mackie srm 450

[strandgsx]

Just had a shipment of 6 srm 450 (the chineese ones) from a club to service.

 

Shall begin monday morning but when I popped into the warehouse this morning I thought id check at least one out.

 

 

Powers up ok, horn works.... no bass driver, opened up and beeps thru fine.

 

The board looks fine, no fuses to blow etc..... so surface mount it hurts.

 

Before I delve..... anyone know the usuall suspects for failure and what to look for?

 

A thanku

[3guk]

Im sure the Chinese ones suffered from heat dissipation problems, I will have a look through my emails, remember speaking to someone about the problems, and how they were fixed.

[cedd]

One of mr SRM350's has trouble dropping to very low levels and then coming back to full if you just wiggle the gain pot from side to side. Liberal doses of switch cleaner work for short periods. The inut/outputs sit on a seperate mini board which is a pretty easy one to take out. Watch out for the 2 connectors your torroidal transformer can fit in dependent on 110v or 230v.

[Rob_Beech]

They all suffer with heat problems. It just seems that as the Chinese ones may have a slightly cheaper build quality (higher tolerance on components) they seem to suffer more.

 

Basically what happens is they get too warm and simply can't get rid of the heat quick enough. Of course the harder you drive them the worse this becomes. It is at its worse when they are flown in the corners of rooms. It gets very hot up there and there is nowhere for it to go and no cool air to aid ventilation. this is where the idea of powered boxes for an install confuses me somewhat. The same issues can also be found when they are used in monitor mode. With the back of the back more or less being on the floor heat can build up. You may argue that they wouldn't be pushed as hard in monitor mode, but we all know that monitors tend to equal or exceed FOH levels for many acts.