How do i change the time on a humax pvr RT-531B. when i record it misses the end of programes and i want to add a minute on the time so that i get the end of recordings

The Humax cannot record from an external source, only from its own tuners.

Record the next program if you can't extend the recording time.

I don't think so. There really isn't anything to know other than installing the two AAA batteries. The PVR manual probably has the info you're looking for.

Please provide the model name/number.

This can sometimes happen if there is another recording starting immediately after. You may find the missing part on the front of another recording.

Otherwise there is an option to add a few minutes 'padding' to the beginning and end of each recording.

Hello
A firmware update is necessary with your Humax Foxsat receiver. Get into Humax site and update the device with latest firmware. OK.

you problaly find one on ebay or google humax rt-531b and you may get it for free

Remove the Aerial.
Switch on or if it's frozen switch off at the mains and on again.
Press Menu
Installation and enter password - 0000
Select 'Default Setting' and OK
Select 'YES' and OK to restore all settings to factory default.
Confirm again to start loading, enter the password again and it will start scanning for channels but won't find any.
Replace the aerial and press OK to rescan and now it will find channels. On completion press SAVE then EXIT on your keypad.
You won't lose any saved programmes but you will have to re-schedule your recordings.

You need to record in timer mode as opposed to program mode. Timer mode allows you to set a time buffer before and after the allotted time slot.

I think the PVR is trying to update the software but is obviously unable to do so.