What problems do you see with this multimeter and/or improvements could be done?

[joshforester]

Recently purchased this multimeter to see how it performed due to the fact it has bluetooth capabilities. Obviously it's not going to be anything like my Fluke or Ideal meters, but there's only so much you'll get for a sub $30 meter. From what I can see is the jacks aren't that good of quality, self tapping plastic screws, non-ceramic HRC fuse, cheap wiring for the 9V connection, and no easy access for fuse replacement & if I'm not mistaken isn't there supposed to be cutouts in the board?

[borjam]

Cat IV? 

[Gyro]

As you have guessed, its safety peformance will not be good. The Cat ratings printed on the front are lies! However you bought it for bluetooth functionality so there is some benefit to you.

Firstly, you will never be able to modify it to meet acceptable safety for mains use. Your best course it simply not do that - just use it for general lab work.

The PCB layout will not support any meaningful adding of slots to improve creapage, you would probably do more harm than good if you tried.

The 10A current range is protected by a glass fuse as you say. You might get some benefit from replacing it with a ceramic one, but you won't find a suitable HRC one in that small a size. The glass one shouldn't be a problem as long as you stay below 50V and I wouldn't go higher even with a ceramic. Forget about modifying it for external fuse access. You will degrade the insulation and explosion protection that there is and having to open the meter to change it will make you more careful about blowing it.

The mA range is only protected by a PTC thermistor - that avoids nuisance fuse blowing but would provide no protection for a high current surge. You could try replacing it with a 250V rated 400mA fuse.

In short, simply avoid using it for mains and it will probably serve well. The most important safety modification would be to take an indelible marker and cover over the front panel CAT ratings printing, just in case anyone else picks it up and tries to use it for high energy circuits.

[Muttley Snickers]

In short, simply avoid using it for mains and it will probably serve well. The most important safety modification would be to take an indelible marker and cover over the front panel CAT ratings printing, just in case anyone else picks it up and tries to use it for high energy circuits.

In addition to Gyro's guidance these Holdpeak 90epc and similar series meters should really be labelled "not for use on mains or other dangerous voltages" and here is the reason why, these particular meters appear to have a deeper banana input receptacle than most other meters so if somebody happened to switch out the original leads to another set and not verify their integrity then the user risks the possibly of the meter giving a false indication that no voltage is present when in fact there could be a live circuit or feed as can be seen in the video linked below, with all due respect the fellow in the video states that this issue could be of annoyance but in my opinion it could be potentially dangerous for those with little or no experience around lethal voltages or equipment. Always test your equipment on a known safe source first and having a simple battery handy just to verify with could save you and others a lot of grief.

Furthermore and just to finish on, some meters are simply not worth the effort or expenditure when it comes to improvements or enhancements and this meter could perhaps be a prime example, without question these multimeters take out the trophy for the worst ever continuity tester and alert of all time and the qc sticker on the back in this instance probably indicates Questionable Components were incorporated.   

HoldPeak HP-90EPC Review by Artur's Lab

[lem_ix]

Front panel reminds me of Sanwa CD772. Any relation?

http://overseas.sanwa-meter.co.jp/items/detail.php?id=21

[Muttley Snickers]

It does have some similarities, they are probably just copy cats, anyway a comparison image below.