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-   -   Meridian 103 overheating (http://www.diyaudio.com/forums/solid-state/174112-meridian-103-overheating.html)

Impman71 22nd September 2010 10:32 PM

Meridian 103 overheating
 
Hi,

Does anyone have any idea why my Meridian 103 amp is overheating?
I changed 2 820ohm 2 watt resistors as you could see they had got hot from the discoloration on the board & this seems to have stopped it distorting through my ls3/5a's, but even when it is just on & not playing anything it gets really hot & when you play anything it trips out within a few minutes! I also re-capped it when I was in there.
I'm a newbie to electronics, so please be gentle with me ;)
Thanks for any suggestions,

Colin

nigelwright7557 23rd September 2010 01:02 AM

Could be a high bias problem.

Is there a fan ? is this working ok ?

Impman71 23rd September 2010 01:15 AM

There isn't a fan, how do I check the bias (in laymans terms please).

Thanks,
Colin

sippy 29th September 2010 02:07 AM

I had a pair of 105's that started to run hot, a freind had been badgering me for a while about swapping for his quad 2's which is what i did.
A few whiles later they self distructed and killed his bose 901's (i think).
my utterly humble oppinion is get shot of it and buy something else if u can, i just bought a mint in boxes cyrus2 + psx for £200...... for my bedroom system.

Doow 27th February 2012 05:39 PM

Hello,
i buyed a broken Meridian 101 - 103 Kombination several Month ago. At this time i start to repair the 101 and it wors fine now.
The 103 was totaly damaged, some Transistors, Diodes and Resistors was dissoldered and lost.
But i was able to complete the lost Parts and changed the broken one.
Now it works fine but.... where are the messurepoints for the BIAS-Adjust ?
The Schematics shows "Iq approx 30mA"
The messurement accross the both R22 (Emitter - Collector Resistors of the Powertransistors)
results aprox 0 to 2.7mA ?
So i speculate that“s are the wrong Pionts ?
Any Ideas ?

sgrossklass 27th February 2012 07:24 PM

You're measuring at the right points, but the wrong thing - Ohm's law is your friend. You should be getting about 6.6 mV across one 0R22 or 13.2 mV across both.

If you can't get to these values, something is still amiss and you'd have to check the adjustment range of the Vbe multiplier, and verify that the current limiting transistors and their diodes are OK.

Doow 9th March 2012 10:15 AM

thanks,
with this information i“ll measure once again.
hopes for me no other surprises will wait. ;)

Doow 10th April 2012 11:15 AM

It work“s great
THX :)


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