AF 540 FGZ internal temperature limit?

**Lowell Goudge** · 12-25-2011, 05:30 AM

I decided to post here as opposed to the flash forum because this is more a problem requiring troubleshooting than "how to". I have noticed that the last 2-3 times I used the flash heavily, that it seems to get into a funny mode after 60-80 shots. It stops charging the flash capacitor, almost as if there was an internal thermal limit or something. Changing batteries does not help, and using it a few hours later on the same batteries exhibits no problem

Any one less noticed this?

The flash is now 6 years old but this is the first I have noticed the problem. Just wondering if there is an internal protection or perhaps a bad solder joint

amoringello · 12-25-2011, 06:05 AM

There is certainly an overheat protection circuit. So if these were fired quickly enough, you probably did set that off.
How fast did you fire those shots?
The manual doesn't state any specifics that I recall, other than in regard to the modeling light where it states something about using it for too long.
Same would apply for normal shots, if in quick succession.

**Lowell Goudge** · 12-25-2011, 06:14 AM

Originally posted by amoringello

There is certainly an overheat protection circuit. So if these were fired quickly enough, you probably did set that off.
How fast did you fire those shots?
The manual doesn't state any specifics that I recall, other than in regard to the modeling light where it states something about using it for too long.
Same would apply for normal shots, if in quick succession.

thanks for the reply

Probably 40-50 shots in 20 minutes. Then the flash became erratic. Switching on and off could get me one or two more shots, same as opening and closing battery door.

Most shots were at relatively high power, as I use bounce flash

As I said , turn camera on this morning, same batteries and everything is fine

Its funny that I had not noticed this before this year

amoringello · 12-25-2011, 06:19 AM

I would not call that an exceptionally rapid pace at all.
The behavior does sound like a heat related issue.
Sadly, things do wear out, and it might simply be time for servicing.

mtansley · 12-25-2011, 06:38 AM

Some electronic components do degrade over time, perhaps it is the temperature sensor now responding at a much lower temperature and thinking things are too hot.

**Lowell Goudge** · 12-26-2011, 07:09 AM

Not too sure what the problem is, but it has me thinking new flash at some time, although he unit works well except for this, it is somewhat unreliable if under heavy use. Maybe I will go away from Pentax. Any thoughts?

mtansley · 12-26-2011, 01:08 PM

I'm biased but my choice would be a Metz 58 AF-2. I have one and love it.

Vistek has it for $399 cdn in stock according to their website. Henry's generally would have to order them in.

12-25-2011, 05:30 AM	#1
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,886	AF 540 FGZ internal temperature limit? I decided to post here as opposed to the flash forum because this is more a problem requiring troubleshooting than "how to". I have noticed that the last 2-3 times I used the flash heavily, that it seems to get into a funny mode after 60-80 shots. It stops charging the flash capacitor, almost as if there was an internal thermal limit or something. Changing batteries does not help, and using it a few hours later on the same batteries exhibits no problem Any one less noticed this? The flash is now 6 years old but this is the first I have noticed the problem. Just wondering if there is an internal protection or perhaps a bad solder joint

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12-25-2011, 06:05 AM	#2
amoringello Veteran Member Join Date: May 2008 Location: Virginia, USA Photos: Gallery Posts: 1,562	There is certainly an overheat protection circuit. So if these were fired quickly enough, you probably did set that off. How fast did you fire those shots? The manual doesn't state any specifics that I recall, other than in regard to the modeling light where it states something about using it for too long. Same would apply for normal shots, if in quick succession.

12-25-2011, 06:14 AM	#3
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,886 Original Poster	Originally posted by amoringello There is certainly an overheat protection circuit. So if these were fired quickly enough, you probably did set that off. How fast did you fire those shots? The manual doesn't state any specifics that I recall, other than in regard to the modeling light where it states something about using it for too long. Same would apply for normal shots, if in quick succession. thanks for the reply Probably 40-50 shots in 20 minutes. Then the flash became erratic. Switching on and off could get me one or two more shots, same as opening and closing battery door. Most shots were at relatively high power, as I use bounce flash As I said , turn camera on this morning, same batteries and everything is fine Its funny that I had not noticed this before this year

12-25-2011, 06:19 AM	#4
amoringello Veteran Member Join Date: May 2008 Location: Virginia, USA Photos: Gallery Posts: 1,562	I would not call that an exceptionally rapid pace at all. The behavior does sound like a heat related issue. Sadly, things do wear out, and it might simply be time for servicing.

12-25-2011, 06:38 AM	#5
mtansley Veteran Member Join Date: Oct 2008 Location: Ajax, Ontario, Canada Photos: Gallery Posts: 1,139	Some electronic components do degrade over time, perhaps it is the temperature sensor now responding at a much lower temperature and thinking things are too hot.

12-26-2011, 07:09 AM	#6
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,886 Original Poster	Not too sure what the problem is, but it has me thinking new flash at some time, although he unit works well except for this, it is somewhat unreliable if under heavy use. Maybe I will go away from Pentax. Any thoughts?

12-26-2011, 01:08 PM	#7
mtansley Veteran Member Join Date: Oct 2008 Location: Ajax, Ontario, Canada Photos: Gallery Posts: 1,139	I'm biased but my choice would be a Metz 58 AF-2. I have one and love it. Vistek has it for $399 cdn in stock according to their website. Henry's generally would have to order them in.

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