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how the h3ll do i remove these
l0rd - 26/4/12 at 09:56 PM

My amp is not working properly.

I need to check the capacitors for dry joints but the frkn mosfets are not willing to part with the sink which is the chassis. I have removed the screws and the covers.




The ones in question are below the screws on the sides.

How should i takle it?

problem is that my 6th output stopped working. Thought fk that i will use just the 5th. Lately the 5th would only work if i slapped the amp and later would cut out again.

The amp in question is an Infinity RA6006.

Other areas i should look on?



[Edited on 26/4/12 by l0rd]


tegwin - 26/4/12 at 10:02 PM

Im guessing the Fets are stuck to the heatsink with heat transfer paste.... can be a bugger to get off sometimes unless you can get a thin plastic scraper in to break the seal.

I have repaired quite a few amps (mainly guitar amps) there the heat and vibration has caused the solder to "dryjoint" on the drive part of the circuit. Re-soldering the lot should help if you can get at it :p


l0rd - 27/4/12 at 06:56 AM

the drive part you mean the one on the left side where the inputs are?


ashg - 27/4/12 at 07:27 AM

just stick a knife, scraper some kind of implement under them and give it a gentle wiggle and they will come free. its just heat transfer paste holding them to the heat sink not glue.


l0rd - 27/4/12 at 08:41 AM

managed to get a screw driver and use the side of the chassis as a leverage. Everything removed.

B0110ks as my multimeter died.

couple of connections do not seem perfecr but cannot test


gremlin1234 - 27/4/12 at 08:51 AM

quote:
Originally posted by l0rd


couple of connections do not seem perfecr but cannot test


you dont need to test the individual connections, just resolder any/all that may be suspect


l0rd - 27/4/12 at 09:00 AM

quite a few then


MikeRJ - 27/4/12 at 11:01 AM

It's very difficult to test a suspected dry solder joint anyway, any pressure you put on it with test probes may make the connection look fine. Components that are most prone to solder joint problems are ones that gets hot and ones that are subject to mechanical stress and/or vibration. This would include any transistors clamped to the heatsink, power resistors, larger capacitors, potentiometers (volume/tone controls) and any connectors, both internal and most especially external ones (i.e. phono connectors).


l0rd - 27/4/12 at 05:34 PM

thank you for the heads up.

It seems a good solid amp. I must admit, if i can get it to work on 5 channels properly i wouldn't mind.

I will have to get a multimeter tomorrow fingers crossed if i find the one i want. just removed all the cabling so i will do all of it again and check things out.

For sure the amp has an isssue but i was not happy 100% with the installation.

i would be more confident if someone had shown me how to troubleshoot circuits.