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JDeV 27th November 2004 12:48 PM

Quad FM4 problem
 
Can anybody please tell me what should the temperature (on average) be of the 12v regulator (T9) and bridge rectifier D9, in this tuner. Mine is getting up to 50.deg.C and I cannot find any faulty component. Had to replace T9 twice already.
Does anybody maybe got a service manual for this unit ?

Thanx for any assistance.

AndrewT 27th November 2004 04:36 PM

Hi,
I'll go & open mine up. It's been playing for the last couple of hours.
Tell me where to find the components.
regards Andrew T.

JDeV 28th November 2004 07:37 AM

2 Attachment(s)
Quote:

Originally posted by AndrewT
Hi,
I'll go & open mine up. It's been playing for the last couple of hours.
Tell me where to find the components.
regards Andrew T.

Hi Andrew,
Those components are underneath the cover in the corner where the mains cable plug in.
See attached pic.
I suspect your's wont have the little heatsink, I fitted that to help with heat problem in the meantime.
Thanx for assistance.

AndrewT 28th November 2004 07:42 AM

Hi, I've found a to220 inside that alloy box to stop your fingers poking the mains.
The transformer runs warm about 20 degrees above ambient.
The to220 with the z heatsink runs in excess of 50 degrees C above ambient. My digital thermometer went off scale!!!
Does that help?
If we are measuring the same thing then it seems a first quality regulator is required to run permanently at these temps, what is the Tj? How about a bigger heatsink? There is just enough room, or series regulators if you fancy modifying. Conrad Johnson run their regs very hard, they claim it improves the sound!
regards Andrew T.

JDeV 28th November 2004 08:04 AM

Quote:

Originally posted by AndrewT
Hi, I've found a to220 inside that alloy box to stop your fingers poking the mains.
The transformer runs warm about 20 degrees above ambient.
The to220 with the z heatsink runs in excess of 50 degrees C above ambient. My digital thermometer went off scale!!!
Does that help?
If we are measuring the same thing then it seems a first quality regulator is required to run permanently at these temps, what is the Tj? How about a bigger heatsink? There is just enough room, or series regulators if you fancy modifying. Conrad Johnson run their regs very hard, they claim it improves the sound!
regards Andrew T.

Those temperatures are about the same as mine, so I suppose they should be like that. I just noticed that the LM7812 got a Tj of 125 and T-operating of 150 and also build in over-temperature
shutoff function. Will except it then like that - might install little CPU fan in there, just in case ;)
Thanx for you help, appreciate. :up:


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