first of what is probably many uncertainties. The idea is to reuse the transformers, 7C5 power tube and 7Y4 ...
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2
votes
1
answer
90
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Trying to find or match an Old Allen Bradley R450 J-Type potentiometer [closed]
I'm looking for any information on how to replace or repair this potentiometer. It's an AB R450 J-type potentiometer on a Brent ceramic wheel from the early 70's, I believe. I cannot find anything ...
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2
votes
2
answers
153
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Identifying different connector symbols in French circuit diagrams from the 80s
I'm trying to troubleshoot an old analog oscilloscope (Metrix ITT instruments OX 725), which seems to come from the late 1980s in France.
There is (part of?) a service manual with circuits diagrams ...
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0
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181
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Why Intel 4004 published schematics uses NMOS, if the 4004 was produced only with PMOS?
According to Wikipedia[0]:
The 4004 employs an 10 μm process silicon-gate enhancement-load pMOS technology on a 12 mm2 die[36]
In 2006 Intel released original schematics of 4004 CPU [1]. Seemingly ...
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0
answers
70
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What type of circuit these vintage 1VNP tantalum caps were used in?
In my junk box I have several capacitors that are marked 1VNP, which I assume means a voltage rating of 1VDC Non Polarized. Looking around online it would appear these are solid tantalum capacitors, ...
1
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0
answers
57
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Does measuring voltage drops between the EBC terminals guarantee the functionality or non-functionality of a BJT?
Do voltage drops across the terminals of a bipolar transistor, which fall within the catalog data, guarantee that such a transistor is working properly?
I am in the process of repairing and restoring ...
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13
votes
6
answers
4k
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Why does this diode/capacitor combination appear on every board in a vintage computer?
I am working with a 1970s era computer system with multiple functional boards on its bus (similar to S100 but not S100.) Unlike S100, this system distributes power as already-regulated 5V (and 12V and ...
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1
vote
1
answer
74
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Need identification of a vintage sound systems outlet
I have wracked my brain and searched across the web only to come up empty handed, I was hoping someone here can finally lay my frustrations to rest.
Closest I can find was the NEMA 5-15P to IEC 60320 ...
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0
votes
1
answer
367
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Understanding passive TTL termination
I've been working with 1970s devices and an unterminated system bus. I am adding termination to that but want to first understand a circuit that I have seen to make sure I understand what's going on. ...
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0
votes
2
answers
95
views
Triridge reed relays data sheets/book? (for max current/voltage specs)
I have a 70s vintage circuit that uses a Triridge brand reed relay. It's marked with part number "220-100", and it's four pin, normally open. The operating voltage for the coil as seen in ...
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2
votes
1
answer
151
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Disc capacitor ratings for replacement
I'm repairing some vintage electronics, and there are a handful of cracked ceramic disc capacitors that need replacement. They're mostly for decoupling, but I want to make sure I'm replacing with ...
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1
vote
1
answer
100
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Why does this Zenith Phonograph schematic separate electrolytic and fixed capacitors
I'm currently in the process of restoring a 1960's phonograph made by Zenith. My plan is to replace all the capacitors among other things. I have the original schematic, purchased from Sam's Technical ...
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0
answers
107
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Can anyone identify this vintage 42 pin IC and the company logo?
The 42-pin chip is labeled as an LC6064 3090 6m2. I am unable to identify it or the company logo. Anyone recognize this?
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1
answer
117
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Can anyone help identify this piece of equipment?
My father—in-law was an electrical engineer and had a great collection of audio and electronic equipment. I’m not sure what this is. Can anyone help?
It has a cable with 3 connectors on one end that ...
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1
answer
126
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Identify vintage automotive connectors
These connectors are from a Ford/Philco electronics unit circa early 1970s. White and blue are male and green is female. Pin pitch is 0.2".
Any ideas for part numbers of modern equivalents that ...
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1
vote
0
answers
115
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Identify old component
I am reverse engineering a circuit board from the early 1970s. Ford FoMoCo/Philco design. It has a metal box with six terminals. Any ideas what this is?
It measures 42x30x19mm.
The ground terminal is ...
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0
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1
answer
137
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What is my next step to debugging an old NTSC video generator circuit that doesn't sync?
I know this is somewhat broad but I hope it's appropriate here. I have a 1970s PCB that is designed to output a sort of bitmap video image via a standard NTSC signal. It came to me as a half-built kit ...
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4
votes
1
answer
122
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Vintage dual 0.25 inch plug connector - Does this have a name or a typical use case?
I found several of this type of connector in an estate, and just wondering if anyone knows if this type of connector has a particular name, or what they are typically used for.
The writing says "...
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0
answers
120
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Diode AM detector linearity
Most valve radios use a vacuum tube diode as a detector. Over the decades, I have used germanium diodes with good apparent performance. In other words, cheap equipment sounds good when the germanium ...
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3
votes
3
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2k
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Replacing 1960s Motor Capacitor - Vintage Sewing Machine
I'm restoring a 1960s sewing machine (a Necchi Lydia 544, pure italian-made robustness). Inside of the foot pedal a capacitor is completely dead (gets hot and fume). I'm confident into changing it, ...
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1
answer
125
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Is there a way to "indirectly" measure the position of a variable capacitor?
I am modifying the insides of a vintage radio. I wish to avoid damaging it or changing it as much as practical.
Here is the insides of the radio in question:
A primary goal is to measure the position ...
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1
vote
1
answer
435
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Identifying a vintage capacitor
This is inside an Allen Wales (Model 9E) adding machine. It was manufactured in the late 30s or maybe sometime in the 40s from what I've read. There are notes from a technician scratched on the inside ...
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1
vote
0
answers
126
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What is the chemical compound leftover on vintage 80s/90s PCBs with their distinctive characteristic smell?
Most people know the smell of vintage/ancient electronics. There a lot of questions about this smell on forums, but nobody explains what the cause actually is or what the chemical formulation of this ...
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3
votes
1
answer
414
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Replacing BJT with MOSFET in a vintage engine ignition circuit
Many moons ago I have recreated the schematic of a vintage Bosch ignition circuit, and confirmed it's working as expected with two prototypes (one can be seen here: https://www.youtube.com/watch?v=...
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1
vote
1
answer
171
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Voltage output on thyratron gas tube relaxation oscillator VCO?
I know that thyratron gas tubes can be used to make a sawtooth like relaxation oscillator:
My question is for a modification of this same circuit that makes it act like a voltage controlled ...
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0
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0
answers
153
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Is this resistor metal film or carbon film?
I am trying to determine if this resistor is metal or carbon film?
Traditionally most of the metal film resistors I've seen have been blue, while most of the carbon film I've seen have been light ...
1
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0
answers
129
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Identify Vintage Power Cord for Sears Electric Tray
I found this vintage Sears electric warming tray but it's missing a power cord. I tried a 2 prong figure 8 cord but the holes were too close together or too small to fit. Here are pictures of the tray,...
2
votes
1
answer
176
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Frequency marking on 1960s radio crystal
I found several of these old radio crystals, but they do not seem to have the frequency clearly marked, which I found unusual.
Most other ones I have seen have a model number (e.g. CR-18/U) and the ...
10
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3
answers
2k
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Is there a name for this vintage 3-pin connector configuration?
I am trying to find a suitable replacement for this connector for a vintage radio, but I'm not sure how to search for it or if they even sell them anymore.
Simply "3 pin male connector" isn'...
0
votes
2
answers
265
views
Feedthrough capacitor measured with an ohmmeter
I'm trying to fix a Motorola 8 track player model Quadraline TM912, and I came across this component which was new to me, the so called feedthrough capacitor. On the image above, if the fuse E6 is not ...
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19
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3
answers
2k
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Identify this type of diode from the 1970s (1.3V forward)?
I am currently reverse engineering the electronics of a Pentax Electro Spotmatic camera from the early 1970s. I have the circuit mostly figured out but now I want to find out more about the particular ...
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0
answers
115
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Is there a name for this 24-pin vintage Howard Jones connector?
Is there a name for this pin layout or style of 24-pin connector?
This is a Howard Jones-style connector, circa 1950s I believe?
I know similar ones are used for vintage radios, but the layout and how ...
5
votes
2
answers
514
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What is the name for this connector socket pin configuration?
Does anyone recognize this female socket pin layout as a standard design of any kind?
I was looking at 5-pin CB Radio Microphone sockets, and they are similar, but not the same layout.
Also, the ones ...
3
votes
4
answers
1k
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How do I clean a badly corroded, jammed rotary switch with 12 position and 4 decks?
The 12-position 4-decked rotary switch on this Roland Re-201 dating back to the '70s or the '80s is completely stuck and won't move at all due to corrosion. The wafers on it's decks seem phenolic.
The ...
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8
votes
1
answer
889
views
Restoring and operating a temperature gauge from the Soviet space shuttle Buran
After the Soviet Buran (БУРАН) program was suspended in the late 1980s, the Buran space shuttle was housed in a hangar at Baikonur. That hanger unfortunately collapsed due to structural failure in ...
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