Forum: General Electronics Technical Discussion
Today, 04:06 AM
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Replies: 52
Views: 2,632
Re: Fixing a multimeter based on VC9805 schematic
Display shows 1___ with those readings?
Pin 40 COM voltage is too low, it needs to be at least 1V above V-. On the schematic it would be QC4,QC3 to check- that would short COM below 1V. On your...
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Forum: General Electronics Technical Discussion
Yesterday, 11:20 AM
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Replies: 3
Views: 74
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Forum: Equipment Usage, Soldering, Techniques, and Reviews
Yesterday, 11:17 AM
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Replies: 9
Views: 169
Re: Buy a Agilent U1242A or Fluke 179 DMM?
I'm repairing three old American-made multimeters, but I might have maxxed out at having 10 lol I've got no Flukes, just HP, Beckman, Wavetek.
I hate Taiwan-built multimeters, either they blow up...
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Forum: General Electronics Technical Discussion
06-25-2022, 02:11 PM
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Replies: 11
Views: 162
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Forum: General Electronics Technical Discussion
06-25-2022, 10:29 AM
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Replies: 11
Views: 162
Re: Conversion of Anolog Voltmeter into Ammeter
Your test setup looks good, I think there is a poor connection or maybe a switch is inside the meter so you must press it down to take a reading.
Usually panel meter specs are two things - the coil...
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Forum: General Electronics Technical Discussion
06-24-2022, 09:54 PM
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Replies: 52
Views: 2,632
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Forum: General Electronics Technical Discussion
06-24-2022, 12:41 PM
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Replies: 18
Views: 764
Re: Using car key fob as generic remote control
Check the RXB6 pinout, it has an enable pin 6 which floats high to enable data, not power save.
Some of those 433MHz RX modules have extremely weak data output 10uA (!) so a low value pullup or LED...
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Forum: Troubleshooting Game Consoles & Other Weird Devices
06-24-2022, 12:26 PM
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Replies: 12
Views: 184
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Forum: Troubleshooting Game Consoles & Other Weird Devices
06-23-2022, 07:17 PM
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Replies: 12
Views: 184
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Forum: Equipment Usage, Soldering, Techniques, and Reviews
06-18-2022, 10:39 PM
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Replies: 6
Views: 254
Re: Short finder
I think you'd need the compliance voltage-limited to say 0.2V to not damage anything. That pretty much rules out the LM317, have to use an op-amp and power transistor.
I also do well with a good...
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Forum: General Electronics Technical Discussion
06-18-2022, 10:34 PM
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Replies: 4
Views: 151
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Forum: General Electronics Technical Discussion
06-17-2022, 04:51 PM
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Replies: 52
Views: 2,632
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Forum: General Electronics Technical Discussion
06-17-2022, 01:20 PM
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Replies: 52
Views: 2,632
Re: Fixing a multimeter based on VC9805 schematic
Which transistor is shorted? poker, do not confuse the power-on transistors with the protection transistors.
On OP schematic for VC9805+ Tp1, Tp2 are for battery power switch. SMT marking L6 (is...
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Forum: General Electronics Technical Discussion
06-17-2022, 10:46 AM
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Replies: 41
Views: 1,698
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Forum: General Electronics Technical Discussion
06-14-2022, 03:58 PM
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Replies: 41
Views: 1,698
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Forum: General Electronics Technical Discussion
06-14-2022, 03:35 PM
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Replies: 6
Views: 252
Re: resistors in parallel ?
The heat to be dissipated would be shared over two parts, each one dissipates a ratio of the value a single part would. Regardless of whether the two are in series or parallel.
50-50 split so 1W...
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Forum: Equipment Usage, Soldering, Techniques, and Reviews
06-14-2022, 01:05 PM
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Replies: 301
Views: 24,529
Re: Soldering station thoughts and guidelines
JBC C210 cartridges (https://www.jbctools.com/c210-cartridge-range-product-18-design-iron.html) there are two knife blades 2.5, 3.4mm.
How about the chisel (screwdriver) tips? The spoon/hoof is...
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Forum: Troubleshooting Audio Equipment
06-13-2022, 11:52 AM
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Replies: 4
Views: 116
Re: TC158R , Sony cass deck schematic please
Check your work- either you didn't put it back together properly or there is a (new) broken connection, bad solder joint, cable connector etc.
Sometimes working on the motor can cause a short with...
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Forum: General Capacitor Questions & Issues
06-12-2022, 10:05 PM
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Replies: 5
Views: 241
Re: Identifying capacitor type (Laserdisc PSU)
To me they look like polyester mylar film capacitors similar to Nichicon QXY. I would replace with Panasonic ECQB (although obsolete) or anything with the same lead spacing and ratings. Polystyrene...
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Forum: General Electronics Technical Discussion
06-12-2022, 08:02 PM
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Replies: 41
Views: 1,698
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Forum: General Electronics Technical Discussion
06-12-2022, 04:29 PM
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Replies: 41
Views: 1,698
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Forum: General Electronics Technical Discussion
06-11-2022, 06:30 PM
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Replies: 41
Views: 1,698
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Forum: General Electronics Technical Discussion
06-11-2022, 06:22 PM
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Replies: 4
Views: 166
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Forum: General Electronics Technical Discussion
06-11-2022, 02:45 PM
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Replies: 4
Views: 166
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