Skytec PRO240 blown output - circuit diagram?

[David Pinnegar]

Hi!

My son has a PRO240 Skytec amp on which he shorted the output at high volume - he's in "I'll learn by my mistakes" mode . . . !

One channel is blown. Two resistors had evaporated together with two of the four output transisitors. I have replaced the resistors and output transistors but upon turning on, the resistors simply caught fire again . . .

Has anyone a circuit diagram of this amp and or experience in carrying out a repair?

Many thanks

David P

[tiefbassuebertr]

perhaps this schematic are similar to that one from Skytec Pro240.

Who knows the exactly manufacturer in China ??

[svokke]

There were different designs sold under this brand and model name. A picture of the front and insides would be helpful to identify it.
Is the front and inside similar to this:
http://www.diyaudio.com/forums/solid...nd-pa-amp.html

[jaycee]

The driver transistor for those output transistors is probably blown as well. If the outputs were Darlingtons, then the VAS transistor will be blown.

These amps look dreadful. Ugh. The only thing I'd use them for is a cheap case, transformer and heatsinks for a Gainclone.

[gruni]

not even the heatsink. its about the size of the heatsinks found in cheap computer power supplies.
i got one of those amps. it was also blown, but i just wanted to use the case for a pa amp designed by myself. it's a much better idea to build a better amplifier than the one originally built into the case than repairing the original one. it's just not worth it, as the performance is terrible. i have a schematic of the revision or model that was sold around 2006/2007 (the time, mine was produced). i can upload it if i find it. it is somewhat different from the schematic posted by tiefbassuebertr, as there are two pairs of output devices per channel and there is no protection at all (not dc nor overcurrent, etc.)

edit: i can't find the schematic, but i remember it is hosted at imageshack and a link has been postet on a well known german forum related to hifi topics.

[nigelwright7557]

Originally Posted by jaycee

These amps look dreadful. Ugh. The only thing I'd use them for is a cheap case, transformer and heatsinks for a Gainclone.

I bought one for a disco. I took the lid off and there was a tiny transformer and a very small power amplifier. It put out no where near the suggested power into my speakers.

I accidentally wired one channel into the others output and fried both channels so now use it as a test jig for class d amplifiers.