GW-Instek GPP-4323 problem to open case

[Dagobert1]

Hello, I have a defective GW-Instek GPP-4323 here and would like to repair it. Unfortunately I can not open the housing. It seems to be blocked in the area of the carrying handle. I have loosened the two screws on the left side of the housing and also the two screws on the right side of the housing. I also loosened the two screws on the back of the housing. The way the housing is constructed, it should only be possible to move the upper part of the housing backwards to open the device. Even with a lot of force, the upper part of the housing cannot be moved. I would be very happy if someone could help me.

[xrunner]

Well, I do not have this unit and I don't know for a fact how to open it. But in many cases (no pun intended) like this, the plastic has "nubs" or clips that have to be pushed in to let the case slide off.

Good luck. 

Note: I've never been wrong. I thought I was wrong once, but that was a mistake.

[Dagobert1]

The housing is made of metal. It can be opened a bit on the left and right sides. However, it is not possible to see what blocks inside the opening. I have the assumption that the carrying handle or its holder prevents the opening. I can't see how the carrying handle holder can be loosened. I think that the carrying handle holder is screwed through the upper part of the case to a frame underneath the case.

[xrunner]

Other models by that company like this one have the handle screwed into a metal bar inside under the cover. Can you not remove the plastic covers on each end of the handle and remove the screws?

[Dagobert1]

Thank you XRunner, the housing is now open. The holder of the carrying handle is attached to a metal frame on the inside by screws through the upper part of the housing. The two plastic covers of the carrying handle holders must be pressed to the center of the housing with a lot of force. Two screws are then hidden underneath the plastic cover. After loosening the screws, the case opens easily. Thanks for the help.

[xrunner]

Good. Let us know what you find wrong and how you repair it. 

[Dagobert1]

The power supply can be switched on, the fan runs, but the display remains dark or the firmware does not start. I will now start to measure the supply voltages. I will keep you informed.

[Dagobert1]

Now, after the case is opened, the power supply starts and the display shows the menu. The output voltage and current can be adjusted and are available correctly. It has a good toroidal transformer and is very good in design. One thing that was noticeable was that the fan ran at full speed after it was turned on with closed housing. The connector and cables from the fan are very close to the upper part of the housing. It is possible that one of the cables to the fan caused a short circuit with the upper part of the case. However, the cables to the fan look fine. I can't find any loose contacts on the circuit board or the connectors, the power supply runs without problems. I was able to buy the power supply with 70% discount. I think it was a good deal

[nctnico]

I'd reseat all the connectors. Likely it is a contact issue. When a board isn't cleaned properly, there can be flux residue on contact surfaces. I have been bitten by that many times. Consider cleaning the contacts with alcohol. Use only alcohol!. Not contact spray as that will corrode the contacts.

[Dagobert1]

Thanks for the hint. I will clean the contacts with alcohol.

[bux98]

I had the exact same crash.
It seemed to me that it was a thermal failure (fan at max stop for the rest).
There are 2 thermistors one on each side of the radiator. I took the welds with lead solder from above without disassembling anything and since then it has worked.
Bad in English I use a translator