the overheating amp saga.

[old-wos-is-name]

Hi again all,

Question: Am I correct in thinking a heat sink does just that? if so, that means some components get hot and need some way of dissipating the heat, which is through a large surface area of metal or some other medium. so, this amp of mine which overheats, and has three steel octagonal shafts standing up from the motherboard, needs some sort of additional cooling system. As I said before, the three shafts have threaded inlets on the top, which indicates to me that something should be screwed into them,( this amp was sold to me as not working, but brand new) so I intend to affix some aluminium strips laterally to them and tilt them towards the vent aperture. question is: is aluminium the best metal, or should I use some copper pipe, opened up and flattened, then convoluted to gain more area? My last resort will be to fit a fan to cool the amp, but that has proven a problem as there is only vents at one end of the chassis, and may mean I have to drill a 60mm hole in the other end. I must just say, in case you have not seen the other postings about this amp, that it works perfectly out of the cabinet,( for hours and hours) but put the chassis back into the cabinet, and after 10 minutes or less it either cuts out or goes haywire, lights flashing,making very loud noises like drum beats (75 watts, so very loud).

[AlBags]

Exactly .. yes.
If there is no heatsink on some chips .. they will burn out in seconds .. or crowbar protect themselves.
Pure copper is the best, with some thermal paste in the joints.

How about adapting a large PC heatsink? ...
I always use Zalman in computer builds .. They clamp down with a couple of screws .. and need a 5 or 12v dc source for fan.
http://www.ebay.co.uk...6.c0.m14.l1581&_pgn=2

[jomifl]

A fan would be more effective, it doesn't need to be very big.

[old-wos-is-name]

Thanks for the input,

I will use copper, I have some thermal paste. I bought a 250v fan as I don't know what voltage I can tap off, but the fan is just too large to fit, but I will try the copper first.

[Mortartube]

The heat sink does dissipate heat and if it is in the form of fins, ensure they are not clogged with fluff. If so brush it out with a paintbrush whilst holding the hoover nozzle just above the fins.

Try running it (fully assembled), with a desk fan beside it blowing into the vents at full whack and see if it lasts longer before going potty. If so this would definitely point to an overheating problem. Also take off the circuit board if you can and look at the solder through a magnifying glass around each component on the back of the board. It may be a dry joint, which will show as a ring or crack in the solder at the bottom of the component. This can expand as things heat up and cause an intermittent fault. Rectify any dry joints by putting a hot soldering iron on them for just enough time to melt the solder and let it fill any crack or gap.