hifi engine

Also Am-2250

I wonder if anyone can help; I have an am-2250 that keeps blowing a 2v fuse. I'm running a pioneer pl-s40 tt through the tape input via a cheap radio shack preamp due to the phono input registering hardly audible distortion. It sounds great when it works but after I power it down I turned it back on and nada- checked the fuse after just having changed it and sure enough it's blown- to the best of my knowledge it's the correct voltage fuse.

Any advice is appreciated- thinking I need to clean the pots to get the phono input working but not sure how to go about this



Re: Also Am-2250

You might look at the solder connections to the two STK463 audio amplifiers and around that area.

Re: Also Am-2250

I'm only seeing one stk-463 and as far as I can tell the solder connections look fine- I checked the service manual and for replacement fuses it lists 2a at different voltage- 250 and 125- not sure what the original fuses were as I've replaced them so many times but I'll try 2a 125v vs the 2a 250v fuses I was using which kept blowing

Re: Also Am-2250

The voltage rating of a fuse has to do with safety and a rating called interrupted current. If you had a 900 volt circuit and you used a 250 volt fuse, it may not interrupt current flow; in other words, current may arc over and be unsafe. If you use a 125 volt fuse where a 250 volt fuse was called, and the voltage was 125, then you are still safe. Speaker levels will not get that high, so the voltage rating is hardly ever important. A fuse will blow if current is exceeded by a certain percentage; it does not matter about voltage--could be 2 or 47 or 91 volts. Most fuses blow within 5 seconds at 100% overload (twice the current), so using a higher rated fuse is a big mistake--the circuit may never be able to supply that current and it will never blow, so other components will fail first.

Re: Also Am-2250

The fuse is there to protect your equipment. If it blows means something is drawing too much current. Never use a higher value. If you look on net you may find videos and other information about cleaning pots and trouble shooting. Could be the amp needs bias and/or DC offset adjusted see service manual. Think about replacing electrolytics in the power supply and driver boards at minimum. Maybe this link will help http://audiokarma.org/forums/index.php?threads/akai-am-2250-blows-fuse-a...

Re: Also Am-2250

Thank you for the advice- I used some deoxit for the pots but haven't been able to resolve the fuse issue- I thought it may have been blowing due to the fact I was using a preamp with the tt but without the preamp it still blows

Re: Akai Am-2250

Damn auto correct- AKAI am-2250 and yes I meant 2amp fuse

Re: Also Am-2250

Who makes the AM-2250? I think you mean 2 amp fuse.