{"id":351,"date":"2015-01-25T20:47:34","date_gmt":"2015-01-26T01:47:34","guid":{"rendered":"http:\/\/paulcarbone.com\/blog\/?p=351"},"modified":"2015-02-17T21:26:05","modified_gmt":"2015-02-18T02:26:05","slug":"archer-power-supply-build","status":"publish","type":"post","link":"https:\/\/paulcarbone.com\/blog\/archer-power-supply-build\/","title":{"rendered":"Archer Power Supply Build"},"content":{"rendered":"

OK, so sometimes I search craigslist for:
\nOscilloscope
\nTektronix
\nHeathkit<\/p>\n

Well this weekend I got lucky, and found someone selling some unbuilt<\/em> heathkits for a great price.\u00a0 He also had a few Archer 5V power supply kits for sale, which I’d never seen before, appeared complete, and were reasonably priced.\u00a0 I bought two, here’s the one that I’m going to build.<\/p>\n

In it’s original box:
\n\"DSC_0696\"<\/a><\/h2>\n

\"DSC_0701\"<\/a><\/p>\n

Unboxing:<\/strong><\/h2>\n

Well, it’s clear how the manual was folded in the box.
\n\"DSC_0703\"<\/p>\n

The enclosure and (stick-on) front panel was in flawless shape.
\n\"DSC_0704\"<\/p>\n

The circuit board showed some signs of age.\u00a0 One or two pads lifted a little while soldering, but nothing tragic.
\n\"DSC_0706\"<\/p>\n

Components neatly packed within the chassis\"DSC_0709\"<\/p>\n

Box-O-Parts\"DSC_0715\"<\/p>\n

The Build<\/h2>\n

 <\/p>\n

\"DSC_0731\"<\/a><\/h2>\n

The screw heads were proud of the surface, which would have compromised the front panel application.\"DSC_0734\"<\/p>\n

And then I remembered I had a drill press and a countersink bit.\"DSC_0737\"<\/a><\/p>\n

The manual suggests soldering the transformer and rectifier together on the bench based on a rough drawing, but given the rigidity of the wire and the tight dimensions, it seemed a better plan was to at least tack-solder the two together while temporarily in situ.\"DSC_0733\"<\/a><\/p>\n

Transformer & rectifier permanently mounted.<\/p>\n

\"DSC_0741\"<\/a><\/h2>\n

All other elements mounted.\"DSC_0742\"<\/a><\/p>\n

\u00a0Testing<\/h2>\n

Brought it up on the variac with no troubles.\u00a0 I was able to trim the voltage to 5.46V, and it held across a wide range of line voltages, without a load.\"DSC_0744\"<\/p>\n

I was unable to calibrate the unit to 5.0V with the stock parts, so first I re-installed the circuit board with the bottom screws in the top holes, so it was easier to access. \"DSC_0745\"<\/a><\/p>\n

Then I soldered in some jumpers in place of R2 and hooked up a decade box. \"DSC_0749\"<\/a><\/p>\n

Then I soldered in some jumpers in place of R2 and hooked up a decade box.\u00a0 1.8k would have put 5.0v directly in the middle of the trimpot range, but I didn’t have any so I got away with 2k.\u00a0 I was able calibrate it to 5.0v, and so far it’s been performing without trouble.<\/p>\n

You’ll notice that there are actually 4 terminals on this supply.\u00a0 That’s because this is a ‘sensing power supply’, which allows it to compensate for losses in the wires from the power supply to the load.\u00a0 The two sense lines can be of a much lower gauge then the supply wires, since they’re not passing any appreciable current.\u00a0 They sense the voltage at the load, and are part of the regulation feedback circuit.\u00a0 The regulator’s target is 5v at the load<\/em> so if it’s gotta output 6.3v to overcome 1.3v of drop, then it happily obliges.<\/p>\n

In addition to being fused both at the line side and low voltage side, it also has short circuit protection.<\/p>\n

Oh, and here’s the schematic. \"Doc<\/a><\/p>\n

I think this is going to be a nice supply for LED tape experimentation.<\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

OK, so sometimes I search craigslist for: Oscilloscope Tektronix Heathkit Well this weekend I got lucky, and found someone selling some unbuilt heathkits for a great price.\u00a0 He also had a few Archer 5V power supply kits for sale, which … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[1],"tags":[],"table_tags":[],"_links":{"self":[{"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/posts\/351"}],"collection":[{"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/comments?post=351"}],"version-history":[{"count":8,"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/posts\/351\/revisions"}],"predecessor-version":[{"id":384,"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/posts\/351\/revisions\/384"}],"wp:attachment":[{"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/media?parent=351"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/categories?post=351"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/tags?post=351"},{"taxonomy":"table_tags","embeddable":true,"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/table_tags?post=351"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}