I got a nice clean H K 330i stereo receiver. Its an 80's model. it blows its two fuses upon power up. each is 4 amp. any ideas what to check first?

I'd start with the power transformer and then any caps in the power supply. Sounds like a dead short in a primary location to blow two four amp fuses on power-up.

Check the bridge rectifier.

If the bridge rectifier is fine proceed to check the caps and transformer. The transformer can be checked easily by disconnecting it's secondary(ies) from the rest of the power supply. If it still over consumes check any safety capacitors on the primary, if the problem is not any components on the primary side then it is the transformer.

If all caps, diodes, and transformer check out, isolate the power supply output(s). If the problem goes away like this the short is somewhere further down. Could be something like shorted output transistors in that case.

HK 330i is a nice, relatively compact, hifi. Not a ton of power, but good sounding and relatively easy to service.

Your units problem is most likely shorted output transistors along with the distinct possibility of some associated components being damaged. Transformers almost never fail. Filter cap failure is also extremely rare. If the outputs crapped out and you kept replacing and blowing fuses, the supply rectifier(s) could have shorted out, but normally would not.

The outputs are complementary pairs of TO-220 power transistors. They can be replaced, as an upgrade, with TIP41C and TIP42C. If you don't have experience working on such circuits, you are advised to take your 330i to a qualified tech in your area.

Thomas Garson
Aural Technology
HK Factory Service for Southern Oregon & Northern California.

tgarson at 100%

Depending on how old the receiver is you may need to replace all the electrolytic caps.

Problem is more than likely the output transistors which will also require the driver transistors to be replaced.

Whether or not you can do the work yourself I suggest buying the service manual. That way if you don't do the work the person who does the work will for sure have the service info and can be sure the amp is adjusted properly and the tuner aligned properly.