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wonder1
2nd January 2009, 07:41 PM
Not sure how hot it should get but after five minutes of the machine turn on you cant put your hand near the heat sink.
I no that they get hot but not sure if there is any other problem as this is the first time it be running for a while.
Tidied up the wiring and re soldered some back onto the hardness ,checked all voltage on the board and all okey.

I don't think it would last 8 hours turn on with that short of heat or am i just worrying about bugger all.
Is there any common fault i should check before the risk of damage.

thanks
Craig

GameDude
3rd January 2009, 02:33 PM
Not sure how hot it should get but after five minutes of the machine turn on you cant put your hand near the heat sink.
I no that they get hot but not sure if there is any other problem as this is the first time it be running for a while.
Tidied up the wiring and re soldered some back onto the hardness ,checked all voltage on the board and all okey.

I don't think it would last 8 hours turn on with that short of heat or am i just worrying about bugger all.
Is there any common fault i should check before the risk of damage.

thanks
Craig

They get hot...
anything above 55deg is consider scalding for humans so touching it is not a real good way of deciding if its getting to hot... after all the heatsink is there for a reason.
If you measured the DC voltage from its output and its in spec and the caps are in good nic it should all be fine.
The only thing that can make the regulators run hotter is aging capacitors, to measure capacitors accuratly you will need an ESR meter and a capacitance meter (especially the ESR meter)

wonder1
5th January 2009, 09:03 AM
Thanks Dorian

Been told they do get hot,going to check caps again and voltage just to make sure that everything is good.
Been told to get a bigger heat sink and remove it of the PCB and mount in cabinet to keep the heat off the board.Putting a cap kit threw the chassis to see if i cant fix the brightness problem so with a bit of luck will test it again at the end of the week.
thanks for you imput

Hewitson
7th January 2009, 02:49 PM
The size of the caps on that PCB are absolutely ridiculous!

wonder1
13th January 2009, 05:42 PM
just thought i check those caps and found that i have 10000uf/32v and should have 8000uf/16v.

The game is working but was just thinking that this could be causing some part of the heat problem,is this possible :unsure

cheers

GameDude
14th January 2009, 11:42 PM
just thought i check those caps and found that i have 10000uf/32v and should have 8000uf/16v.

The game is working but was just thinking that this could be causing some part of the heat problem,is this possible :unsure

cheers

No I doubt it very much unless the cap is faulty, generally in power supply/smoothing caps you can use higher voltage and usually a tad higher rated "uf" without problems.

AskJacob
15th January 2009, 12:04 AM
Higher voltage is no problem, as they will work perfectly fine with a lower voltage across the cap. Try putting 35v across a 16v cap though, and it will either burst or squirt stinky crap everywhere.

As for the uf rating, a bit larger is OK and often done - keep in mind these caps often have a tolerance of 20 percent or so anyway so an 8000 uf cap could be anywhere between 6400 to 9600 uf , so there is plenty of leeway there...

High temps on the regulator are normal - a rough guide is if it is too hot to touch quicky then there is a problem, however if you can press your finger on it for a second or two before it gets too hot to hold on then it is OK.

If it is running hotter than normal, then dried out caps may cause the problem as instead of just being a voltage regulator they can become an oscillator, creating a lot of waste heat and giving you stability issues/hangs etc as well. Additionally, as they run hot, the regulator itself can get out of spec or faulty. They are still a pretty common item and easy to replace if necessary.

Cheers
Jacob