Forum: General Electronics Technical Discussion
Today, 10:37 PM
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Replies: 26
Views: 584
Re: Help identify component
It won't start charging unless a battery is present.
The SCR's will stay off until the UJT starts oscillating and driving the trigger transformer- which needs power downstream of the SCR's.
You...
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Forum: General Electronics Technical Discussion
Yesterday, 10:23 PM
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Replies: 26
Views: 584
Re: Help identify component
OK your datasheet pic is showing a transistor style TO-18 pinout :confused: I've seen many different pinouts for the 2N2646 on the Web.
You can ID the emitter as (+) on multimeter diode-test and...
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Forum: General Electronics Technical Discussion
12-13-2019, 11:16 PM
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Replies: 26
Views: 584
Re: Help identify component
2N2646 pinout seems to be an oddball metal can, non-standard TO-18 case. TO-18 (UJT) so the tab is at a weird angle compared to the typical transistor TO-18 configuration. Note they use bottom view...
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Forum: General Electronics Technical Discussion
12-11-2019, 12:02 PM
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Replies: 4
Views: 135
Re: Car Ammeter
OP I think you've asked the same question before:
https://www.badcaps.net/forum/showthread.php?t=68684
https://www.badcaps.net/forum/showthread.php?t=45512
I remember seeing a circuit in an...
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Forum: General Capacitor Questions & Issues
12-09-2019, 04:30 PM
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Replies: 2
Views: 66
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Forum: General Electronics Technical Discussion
12-09-2019, 04:17 PM
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Replies: 7
Views: 115
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Forum: General Capacitor Questions & Issues
12-08-2019, 02:51 PM
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Replies: 3
Views: 83
Re: Mitre Saw start capacitor
You should get continuity across the motor's terminals at the brushes.
If you don't, try turn the shaft (by hand, it's unplugged) in case there is a dead spot.
Sometimes a brush wears out, or they...
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Forum: Troubleshooting Power Supplies and Power Supply Design
12-07-2019, 02:29 PM
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Replies: 29
Views: 424
Re: Powering up a Car Antenna a "different" way
When you connect the battery (nothing on green relay coil wire) , the antenna should (now) move down and then stop, as it goes past the limit switch which disconnects the motor.
Instead, it's not...
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Forum: Troubleshooting Power Supplies and Power Supply Design
12-05-2019, 03:06 PM
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Replies: 29
Views: 424
Re: Powering up a Car Antenna a "different" way
First use a felt pen and put some dots/stripes 1,2,3,4 on the blue wires, so they don't get mixed up.
I think this is right:
Swap the two wires at the motor's terminals. (D2 and B2)
Swap the two...
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Forum: Troubleshooting Power Supplies and Power Supply Design
12-04-2019, 02:48 PM
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Replies: 29
Views: 424
Re: Powering up a Car Antenna a "different" way
With nothing to the relay coil (green), see the diagram- it shows power can flow to the motor until the antenna-down limit-switch upper contact opens and disconnects the motor power.
With the...
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Forum: Troubleshooting Power Supplies and Power Supply Design
12-04-2019, 12:53 AM
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Replies: 29
Views: 424
Re: Powering up a Car Antenna a "different" way
The limit switch is what latches power and keeps the motor running until it reaches an endstop. Not SPDT but it shorts the two ends until an endpoint. No need for diodes then.
Schematic might look...
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Forum: Troubleshooting Game Consoles & Other Weird Devices
12-03-2019, 01:35 PM
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Replies: 13
Views: 196
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Forum: General Capacitor Questions & Issues
12-03-2019, 01:29 PM
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Replies: 9
Views: 261
Re: What value is this capacitor?
It will not do anything if there is an open light bulb, that charges the cap in series with the 150 ohm resistor I think.
You can't use a timer IC or electronics here because it's a two-prong part....
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Forum: Other Devices with Bad Capacitors
12-02-2019, 11:54 PM
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Replies: 70
Views: 3,263
Re: Whirlpool Refrigerator LED lights flickering
I worry the door switches can handle the inrush currents for a larger SMPS?
It's too bad we don't have one of these boards to sketch a schematic, or know any of the semiconductor part numbers.
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Forum: Equipment Usage, Soldering, Techniques, and Reviews
12-01-2019, 12:42 PM
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Replies: 239
Views: 8,764
Re: Soldering station thoughts and guidelines
It was Hakko's idea, T12 came from the patent, now expired: US 6087631 (https://patents.google.com/patent/US6087631A/enhttps://patents.google.com/patent/US6087631A/en)
It's just a spot weld with a...
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Forum: Equipment Usage, Soldering, Techniques, and Reviews
11-30-2019, 01:25 PM
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Replies: 113
Views: 2,733
Re: DPS5020 dual power supply build
It turns out dual-switch contacts are never identical, so one will close last (power-on inrush current) and another will open last (power-off arc). I had a boss yell at me that it would not last any...
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Forum: General Capacitor Questions & Issues
11-30-2019, 01:14 PM
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Replies: 34
Views: 489
Re: Tumble Dryer start capacitor
The motor has an open-circuit on the black wire, take it apart.
You might be able to find the break and do surgery to fix it. Or just get a replacement motor. It might be broken from a tug on its...
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Forum: Troubleshooting Power Supplies and Power Supply Design
11-30-2019, 01:07 PM
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Replies: 2
Views: 112
12V 2A battery charger/maintainer
Bought this chinese 12V 2A car/motorcycle battery charger/maintainer $7. It looked OK hardware wise in pics.
But... everything runs quite hot at 2A - IC, transformer, capacitors, output rectifier....
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Forum: General Capacitor Questions & Issues
11-30-2019, 06:01 AM
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Replies: 34
Views: 489
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Forum: General Capacitor Questions & Issues
11-29-2019, 08:05 PM
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Replies: 34
Views: 489
Re: Tumble Dryer start capacitor
I read it in a service manual for another Hotpoint Aquarius tumble dryer AQC851. It has an "anti-allergy program" that uses two directions, so the drum must have strange tines. The motor has the same...
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