GODOX tt600 malfunction

I bought a godox tt600 2 weeks ago, i used it first time on cameracfor a wedding ceremony it was working perfectly in the morning on 1/16 mostly, but the reception was in a hall and was dark so I was using 1/1 boncing from the white ceiling, at the end of the ceremony money it started malfunctioning, the red button would ready to flash, but it wouldn't glash, I tried several times keeping it at rest for some minutes it would flash once then it wouldn't flash again, I left it to use it again yesterday on 1/2 it worked on most shots but sonsometi it wasn't, today it just worked on two shots now it's not flashing but the batteries have power, even the test flash can't work, I have been using on manual mode, my camera is Canon 1200D,

I don't have TT600 nor a canon shooter.

However I have a TT350O shared among various Panasonic M43 mirrorless ILCs for a few years. I found on certain models there might be a tiny discrepency on the contact points.

I needed to adjust the flash slightly in/out on the hot shoe. Otherwise the flash might not fire... As long as the flash can sit properly on the hot shoe, my flash works well.

Mata_gallery wrote:

I bought a godox tt600 2 weeks ago... I was using 1/1 [bouncing] from the white ceiling, at the end of the ceremony money it started malfunctioning, the red button would ready to flash, but it wouldn't flash,

Sounds like overheat protection kicked in.

Did you happen to notice if there was a little "thermometer" icon on the LCD (it's labelled as 27 on this page in the manual)? That indicates the flash has overheated. It stops firing so you don't burn up your flash tube and possibly set things on fire. This is a feature not a bug, IOW, your TT600 is doing what it's supposed to, it's not malfunctioning.

From the TT600 manual (page 34):

• To avoid overheating and deteriorating the flash head, do not fire
  more than 30 continuous flashes in fast succession at 1/1 full
  power. After 30 continuous flashes, allow a rest time of at least 10
  minutes.
• If you fire more than 30 continuous flashes and then fire more
  flashes in short intervals, the inner over-temperature protection
  function may be activated and make the recycling time about 10
  to 15 seconds. If this occurs, allow a rest time of about 10
  minutes, and the flash unit will then return to normal.

Now you know why using repeated full-power bursts is not good. OEM flashes can be better on overheat protection. Sometimes there are reasons to pay more for a speedlight. Granted, not everyone can afford a $1100 Canon EL-1 for its active cooling system and being able to fire 170 full-power bursts before overheat protection kicks in. But just saying. A TT600 is a $60 speedlight. The low-low cost had to come from somewhere.

Using bounce flash with a speedlight for event shooting typically involves using high ISO settings and wider aperture settings so that the ambient does the heavy lifting, and you don't overtax the speedlight. It's only powered by 4xAAs.

I tried several times keeping it at rest for some minutes it would flash once then it wouldn't flash again,

You probably didn't wait long enough.

I left it to use it again yesterday on 1/2 it worked on most shots but sonsometi it wasn't,

You can still overheat the flash if you use it repeatedly on higher power settings too frequently. This is also why HSS use is hard on a flash: repeated rapid pulsing is hard on the flash. In fact, if you use HSS, then the overheat protection kicks in even faster.

today it just worked on two shots now it's not flashing but the batteries have power, even the test flash can't work,

You may have damaged the flash if you repeatedly overheated it. But if you didn't swap for a fresh set of batteries, it's more likely you're running out of juice. As batteries deplete, the recycle time gets longer. It's one of the reasons why wedding shooters prefer the "V" li-ion powered Godox models, because with 2.8x the capacity of a set of 4xAAs, it takes a lot longer for that to start happening.

Also, if any one of the four AAs is depleted, the flash won't fire. Have you checked/charged the batteries individually or tried a different set? A fully-charged set of NiMh 4xAAs is only speced to last for 230 full power bursts.

Consider bumping your ISO up to the 1600+ range, so you'll be at 1/4 power or lower. See where Neil van Niekerk sets his flash when he's bouncing at weddings. particularly in large venues. ISO 100 and f/8 is a big ask of any flash, let alone a tiny AA-powered speedlight, let alone a bounced one (where you're losing more power/light to bouncing vs. direct flash).