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 Forum: General Discussion   Topic: Hammond die cast al case, heat sink?

Posted: Fri Jan 19, 2018 8:20 pm 

Replies: 9
Views: 66


if the polished surface still looks like round beads with voids between, I will believe it but the "Die cast" process formally uses molten metal and the molds are often very rough, maybe even sand molds or bead blasted surface. its not very different from plastic molding for a low melt tem...

 Forum: General Discussion   Topic: did I blow my Amp

 Post subject: Re: did I blow my Amp
Posted: Wed Jan 17, 2018 8:53 pm 

Replies: 6
Views: 77


Not the fuse. Initially I didn't check because the pilot lamp was turning on and off with the remote switch as expected but than I worried there might be a current path to the LED without power but although there is, the resistance is too high to light the lamp. I checked it today and was good. Mute...

 Forum: General Discussion   Topic: did I blow my Amp

 Post subject: Re: did I blow my Amp
Posted: Tue Jan 16, 2018 5:15 pm 

Replies: 6
Views: 77


I agree it is repairable, I need to take it out of the car and put together a bench setup with some signal sources first. I've had these sitting on a shelf for nearly a decade and now I am completely refurbishing my 93 Explorer and these fit well under the seats. (they were insurance replacements fo...

 Forum: General Discussion   Topic: LOREX LW2742 Wireless Monitor........

Posted: Tue Jan 16, 2018 5:01 pm 

Replies: 10
Views: 98


one can still change the front glass on a smart phone but that's just about it in 2018. On the flip side, we have never had such a large selection of prebuilt electronic modules and boards and dev kits.

 Forum: General Discussion   Topic: did I blow my Amp

 Post subject: did I blow my Amp
Posted: Mon Jan 15, 2018 3:26 pm 

Replies: 6
Views: 77


I was working with an Alpine 2 channel car amp and trying to bridge outputs to a dual voice coil subwoofer. 4 ohms x2 Initially I got some output putting each coil on Left and Right but that's not a proper hookup. next step I paralleled the VC to obtain 2 ohms impedance and placed it across (what I ...

 Forum: General Discussion   Topic: Hammond die cast al case, heat sink?

Posted: Mon Jan 15, 2018 11:53 am 

Replies: 9
Views: 66


The difference in surface appearance is probably from the casting process which takes up imperfections and texture of the mold surface. if you are comparing to extruded aluminum or machined aluminum then that surface will be smoother and brighter and have less dark oxides from cooling. Sand with 220...

 Forum: General Discussion   Topic: LOREX LW2742 Wireless Monitor........

Posted: Thu Jan 11, 2018 1:46 pm 

Replies: 10
Views: 98


Engineered to mess specifically with you. Seems like you offered the best option. Another would be to replace the power supply with one with a cord you could match with the socket or splice a new connector, not as neat as you would like I suppose.

 Forum: General Discussion   Topic: Laptop charger voltage...

Posted: Fri Jan 05, 2018 1:46 pm 

Replies: 1
Views: 61


I think you probably could charge direct from a car but since that source is not regulated, it might e a bit hard on the battery or charging circuits. Not running, my car battery hovers at 11.4 (its a little old) and when running is 14.5. With the car running it might work OK but with the car off, y...

 Forum: General Discussion   Topic: LM 1084/338/317/etc... voltage drop at < 1A

Posted: Fri Jan 05, 2018 1:39 pm 

Replies: 23
Views: 219


the max Vin-Vout on all of these parts is 40V so you may be too close to the max. Furthermore, the greater Vin-Vout is, the more power you will need to dissipate in the regulator. to get the full 40V drop at full current you would need an exceptional heatsink. (just take the voltage drop times the c...

 Forum: General Discussion   Topic: LM 1084/338/317/etc... voltage drop at < 1A

Posted: Thu Jan 04, 2018 10:25 am 

Replies: 23
Views: 219


If you measures 34V peak to peak, it would be 24VRMS (34*0.707) 120Hz is expected but says nothing about the current you are sourcing from the transformer. your probablem may not be voltage, it acts like you are running short of current. So if the transformer is 5A ish then maybe the diodes or filte...

 Forum: General Discussion   Topic: LM 1084/338/317/etc... voltage drop at < 1A

Posted: Wed Jan 03, 2018 5:58 pm 

Replies: 23
Views: 219


if no oscilloscope you can still measure ripple with a DMM. just observe the AC and DC voltages separately. you should have a large cap near the rectifier to filter but you probably need another smaller cap near the regulator to shunt higher frequency operating transients to ground (which might be b...

 Forum: General Discussion   Topic: LM 1084/338/317/etc... voltage drop at < 1A

Posted: Wed Jan 03, 2018 12:27 pm 

Replies: 23
Views: 219


do you have an oscilloscope. it would be useful to see how much ripple there is at the input and output nodes. Usually bigger is better WRT the filter cap size, you can go a lot larger if you have the parts. We use 33,000uF (soda cans), Certainly a resistive connection on any wire can drop voltage a...

 Forum: General Discussion   Topic: True green 'neon' pilot bulbs...

Posted: Wed Jan 03, 2018 11:45 am 

Replies: 3
Views: 75


probably a mixture of neon and other gasses From: https://en.wikipedia.org/wiki/Neon_lamp#Color A mixture of 95% neon, 2.5% krypton, and 2.5% argon can be used for a green glow,[29] but nevertheless "green neon" lamps are more commonly phosphor-based. Plenty on Alibaba if you want 10k or m...

 Forum: General Discussion   Topic: Very unusual desoldering method...

Posted: Tue Jan 02, 2018 4:35 pm 

Replies: 6
Views: 90


I didn't think that was a headlamp, just a low voltage lamp for indoor use, I scrapped some 75 and 150W potlights for LED a few years ago. 55W would be obsolete since many new cars have LED lamps rated in Lumens and you can get some pretty bright ones now on ebay but I couldn't say if they are non c...

 Forum: General Discussion   Topic: Very unusual desoldering method...

Posted: Tue Jan 02, 2018 12:41 pm 

Replies: 6
Views: 90


Seems like it would blind the operator somewhat when used as a wand. Practically like Welding, you would need glasses so dark, all you would see is the bulb and immediate work area. Its not surprising considering Halogen lamps are often well over 100W. A better application would be to power it using...
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