Yes and No. The V90 handheld test platform uses smart USB-C PD chargers and cables, capable of 15V / 3A (45W). Using a 5V / 1A USB charger won't damage the unit, however, it may not charge in full or take longer.
The official recommendation is to use the smart USB-C PD (Power Delivery) charger and cable supplied by VeEX with the product. Both the charger and cable are capable of handling up to 45W (15V @ 3A) and have the required PD communication channel.
The use of any other charger or cable will not be covered by the warranty.
However, if you forgot to pack the charger and/or cable supplied by VeEX or misplaced them, you may check the specs printed on your trusted modern smartphone's or tablet's USB-C charger. They may have smart USB-C PD chargers. They may not specifically state "USB-C PD" compatibility, but they may list all the different voltages and currents they support.
Verify that it supports 15V / 3A. If so, there should be a reduced risk and you could consider using them, at your own risk, for an emergency. If the information printed on the charger is vague or confusing, don't take any chances.
USB-C cables are more difficult to identify, since they don't have PD markings to confirm whether they would allow the test set and charger to communicate their power settings and requirements. Also, the construction quality of no-brand cables is very difficult to judge.
Older USB-A chargers, and their USB-C converter cables, definitely don't support PD communications, so they should be avoided. They are also limited to 5V and 1A (some may go up to 3A). They won't damage the test set, since the platform itself will adjust to the available source. However, if the battery is low, it may not charge the test set while it is being used, as it keeps on discharging. It needs to be OFF to get some charge.
WARNING! Using a 5V / 1A USB charger, while the battery is low and the test set is being used, may bring the battery to a deep discharge level, degrade its performance or cause permanent damage. In this condition, the battery status icon will not display an estimated Charging Time, since the adapter cannot provide enough power to charge the battery and operate the test set at the same time. Turn the test set OFF!
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V90-series Test Sets: