Here is the Used HY3005F-3 I got on Fee-Bay From a Private Seller.. (Looks Like UPS Mishandled the package damaged in transit) so this post will be a Tear-Down Post Now.. Possibly a Diagnostics and Repair!! Maybe a Hunt For The Actual Manufacture that Builds then Under 10 Different Names!!

Arrival Function Test.. FAIL!!

More to Follow.. Will let the screw driver tell the tale!!

It looks like the display board was broken I did not see any magic smoke on power up but the main board for that channel was loose and shifted due to a broken stand off which I will assume happened during shipping.

On initial inspection it looks like a over volt at some point let the smoke out C43 on the display board. The way the board was pushed back look like it shorted the pins on the 7 way they are really long.

Not sure if the displaced power board or pushed back display board part # HY149 took out some other passive on the display board or maybe killed the HEF4069UBT Hex Inverter or the ICL7107 3 1/2 Digit A/D Converters or all!! I did swap cable and it is the channel on that side of the display board that has a failure.  I will look further in to it when I have some more time.

Here Are the Schematics From The Mastech HY3005F-3 which I believe this the main manufacture of these power supplies and is a rebadge to dr. meter but I may be Wrong.. The component placement numbers are different but the circuit looks the similar.

I did learn something right off from communication with Dr. Meter they do not sell replacement or service parts like the display board in their own words they only sell entire units so if anything fails on these or we need to service them we are on our own. This supports my theory they are just a china tech flipper of rebadged items and Dr. Meter offers no after sale service parts. Their e-mails are funny.. find at a local place?  Anyone know of an American Shenzhen Electronics Market in the Portland Oregon Metro Area?

On a positive note I noticed that the display board and some other boards have Rubycon electrolytic capacitors?? Not sure if that was factory or someone at some point recapped this unit they all look hand soldered. If they are using quality electrolytic capacitors then that is a bonus for who ever if making these for dr. Meter.

The ICL7107 meter circuit is basic and has been used on cheap meters for many years.

Right now no time to mess I will contact Mastech and others on Ali-express to see if they will sell a display board for their HY3005F-3 and see of that will work.  The lucky winner that sells service/repair parts will get a mention here on my blog.

Quick Reference Schematic.

Little bit of tinkering.. Traced it to an issue what looks like the 4069 Hex Inverter may have an issue.. was seeing weird issues on C7 so removed C7

Guess What.. With C7 Removed and it Shows 31.1 V So I am thinking that the  4069 Hex Inverter is toast.. I will have to check with some other sources on testing that IC but I am pretty sure it’s shorted. Yea, I know lots of flux residue on some spots just did not clean why testing.

I may have time next week to do a full out of chassis tear-down.

I called the friendly English speaking folks at Mastech Now VolteQ even though they have discontinued this model, They confirmed this is not their product and a clone,  they are still willing to sell me a replacement display board for a very nominal price with the understanding there may be differences and may not work. They even had me send photos of this display board. The guy did not understand and was confused why dr.meter would not sell a part. But from the looks of their schematic it should work for the blog I will give it a go.

Will be updating this week 2/17 with the out of chassis photos of the boards.

I did get a a reply form dr.meter of china kind of interesting… I will update to see what happens.

I Was hoping they would have sold me a display board? No!! I guess they elected to send me an entire Parts Unit 22lbs?? Tracking Details Here if link does not work.. 1Z227EW80397583913not sure how sustainable that business model is? Let’s see what arrives Wednesday the 19th??

Arriving From..
NEWARK, CA, 94560-4347

I Got a Package.. From Dr.Meter!! (Please Note I did not ask for a complete item, all I wanted to do is be able to buy a buy a part!!)

I Did Scan The User Manual.. Click Here For the HY3005F-3 & HY3003D-3 User Manual. (Not Available On Dr.meter ‘s Web Site)

I will do a full test on the system soon.. I will Also get the value of the C43 and see if there are any differences in the psu’s!!

Update 5-2020 There are Major Differences.

Old on the Top New Version on the Bottom.. I get a List of chip numbers U3 Looks to have had the numbers removed.

Internal Photo of Replacement Unit.

When hooked to a Tekpower 3710A DC Digital Load there is way to much Voltage Drop I Will Get Photos Shortly.

After some use the Pots are Way to Sensitive just breathing on them can change the Voltage!

Stay Tuned..

Last Updated on July 7, 2021 by Steven Rhine