New 2016 Gopher CPS-3205C Review & Teardown

[Shock]

Saw this video come out today so sharing.

[Dojdoj]

I saw this video and I was convinced enought to buy a 2016 Gopher (Gophert) CPS-3205E from AliExpress for $55 in june.

It gave in after two weeks of very lite use in an arduino project. A voltage spike and it was dead. Fortunately I did not kill off any serious equipment ...

It looks nice and has a quality feel in the rotary encoder but the buttons are on the stiff side, so the unit slides away if pressed without support.

Since it was no use to try switch it on, I ripped it apart:

The board for the switching components looks hand soldered and several soldering joints are so crusty I cannot imagine how the unit could last for almost two weeks... 

Worse then the crusty feeling of the board is that the copper foil is bubbly on several places both on upper and lower layer of the PCB. It looks like the foil is slowly peeling off, and this is very appearant around the earth-point tap (cracked in soldering and rusty) which connects to the aluminium casing.

One of the mains cable were very thin at the soldering joint.

The TI TL494 PWM-IC has some genuine rust to it...

The smaller logic control board is owen reflowed and look pretty good, no problem what so ever with that specific part!

[Dojdoj]

I actually have two of those Gopher (Gophert) 3205E of which one is still functional. I thought I crack it open to see if it is as bad as the one I ripped apart.

It looked somewhat better but the PCB is of ridiculous low quality, it has started peeling and bulging just as the former one - How long does it take before this will fail just as the other one???

What is worse  is the safety issue. The PCB is vulnerable and should be insulated from the casing, if a screw come lose or the copper peeling dips down you have mains voltage in the case. The only safety left is a rusty iron tap. A very bad design, this tap has stresses to it and in the former tear down the soldering was cracked as well as rusty, it should have been implemented with a proper wire.

I realized a bit late the bad economy of buying cheapish noname crap ... After the first Gopher broke down, I gave up looking for the "perfect power supply", I.E. cheap, handy, reliable and decent quality.

I went off with a reputable brand, standard power supply (TTi EL302R) and I'm absolutely 100% convinced it is a fraction of the cost per hour used compared to the noname stuff

1) Gopher CPS-3205E; $55 + VAT; died after two weeks
2) Gopher CPS-3205E; $55 + VAT; lasts how long?
3) Thurlby Thandar Instruments, TTI EL302R; $280; Has a track record of first class quality

Those two Gopher cost me more then half the TTi - a total waste of money

Do yourself a favor, go for a reputable brand from a reputable dealer, its cheaper even in a short perspective and definitely in the long term!

[ted572]

GOPHERT CPS-3205E Poer Supply:
I have attached the Calibration Procedure and Specifications for the GOPHERT CPS-3205E.

By the way I added a small piece of thin (~ 0.03" thick) dark light filter (sheet stock) material between the LED Display on the PCB and the Front Panel on my units.  This is to increase the contrast between the LED segments that are ON vs those that are OFF.  This greatly improves the display so that you essentially only see the LED Display's active segments. This is a modification that could/should be done in all of the GOPHERT Power Supply models.  I got samples of Sunlight Filter Sheet material from a store that sells and installs this stuff on home and commercial building windows to block uV, bright sunlight, etc.
I have had my CPS-3205E for at least a year and it has been very reliable.  It is a awesome Power Supply for it's capability, size, weight, accuracy, and cost.

[Dojdoj]

Glad you had greater luck than me

If you had the time to crack it open and post some photos, it would be of great interest!

[tomeo.gonzales]

It is possible to add sense terminals to GOPHERT CPS-3205E ?

[electr_peter]

By the way I added a small piece of thin (~ 0.03" thick) dark light filter (sheet stock) material between the LED Display on the PCB and the Front Panel on my units.  This is to increase the contrast between the LED segments that are ON vs those that are OFF.  This greatly improves the display so that you essentially only see the LED Display's active segments. This is a modification that could/should be done in all of the GOPHERT Power Supply models.  I got samples of Sunlight Filter Sheet material from a store that sells and installs this stuff on home and commercial building windows to block uV, bright sunlight, etc.

Could add a link to filter or add filter specification? I tried several filters (light colour plastic sheets) but did not find good combination.

[ted572]

Re. Reply #5  Is it possible to add sense terminals to GOPHERT CPS-3205E ?
Sure it probably is possible to add voltage sense terminals, but why bother (I certainly wouldn't) as this Power Supply (PS) is only for up to 5A max.  If your having a problem with voltage drop at this low of a current, you may want to simply consider using heavier gauge wire between your PS and the UUT.  Sense Terminals are normally found (or required) on high current PS', typically 20A and above.  You may find sense terminals on a lower current PS, but generally not down to 5A.

Re. Reply #6  Could you add a link to filter or add filter specification? I tried several filters (light colour plastic sheets) but did not find good combination.
Sorry, I do not have a part number or specification.  But you need to use a DARK filter.  A Light filter isn't going to do anything to attenuate the LED segments that aren't active (not illuminated).  If you can' t find a appropriate single filter material, you can use two pieces of polarized light filters (but, NOT 'circular polarized').  Just overlap them and rotate one piece until you have the filtering attenuation level that works best for you.  Then secure them together and cut out a piece that covers your PS LED display.  And then of course put it inside the PS case between the LED display and the front panel.  Oh, your going to be be so, so, happy with what will seem like different PS with a new easy to read LED display in any light level or viewing angle.

Edit:  By the way the picture of the Power Supply in the Calibration Procedure for the CPS-3205E I provided in Reply #3 is not of my unit.  If it were you would not see the unenergised LED display segments.  This is just a picture I included of a unit that represents the basic CPS-3205E front panel layout.

[igendel]

If your having a problem with voltage drop at this low of a current, you may want to simply consider using heavier gauge wire between your PS and the UUT.

Yes, that's exactly the problem I had and its solution:
https://www.eevblog.com/forum/beginners/gophert-cps-3205-power-supply-really-that-bad/