[justhavingfun]

I just populated the Tangentsoft TREAD PS with AMVECO toroidal transformer (12V + 12V) to give me 24V but I am not getting much DC voltage between TP1 & TP3 when I applied the 120V AC voltage

. It only registers 0.08V DC from multimeter. Does anybody have any idea what I did wrong? I am going to post some pictures later. This is my first attempt to build the PS but I guess I did something wrong

.

 

[justhavingfun]

Man, I really should buy better digital camera. My P&S camera takes really horrible pictures but that's all I got for now.

Hopefully I can repair this TREAD but maybe I will learn something from my mistakes.

 

[MisterX]

Don't see any obvious problems.
How about a picture of the bottom?

(very little solder has wicked through to the top side of the component leads so I have to wonder......)

 

[heatmizer]

Did you check the voltage out of the transformer? About the toroid what series is that? Its hard to tell from the picture but of the Amveco I am aware of black and violet to hot. red and yellow to common. Is that how its hooked up? The secondaries look correct red and brown together. green and blue out.

 

[justhavingfun]

MisterX: I will try to reflow all the points again to be sure and try it again. Thanks for the tip.

heatmizer: I have tried different combination with same result. But first, I followed exactly according to the manufacture's instruction.

Little late for tonight but I will try tomorrow again to repair.

 

[MrMajestic2]

Quote:

Originally Posted by justhavingfun /img/forum/go_quote.gif I just populated the Tangentsoft TREAD PS with AMVECO toroidal transformer (12V + 12V) to give me 24V but I am not getting much DC voltage between TP1 & TP3 when I applied the 120V AC voltage . It only registers 0.08V DC from multimeter. Does anybody have any idea what I did wrong? I am going to post some pictures later. This is my first attempt to build the PS but I guess I did something wrong .

Since you are using an AC transformer I dont think you will get much DC on TP1 & TP3. It only shows the unregulated voltage, not sure if you can test for AC here. Measure TP2 & TP3 to see regulated DC voltage.

 

[tangent]

Quote:

Originally Posted by justhavingfun /img/forum/go_quote.gif Man, I really should buy better digital camera. My P&S camera takes really horrible pictures but that's all I got for now.

The picture tells me the camera is fine. The technique is just a little wanting.

The blurriness you're seeing is because you're getting too close without using the camera's macro mode. If your camera doesn't have a macro mode, just move back farther so you will have enough depth of field. For pics posted to forums, you don't have to fill the frame. Even cropping deeply into the picture will still leave you enough to post, and it'll all be sharp.

You should also consider using a tripod, which will let you disable the flash. that would prevent the hot spots on top of C5 and VSET, and the deep shadow between C5 and B1. You'll probably need something like Photoshop Elements or Paint Shop Pro to color correct the result: most cameras don't do automatic color balancing of this sort of shot very well when the flash is off.

Quote:

Originally Posted by MrMajestic2 I dont think you will get much DC on TP1 & TP3...not sure if you can test for AC here.

Yes, you can do both. It's unregulated DC, which means you see both DC and AC components here.

Quote:

Measure TP2 & TP3 to see regulated DC voltage.

If there's almost no unregulated DC, there won't be any regulated DC, either.

 

[MrMajestic2]

Quote:

Originally Posted by tangent /img/forum/go_quote.gif Yes, you can do both. It's unregulated DC, which means you see both DC and AC components here. If there's almost no unregulated DC, there won't be any regulated DC, either.

Goes to show hos little I know about the TREAD circuit

Good thing the TREAD guru is here

(not sarcasm)

justhavingfun, did you check for voltage coming out of the transformer? Also, on the multimeter, I sometimes set the incorrect range so I get really weird readings. Like setting it on 20v range when trying to check for millivolts. I do stuff like that when Im tired, drawback of having kids and having to DIY at night.

 

[justhavingfun]

I reflow all the solder points but same result. At this time, I think the AC transformer might be the culprit. But since I do not have any extra transformer, I might have to wait until I get extra transformer at hand to try out again. I am getting only 0.5V DC only on both voltage TPs following Tangentsoft direction. I am not measuring any significant voltage out of transformer either thus suspecting malfunctioning AC transformer.

Either way, the LED doesn't lit up so far. I will have to order some extra AC transformer on my next future order.

 

[amb]

A note about these Amveco leaded toroids, if you had trimmed the transformer's leads shorter, after stripping the insulation off the wires, the conductor inside is still coated with a layer of enamel. They may not be making good contact with whatever you connected them to. Be sure to scrape away the enamel.

 

[justhavingfun]

Quote:

Originally Posted by amb /img/forum/go_quote.gif A note about these Amveco leaded toroids, if you had trimmed the transformer's leads shorter, after stripping the insulation off the wires, the conductor inside is still coated with a layer of enamel. They may not be making good contact with whatever you connected them to. Be sure to scrape away the enamel.

Now that is news to me. I am going to try your tip and report back if I am successful. Thanks.

 

[justhavingfun]

amb, holy cow! Your suggestion was right on target. After stripping the shortened exposed wires, my LED is working ok with my TREAD now

. Thank you very much for your help. One of the mistake I made was not looking closely into what actual transformer that I received. I thought I ordered 12V + 12V to make it 24V but checking closely the spec data of my transformer is rated differently. I was able to read the part number which is Amveco 62052: rated to have 2 x 14.48V unloaded DC voltage. But I am getting close to 40V DC between TP1 and TP3. This unloaded 40V is too much to step down to regulated 24V in the TREAD right? From my reading, this situation will create too much heat and can become unreliable PS. If you guys who are more experienced on this matter tell me that this is not good situation, I will order proper voltage transformer and try it again. At least I know that my TREAD is working.

 

[amb]

Glad to help.

A higher transformer secondary voltage means that the regulator has to drop more voltage to give you the voltage you want. That voltage has to be dissipated as heat. The amount of heat is the voltage drop across the regulator, multiplied by the amount of current draw. So, whether this is a problem depends on what you're going to be using the TREAD for (and thus the current draw), and how much heatsinking you have on the regulator.

 

[justhavingfun]

Ok, here are the measurements so far when I took them again:

TREAD IN+ and IN- measures 30V AC
TREAD TP1 and TP3 measures 40V DC
TREAD TP2 and TP3 measures 24V DC (after VSET adjustment)

So far it is very stable and holding at 24V DC at final output. I want to thank all of you who offered very helpful hints and tips, specially "amb", without his helpful tip, I probably thought the transformer was defective.

 

[justhavingfun]

I finally able to finish the case work on my TREAD PS. I now do have new admiration of other DIYers who can build all those beautiful case works. It really took me lot longer than I anticipated and this is lowly Hammond aluminum case with TREAD in it. Anyway since everybody likes to see DIY pictures, I thought I post mine as well. This Hammond case is same size as the recommended case for STEPS at Tangentsoft website.