Search found 1182 matches

by Bob Scott
Tue Jan 15, 2013 5:05 pm
Forum: General Discussion
Topic: USB port on television...
Replies: 9
Views: 2661

Re: USB port on television...

On the Motorola PVR DCT6400 Phase III. http://www.motorola.com/staticfiles/Video-Solutions/Products/TV%20Video%20Distribution/Set-tops/QAM%20Set-tops/Digital-Analog%20QAM%20Set-tops/DCT6400/_Documents/Static%20Files/DCT6400%20Series%20User%20Guide.pdf The USB Port seems to be a universal port. Bein...
by Bob Scott
Sat Jan 12, 2013 10:51 am
Forum: General Discussion
Topic: USB port on television...
Replies: 9
Views: 2661

Re: USB port on television...

I have a Motorola PVR that also has a host type USB connector on the front. I have no idea what it is for either. There is no mention of it in the instruction book. (I was thinking of jamming a thumb drive in there and see if I get more recording space, but I don't want to damage anything.) Maybe it...
by Bob Scott
Fri Jan 04, 2013 4:39 pm
Forum: General Discussion
Topic: B&D Gyro Screwdriver
Replies: 12
Views: 2279

Re: B&D Gyro Screwdriver

Haha! What's next? A hammer with an aiming computer? Smart nails? :mrgreen:
by Bob Scott
Sun Dec 09, 2012 11:14 am
Forum: General Discussion
Topic: Motor Speed Controller
Replies: 4
Views: 1684

Re: Motor Speed Controller

I have been searching for a device that will control the speed of a standard 1/2 horse, 120 VAC, 8 Amp brush-less motor - induction typeThanks Terry Hayward Hi Terry. There are several types of induction motors. Some are synchronous and will seek to keep their speed phase-locked to the power line f...
by Bob Scott
Wed Nov 14, 2012 5:18 pm
Forum: General Discussion
Topic: Winding toroidal coils...
Replies: 2
Views: 792

Re: Winding toroidal coils...

Thanks Miguel. Now I know how it is done professionally. I looked up "toroid winding machine" at ebay and saw a couple of those winders for sale for $2,999. Too much. Building on of those would be like trying to make your own sewing machine without access to a machine shop. Sigh...
by Bob Scott
Wed Nov 14, 2012 4:49 pm
Forum: General Discussion
Topic: What Type of Rubber?
Replies: 2
Views: 725

What Type of Rubber?

Hi Guys, When real rubber gets old it dries up and cracks. There is a kind of artificial rubber that turns into a black viscous flowing ooze. Ocasionally, I used to see black "rubber" tape recorder belts melt down this way due to their age. Does anyone know what type of rubber this is? I looked behi...
by Bob Scott
Mon Nov 05, 2012 5:21 pm
Forum: General Discussion
Topic: Stepper Motors
Replies: 13
Views: 2291

Re: Stepper Motors

As an alternative to reducing the power supply and the holding voltage/current I think the average power would drop if after the last step in a sequence, you change that same phase to either a very fast frequency or a PWM output. That is a brilliant idea. It is the same way that RC electric motor c...
by Bob Scott
Mon Nov 05, 2012 11:22 am
Forum: General Discussion
Topic: Stepper Motors
Replies: 13
Views: 2291

Re: Stepper Motors

Question on steppers: Is it possible to change the "holding current" independent of the "running current"? Sure. When actively stepping the circuit becomes inactive, then lower the power supply voltage going to the windings. How you incorporate that would be dependent on the circuit you are using. ...
by Bob Scott
Sun Oct 28, 2012 12:08 am
Forum: General Discussion
Topic: Another Car Audio Amp ( 5,000W - Mono ) :O
Replies: 28
Views: 5171

Re: Another Car Audio Amp ( 5,000W - Mono ) :O

Break out the ESR meter, and start working through the board, concentrating on the pre-amp section. There are still bad batches of cap's still floating around out there. Signed: Janitor Tzap Hey Tzap, This would be something new to me, working through a board with an ESR meter. I usually troublesho...
by Bob Scott
Fri Oct 26, 2012 8:58 am
Forum: General Discussion
Topic: Dc to DC
Replies: 12
Views: 2453

Re: Dc to DC

I did find a 12-15V booster http://www.digikey.com/scripts/DkSearch/dksus.dll?KeyWords=VHK75W-Q24-S15&WT.z_cid=sp_102_buynow&cur=USD r about $130 that has real promise. CUI makes several models so maybe one of these is the simple answer. As usual, thanks for the opinions and comments! Len That look...
by Bob Scott
Wed Oct 24, 2012 5:00 pm
Forum: General Discussion
Topic: 12VDC fan driven by 120VAC...
Replies: 9
Views: 1702

Re: 12VDC fan driven by 120VAC...

What was the original intention, having two rails at the breaker box, one for each? Which was never implemented; or what happened ? Is it related to non-polarized plugs applying phase to non-insulated metal cabinets? Miguel I'm waiting for Dean . He's so much better at explaining these things in de...
by Bob Scott
Wed Oct 24, 2012 10:14 am
Forum: General Discussion
Topic: Dc to DC
Replies: 12
Views: 2453

Re: Dc to DC

Do you have a copy of the schematic for the 12-15VDC converter?

I'm thinking that if the secondary is isolated, then you may be able to rewire it as a 12V to 3V converter and wire the secondary in series with the existing 12V. Same power output with less power load on the circuit?
by Bob Scott
Wed Oct 24, 2012 9:16 am
Forum: General Discussion
Topic: Stepper Motors
Replies: 13
Views: 2291

Re: Stepper Motors

Thanks Bob, So with the unipolar I can run it in either mode and that looks like the best choice! I'll have to scour the junk box and see what I have. I just modified an old 12 position rotary switch by taking out the stop and the detent then wiring the contacts 123412341234. I can use it to manual...
by Bob Scott
Wed Oct 24, 2012 8:53 am
Forum: General Discussion
Topic: 12VDC fan driven by 120VAC...
Replies: 9
Views: 1702

Re: 12VDC fan driven by 120VAC...

There are a few types listed here, personally I have no experience with them. http://www.daycounter.com/Circuits/Transformerless-Power-Supplies/Transformerless-Power-Supplies.phtml And another..http://ww1.microchip.com/downloads/en/appnotes/00954A.pdf Perhaps the authors of the schematics in those ...
by Bob Scott
Mon Oct 22, 2012 8:32 am
Forum: General Discussion
Topic: transformer question - how to calculate?
Replies: 6
Views: 1351

Re: transformer question - how to calculate?

Test Questions! Why didn't you say so!

God luck with the test. :grin: